From personal_submersibles at psubs.org Tue Aug 1 03:59:19 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Tue, 1 Aug 2023 07:59:19 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <2121927795.278612.1690853245102@mail.yahoo.com> References: <437225875.7179347.1690727568817.ref@mail.yahoo.com> <437225875.7179347.1690727568817@mail.yahoo.com> <1268330047.7247663.1690744717505@mail.yahoo.com> <1044343654.7429288.1690796009127@mail.yahoo.com> <1936723614.191383.1690840053202@mail.yahoo.com> <2121927795.278612.1690853245102@mail.yahoo.com> Message-ID: <1273529025.355541.1690876759897@mail.yahoo.com> I agree, we should all follow a path that makes sense for our own application to come up with a plug and play reliable motor. ?Before I invest a lot of time with magnetic couplers, I want to exhaust the option of air compensation. ?I now have all four motors on air and will dive Thursday or Friday to see if the air flow is enough. ?Pity the lake is only 60 feet, but the deeper lakes have too many people clogging up the access. ?Hank On Monday, July 31, 2023, 07:27:43 PM MDT, Jon Wallace via Personal_Submersibles wrote: Hi Alan, point taken however I?m not convinced oil has been completely discredited yet. ?The issues with air is not solely with cost but also with logistics. ?Potentially carrying extra tanks and/or investing in a compressor if a dive shop is not readily available. ?Our expedition to Lake Tahoe in 2018 was not exactly a remote location however the nearest dive shop for air was over an hour distant from our dive operations. Assuming an oil or 1-atm solution can be found I?d have a hard time arguing against a ?set it and forget it? configuration. ?Let?s not forget also that air has its issues. ?Cliff flooded a motor using air, Carsten mentioned water ingress with air, and plumbing for air has potential for issues as documented by Stanley. I see either method as a clear winner which is why I support development of both. Jon On Monday, July 31, 2023 at 05:49:14 PM EDT, Alan James via Personal_Submersibles wrote: Jon,?can you describe a reasonable & cheap oil compensation system?All the commercial units & X navy literature describe an over-pressure system that is not easy to build.I would consider the air used in an air compensation system to be minimal compared with blowing your ballast tanks every dive. Scuba systems seem to have very few failures so, that shouldn't be an issue.Alan Sent from Yahoo Mail on Android On Mon, 31 Jul 2023 at 9:36 pm, Jon Wallace via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 1 04:02:59 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Tue, 1 Aug 2023 08:02:59 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <834807551.132992.1690852147832@mail.yahoo.com> References: <437225875.7179347.1690727568817.ref@mail.yahoo.com> <437225875.7179347.1690727568817@mail.yahoo.com> <1268330047.7247663.1690744717505@mail.yahoo.com> <1044343654.7429288.1690796009127@mail.yahoo.com> <1936723614.191383.1690840053202@mail.yahoo.com> <834807551.132992.1690852147832@mail.yahoo.com> Message-ID: <556811265.351759.1690876979506@mail.yahoo.com> Vance, you just described a modern day submersible well pump, that run for many years. ?Did these motors have brushes and what type of oil did they use?Hank On Monday, July 31, 2023, 07:09:26 PM MDT, vbra676539 at aol.com via Personal_Submersibles wrote: Alan, Pardon me for butting in, but I can shed at least a little light on this The HYCO Hymak thrusters were oil compensated, and about as simple as you could get. The nose you see in the pictures is actaally a free flooding fiberglass cap and flange retainer for a Haldex rubber diaphragm screwed down to the forward end of the motor cyleinger. Fill and spill valves were top and bottom about mid-way down the motor housing, and the seals were rudimentary as there was effectively no pressure differential internal to external. No tubing. No seperate bladders. As a side note, the stators were cast in epoxy and machined to tolerance to reduce internal turbulance. Also, the motors were custom wound with square wire, which gave us a very compact 120 volt motor drawing about 50 amps to produce 5 horsepower. And just for base information, this hard-hearted little monster fed straight into a planetary reduction gear set that let us turn that 14 X 14 prop in a Kort nozzle. Very beefy for its day. You want a little contrast now to then, have a look at the ring thrusters on Pisces VI. They produce 50# more thrust for fewer amps at the same voltage, and weight 17 pounds apiece. The Hymaks weigh over a 100# apiece. Meaning that ?the current propulsion system on P6 (4 thrusters, cables, and controllers) all added together weigh less than a single original Hymak thruster. Vance On Monday, July 31, 2023, 05:47:59 PM EDT, Alan James via Personal_Submersibles wrote: Jon,?can you describe a reasonable & cheap oil compensation system?All the commercial units & X navy literature describe an over-pressure system that is not easy to build.I would consider the air used in an air compensation system to be minimal compared with blowing your ballast tanks every dive. Scuba systems seem to have very few failures so, that shouldn't be an issue.Alan Sent from Yahoo Mail on Android On Mon, 31 Jul 2023 at 9:36 pm, Jon Wallace via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 1 07:33:09 2023 From: personal_submersibles at psubs.org (Alec Smyth via Personal_Submersibles) Date: Tue, 1 Aug 2023 07:33:09 -0400 Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> Message-ID: I originally used the little Parker SS pressure relieving regulator to compensate everything, which included four Minnkota 101s. I had a differential pressure gauge in the sub so I could see the delta between ambient and compensation pressure in real-time. It had no problem at all keeping up when submerging, but the delta would overshoot surfacing. My first attempt at resolving that was to use a SCUBA 2nd stage, but I kept getting water in the system. I still have no idea why, the entire PSUBS brain trust at last year's convention couldn't resolve that maddening leak despite the approach having worked fine for countless other people. This year I went back to oil, and had the same maddening issues as Cliff. But I retained the air compensation for the arm, because the motors there are so small I didn't like the idea of the tiny brushes swimming in oil. The volume being compensated is far smaller than with the thrusters, but just in case I added a pressure relief valve to the compensated line, as I thought the actuators might blow up if I surfaced fast. If ever anything should leak it's the arm, because there's a lot of seals, and there's movement. The junction box is intended for electronics on land, it's sealed with a little rubber gasket but it's a square box, so although the gasket has a round section, calling it an O-ring would be a bit of a stretch. Yet the air compensation worked perfectly, I never got a drop of water in any of it. It was pressurized at 3psi. That system will now stay as it is. I should mention that both the thrusters and arm are jettisonable. The arm is pressurized by a little pony bottle on the arm itself, like Hank used to have on Gamma. If I jettison the arm, the air compensation setup goes with it. But on the thrusters, I need to disconnect the air supply if jettisoning. That could be done without much difficulty, but I tried oil because it has no tubing at all in an area that I'm trying to keep hydrodynamically clean. I'm going to research putting a ceramic seal on the 101's and running them at 1 atmosphere. If that doesn't work, then it's back to air. Either with a Parker and OP valve, or using the SCUBA 1st stage method Hank described, with disconnects for the thrusters to jettison. But the 1 atm solution would be so clean and tidy, I'd like to at least explore it first. Best, Alec On Mon, Jul 31, 2023 at 10:47?PM Sean T. Stevenson via Personal_Submersibles wrote: > I would be inclined to use a Tescom 44-4069 regulator for this purpose. > Not sure what these sell for. > > Sean > > > > > -------- Original Message -------- > On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > > My original air competition for the R300 used the regulator that Hugh > Fulton has on QSub. These are pricey new but you can get them used on > eBay. I was operating all four of my Minn kotas 101 off this single > regulator. It was a special ss pressure reducing/pressure releasing > regulator. I had it installed on my last Florida dive which I went down > about 100 ft . Unit worked fine. My first failure was on Flathead lake > expedition in which one of my aft thrusters flooded. After that I switched > to oil compensation. Alec is using same regular on his articulated arm and > not the thrusters. He felt issue with the regulator was that the port for > releasing pressure on ascent was too small. I believe he has addressed > this by adding a pressure release valve or OP valve. He can elaborate more > on his current strategy. > > Cliff > > Sent from my iPhone > > On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > ?John, > I am happy with both air & oil. > Am intending to fill my thrusters with oil, but have the oil pressurized > off my air comp system. This will reduce air use to just whats in the lines. > My electric manipulator will be air compensated off the same unit. Putting > oil in it adds another layer of complexity. > I think I need to put out a long video once I've finished this > air compensator. > From what I am hearing from Cliff, he didn't get enough air delivery from > the single regulator he was using. However I thought this was the same unit > that Alec is using & was now happy with. > Alan > > > Sent from Yahoo Mail on Android > > > On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles > wrote: > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 1 08:35:05 2023 From: personal_submersibles at psubs.org (vbra676539@aol.com via Personal_Submersibles) Date: Tue, 1 Aug 2023 12:35:05 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <556811265.351759.1690876979506@mail.yahoo.com> References: <437225875.7179347.1690727568817.ref@mail.yahoo.com> <437225875.7179347.1690727568817@mail.yahoo.com> <1268330047.7247663.1690744717505@mail.yahoo.com> <1044343654.7429288.1690796009127@mail.yahoo.com> <1936723614.191383.1690840053202@mail.yahoo.com> <834807551.132992.1690852147832@mail.yahoo.com> <556811265.351759.1690876979506@mail.yahoo.com> Message-ID: <1672055429.221130.1690893305525@mail.yahoo.com> Brushed DC motors swimming in light (red) Shell dielectric transformer oil.Vance On Tuesday, August 1, 2023, 04:03:18 AM EDT, hank pronk via Personal_Submersibles wrote: Vance, you just described a modern day submersible well pump, that run for many years. ?Did these motors have brushes and what type of oil did they use?Hank On Monday, July 31, 2023, 07:09:26 PM MDT, vbra676539 at aol.com via Personal_Submersibles wrote: Alan, Pardon me for butting in, but I can shed at least a little light on this The HYCO Hymak thrusters were oil compensated, and about as simple as you could get. The nose you see in the pictures is actaally a free flooding fiberglass cap and flange retainer for a Haldex rubber diaphragm screwed down to the forward end of the motor cyleinger. Fill and spill valves were top and bottom about mid-way down the motor housing, and the seals were rudimentary as there was effectively no pressure differential internal to external. No tubing. No seperate bladders. As a side note, the stators were cast in epoxy and machined to tolerance to reduce internal turbulance. Also, the motors were custom wound with square wire, which gave us a very compact 120 volt motor drawing about 50 amps to produce 5 horsepower. And just for base information, this hard-hearted little monster fed straight into a planetary reduction gear set that let us turn that 14 X 14 prop in a Kort nozzle. Very beefy for its day. You want a little contrast now to then, have a look at the ring thrusters on Pisces VI. They produce 50# more thrust for fewer amps at the same voltage, and weight 17 pounds apiece. The Hymaks weigh over a 100# apiece. Meaning that ?the current propulsion system on P6 (4 thrusters, cables, and controllers) all added together weigh less than a single original Hymak thruster. Vance On Monday, July 31, 2023, 05:47:59 PM EDT, Alan James via Personal_Submersibles wrote: Jon,?can you describe a reasonable & cheap oil compensation system?All the commercial units & X navy literature describe an over-pressure system that is not easy to build.I would consider the air used in an air compensation system to be minimal compared with blowing your ballast tanks every dive. Scuba systems seem to have very few failures so, that shouldn't be an issue.Alan Sent from Yahoo Mail on Android On Mon, 31 Jul 2023 at 9:36 pm, Jon Wallace via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 1 08:45:55 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Tue, 1 Aug 2023 12:45:55 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> Message-ID: <868422159.425979.1690893955989@mail.yahoo.com> Alec, I was looking at small cartridge seals on my favourite site, Amazon. ?They have some real nice little seals there. ?Hank On Tuesday, August 1, 2023, 05:33:38 AM MDT, Alec Smyth via Personal_Submersibles wrote: I originally?used the little Parker SS pressure relieving regulator to compensate everything, which included four Minnkota 101s. I had a differential pressure gauge in the sub so I could see the delta between ambient and compensation pressure in real-time. It had no problem at all keeping up when submerging, but the delta would overshoot surfacing.? My first attempt at resolving that was to use a SCUBA 2nd stage, but I kept getting water in the system. I still have no idea why, the entire PSUBS brain trust at last year's convention couldn't resolve that maddening leak despite the approach having worked fine for countless other people.? This year I went back to oil, and had the same maddening issues as Cliff. But I retained the air compensation for the arm, because the motors there are so small I didn't like the idea of the tiny brushes swimming in oil. The volume being compensated is far smaller than with the thrusters, but just in case I added a pressure relief valve to the compensated line, as I thought the actuators might blow up if I surfaced fast. If ever anything should leak it's the arm, because there's a lot of seals, and there's movement. The junction box is intended for electronics on land, it's sealed with a little rubber gasket but it's a square box, so although the gasket has a round section, calling it an O-ring would be a bit of a stretch. Yet the air compensation worked perfectly, I never got a drop of water in any of it. It was pressurized at 3psi. That system will now stay as it is. I should mention that both the thrusters and arm are jettisonable. The arm is pressurized by a little pony bottle on the arm itself, like Hank used to have on Gamma. If I jettison the arm, the air compensation setup goes with it. But on the thrusters, I need to disconnect the?air supply if jettisoning. That could be done without much difficulty, but I tried oil because it has no tubing at all in an area that I'm trying to keep hydrodynamically clean.?? I'm going to research putting a ceramic seal on the 101's and running?them at 1 atmosphere. If that doesn't work, then it's back to air. Either with a Parker and OP valve, or using the SCUBA 1st stage method Hank described, with disconnects for the thrusters to jettison. But the 1 atm solution would be so clean and tidy, I'd like to at least explore it first. Best,Alec On Mon, Jul 31, 2023 at 10:47?PM Sean T. Stevenson via Personal_Submersibles wrote: I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. Sean -------- Original Message -------- On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: My original air competition for the R300 used the regulator that Hugh Fulton has on QSub.? These are pricey new but you can get them used on eBay.? I was operating all four of my Minn kotas 101 off this single regulator.? It was a special ss pressure reducing/pressure releasing regulator.? I had it installed on my last Florida dive which I went down about 100 ft .? Unit worked fine.? My first failure was on Flathead lake expedition in which one of my aft thrusters flooded.? After that I switched to oil compensation.? Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small.? I believe he has addressed this by adding a pressure release valve or OP valve.? He can elaborate more on his current strategy. Cliff Sent from my iPhone On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles wrote: ?John,I am happy with both air & oil.?Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines.My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity.I think I need to put out a long video once I've finished thisair compensator.From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with.Alan Sent from Yahoo Mail on Android On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 1 11:09:12 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Tue, 1 Aug 2023 15:09:12 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <868422159.425979.1690893955989@mail.yahoo.com> References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <868422159.425979.1690893955989@mail.yahoo.com> Message-ID: <2069343830.522337.1690902552399@mail.yahoo.com> A new development to consider with air compensating. ?I just removed one of my vertical thrusters that was on air because it was making a noise. ?The magnet detached, but was still running. ?The glue let go, maybe from the oil from previous use? ?or from the rough bush road? ?Also the seal has push out until it hits the prop pin. ?I will have to put some SS washers in to hold it down. ?It was not leaking but should be secured.Hank On Tuesday, August 1, 2023, 06:46:11 AM MDT, hank pronk via Personal_Submersibles wrote: Alec, I was looking at small cartridge seals on my favourite site, Amazon. ?They have some real nice little seals there. ?Hank On Tuesday, August 1, 2023, 05:33:38 AM MDT, Alec Smyth via Personal_Submersibles wrote: I originally?used the little Parker SS pressure relieving regulator to compensate everything, which included four Minnkota 101s. I had a differential pressure gauge in the sub so I could see the delta between ambient and compensation pressure in real-time. It had no problem at all keeping up when submerging, but the delta would overshoot surfacing.? My first attempt at resolving that was to use a SCUBA 2nd stage, but I kept getting water in the system. I still have no idea why, the entire PSUBS brain trust at last year's convention couldn't resolve that maddening leak despite the approach having worked fine for countless other people.? This year I went back to oil, and had the same maddening issues as Cliff. But I retained the air compensation for the arm, because the motors there are so small I didn't like the idea of the tiny brushes swimming in oil. The volume being compensated is far smaller than with the thrusters, but just in case I added a pressure relief valve to the compensated line, as I thought the actuators might blow up if I surfaced fast. If ever anything should leak it's the arm, because there's a lot of seals, and there's movement. The junction box is intended for electronics on land, it's sealed with a little rubber gasket but it's a square box, so although the gasket has a round section, calling it an O-ring would be a bit of a stretch. Yet the air compensation worked perfectly, I never got a drop of water in any of it. It was pressurized at 3psi. That system will now stay as it is. I should mention that both the thrusters and arm are jettisonable. The arm is pressurized by a little pony bottle on the arm itself, like Hank used to have on Gamma. If I jettison the arm, the air compensation setup goes with it. But on the thrusters, I need to disconnect the?air supply if jettisoning. That could be done without much difficulty, but I tried oil because it has no tubing at all in an area that I'm trying to keep hydrodynamically clean.?? I'm going to research putting a ceramic seal on the 101's and running?them at 1 atmosphere. If that doesn't work, then it's back to air. Either with a Parker and OP valve, or using the SCUBA 1st stage method Hank described, with disconnects for the thrusters to jettison. But the 1 atm solution would be so clean and tidy, I'd like to at least explore it first. Best,Alec On Mon, Jul 31, 2023 at 10:47?PM Sean T. Stevenson via Personal_Submersibles wrote: I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. Sean -------- Original Message -------- On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: My original air competition for the R300 used the regulator that Hugh Fulton has on QSub.? These are pricey new but you can get them used on eBay.? I was operating all four of my Minn kotas 101 off this single regulator.? It was a special ss pressure reducing/pressure releasing regulator.? I had it installed on my last Florida dive which I went down about 100 ft .? Unit worked fine.? My first failure was on Flathead lake expedition in which one of my aft thrusters flooded.? After that I switched to oil compensation.? Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small.? I believe he has addressed this by adding a pressure release valve or OP valve.? He can elaborate more on his current strategy. Cliff Sent from my iPhone On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles wrote: ?John,I am happy with both air & oil.?Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines.My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity.I think I need to put out a long video once I've finished thisair compensator.From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with.Alan Sent from Yahoo Mail on Android On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 1 12:17:02 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Tue, 1 Aug 2023 16:17:02 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> Message-ID: <1697183893.555377.1690906622926@mail.yahoo.com> Sean, the specs do look good on this unit.? To me the issue is going to be the cost.? As background, the Parker regulator that Hugh, Alec and I have used for this application is the?364-02BSS/M1 Parker Watts Pneumatic Regulator. https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator?at $217.51.? I purchased mine off ebay for a fraction of this. When I had the Parker?364-02BSS/M1 installed for pressure compensating for my four MK 101s, it was connected to the LP port from my AquaLung Titan balanced diaphragm first stage regulator. I had the?Parker?364-02BSS/M1 adjusted?to give about 2 psi over ambient.? I had the first stage set to 50 psi over ambient water pressure.? I use this for BIBBS and blowing the MBTs.? The?Tescom 44-4069 regulator would run directly off the HP air tank pressure then output go directly?to thrusters.? It would be interesting to compare the Cv's for both regulators to get a feel on how much air flow rate they can provide to the thrusters?descending?and venting when ascending.?? The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator.? From the output port?of the Tescom 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two more "T"s to give four 1/4 SS tubing runs to the thrusters. We need to get a RFQ on one of these regulators.? Do you have a preferred supplier? Cliff On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. Sean -------- Original Message -------- On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: My original air competition for the R300 used the regulator that Hugh Fulton has on QSub. ?These are pricey new but you can get them used on eBay. ?I was operating all four of my Minn kotas 101 off this single regulator. ?It was a special ss pressure reducing/pressure releasing regulator. ?I had it installed on my last Florida dive which I went down about 100 ft . ?Unit worked fine. ?My first failure was on Flathead lake expedition in which one of my aft thrusters flooded. ?After that I switched to oil compensation. ?Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small. ?I believe he has addressed this by adding a pressure release valve or OP valve. ?He can elaborate more on his current strategy. Cliff Sent from my iPhone On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles wrote: ?John,I am happy with both air & oil.?Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines.My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity.I think I need to put out a long video once I've finished thisair compensator.From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with.Alan Sent from Yahoo Mail on Android On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 1 12:24:15 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Tue, 1 Aug 2023 16:24:15 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <2069343830.522337.1690902552399@mail.yahoo.com> References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <868422159.425979.1690893955989@mail.yahoo.com> <2069343830.522337.1690902552399@mail.yahoo.com> Message-ID: <938685103.549958.1690907055041@mail.yahoo.com> I would figure out why the lip seal was pushed out.? Sounds like the OP valve was not venting the pressure correctly.? It would take quite a bit of pressure to unseat one of these lip seals.? You would have thought that with the lip seal oriented to see higher pressure from outside that an overpressure event would send air out as a leak from around the lip seal. Cliff On Tuesday, August 1, 2023 at 10:10:05 AM CDT, hank pronk via Personal_Submersibles wrote: A new development to consider with air compensating. ?I just removed one of my vertical thrusters that was on air because it was making a noise. ?The magnet detached, but was still running. ?The glue let go, maybe from the oil from previous use? ?or from the rough bush road? ?Also the seal has push out until it hits the prop pin. ?I will have to put some SS washers in to hold it down. ?It was not leaking but should be secured.Hank On Tuesday, August 1, 2023, 06:46:11 AM MDT, hank pronk via Personal_Submersibles wrote: Alec, I was looking at small cartridge seals on my favourite site, Amazon. ?They have some real nice little seals there. ?Hank On Tuesday, August 1, 2023, 05:33:38 AM MDT, Alec Smyth via Personal_Submersibles wrote: I originally?used the little Parker SS pressure relieving regulator to compensate everything, which included four Minnkota 101s. I had a differential pressure gauge in the sub so I could see the delta between ambient and compensation pressure in real-time. It had no problem at all keeping up when submerging, but the delta would overshoot surfacing.? My first attempt at resolving that was to use a SCUBA 2nd stage, but I kept getting water in the system. I still have no idea why, the entire PSUBS brain trust at last year's convention couldn't resolve that maddening leak despite the approach having worked fine for countless other people.? This year I went back to oil, and had the same maddening issues as Cliff. But I retained the air compensation for the arm, because the motors there are so small I didn't like the idea of the tiny brushes swimming in oil. The volume being compensated is far smaller than with the thrusters, but just in case I added a pressure relief valve to the compensated line, as I thought the actuators might blow up if I surfaced fast. If ever anything should leak it's the arm, because there's a lot of seals, and there's movement. The junction box is intended for electronics on land, it's sealed with a little rubber gasket but it's a square box, so although the gasket has a round section, calling it an O-ring would be a bit of a stretch. Yet the air compensation worked perfectly, I never got a drop of water in any of it. It was pressurized at 3psi. That system will now stay as it is. I should mention that both the thrusters and arm are jettisonable. The arm is pressurized by a little pony bottle on the arm itself, like Hank used to have on Gamma. If I jettison the arm, the air compensation setup goes with it. But on the thrusters, I need to disconnect the?air supply if jettisoning. That could be done without much difficulty, but I tried oil because it has no tubing at all in an area that I'm trying to keep hydrodynamically clean.?? I'm going to research putting a ceramic seal on the 101's and running?them at 1 atmosphere. If that doesn't work, then it's back to air. Either with a Parker and OP valve, or using the SCUBA 1st stage method Hank described, with disconnects for the thrusters to jettison. But the 1 atm solution would be so clean and tidy, I'd like to at least explore it first. Best,Alec On Mon, Jul 31, 2023 at 10:47?PM Sean T. Stevenson via Personal_Submersibles wrote: I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. Sean -------- Original Message -------- On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: My original air competition for the R300 used the regulator that Hugh Fulton has on QSub.? These are pricey new but you can get them used on eBay.? I was operating all four of my Minn kotas 101 off this single regulator.? It was a special ss pressure reducing/pressure releasing regulator.? I had it installed on my last Florida dive which I went down about 100 ft .? Unit worked fine.? My first failure was on Flathead lake expedition in which one of my aft thrusters flooded.? After that I switched to oil compensation.? Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small.? I believe he has addressed this by adding a pressure release valve or OP valve.? He can elaborate more on his current strategy. Cliff Sent from my iPhone On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles wrote: ?John,I am happy with both air & oil.?Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines.My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity.I think I need to put out a long video once I've finished thisair compensator.From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with.Alan Sent from Yahoo Mail on Android On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 1 12:25:20 2023 From: personal_submersibles at psubs.org (Sean T. Stevenson via Personal_Submersibles) Date: Tue, 01 Aug 2023 16:25:20 +0000 Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <1697183893.555377.1690906622926@mail.yahoo.com> References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> Message-ID: I have a local supplier for Tescom (Zimco Instrumentation), but my RFQ would come back with our industrial contract price in Canadian dollars, so maybe not relevant to the group at large. Sean -------- Original Message -------- On Aug. 1, 2023, 10:17, Cliff Redus via Personal_Submersibles wrote: > Sean, the specs do look good on this unit. To me the issue is going to be the cost. As background, the Parker regulator that Hugh, Alec and I have used for this application is the 364-02BSS/M1 Parker Watts Pneumatic Regulator. > > https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator at $217.51. I purchased mine off ebay for a fraction of this. > > When I had the Parker 364-02BSS/M1 installed for pressure compensating for my four MK 101s, it was connected to the LP port from my AquaLung Titan balanced diaphragm first stage regulator. I had the Parker 364-02BSS/M1 adjusted to give about 2 psi over ambient. I had the first stage set to 50 psi over ambient water pressure. I use this for BIBBS and blowing the MBTs. > > The Tescom 44-4069 regulator would run directly off the HP air tank pressure then output go directly to thrusters. It would be interesting to compare the Cv's for both regulators to get a feel on how much air flow rate they can provide to the thrusters descending and venting when ascending. > > The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input port of Tescom 44-4069 regulator. From the output port of the Tescom 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two more "T"s to give four 1/4 SS tubing runs to the thrusters. > > We need to get a RFQ on one of these regulators. Do you have a preferred supplier? > > Cliff > > On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: > > I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. > > Sean > > -------- Original Message -------- > On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > >> > > My original air competition for the R300 used the regulator that Hugh Fulton has on QSub. These are pricey new but you can get them used on eBay. I was operating all four of my Minn kotas 101 off this single regulator. It was a special ss pressure reducing/pressure releasing regulator. I had it installed on my last Florida dive which I went down about 100 ft . Unit worked fine. My first failure was on Flathead lake expedition in which one of my aft thrusters flooded. After that I switched to oil compensation. Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small. I believe he has addressed this by adding a pressure release valve or OP valve. He can elaborate more on his current strategy. > > Cliff > > Sent from my iPhone > >> On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles wrote: > >> ?John, >> I am happy with both air & oil. >> Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines. >> My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity. >> I think I need to put out a long video once I've finished this >> air compensator. >> From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with. >> Alan >> >> [Sent from Yahoo Mail on Android](https://mail.onelink.me/107872968?pid=nativeplacement&c=Global_Acquisition_YMktg_315_Internal_EmailSignature&af_sub1=Acquisition&af_sub2=Global_YMktg&af_sub3=&af_sub4=100000604&af_sub5=EmailSignature__Static_) >> >>> On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles >>> wrote: >>> _______________________________________________ >>> Personal_Submersibles mailing list >>> Personal_Submersibles at psubs.org >>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >> >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 1 13:57:54 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Tue, 1 Aug 2023 11:57:54 -0600 Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: Message-ID: <88FFF9BA-3D51-4E04-927F-AC1A25D41537@yahoo.ca> An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 1 14:58:21 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Tue, 1 Aug 2023 13:58:21 -0500 Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <88FFF9BA-3D51-4E04-927F-AC1A25D41537@yahoo.ca> References: <88FFF9BA-3D51-4E04-927F-AC1A25D41537@yahoo.ca> Message-ID: <9120FE56-C40E-4300-ADD7-FCD5CAABC300@gmail.com> An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 1 17:08:20 2023 From: personal_submersibles at psubs.org (Alec Smyth via Personal_Submersibles) Date: Tue, 1 Aug 2023 17:08:20 -0400 Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <1697183893.555377.1690906622926@mail.yahoo.com> References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> Message-ID: Hi Cliff, "The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input port of Tescom 44-4069 regulator." There's a little problem with this plan, though easy to work around. The HP ports on regulators have a tiny orifice, in order to prevent rapid loss of air if a hose or SPG fails. These ports cannot provide the sort of flow you would want. Best, Alec On Tue, Aug 1, 2023 at 12:17?PM Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Sean, the specs do look good on this unit. To me the issue is going to be > the cost. As background, the Parker regulator that Hugh, Alec and I have > used for this application is the 364-02BSS/M1 Parker Watts Pneumatic > Regulator. > > https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator at > $217.51. I purchased mine off ebay for a fraction of this. > > When I had the Parker 364-02BSS/M1 installed for pressure compensating > for my four MK 101s, it was connected to the LP port from my AquaLung Titan > balanced diaphragm first stage regulator. I had the Parker 364-02BSS/M1 > adjusted to give about 2 psi over ambient. I had the first stage set to > 50 psi over ambient water pressure. I use this for BIBBS and blowing the > MBTs. > > The Tescom 44-4069 regulator would run directly off the HP air tank > pressure then output go directly to thrusters. It would be interesting to > compare the Cv's for both regulators to get a feel on how much air flow > rate they can provide to the thrusters descending and venting when > ascending. > > The Tescom 44-4069 regulator would be a clean installation with just a > single 1/4 SS tubing run from the HP port of the 1st stage regulator to the > input port of Tescom 44-4069 regulator. From the output port of the Tescom > 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two > more "T"s to give four 1/4 SS tubing runs to the thrusters. > > We need to get a RFQ on one of these regulators. Do you have a preferred > supplier? > > Cliff > > > On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via > Personal_Submersibles wrote: > > > I would be inclined to use a Tescom 44-4069 regulator for this purpose. > Not sure what these sell for. > > Sean > > > > -------- Original Message -------- > On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > > My original air competition for the R300 used the regulator that Hugh > Fulton has on QSub. These are pricey new but you can get them used on > eBay. I was operating all four of my Minn kotas 101 off this single > regulator. It was a special ss pressure reducing/pressure releasing > regulator. I had it installed on my last Florida dive which I went down > about 100 ft . Unit worked fine. My first failure was on Flathead lake > expedition in which one of my aft thrusters flooded. After that I switched > to oil compensation. Alec is using same regular on his articulated arm and > not the thrusters. He felt issue with the regulator was that the port for > releasing pressure on ascent was too small. I believe he has addressed > this by adding a pressure release valve or OP valve. He can elaborate more > on his current strategy. > > Cliff > > Sent from my iPhone > > On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > ?John, > I am happy with both air & oil. > Am intending to fill my thrusters with oil, but have the oil pressurized > off my air comp system. This will reduce air use to just whats in the lines. > My electric manipulator will be air compensated off the same unit. Putting > oil in it adds another layer of complexity. > I think I need to put out a long video once I've finished this > air compensator. > From what I am hearing from Cliff, he didn't get enough air delivery from > the single regulator he was using. However I thought this was the same unit > that Alec is using & was now happy with. > Alan > > > Sent from Yahoo Mail on Android > > > On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles > wrote: > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 1 18:41:56 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Tue, 1 Aug 2023 22:41:56 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> Message-ID: <287211810.780534.1690929716573@mail.yahoo.com> My guess is there would be adequate flow rate.? First stage scuba regulator has to pass enough air to supply demand of the largest diver.? My guess is filling four MD 101 thrusters at the descent rate of a psub would be less than required for a diver.? Easy enough to make a calculation. Sense the downstream pressure at the HP port orifice is way less than half the upstream tank pressure, the flow of air through the small orifice is in critical flow.? As such a shock wave forms at the orifice and mass flow rate becomes independent of downstream pressure. It is a function of only upstream (tank) pressure and the orifice diameter.?? When I get a chance, I will make a quick calc and see what the rates are.? Good to check this. Best On Tuesday, August 1, 2023 at 04:09:41 PM CDT, Alec Smyth via Personal_Submersibles wrote: Hi Cliff, "The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator." There's a little problem with this plan, though easy to work around.?The HP ports on regulators have a tiny orifice, in order to prevent rapid loss of air if a hose or SPG fails. These ports cannot provide the sort of flow you would want.? Best,Alec On Tue, Aug 1, 2023 at 12:17?PM Cliff Redus via Personal_Submersibles wrote: Sean, the specs do look good on this unit.? To me the issue is going to be the cost.? As background, the Parker regulator that Hugh, Alec and I have used for this application is the?364-02BSS/M1 Parker Watts Pneumatic Regulator. https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator?at $217.51.? I purchased mine off ebay for a fraction of this. When I had the Parker?364-02BSS/M1 installed for pressure compensating for my four MK 101s, it was connected to the LP port from my AquaLung Titan balanced diaphragm first stage regulator. I had the?Parker?364-02BSS/M1 adjusted?to give about 2 psi over ambient.? I had the first stage set to 50 psi over ambient water pressure.? I use this for BIBBS and blowing the MBTs.? The?Tescom 44-4069 regulator would run directly off the HP air tank pressure then output go directly?to thrusters.? It would be interesting to compare the Cv's for both regulators to get a feel on how much air flow rate they can provide to the thrusters?descending?and venting when ascending.?? The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator.? From the output port?of the Tescom 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two more "T"s to give four 1/4 SS tubing runs to the thrusters. We need to get a RFQ on one of these regulators.? Do you have a preferred supplier? Cliff On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. Sean -------- Original Message -------- On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: My original air competition for the R300 used the regulator that Hugh Fulton has on QSub.? These are pricey new but you can get them used on eBay.? I was operating all four of my Minn kotas 101 off this single regulator.? It was a special ss pressure reducing/pressure releasing regulator.? I had it installed on my last Florida dive which I went down about 100 ft .? Unit worked fine.? My first failure was on Flathead lake expedition in which one of my aft thrusters flooded.? After that I switched to oil compensation.? Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small.? I believe he has addressed this by adding a pressure release valve or OP valve.? He can elaborate more on his current strategy. Cliff Sent from my iPhone On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles wrote: ?John,I am happy with both air & oil.?Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines.My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity.I think I need to put out a long video once I've finished thisair compensator.From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with.Alan Sent from Yahoo Mail on Android On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 1 18:55:39 2023 From: personal_submersibles at psubs.org (Sean T. Stevenson via Personal_Submersibles) Date: Tue, 01 Aug 2023 22:55:39 +0000 Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <287211810.780534.1690929716573@mail.yahoo.com> References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> <287211810.780534.1690929716573@mail.yahoo.com> Message-ID: I think Alec was trying to point out that HP ports on SCUBA 1st stages are not designed to supply flow of any kind. Diver consumption only occurs via the LP ports. The HP ports are deadheaded in ordinary service, designed only to communicate a HP pressure signal to a SPG or transmitter. As such, on all modern SCUBA regulators, the supply orifice at the HP port and/or the mating fitting on a HP SCUBA SPG hose is nothing more than a pinhole, specifically designed to reduce gas loss in the event of a HP hose or downsteam equipment failure. Any downstream devices requiring a HP supply should source that supply directly from the HP storage or plumbing upstream of the SCUBA regulator, or from a different regulator designed to service HP flow, which SCUBA 1st stages are not. Sean -------- Original Message -------- On Aug. 1, 2023, 16:41, Cliff Redus via Personal_Submersibles wrote: > My guess is there would be adequate flow rate. First stage scuba regulator has to pass enough air to supply demand of the largest diver. My guess is filling four MD 101 thrusters at the descent rate of a psub would be less than required for a diver. Easy enough to make a calculation. Sense the downstream pressure at the HP port orifice is way less than half the upstream tank pressure, the flow of air through the small orifice is in critical flow. As such a shock wave forms at the orifice and mass flow rate becomes independent of downstream pressure. It is a function of only upstream (tank) pressure and the orifice diameter. > > When I get a chance, I will make a quick calc and see what the rates are. Good to check this. > > Best > > On Tuesday, August 1, 2023 at 04:09:41 PM CDT, Alec Smyth via Personal_Submersibles wrote: > > Hi Cliff, > > "The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input port of Tescom 44-4069 regulator." > > There's a little problem with this plan, though easy to work around. The HP ports on regulators have a tiny orifice, in order to prevent rapid loss of air if a hose or SPG fails. These ports cannot provide the sort of flow you would want. > > Best, > Alec > > On Tue, Aug 1, 2023 at 12:17?PM Cliff Redus via Personal_Submersibles wrote: > >> Sean, the specs do look good on this unit. To me the issue is going to be the cost. As background, the Parker regulator that Hugh, Alec and I have used for this application is the 364-02BSS/M1 Parker Watts Pneumatic Regulator. >> >> https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator at $217.51. I purchased mine off ebay for a fraction of this. >> >> When I had the Parker 364-02BSS/M1 installed for pressure compensating for my four MK 101s, it was connected to the LP port from my AquaLung Titan balanced diaphragm first stage regulator. I had the Parker 364-02BSS/M1 adjusted to give about 2 psi over ambient. I had the first stage set to 50 psi over ambient water pressure. I use this for BIBBS and blowing the MBTs. >> >> The Tescom 44-4069 regulator would run directly off the HP air tank pressure then output go directly to thrusters. It would be interesting to compare the Cv's for both regulators to get a feel on how much air flow rate they can provide to the thrusters descending and venting when ascending. >> >> The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input port of Tescom 44-4069 regulator. From the output port of the Tescom 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two more "T"s to give four 1/4 SS tubing runs to the thrusters. >> >> We need to get a RFQ on one of these regulators. Do you have a preferred supplier? >> >> Cliff >> >> On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: >> >> I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. >> >> Sean >> >> -------- Original Message -------- >> On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: >> >>> >> >> My original air competition for the R300 used the regulator that Hugh Fulton has on QSub. These are pricey new but you can get them used on eBay. I was operating all four of my Minn kotas 101 off this single regulator. It was a special ss pressure reducing/pressure releasing regulator. I had it installed on my last Florida dive which I went down about 100 ft . Unit worked fine. My first failure was on Flathead lake expedition in which one of my aft thrusters flooded. After that I switched to oil compensation. Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small. I believe he has addressed this by adding a pressure release valve or OP valve. He can elaborate more on his current strategy. >> >> Cliff >> >> Sent from my iPhone >> >>> On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles wrote: >> >>> ?John, >>> I am happy with both air & oil. >>> Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines. >>> My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity. >>> I think I need to put out a long video once I've finished this >>> air compensator. >>> From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with. >>> Alan >>> >>> [Sent from Yahoo Mail on Android](https://mail.onelink.me/107872968?pid=nativeplacement&c=Global_Acquisition_YMktg_315_Internal_EmailSignature&af_sub1=Acquisition&af_sub2=Global_YMktg&af_sub3=&af_sub4=100000604&af_sub5=EmailSignature__Static_) >>> >>>> On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles >>>> wrote: >>>> _______________________________________________ >>>> Personal_Submersibles mailing list >>>> Personal_Submersibles at psubs.org >>>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >>> >>> _______________________________________________ >>> Personal_Submersibles mailing list >>> Personal_Submersibles at psubs.org >>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >> >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >> >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 1 19:02:40 2023 From: personal_submersibles at psubs.org (Sean T. Stevenson via Personal_Submersibles) Date: Tue, 01 Aug 2023 23:02:40 +0000 Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> <287211810.780534.1690929716573@mail.yahoo.com> Message-ID: <8tWxU9n_Gjvn35Qnr2kOznynocjqUOQaMojC2qG1eCqEwTJhllTADvPUetmV29gqmhs217T-QVy40VINjvvXrr0qkeDhIcR_DspqiPZ9LNw=@protonmail.com> That said, sourcing your supply from a LP port of a SCUBA regulator should be sufficient. Off the shelf, most SCUBA 1st stages will deliver 120 - 160 psi over ambient to the LP ports, and are designed to provide sufficient flow at that pressure (once reduced to ambient pressure by SCUBA 2nd stages) to simultaneously support two divers at moderate workload. Sean -------- Original Message -------- On Aug. 1, 2023, 16:55, Sean T. Stevenson wrote: > I think Alec was trying to point out that HP ports on SCUBA 1st stages are not designed to supply flow of any kind. Diver consumption only occurs via the LP ports. The HP ports are deadheaded in ordinary service, designed only to communicate a HP pressure signal to a SPG or transmitter. As such, on all modern SCUBA regulators, the supply orifice at the HP port and/or the mating fitting on a HP SCUBA SPG hose is nothing more than a pinhole, specifically designed to reduce gas loss in the event of a HP hose or downsteam equipment failure. Any downstream devices requiring a HP supply should source that supply directly from the HP storage or plumbing upstream of the SCUBA regulator, or from a different regulator designed to service HP flow, which SCUBA 1st stages are not. > > Sean > > -------- Original Message -------- > On Aug. 1, 2023, 16:41, Cliff Redus via Personal_Submersibles wrote: > >> My guess is there would be adequate flow rate. First stage scuba regulator has to pass enough air to supply demand of the largest diver. My guess is filling four MD 101 thrusters at the descent rate of a psub would be less than required for a diver. Easy enough to make a calculation. Sense the downstream pressure at the HP port orifice is way less than half the upstream tank pressure, the flow of air through the small orifice is in critical flow. As such a shock wave forms at the orifice and mass flow rate becomes independent of downstream pressure. It is a function of only upstream (tank) pressure and the orifice diameter. >> >> When I get a chance, I will make a quick calc and see what the rates are. Good to check this. >> >> Best >> >> On Tuesday, August 1, 2023 at 04:09:41 PM CDT, Alec Smyth via Personal_Submersibles wrote: >> >> Hi Cliff, >> >> "The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input port of Tescom 44-4069 regulator." >> >> There's a little problem with this plan, though easy to work around. The HP ports on regulators have a tiny orifice, in order to prevent rapid loss of air if a hose or SPG fails. These ports cannot provide the sort of flow you would want. >> >> Best, >> Alec >> >> On Tue, Aug 1, 2023 at 12:17?PM Cliff Redus via Personal_Submersibles wrote: >> >>> Sean, the specs do look good on this unit. To me the issue is going to be the cost. As background, the Parker regulator that Hugh, Alec and I have used for this application is the 364-02BSS/M1 Parker Watts Pneumatic Regulator. >>> >>> https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator at $217.51. I purchased mine off ebay for a fraction of this. >>> >>> When I had the Parker 364-02BSS/M1 installed for pressure compensating for my four MK 101s, it was connected to the LP port from my AquaLung Titan balanced diaphragm first stage regulator. I had the Parker 364-02BSS/M1 adjusted to give about 2 psi over ambient. I had the first stage set to 50 psi over ambient water pressure. I use this for BIBBS and blowing the MBTs. >>> >>> The Tescom 44-4069 regulator would run directly off the HP air tank pressure then output go directly to thrusters. It would be interesting to compare the Cv's for both regulators to get a feel on how much air flow rate they can provide to the thrusters descending and venting when ascending. >>> >>> The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input port of Tescom 44-4069 regulator. From the output port of the Tescom 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two more "T"s to give four 1/4 SS tubing runs to the thrusters. >>> >>> We need to get a RFQ on one of these regulators. Do you have a preferred supplier? >>> >>> Cliff >>> >>> On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: >>> >>> I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. >>> >>> Sean >>> >>> -------- Original Message -------- >>> On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: >>> >>>> >>> >>> My original air competition for the R300 used the regulator that Hugh Fulton has on QSub. These are pricey new but you can get them used on eBay. I was operating all four of my Minn kotas 101 off this single regulator. It was a special ss pressure reducing/pressure releasing regulator. I had it installed on my last Florida dive which I went down about 100 ft . Unit worked fine. My first failure was on Flathead lake expedition in which one of my aft thrusters flooded. After that I switched to oil compensation. Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small. I believe he has addressed this by adding a pressure release valve or OP valve. He can elaborate more on his current strategy. >>> >>> Cliff >>> >>> Sent from my iPhone >>> >>>> On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles wrote: >>> >>>> ?John, >>>> I am happy with both air & oil. >>>> Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines. >>>> My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity. >>>> I think I need to put out a long video once I've finished this >>>> air compensator. >>>> From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with. >>>> Alan >>>> >>>> [Sent from Yahoo Mail on Android](https://mail.onelink.me/107872968?pid=nativeplacement&c=Global_Acquisition_YMktg_315_Internal_EmailSignature&af_sub1=Acquisition&af_sub2=Global_YMktg&af_sub3=&af_sub4=100000604&af_sub5=EmailSignature__Static_) >>>> >>>>> On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles >>>>> wrote: >>>>> _______________________________________________ >>>>> Personal_Submersibles mailing list >>>>> Personal_Submersibles at psubs.org >>>>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >>>> >>>> _______________________________________________ >>>> Personal_Submersibles mailing list >>>> Personal_Submersibles at psubs.org >>>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >>> >>> _______________________________________________ >>> Personal_Submersibles mailing list >>> Personal_Submersibles at psubs.org >>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >>> >>> _______________________________________________ >>> Personal_Submersibles mailing list >>> Personal_Submersibles at psubs.org >>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >> >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 1 20:04:42 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Wed, 2 Aug 2023 00:04:42 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> Message-ID: <1875878821.811179.1690934682829@mail.yahoo.com> Alec, yes, the HP port of first stage has a tiny hole and is made to measure pressure. Having said that because of the high tank pressure you can still pass a significant amount of air.? As an example, on my Titan 1st state, it is approximately 0.03" diameter.? A quick calculation assuming 3000 psig tank and 70F tank temperature, the flow rate through this tiny hole is 32 scf/min.? ?At 1000 psig tank pressure, the rate would be 16 scf/min.? These rates are independent of water ambient pressure because the flow is in critical flow.? The rates would change somewhat with tank temperature.? Would need to complete the calculation to see what the demand would be to fill the four thrusters on the descent but their volume of 37 fl oz each is quite small. My guess it would work off both the HP or LP ports but I need to finish?the calc.?? Cliff On Tuesday, August 1, 2023 at 04:09:41 PM CDT, Alec Smyth via Personal_Submersibles wrote: Hi Cliff, "The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator." There's a little problem with this plan, though easy to work around.?The HP ports on regulators have a tiny orifice, in order to prevent rapid loss of air if a hose or SPG fails. These ports cannot provide the sort of flow you would want.? Best,Alec On Tue, Aug 1, 2023 at 12:17?PM Cliff Redus via Personal_Submersibles wrote: Sean, the specs do look good on this unit.? To me the issue is going to be the cost.? As background, the Parker regulator that Hugh, Alec and I have used for this application is the?364-02BSS/M1 Parker Watts Pneumatic Regulator. https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator?at $217.51.? I purchased mine off ebay for a fraction of this. When I had the Parker?364-02BSS/M1 installed for pressure compensating for my four MK 101s, it was connected to the LP port from my AquaLung Titan balanced diaphragm first stage regulator. I had the?Parker?364-02BSS/M1 adjusted?to give about 2 psi over ambient.? I had the first stage set to 50 psi over ambient water pressure.? I use this for BIBBS and blowing the MBTs.? The?Tescom 44-4069 regulator would run directly off the HP air tank pressure then output go directly?to thrusters.? It would be interesting to compare the Cv's for both regulators to get a feel on how much air flow rate they can provide to the thrusters?descending?and venting when ascending.?? The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator.? From the output port?of the Tescom 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two more "T"s to give four 1/4 SS tubing runs to the thrusters. We need to get a RFQ on one of these regulators.? Do you have a preferred supplier? Cliff On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. Sean -------- Original Message -------- On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: My original air competition for the R300 used the regulator that Hugh Fulton has on QSub.? These are pricey new but you can get them used on eBay.? I was operating all four of my Minn kotas 101 off this single regulator.? It was a special ss pressure reducing/pressure releasing regulator.? I had it installed on my last Florida dive which I went down about 100 ft .? Unit worked fine.? My first failure was on Flathead lake expedition in which one of my aft thrusters flooded.? After that I switched to oil compensation.? Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small.? I believe he has addressed this by adding a pressure release valve or OP valve.? He can elaborate more on his current strategy. Cliff Sent from my iPhone On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles wrote: ?John,I am happy with both air & oil.?Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines.My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity.I think I need to put out a long video once I've finished thisair compensator.From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with.Alan Sent from Yahoo Mail on Android On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 2 00:17:39 2023 From: personal_submersibles at psubs.org (Alan James via Personal_Submersibles) Date: Wed, 2 Aug 2023 04:17:39 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <1875878821.811179.1690934682829@mail.yahoo.com> References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> <1875878821.811179.1690934682829@mail.yahoo.com> Message-ID: <1111140276.870758.1690949859042@mail.yahoo.com> Cliff, (or anyone)Could a large flow through that small orifice cause it toice up? I don't personally know, but had ice forming on a tank valve when I was discharging the contents.Alan Sent from Yahoo Mail on Android On Wed, 2 Aug 2023 at 12:06 pm, Cliff Redus via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 2 06:58:45 2023 From: personal_submersibles at psubs.org (Jon Wallace via Personal_Submersibles) Date: Wed, 2 Aug 2023 10:58:45 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <9120FE56-C40E-4300-ADD7-FCD5CAABC300@gmail.com> References: <88FFF9BA-3D51-4E04-927F-AC1A25D41537@yahoo.ca> <9120FE56-C40E-4300-ADD7-FCD5CAABC300@gmail.com> Message-ID: <1118925377.965925.1690973925793@mail.yahoo.com> I would be interested in seeing the brush wear on the commutator of an air compensated 101. ?Anyone have one that has been in service for a while willing to break it down and share photos? Jon -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 2 09:02:28 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Wed, 2 Aug 2023 13:02:28 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <1111140276.870758.1690949859042@mail.yahoo.com> References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> <1875878821.811179.1690934682829@mail.yahoo.com> <1111140276.870758.1690949859042@mail.yahoo.com> Message-ID: <462742814.1010298.1690981348479@mail.yahoo.com> No ice blockage if you use scuba air.? Scuba air is dry, meaning very little water vapor.? Scuba air has a dew point of -50F which is very dry.? To get ice, the water vapor must condense to liquid water then be at a temperature below the freezing point.? Most psubbers use scuba air if they use a BIBS system that is attached to the air used to blow MBT.? As such, they would fill tanks with dry air from a local scuba shop or portable scuba compressor that has a dryer. Cliff On Tuesday, August 1, 2023 at 11:18:23 PM CDT, Alan James via Personal_Submersibles wrote: Cliff, (or anyone)Could a large flow through that small orifice cause it toice up? I don't personally know, but had ice forming on a tank valve when I was discharging the contents.Alan Sent from Yahoo Mail on Android On Wed, 2 Aug 2023 at 12:06 pm, Cliff Redus via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 2 09:18:34 2023 From: personal_submersibles at psubs.org (vbra676539@aol.com via Personal_Submersibles) Date: Wed, 2 Aug 2023 13:18:34 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <462742814.1010298.1690981348479@mail.yahoo.com> References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> <1875878821.811179.1690934682829@mail.yahoo.com> <1111140276.870758.1690949859042@mail.yahoo.com> <462742814.1010298.1690981348479@mail.yahoo.com> Message-ID: <60474989.542501.1690982314071@mail.yahoo.com> Um...well... During normal sub ops we charged HP air with our own onboard compressors. Through dryers, of course. The problem you get is that old Hydrogen and Oxygen thing. Water out of thin air. The US NAvy doesn't call their emergency MBT blow valves the "chicken switches" for nothing. Blowing down chambers and DLO compartments could get pretty chilly, too, depending on how hard and how fast.Vance On Wednesday, August 2, 2023, 09:02:56 AM EDT, Cliff Redus via Personal_Submersibles wrote: No ice blockage if you use scuba air.? Scuba air is dry, meaning very little water vapor.? Scuba air has a dew point of -50F which is very dry.? To get ice, the water vapor must condense to liquid water then be at a temperature below the freezing point.? Most psubbers use scuba air if they use a BIBS system that is attached to the air used to blow MBT.? As such, they would fill tanks with dry air from a local scuba shop or portable scuba compressor that has a dryer. Cliff On Tuesday, August 1, 2023 at 11:18:23 PM CDT, Alan James via Personal_Submersibles wrote: Cliff, (or anyone)Could a large flow through that small orifice cause it toice up? I don't personally know, but had ice forming on a tank valve when I was discharging the contents.Alan Sent from Yahoo Mail on Android On Wed, 2 Aug 2023 at 12:06 pm, Cliff Redus via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 2 12:23:10 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Wed, 2 Aug 2023 16:23:10 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> Message-ID: <34406105.1116009.1690993390299@mail.yahoo.com> Alec, see attached spreadsheet calcs using the Tescom 44-4069 regulator connected to HP port of AquaLung Titan regulator.? Ran spreadsheet for descent to 400 ft using a single 80 scf tank with initial pressures of 3000 psig and then with 500 psig. Calculation shows that the tiny orifice can meet the demand of keeping the four MD 101 filled to ambient pressure plus 5 psi over pressure during this descent.? I will double check the equations but my take from this is we can connect the regulator either to the LP or HP ports and we should be OK with room to spare. Cliff On Tuesday, August 1, 2023 at 04:09:41 PM CDT, Alec Smyth via Personal_Submersibles wrote: Hi Cliff, "The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator." There's a little problem with this plan, though easy to work around.?The HP ports on regulators have a tiny orifice, in order to prevent rapid loss of air if a hose or SPG fails. These ports cannot provide the sort of flow you would want.? Best,Alec On Tue, Aug 1, 2023 at 12:17?PM Cliff Redus via Personal_Submersibles wrote: Sean, the specs do look good on this unit.? To me the issue is going to be the cost.? As background, the Parker regulator that Hugh, Alec and I have used for this application is the?364-02BSS/M1 Parker Watts Pneumatic Regulator. https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator?at $217.51.? I purchased mine off ebay for a fraction of this. When I had the Parker?364-02BSS/M1 installed for pressure compensating for my four MK 101s, it was connected to the LP port from my AquaLung Titan balanced diaphragm first stage regulator. I had the?Parker?364-02BSS/M1 adjusted?to give about 2 psi over ambient.? I had the first stage set to 50 psi over ambient water pressure.? I use this for BIBBS and blowing the MBTs.? The?Tescom 44-4069 regulator would run directly off the HP air tank pressure then output go directly?to thrusters.? It would be interesting to compare the Cv's for both regulators to get a feel on how much air flow rate they can provide to the thrusters?descending?and venting when ascending.?? The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator.? From the output port?of the Tescom 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two more "T"s to give four 1/4 SS tubing runs to the thrusters. We need to get a RFQ on one of these regulators.? Do you have a preferred supplier? Cliff On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. Sean -------- Original Message -------- On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: My original air competition for the R300 used the regulator that Hugh Fulton has on QSub.? These are pricey new but you can get them used on eBay.? I was operating all four of my Minn kotas 101 off this single regulator.? It was a special ss pressure reducing/pressure releasing regulator.? I had it installed on my last Florida dive which I went down about 100 ft .? Unit worked fine.? My first failure was on Flathead lake expedition in which one of my aft thrusters flooded.? After that I switched to oil compensation.? Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small.? I believe he has addressed this by adding a pressure release valve or OP valve.? He can elaborate more on his current strategy. Cliff Sent from my iPhone On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles wrote: ?John,I am happy with both air & oil.?Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines.My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity.I think I need to put out a long video once I've finished thisair compensator.From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with.Alan Sent from Yahoo Mail on Android On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: Calculation of filling MK 101 on decent to 400 ft using Tescom 44-4069 regulator connected to HP port of Aqualung Titan balanced diaphragm first stage regulator assuming 80 scf tank and 500 psig inital pressure.pdf Type: application/pdf Size: 220028 bytes Desc: not available URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: Calculation of filling MK 101 on decent to 400 ft using Tescom 44-4069 regulator connected to HP port of Aqualung Titan balanced diaphragm first stage regulator assuming 80 scf tank and 3000 psig inital pressure.pdf Type: application/pdf Size: 220379 bytes Desc: not available URL: From personal_submersibles at psubs.org Wed Aug 2 12:34:11 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Wed, 2 Aug 2023 16:34:11 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> Message-ID: <1954900241.1115882.1690994051989@mail.yahoo.com> Resending spreadsheets.? Depth had dropped off prior sheets. Cliff On Tuesday, August 1, 2023 at 04:09:41 PM CDT, Alec Smyth via Personal_Submersibles wrote: Hi Cliff, "The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator." There's a little problem with this plan, though easy to work around.?The HP ports on regulators have a tiny orifice, in order to prevent rapid loss of air if a hose or SPG fails. These ports cannot provide the sort of flow you would want.? Best,Alec On Tue, Aug 1, 2023 at 12:17?PM Cliff Redus via Personal_Submersibles wrote: Sean, the specs do look good on this unit.? To me the issue is going to be the cost.? As background, the Parker regulator that Hugh, Alec and I have used for this application is the?364-02BSS/M1 Parker Watts Pneumatic Regulator. https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator?at $217.51.? I purchased mine off ebay for a fraction of this. When I had the Parker?364-02BSS/M1 installed for pressure compensating for my four MK 101s, it was connected to the LP port from my AquaLung Titan balanced diaphragm first stage regulator. I had the?Parker?364-02BSS/M1 adjusted?to give about 2 psi over ambient.? I had the first stage set to 50 psi over ambient water pressure.? I use this for BIBBS and blowing the MBTs.? The?Tescom 44-4069 regulator would run directly off the HP air tank pressure then output go directly?to thrusters.? It would be interesting to compare the Cv's for both regulators to get a feel on how much air flow rate they can provide to the thrusters?descending?and venting when ascending.?? The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator.? From the output port?of the Tescom 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two more "T"s to give four 1/4 SS tubing runs to the thrusters. We need to get a RFQ on one of these regulators.? Do you have a preferred supplier? Cliff On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. Sean -------- Original Message -------- On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: My original air competition for the R300 used the regulator that Hugh Fulton has on QSub.? These are pricey new but you can get them used on eBay.? I was operating all four of my Minn kotas 101 off this single regulator.? It was a special ss pressure reducing/pressure releasing regulator.? I had it installed on my last Florida dive which I went down about 100 ft .? Unit worked fine.? My first failure was on Flathead lake expedition in which one of my aft thrusters flooded.? After that I switched to oil compensation.? Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small.? I believe he has addressed this by adding a pressure release valve or OP valve.? He can elaborate more on his current strategy. Cliff Sent from my iPhone On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles wrote: ?John,I am happy with both air & oil.?Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines.My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity.I think I need to put out a long video once I've finished thisair compensator.From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with.Alan Sent from Yahoo Mail on Android On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: Calculation of filling MK 101 on decent to 400 ft using Tescom 44-4069 regulator connected to HP port of Aqualung Titan balanced diaphragm first stage regulator assuming 80 scf tank and 500 psig inital pressure.pdf Type: application/pdf Size: 223456 bytes Desc: not available URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: Calculation of filling MK 101 on decent to 400 ft using Tescom 44-4069 regulator connected to HP port of Aqualung Titan balanced diaphragm first stage regulator assuming 80 scf tank and 3000 psig inital pressure.pdf Type: application/pdf Size: 223798 bytes Desc: not available URL: From personal_submersibles at psubs.org Wed Aug 2 12:43:09 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Wed, 2 Aug 2023 16:43:09 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <60474989.542501.1690982314071@mail.yahoo.com> References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> <1875878821.811179.1690934682829@mail.yahoo.com> <1111140276.870758.1690949859042@mail.yahoo.com> <462742814.1010298.1690981348479@mail.yahoo.com> <60474989.542501.1690982314071@mail.yahoo.com> Message-ID: <1500233549.1137658.1690994589695@mail.yahoo.com> Vance good to hear from you.? Thanks for your contributions on air/oil compensations.? Always glad when a real expert chimes in.? The statement below was based on using scuba air from dive shop or portable scuba compressor that meets a very high standard for being dry as specied by the air dew point temperature.? This specification says that the temperature would have to drop to below -50F for the first molecules of water vapor to condense to drinking water.?? So seeing ice is really all about how dry is dry.? My guess is the case you describe with using onboard compressors is that the drying was not down to -50F dewpoint. Hope to see you at next Psub event. Cliff On Wednesday, August 2, 2023 at 08:19:15 AM CDT, vbra676539 at aol.com via Personal_Submersibles wrote: Um...well... During normal sub ops we charged HP air with our own onboard compressors. Through dryers, of course. The problem you get is that old Hydrogen and Oxygen thing. Water out of thin air. The US NAvy doesn't call their emergency MBT blow valves the "chicken switches" for nothing. Blowing down chambers and DLO compartments could get pretty chilly, too, depending on how hard and how fast.Vance On Wednesday, August 2, 2023, 09:02:56 AM EDT, Cliff Redus via Personal_Submersibles wrote: No ice blockage if you use scuba air.? Scuba air is dry, meaning very little water vapor.? Scuba air has a dew point of -50F which is very dry.? To get ice, the water vapor must condense to liquid water then be at a temperature below the freezing point.? Most psubbers use scuba air if they use a BIBS system that is attached to the air used to blow MBT.? As such, they would fill tanks with dry air from a local scuba shop or portable scuba compressor that has a dryer. Cliff On Tuesday, August 1, 2023 at 11:18:23 PM CDT, Alan James via Personal_Submersibles wrote: Cliff, (or anyone)Could a large flow through that small orifice cause it toice up? I don't personally know, but had ice forming on a tank valve when I was discharging the contents.Alan Sent from Yahoo Mail on Android On Wed, 2 Aug 2023 at 12:06 pm, Cliff Redus via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 2 15:21:49 2023 From: personal_submersibles at psubs.org (vbra676539@aol.com via Personal_Submersibles) Date: Wed, 2 Aug 2023 19:21:49 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <1500233549.1137658.1690994589695@mail.yahoo.com> References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> <1875878821.811179.1690934682829@mail.yahoo.com> <1111140276.870758.1690949859042@mail.yahoo.com> <462742814.1010298.1690981348479@mail.yahoo.com> <60474989.542501.1690982314071@mail.yahoo.com> <1500233549.1137658.1690994589695@mail.yahoo.com> Message-ID: <1202620483.659338.1691004109127@mail.yahoo.com> Hi CliffSame here. It's always interesting to hear your take on this and that. And along those lines, has anyone looked at the new Minn-Kota brushless motors? I have no idea what they cost, but it does solve the old brush problem.Vance. On Wednesday, August 2, 2023, 12:43:28 PM EDT, Cliff Redus via Personal_Submersibles wrote: Vance good to hear from you.? Thanks for your contributions on air/oil compensations.? Always glad when a real expert chimes in.? The statement below was based on using scuba air from dive shop or portable scuba compressor that meets a very high standard for being dry as specied by the air dew point temperature.? This specification says that the temperature would have to drop to below -50F for the first molecules of water vapor to condense to drinking water.?? So seeing ice is really all about how dry is dry.? My guess is the case you describe with using onboard compressors is that the drying was not down to -50F dewpoint. Hope to see you at next Psub event. Cliff On Wednesday, August 2, 2023 at 08:19:15 AM CDT, vbra676539 at aol.com via Personal_Submersibles wrote: Um...well... During normal sub ops we charged HP air with our own onboard compressors. Through dryers, of course. The problem you get is that old Hydrogen and Oxygen thing. Water out of thin air. The US NAvy doesn't call their emergency MBT blow valves the "chicken switches" for nothing. Blowing down chambers and DLO compartments could get pretty chilly, too, depending on how hard and how fast.Vance On Wednesday, August 2, 2023, 09:02:56 AM EDT, Cliff Redus via Personal_Submersibles wrote: No ice blockage if you use scuba air.? Scuba air is dry, meaning very little water vapor.? Scuba air has a dew point of -50F which is very dry.? To get ice, the water vapor must condense to liquid water then be at a temperature below the freezing point.? Most psubbers use scuba air if they use a BIBS system that is attached to the air used to blow MBT.? As such, they would fill tanks with dry air from a local scuba shop or portable scuba compressor that has a dryer. Cliff On Tuesday, August 1, 2023 at 11:18:23 PM CDT, Alan James via Personal_Submersibles wrote: Cliff, (or anyone)Could a large flow through that small orifice cause it toice up? I don't personally know, but had ice forming on a tank valve when I was discharging the contents.Alan Sent from Yahoo Mail on Android On Wed, 2 Aug 2023 at 12:06 pm, Cliff Redus via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 2 17:55:48 2023 From: personal_submersibles at psubs.org (Alan James via Personal_Submersibles) Date: Wed, 2 Aug 2023 21:55:48 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <462742814.1010298.1690981348479@mail.yahoo.com> References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> <1875878821.811179.1690934682829@mail.yahoo.com> <1111140276.870758.1690949859042@mail.yahoo.com> <462742814.1010298.1690981348479@mail.yahoo.com> Message-ID: <963102518.1301879.1691013348711@mail.yahoo.com> Cliff,I could have been seeing ice form from the condensation in the room where I was emptying the tank. The tank valve orifice became freezing cold due to the fast rate of air leaving it, & moisture in the atmosphere froze on it.(Maybe)Alan Sent from Yahoo Mail on Android On Thu, 3 Aug 2023 at 1:04 am, Cliff Redus via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 2 19:03:04 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Wed, 2 Aug 2023 23:03:04 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <963102518.1301879.1691013348711@mail.yahoo.com> References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> <1875878821.811179.1690934682829@mail.yahoo.com> <1111140276.870758.1690949859042@mail.yahoo.com> <462742814.1010298.1690981348479@mail.yahoo.com> <963102518.1301879.1691013348711@mail.yahoo.com> Message-ID: <1880286369.1346116.1691017384440@mail.yahoo.com> Alan for sure when the dry air expands after exiting the orifice, Joule Thompson cooling occurs which cools down the first state regulator.? The air in the room is not dry, it has a certain relative humidity.? The air around the regulator then is cooled dropping it below the dew point of the air so water vapor in the room air near the surface condenses to free water.? Because the air temperature near the surface of the regulator has dropped below the freezing, the free water forms ice crystals.? ? Cliff On Wednesday, August 2, 2023 at 04:56:32 PM CDT, Alan James via Personal_Submersibles wrote: Cliff,I could have been seeing ice form from the condensation in the room where I was emptying the tank. The tank valve orifice became freezing cold due to the fast rate of air leaving it, & moisture in the atmosphere froze on it.(Maybe)Alan Sent from Yahoo Mail on Android On Thu, 3 Aug 2023 at 1:04 am, Cliff Redus via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 2 19:35:18 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Wed, 2 Aug 2023 23:35:18 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> Message-ID: <1254281258.1357257.1691019318874@mail.yahoo.com> Alec, I setup a spreadsheet to analyze the following setup. ?A scuba tank has a 1st stage regulator attached.? A Tescom 44-4069 pressure reducing regulatorwith venting is attached and tubing is connected from the HP port to a set ofMinn-Kota 101 motors. ?The question iscan the small orifice in the HP port pass sufficient air to handle the demandfor air in thrusters to keep the pressure a fixed differential pressure aboveambient water pressure. The calculation indicates this arrangement will work.? If anyone wants a copy of the spreadsheet,please email me your email address and I will send. The calculation indicates the HP port could be used forthis.? Having said that, yes, this asimple clean setup but so is connecting to a spare LP port.? The advantage of the LP port is that pressurerating of the regulator body can be less so less 316 stainless and less cost.? Would be good to spec a regulator like theTescom 44-4069 regulator with its venting capacity but for pressures one would expect from the LP port. Cliff PS: Hope you got your Land Rover back from the shop. On Tuesday, August 1, 2023 at 04:09:41 PM CDT, Alec Smyth via Personal_Submersibles wrote: Hi Cliff, "The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator." There's a little problem with this plan, though easy to work around.?The HP ports on regulators have a tiny orifice, in order to prevent rapid loss of air if a hose or SPG fails. These ports cannot provide the sort of flow you would want.? Best,Alec On Tue, Aug 1, 2023 at 12:17?PM Cliff Redus via Personal_Submersibles wrote: Sean, the specs do look good on this unit.? To me the issue is going to be the cost.? As background, the Parker regulator that Hugh, Alec and I have used for this application is the?364-02BSS/M1 Parker Watts Pneumatic Regulator. https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator?at $217.51.? I purchased mine off ebay for a fraction of this. When I had the Parker?364-02BSS/M1 installed for pressure compensating for my four MK 101s, it was connected to the LP port from my AquaLung Titan balanced diaphragm first stage regulator. I had the?Parker?364-02BSS/M1 adjusted?to give about 2 psi over ambient.? I had the first stage set to 50 psi over ambient water pressure.? I use this for BIBBS and blowing the MBTs.? The?Tescom 44-4069 regulator would run directly off the HP air tank pressure then output go directly?to thrusters.? It would be interesting to compare the Cv's for both regulators to get a feel on how much air flow rate they can provide to the thrusters?descending?and venting when ascending.?? The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator.? From the output port?of the Tescom 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two more "T"s to give four 1/4 SS tubing runs to the thrusters. We need to get a RFQ on one of these regulators.? Do you have a preferred supplier? Cliff On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. Sean -------- Original Message -------- On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: My original air competition for the R300 used the regulator that Hugh Fulton has on QSub.? These are pricey new but you can get them used on eBay.? I was operating all four of my Minn kotas 101 off this single regulator.? It was a special ss pressure reducing/pressure releasing regulator.? I had it installed on my last Florida dive which I went down about 100 ft .? Unit worked fine.? My first failure was on Flathead lake expedition in which one of my aft thrusters flooded.? After that I switched to oil compensation.? Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small.? I believe he has addressed this by adding a pressure release valve or OP valve.? He can elaborate more on his current strategy. Cliff Sent from my iPhone On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles wrote: ?John,I am happy with both air & oil.?Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines.My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity.I think I need to put out a long video once I've finished thisair compensator.From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with.Alan Sent from Yahoo Mail on Android On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 2 20:20:37 2023 From: personal_submersibles at psubs.org (Alec Smyth via Personal_Submersibles) Date: Wed, 2 Aug 2023 20:20:37 -0400 Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <1254281258.1357257.1691019318874@mail.yahoo.com> References: <1254281258.1357257.1691019318874@mail.yahoo.com> Message-ID: An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 2 21:22:34 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Wed, 2 Aug 2023 20:22:34 -0500 Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: Message-ID: <07A09AFA-47F3-4BBA-BDDF-C473219344B3@gmail.com> An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 2 22:13:28 2023 From: personal_submersibles at psubs.org (David Colombo via Personal_Submersibles) Date: Wed, 2 Aug 2023 19:13:28 -0700 Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <07A09AFA-47F3-4BBA-BDDF-C473219344B3@gmail.com> References: <07A09AFA-47F3-4BBA-BDDF-C473219344B3@gmail.com> Message-ID: Hi Guys, I've been following this thread on air compensation with great interest. So today I reached out to my Minn Kota contact to inquire about the new brushless 120# thrusters and if lower units could be purchased. The new units will not be available to the public most likely till March of next year and no parts will be available for at least the first 6 months after, as all warranty work and repairs will be going back to the factory to qc this product. The projected cost on the lower unit is expected to be in the $800 to $1000 range, (fully outfitted bow unit, around $3600). Not too bad as my cost for my 101 lower units was right around $575 , six years ago. Here is the bad news. The only unit being released is the Bow mount unit which requires all of the hummingbird technology to operate, with the built in speed controller, foot control and the BMS system, all of which is proprietary. From what I understand there is no way to run the brushless motor without the technology, so essentially useless as a sub motor and not able to be disabled and not able to be rebuilt. The other bad news is the 101 series is also being discontinued in favor of new bluetooth technology and the reliance entirely on a closed loop proprietary software system being sold as what fishermen really want and need to be able to fish. Even the built in transducer in the lower unit will only work with Hummingbird, or will work with say Garmin but only a very limited basic sidescan and none of the 3d scanning , panoptics , etc. The new brushless unit at 24v = 96# thrust, and the 36v=115# thrust. Not actually much better than the 101's. Good thing I currently have six of them in my shop. Once I get my test pool assembled for the VAST, after I complete the outfitting, I will test my 36v 101's with an air compensation system, all I need are the extra regulator and op valves. Best Regards, David Colombo 804 College Ave Santa Rosa, CA. 95404 (707) 536-1424 www.SeaQuestor.com On Wed, Aug 2, 2023 at 6:23?PM Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > After a successful Inner-space Science Expedition at Beaver Island this > year I know it feels good to recover Shackleton and be on the way home. > > Cliff > > Sent from my iPhone > > On Aug 2, 2023, at 7:21 PM, Alec Smyth via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > ?Guess where this finds me? We picked up Shackleton from Bernie?s a couple > of hours ago and are homeward bound. Bernie as always super helpful. > > Sent from my iPhone > > On Aug 2, 2023, at 7:36 PM, Cliff Redus via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > ? > > Alec, I setup a spreadsheet to analyze the following setup. > > A scuba tank has a 1st stage regulator attached. A Tescom 44-4069 > pressure reducing regulator with venting is attached and tubing is > connected from the HP port to a set of Minn-Kota 101 motors. The question > is can the small orifice in the HP port pass sufficient air to handle the > demand for air in thrusters to keep the pressure a fixed differential > pressure above ambient water pressure. > > The calculation indicates this arrangement will work. If anyone wants a > copy of the spreadsheet, please email me your email address and I will send. > > The calculation indicates the HP port could be used for this. Having > said that, yes, this a simple clean setup but so is connecting to a spare > LP port. The advantage of the LP port is that pressure rating of the > regulator body can be less so less 316 stainless and less cost. Would be > good to spec a regulator like the Tescom 44-4069 regulator with its venting > capacity but for pressures one would expect from the LP port. > > Cliff > > PS: Hope you got your Land Rover back from the shop. > > > > > On Tuesday, August 1, 2023 at 04:09:41 PM CDT, Alec Smyth via > Personal_Submersibles wrote: > > > Hi Cliff, > > "The Tescom 44-4069 regulator would be a clean installation with just a > single 1/4 SS tubing run from the HP port of the 1st stage regulator to the > input port of Tescom 44-4069 regulator." > > There's a little problem with this plan, though easy to work around. The > HP ports on regulators have a tiny orifice, in order to prevent rapid loss > of air if a hose or SPG fails. These ports cannot provide the sort of flow > you would want. > > Best, > Alec > > On Tue, Aug 1, 2023 at 12:17?PM Cliff Redus via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > Sean, the specs do look good on this unit. To me the issue is going to be > the cost. As background, the Parker regulator that Hugh, Alec and I have > used for this application is the 364-02BSS/M1 Parker Watts Pneumatic > Regulator. > > https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator at > $217.51. I purchased mine off ebay for a fraction of this. > > When I had the Parker 364-02BSS/M1 installed for pressure compensating > for my four MK 101s, it was connected to the LP port from my AquaLung Titan > balanced diaphragm first stage regulator. I had the Parker 364-02BSS/M1 > adjusted to give about 2 psi over ambient. I had the first stage set to > 50 psi over ambient water pressure. I use this for BIBBS and blowing the > MBTs. > > The Tescom 44-4069 regulator would run directly off the HP air tank > pressure then output go directly to thrusters. It would be interesting to > compare the Cv's for both regulators to get a feel on how much air flow > rate they can provide to the thrusters descending and venting when > ascending. > > The Tescom 44-4069 regulator would be a clean installation with just a > single 1/4 SS tubing run from the HP port of the 1st stage regulator to the > input port of Tescom 44-4069 regulator. From the output port of the Tescom > 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two > more "T"s to give four 1/4 SS tubing runs to the thrusters. > > We need to get a RFQ on one of these regulators. Do you have a preferred > supplier? > > Cliff > > > On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via > Personal_Submersibles wrote: > > > I would be inclined to use a Tescom 44-4069 regulator for this purpose. > Not sure what these sell for. > > Sean > > > > -------- Original Message -------- > On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > > My original air competition for the R300 used the regulator that Hugh > Fulton has on QSub. These are pricey new but you can get them used on > eBay. I was operating all four of my Minn kotas 101 off this single > regulator. It was a special ss pressure reducing/pressure releasing > regulator. I had it installed on my last Florida dive which I went down > about 100 ft . Unit worked fine. My first failure was on Flathead lake > expedition in which one of my aft thrusters flooded. After that I switched > to oil compensation. Alec is using same regular on his articulated arm and > not the thrusters. He felt issue with the regulator was that the port for > releasing pressure on ascent was too small. I believe he has addressed > this by adding a pressure release valve or OP valve. He can elaborate more > on his current strategy. > > Cliff > > Sent from my iPhone > > On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > ?John, > I am happy with both air & oil. > Am intending to fill my thrusters with oil, but have the oil pressurized > off my air comp system. This will reduce air use to just whats in the lines. > My electric manipulator will be air compensated off the same unit. Putting > oil in it adds another layer of complexity. > I think I need to put out a long video once I've finished this > air compensator. > From what I am hearing from Cliff, he didn't get enough air delivery from > the single regulator he was using. However I thought this was the same unit > that Alec is using & was now happy with. > Alan > > > Sent from Yahoo Mail on Android > > > On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles > wrote: > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 2 22:23:32 2023 From: personal_submersibles at psubs.org (David Colombo via Personal_Submersibles) Date: Wed, 2 Aug 2023 19:23:32 -0700 Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <1254281258.1357257.1691019318874@mail.yahoo.com> References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> <1254281258.1357257.1691019318874@mail.yahoo.com> Message-ID: Cliff, something I experienced at Charlevoix, was the first stage regulator in the VAST was going into a freeze cycle when dumping air into the ballast tanks when we were getting the ballast corrected with multiple short dive attempts and then back to the surface. It now has me wondering whether the air we got from Bernie moist, or the formation of ice crystals on the outside of the regulator was from the air coming from the hp vs lp port. I need to look at the regulator tonight to think this thru. Best Regards, David Colombo 804 College Ave Santa Rosa, CA. 95404 (707) 536-1424 www.SeaQuestor.com On Wed, Aug 2, 2023 at 4:36?PM Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Alec, I setup a spreadsheet to analyze the following setup. > > A scuba tank has a 1st stage regulator attached. A Tescom 44-4069 > pressure reducing regulator with venting is attached and tubing is > connected from the HP port to a set of Minn-Kota 101 motors. The question > is can the small orifice in the HP port pass sufficient air to handle the > demand for air in thrusters to keep the pressure a fixed differential > pressure above ambient water pressure. > > The calculation indicates this arrangement will work. If anyone wants a > copy of the spreadsheet, please email me your email address and I will send. > > The calculation indicates the HP port could be used for this. Having > said that, yes, this a simple clean setup but so is connecting to a spare > LP port. The advantage of the LP port is that pressure rating of the > regulator body can be less so less 316 stainless and less cost. Would be > good to spec a regulator like the Tescom 44-4069 regulator with its venting > capacity but for pressures one would expect from the LP port. > > Cliff > > PS: Hope you got your Land Rover back from the shop. > > > > > On Tuesday, August 1, 2023 at 04:09:41 PM CDT, Alec Smyth via > Personal_Submersibles wrote: > > > Hi Cliff, > > "The Tescom 44-4069 regulator would be a clean installation with just a > single 1/4 SS tubing run from the HP port of the 1st stage regulator to the > input port of Tescom 44-4069 regulator." > > There's a little problem with this plan, though easy to work around. The > HP ports on regulators have a tiny orifice, in order to prevent rapid loss > of air if a hose or SPG fails. These ports cannot provide the sort of flow > you would want. > > Best, > Alec > > On Tue, Aug 1, 2023 at 12:17?PM Cliff Redus via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > Sean, the specs do look good on this unit. To me the issue is going to be > the cost. As background, the Parker regulator that Hugh, Alec and I have > used for this application is the 364-02BSS/M1 Parker Watts Pneumatic > Regulator. > > https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator at > $217.51. I purchased mine off ebay for a fraction of this. > > When I had the Parker 364-02BSS/M1 installed for pressure compensating > for my four MK 101s, it was connected to the LP port from my AquaLung Titan > balanced diaphragm first stage regulator. I had the Parker 364-02BSS/M1 > adjusted to give about 2 psi over ambient. I had the first stage set to > 50 psi over ambient water pressure. I use this for BIBBS and blowing the > MBTs. > > The Tescom 44-4069 regulator would run directly off the HP air tank > pressure then output go directly to thrusters. It would be interesting to > compare the Cv's for both regulators to get a feel on how much air flow > rate they can provide to the thrusters descending and venting when > ascending. > > The Tescom 44-4069 regulator would be a clean installation with just a > single 1/4 SS tubing run from the HP port of the 1st stage regulator to the > input port of Tescom 44-4069 regulator. From the output port of the Tescom > 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two > more "T"s to give four 1/4 SS tubing runs to the thrusters. > > We need to get a RFQ on one of these regulators. Do you have a preferred > supplier? > > Cliff > > > On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via > Personal_Submersibles wrote: > > > I would be inclined to use a Tescom 44-4069 regulator for this purpose. > Not sure what these sell for. > > Sean > > > > -------- Original Message -------- > On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > > My original air competition for the R300 used the regulator that Hugh > Fulton has on QSub. These are pricey new but you can get them used on > eBay. I was operating all four of my Minn kotas 101 off this single > regulator. It was a special ss pressure reducing/pressure releasing > regulator. I had it installed on my last Florida dive which I went down > about 100 ft . Unit worked fine. My first failure was on Flathead lake > expedition in which one of my aft thrusters flooded. After that I switched > to oil compensation. Alec is using same regular on his articulated arm and > not the thrusters. He felt issue with the regulator was that the port for > releasing pressure on ascent was too small. I believe he has addressed > this by adding a pressure release valve or OP valve. He can elaborate more > on his current strategy. > > Cliff > > Sent from my iPhone > > On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > ?John, > I am happy with both air & oil. > Am intending to fill my thrusters with oil, but have the oil pressurized > off my air comp system. This will reduce air use to just whats in the lines. > My electric manipulator will be air compensated off the same unit. Putting > oil in it adds another layer of complexity. > I think I need to put out a long video once I've finished this > air compensator. > From what I am hearing from Cliff, he didn't get enough air delivery from > the single regulator he was using. However I thought this was the same unit > that Alec is using & was now happy with. > Alan > > > Sent from Yahoo Mail on Android > > > On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles > wrote: > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 2 22:38:39 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Thu, 3 Aug 2023 02:38:39 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: <07A09AFA-47F3-4BBA-BDDF-C473219344B3@gmail.com> Message-ID: <1400400652.1414721.1691030320010@mail.yahoo.com> Good Update David.?? Best On Wednesday, August 2, 2023 at 09:14:23 PM CDT, David Colombo via Personal_Submersibles wrote: Hi Guys, I've been following this thread on air compensation with great interest. So today I reached out to my Minn Kota contact to inquire about the new brushless 120# thrusters and if lower units could be purchased. The new units will not be available to the public most likely till March of next year and no parts will be available for at least the first 6 months after, as all warranty work and repairs will be going back to the factory to qc this product. The projected cost on the lower unit is expected to be in the $800 to $1000 range, (fully outfitted? bow unit, around $3600). Not too bad as my cost for my 101 lower units was right around $575 , six years ago. Here is the bad news. The only unit being released is the Bow mount unit which requires all of the hummingbird technology to operate, with the built in speed controller, foot control and the BMS system, all of which is proprietary.? From what I understand there is no way to run the brushless motor without the technology, so essentially useless as a sub motor and not able to be disabled and not able to be rebuilt.? The other bad news is the 101 series is also being discontinued in favor of new bluetooth technology and the reliance entirely on a closed loop proprietary software system being sold as what fishermen really want and need to be able to fish. Even the built in transducer in the lower unit will only work with Hummingbird, or will work with say Garmin but only a very limited basic sidescan and none of the 3d scanning , panoptics , etc. The new brushless unit at 24v = 96# thrust, and the 36v=115# thrust. Not actually much better than the 101's.? Good thing I currently have six of them in my shop. Once I get my test pool assembled for the VAST, after I complete the outfitting, I will test my 36v 101's with an air compensation system, all? I need are the extra regulator and op valves.? ? ? ? Best Regards, David Colombo 804 College Ave Santa Rosa, CA. 95404 (707) 536-1424 www.SeaQuestor.com On Wed, Aug 2, 2023 at 6:23?PM Cliff Redus via Personal_Submersibles wrote: After a successful Inner-space Science Expedition at Beaver Island this year I know it feels good to recover Shackleton and be on the way home. Cliff Sent from my iPhone On Aug 2, 2023, at 7:21 PM, Alec Smyth via Personal_Submersibles wrote: ?Guess where this finds me? We picked up Shackleton from Bernie?s a couple of hours ago and are homeward bound. Bernie as always super helpful.? Sent from my iPhone On Aug 2, 2023, at 7:36 PM, Cliff Redus via Personal_Submersibles wrote: ? Alec, I setup a spreadsheet to analyze the following setup. ?A scuba tank has a 1st stage regulator attached.? A Tescom 44-4069 pressure reducing regulatorwith venting is attached and tubing is connected from the HP port to a set ofMinn-Kota 101 motors.? The question iscan the small orifice in the HP port pass sufficient air to handle the demandfor air in thrusters to keep the pressure a fixed differential pressure aboveambient water pressure. The calculation indicates this arrangement will work.? If anyone wants a copy of the spreadsheet,please email me your email address and I will send. The calculation indicates the HP port could be used forthis.? Having said that, yes, this asimple clean setup but so is connecting to a spare LP port.? The advantage of the LP port is that pressurerating of the regulator body can be less so less 316 stainless and less cost.? Would be good to spec a regulator like theTescom 44-4069 regulator with its venting capacity but for pressures one would expect from the LP port. Cliff PS: Hope you got your Land Rover back from the shop. On Tuesday, August 1, 2023 at 04:09:41 PM CDT, Alec Smyth via Personal_Submersibles wrote: Hi Cliff, "The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator." There's a little problem with this plan, though easy to work around.?The HP ports on regulators have a tiny orifice, in order to prevent rapid loss of air if a hose or SPG fails. These ports cannot provide the sort of flow you would want.? Best,Alec On Tue, Aug 1, 2023 at 12:17?PM Cliff Redus via Personal_Submersibles wrote: Sean, the specs do look good on this unit.? To me the issue is going to be the cost.? As background, the Parker regulator that Hugh, Alec and I have used for this application is the?364-02BSS/M1 Parker Watts Pneumatic Regulator. https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator?at $217.51.? I purchased mine off ebay for a fraction of this. When I had the Parker?364-02BSS/M1 installed for pressure compensating for my four MK 101s, it was connected to the LP port from my AquaLung Titan balanced diaphragm first stage regulator. I had the?Parker?364-02BSS/M1 adjusted?to give about 2 psi over ambient.? I had the first stage set to 50 psi over ambient water pressure.? I use this for BIBBS and blowing the MBTs.? The?Tescom 44-4069 regulator would run directly off the HP air tank pressure then output go directly?to thrusters.? It would be interesting to compare the Cv's for both regulators to get a feel on how much air flow rate they can provide to the thrusters?descending?and venting when ascending.?? The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator.? From the output port?of the Tescom 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two more "T"s to give four 1/4 SS tubing runs to the thrusters. We need to get a RFQ on one of these regulators.? Do you have a preferred supplier? Cliff On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. Sean -------- Original Message -------- On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: My original air competition for the R300 used the regulator that Hugh Fulton has on QSub.? These are pricey new but you can get them used on eBay.? I was operating all four of my Minn kotas 101 off this single regulator.? It was a special ss pressure reducing/pressure releasing regulator.? I had it installed on my last Florida dive which I went down about 100 ft .? Unit worked fine.? My first failure was on Flathead lake expedition in which one of my aft thrusters flooded.? After that I switched to oil compensation.? Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small.? I believe he has addressed this by adding a pressure release valve or OP valve.? He can elaborate more on his current strategy. Cliff Sent from my iPhone On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles wrote: ?John,I am happy with both air & oil.?Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines.My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity.I think I need to put out a long video once I've finished thisair compensator.From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with.Alan Sent from Yahoo Mail on Android On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 2 22:39:45 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Thu, 3 Aug 2023 02:39:45 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: <1967599098.286784.1690856011585@mail.yahoo.com> <84699DC8-D141-4D5D-B58A-3BAA8631BF05@gmail.com> <1697183893.555377.1690906622926@mail.yahoo.com> <1254281258.1357257.1691019318874@mail.yahoo.com> Message-ID: <1858988283.1417015.1691030385651@mail.yahoo.com> Let us know what you find. Best On Wednesday, August 2, 2023 at 09:24:18 PM CDT, David Colombo via Personal_Submersibles wrote: Cliff, something I experienced at Charlevoix, was the first stage regulator in the VAST was going into a freeze cycle when dumping air into the ballast tanks when we were getting the ballast corrected with multiple short dive attempts and then back to the surface. It now has me wondering whether the air we got from Bernie moist, or the formation of ice crystals on the outside of the regulator was from the air coming from the hp vs lp port. I need to look at the regulator tonight to think this thru. Best Regards, David Colombo 804 College Ave Santa Rosa, CA. 95404 (707) 536-1424 www.SeaQuestor.com On Wed, Aug 2, 2023 at 4:36?PM Cliff Redus via Personal_Submersibles wrote: Alec, I setup a spreadsheet to analyze the following setup. ?A scuba tank has a 1st stage regulator attached.? A Tescom 44-4069 pressure reducing regulatorwith venting is attached and tubing is connected from the HP port to a set ofMinn-Kota 101 motors.? The question iscan the small orifice in the HP port pass sufficient air to handle the demandfor air in thrusters to keep the pressure a fixed differential pressure aboveambient water pressure. The calculation indicates this arrangement will work.? If anyone wants a copy of the spreadsheet,please email me your email address and I will send. The calculation indicates the HP port could be used forthis.? Having said that, yes, this asimple clean setup but so is connecting to a spare LP port.? The advantage of the LP port is that pressurerating of the regulator body can be less so less 316 stainless and less cost.? Would be good to spec a regulator like theTescom 44-4069 regulator with its venting capacity but for pressures one would expect from the LP port. Cliff PS: Hope you got your Land Rover back from the shop. On Tuesday, August 1, 2023 at 04:09:41 PM CDT, Alec Smyth via Personal_Submersibles wrote: Hi Cliff, "The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator." There's a little problem with this plan, though easy to work around.?The HP ports on regulators have a tiny orifice, in order to prevent rapid loss of air if a hose or SPG fails. These ports cannot provide the sort of flow you would want.? Best,Alec On Tue, Aug 1, 2023 at 12:17?PM Cliff Redus via Personal_Submersibles wrote: Sean, the specs do look good on this unit.? To me the issue is going to be the cost.? As background, the Parker regulator that Hugh, Alec and I have used for this application is the?364-02BSS/M1 Parker Watts Pneumatic Regulator. https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator?at $217.51.? I purchased mine off ebay for a fraction of this. When I had the Parker?364-02BSS/M1 installed for pressure compensating for my four MK 101s, it was connected to the LP port from my AquaLung Titan balanced diaphragm first stage regulator. I had the?Parker?364-02BSS/M1 adjusted?to give about 2 psi over ambient.? I had the first stage set to 50 psi over ambient water pressure.? I use this for BIBBS and blowing the MBTs.? The?Tescom 44-4069 regulator would run directly off the HP air tank pressure then output go directly?to thrusters.? It would be interesting to compare the Cv's for both regulators to get a feel on how much air flow rate they can provide to the thrusters?descending?and venting when ascending.?? The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator.? From the output port?of the Tescom 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two more "T"s to give four 1/4 SS tubing runs to the thrusters. We need to get a RFQ on one of these regulators.? Do you have a preferred supplier? Cliff On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. Sean -------- Original Message -------- On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: My original air competition for the R300 used the regulator that Hugh Fulton has on QSub.? These are pricey new but you can get them used on eBay.? I was operating all four of my Minn kotas 101 off this single regulator.? It was a special ss pressure reducing/pressure releasing regulator.? I had it installed on my last Florida dive which I went down about 100 ft .? Unit worked fine.? My first failure was on Flathead lake expedition in which one of my aft thrusters flooded.? After that I switched to oil compensation.? Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small.? I believe he has addressed this by adding a pressure release valve or OP valve.? He can elaborate more on his current strategy. Cliff Sent from my iPhone On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles wrote: ?John,I am happy with both air & oil.?Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines.My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity.I think I need to put out a long video once I've finished thisair compensator.From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with.Alan Sent from Yahoo Mail on Android On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Thu Aug 3 11:45:38 2023 From: personal_submersibles at psubs.org (Bernie Hellstrom via Personal_Submersibles) Date: Thu, 3 Aug 2023 15:45:38 +0000 Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <1858988283.1417015.1691030385651@mail.yahoo.com> References: <1858988283.1417015.1691030385651@mail.yahoo.com> Message-ID: Sent from my iPhone On Aug 2, 2023, at 10:40 PM, Cliff Redus via Personal_Submersibles wrote: ? Let us know what you find. Best On Wednesday, August 2, 2023 at 09:24:18 PM CDT, David Colombo via Personal_Submersibles wrote: Cliff, something I experienced at Charlevoix, was the first stage regulator in the VAST was going into a freeze cycle when dumping air into the ballast tanks when we were getting the ballast corrected with multiple short dive attempts and then back to the surface. It now has me wondering whether the air we got from Bernie moist, or the formation of ice crystals on the outside of the regulator was from the air coming from the hp vs lp port. I need to look at the regulator tonight to think this thru. Best Regards, David Colombo [http://static.squarespace.com/static/533310a9e4b0fba62008a464/t/5339c1f2e4b041bac4e25d1b/1396294132055/?format=500w] 804 College Ave Santa Rosa, CA. 95404 (707) 536-1424 www.SeaQuestor.com On Wed, Aug 2, 2023 at 4:36?PM Cliff Redus via Personal_Submersibles > wrote: Alec, I setup a spreadsheet to analyze the following setup. A scuba tank has a 1st stage regulator attached. A Tescom 44-4069 pressure reducing regulator with venting is attached and tubing is connected from the HP port to a set of Minn-Kota 101 motors. The question is can the small orifice in the HP port pass sufficient air to handle the demand for air in thrusters to keep the pressure a fixed differential pressure above ambient water pressure. The calculation indicates this arrangement will work. If anyone wants a copy of the spreadsheet, please email me your email address and I will send. The calculation indicates the HP port could be used for this. Having said that, yes, this a simple clean setup but so is connecting to a spare LP port. The advantage of the LP port is that pressure rating of the regulator body can be less so less 316 stainless and less cost. Would be good to spec a regulator like the Tescom 44-4069 regulator with its venting capacity but for pressures one would expect from the LP port. Cliff PS: Hope you got your Land Rover back from the shop. On Tuesday, August 1, 2023 at 04:09:41 PM CDT, Alec Smyth via Personal_Submersibles > wrote: Hi Cliff, "The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input port of Tescom 44-4069 regulator." There's a little problem with this plan, though easy to work around. The HP ports on regulators have a tiny orifice, in order to prevent rapid loss of air if a hose or SPG fails. These ports cannot provide the sort of flow you would want. Best, Alec On Tue, Aug 1, 2023 at 12:17?PM Cliff Redus via Personal_Submersibles > wrote: Sean, the specs do look good on this unit. To me the issue is going to be the cost. As background, the Parker regulator that Hugh, Alec and I have used for this application is the 364-02BSS/M1 Parker Watts Pneumatic Regulator. https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator at $217.51. I purchased mine off ebay for a fraction of this. When I had the Parker 364-02BSS/M1 installed for pressure compensating for my four MK 101s, it was connected to the LP port from my AquaLung Titan balanced diaphragm first stage regulator. I had the Parker 364-02BSS/M1 adjusted to give about 2 psi over ambient. I had the first stage set to 50 psi over ambient water pressure. I use this for BIBBS and blowing the MBTs. The Tescom 44-4069 regulator would run directly off the HP air tank pressure then output go directly to thrusters. It would be interesting to compare the Cv's for both regulators to get a feel on how much air flow rate they can provide to the thrusters descending and venting when ascending. The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input port of Tescom 44-4069 regulator. From the output port of the Tescom 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two more "T"s to give four 1/4 SS tubing runs to the thrusters. We need to get a RFQ on one of these regulators. Do you have a preferred supplier? Cliff On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via Personal_Submersibles > wrote: I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. Sean -------- Original Message -------- On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: My original air competition for the R300 used the regulator that Hugh Fulton has on QSub. These are pricey new but you can get them used on eBay. I was operating all four of my Minn kotas 101 off this single regulator. It was a special ss pressure reducing/pressure releasing regulator. I had it installed on my last Florida dive which I went down about 100 ft . Unit worked fine. My first failure was on Flathead lake expedition in which one of my aft thrusters flooded. After that I switched to oil compensation. Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small. I believe he has addressed this by adding a pressure release valve or OP valve. He can elaborate more on his current strategy. Cliff Sent from my iPhone On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles > wrote: ?John, I am happy with both air & oil. Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines. My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity. I think I need to put out a long video once I've finished this air compensator. From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with. Alan Sent from Yahoo Mail on Android On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles > wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Thu Aug 3 13:07:16 2023 From: personal_submersibles at psubs.org (Bernie Hellstrom via Personal_Submersibles) Date: Thu, 3 Aug 2023 17:07:16 +0000 Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: <1858988283.1417015.1691030385651@mail.yahoo.com> Message-ID: Hi David Been following the thread and the first stage regulator will freeze up from the outside moisture. We use environmental kits on our first stages , the rubber boot/bladder, that are filled with vodka ?. (Gray Goose). This keeps the external parts from contact with water. The air I have here is very dry as I have special filters . Last test was -61F. The first stage regs are not intended to have continuous hi rate flows because of the expansion cooling . [image0.jpeg][image1.jpeg][image2.jpeg] Sent from my iPhone On Aug 3, 2023, at 11:46 AM, Bernie Hellstrom via Personal_Submersibles wrote: ? Sent from my iPhone On Aug 2, 2023, at 10:40 PM, Cliff Redus via Personal_Submersibles wrote: ? Let us know what you find. Best On Wednesday, August 2, 2023 at 09:24:18 PM CDT, David Colombo via Personal_Submersibles wrote: Cliff, something I experienced at Charlevoix, was the first stage regulator in the VAST was going into a freeze cycle when dumping air into the ballast tanks when we were getting the ballast corrected with multiple short dive attempts and then back to the surface. It now has me wondering whether the air we got from Bernie moist, or the formation of ice crystals on the outside of the regulator was from the air coming from the hp vs lp port. I need to look at the regulator tonight to think this thru. Best Regards, David Colombo [http://static.squarespace.com/static/533310a9e4b0fba62008a464/t/5339c1f2e4b041bac4e25d1b/1396294132055/?format=500w] 804 College Ave Santa Rosa, CA. 95404 (707) 536-1424 www.SeaQuestor.com On Wed, Aug 2, 2023 at 4:36?PM Cliff Redus via Personal_Submersibles > wrote: Alec, I setup a spreadsheet to analyze the following setup. A scuba tank has a 1st stage regulator attached. A Tescom 44-4069 pressure reducing regulator with venting is attached and tubing is connected from the HP port to a set of Minn-Kota 101 motors. The question is can the small orifice in the HP port pass sufficient air to handle the demand for air in thrusters to keep the pressure a fixed differential pressure above ambient water pressure. The calculation indicates this arrangement will work. If anyone wants a copy of the spreadsheet, please email me your email address and I will send. The calculation indicates the HP port could be used for this. Having said that, yes, this a simple clean setup but so is connecting to a spare LP port. The advantage of the LP port is that pressure rating of the regulator body can be less so less 316 stainless and less cost. Would be good to spec a regulator like the Tescom 44-4069 regulator with its venting capacity but for pressures one would expect from the LP port. Cliff PS: Hope you got your Land Rover back from the shop. On Tuesday, August 1, 2023 at 04:09:41 PM CDT, Alec Smyth via Personal_Submersibles > wrote: Hi Cliff, "The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input port of Tescom 44-4069 regulator." There's a little problem with this plan, though easy to work around. The HP ports on regulators have a tiny orifice, in order to prevent rapid loss of air if a hose or SPG fails. These ports cannot provide the sort of flow you would want. Best, Alec On Tue, Aug 1, 2023 at 12:17?PM Cliff Redus via Personal_Submersibles > wrote: Sean, the specs do look good on this unit. To me the issue is going to be the cost. As background, the Parker regulator that Hugh, Alec and I have used for this application is the 364-02BSS/M1 Parker Watts Pneumatic Regulator. https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator at $217.51. I purchased mine off ebay for a fraction of this. When I had the Parker 364-02BSS/M1 installed for pressure compensating for my four MK 101s, it was connected to the LP port from my AquaLung Titan balanced diaphragm first stage regulator. I had the Parker 364-02BSS/M1 adjusted to give about 2 psi over ambient. I had the first stage set to 50 psi over ambient water pressure. I use this for BIBBS and blowing the MBTs. The Tescom 44-4069 regulator would run directly off the HP air tank pressure then output go directly to thrusters. It would be interesting to compare the Cv's for both regulators to get a feel on how much air flow rate they can provide to the thrusters descending and venting when ascending. The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input port of Tescom 44-4069 regulator. From the output port of the Tescom 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two more "T"s to give four 1/4 SS tubing runs to the thrusters. We need to get a RFQ on one of these regulators. Do you have a preferred supplier? Cliff On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via Personal_Submersibles > wrote: I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. Sean -------- Original Message -------- On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: My original air competition for the R300 used the regulator that Hugh Fulton has on QSub. These are pricey new but you can get them used on eBay. I was operating all four of my Minn kotas 101 off this single regulator. It was a special ss pressure reducing/pressure releasing regulator. I had it installed on my last Florida dive which I went down about 100 ft . Unit worked fine. My first failure was on Flathead lake expedition in which one of my aft thrusters flooded. After that I switched to oil compensation. Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small. I believe he has addressed this by adding a pressure release valve or OP valve. He can elaborate more on his current strategy. Cliff Sent from my iPhone On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles > wrote: ?John, I am happy with both air & oil. Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines. My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity. I think I need to put out a long video once I've finished this air compensator. From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with. Alan Sent from Yahoo Mail on Android On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles > wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: image0.jpeg Type: image/jpeg Size: 65032 bytes Desc: image0.jpeg URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: image1.jpeg Type: image/jpeg Size: 72845 bytes Desc: image1.jpeg URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: image2.jpeg Type: image/jpeg Size: 58695 bytes Desc: image2.jpeg URL: From personal_submersibles at psubs.org Thu Aug 3 15:22:03 2023 From: personal_submersibles at psubs.org (vbra676539@aol.com via Personal_Submersibles) Date: Thu, 3 Aug 2023 19:22:03 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: <07A09AFA-47F3-4BBA-BDDF-C473219344B3@gmail.com> Message-ID: <538663494.957767.1691090523553@mail.yahoo.com> Thanks Dave. I guess that means my stack of 101 lower units will hold their value around here.Vance On Wednesday, August 2, 2023, 10:13:57 PM EDT, David Colombo via Personal_Submersibles wrote: Hi Guys, I've been following this thread on air compensation with great interest. So today I reached out to my Minn Kota contact to inquire about the new brushless 120# thrusters and if lower units could be purchased. The new units will not be available to the public most likely till March of next year and no parts will be available for at least the first 6 months after, as all warranty work and repairs will be going back to the factory to qc this product. The projected cost on the lower unit is expected to be in the $800 to $1000 range, (fully outfitted? bow unit, around $3600). Not too bad as my cost for my 101 lower units was right around $575 , six years ago. Here is the bad news. The only unit being released is the Bow mount unit which requires all of the hummingbird technology to operate, with the built in speed controller, foot control and the BMS system, all of which is proprietary.? From what I understand there is no way to run the brushless motor without the technology, so essentially useless as a sub motor and not able to be disabled and not able to be rebuilt.? The other bad news is the 101 series is also being discontinued in favor of new bluetooth technology and the reliance entirely on a closed loop proprietary software system being sold as what fishermen really want and need to be able to fish. Even the built in transducer in the lower unit will only work with Hummingbird, or will work with say Garmin but only a very limited basic sidescan and none of the 3d scanning , panoptics , etc. The new brushless unit at 24v = 96# thrust, and the 36v=115# thrust. Not actually much better than the 101's.? Good thing I currently have six of them in my shop. Once I get my test pool assembled for the VAST, after I complete the outfitting, I will test my 36v 101's with an air compensation system, all? I need are the extra regulator and op valves.? ? ? ? Best Regards, David Colombo 804 College Ave Santa Rosa, CA. 95404 (707) 536-1424 www.SeaQuestor.com On Wed, Aug 2, 2023 at 6:23?PM Cliff Redus via Personal_Submersibles wrote: After a successful Inner-space Science Expedition at Beaver Island this year I know it feels good to recover Shackleton and be on the way home. Cliff Sent from my iPhone On Aug 2, 2023, at 7:21 PM, Alec Smyth via Personal_Submersibles wrote: ?Guess where this finds me? We picked up Shackleton from Bernie?s a couple of hours ago and are homeward bound. Bernie as always super helpful.? Sent from my iPhone On Aug 2, 2023, at 7:36 PM, Cliff Redus via Personal_Submersibles wrote: ? Alec, I setup a spreadsheet to analyze the following setup. ?A scuba tank has a 1st stage regulator attached.? A Tescom 44-4069 pressure reducing regulatorwith venting is attached and tubing is connected from the HP port to a set ofMinn-Kota 101 motors.? The question iscan the small orifice in the HP port pass sufficient air to handle the demandfor air in thrusters to keep the pressure a fixed differential pressure aboveambient water pressure. The calculation indicates this arrangement will work.? If anyone wants a copy of the spreadsheet,please email me your email address and I will send. The calculation indicates the HP port could be used forthis.? Having said that, yes, this asimple clean setup but so is connecting to a spare LP port.? The advantage of the LP port is that pressurerating of the regulator body can be less so less 316 stainless and less cost.? Would be good to spec a regulator like theTescom 44-4069 regulator with its venting capacity but for pressures one would expect from the LP port. Cliff PS: Hope you got your Land Rover back from the shop. On Tuesday, August 1, 2023 at 04:09:41 PM CDT, Alec Smyth via Personal_Submersibles wrote: Hi Cliff, "The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator." There's a little problem with this plan, though easy to work around.?The HP ports on regulators have a tiny orifice, in order to prevent rapid loss of air if a hose or SPG fails. These ports cannot provide the sort of flow you would want.? Best,Alec On Tue, Aug 1, 2023 at 12:17?PM Cliff Redus via Personal_Submersibles wrote: Sean, the specs do look good on this unit.? To me the issue is going to be the cost.? As background, the Parker regulator that Hugh, Alec and I have used for this application is the?364-02BSS/M1 Parker Watts Pneumatic Regulator. https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator?at $217.51.? I purchased mine off ebay for a fraction of this. When I had the Parker?364-02BSS/M1 installed for pressure compensating for my four MK 101s, it was connected to the LP port from my AquaLung Titan balanced diaphragm first stage regulator. I had the?Parker?364-02BSS/M1 adjusted?to give about 2 psi over ambient.? I had the first stage set to 50 psi over ambient water pressure.? I use this for BIBBS and blowing the MBTs.? The?Tescom 44-4069 regulator would run directly off the HP air tank pressure then output go directly?to thrusters.? It would be interesting to compare the Cv's for both regulators to get a feel on how much air flow rate they can provide to the thrusters?descending?and venting when ascending.?? The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input?port of?Tescom 44-4069 regulator.? From the output port?of the Tescom 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two more "T"s to give four 1/4 SS tubing runs to the thrusters. We need to get a RFQ on one of these regulators.? Do you have a preferred supplier? Cliff On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for. Sean -------- Original Message -------- On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: My original air competition for the R300 used the regulator that Hugh Fulton has on QSub.? These are pricey new but you can get them used on eBay.? I was operating all four of my Minn kotas 101 off this single regulator.? It was a special ss pressure reducing/pressure releasing regulator.? I had it installed on my last Florida dive which I went down about 100 ft .? Unit worked fine.? My first failure was on Flathead lake expedition in which one of my aft thrusters flooded.? After that I switched to oil compensation.? Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small.? I believe he has addressed this by adding a pressure release valve or OP valve.? He can elaborate more on his current strategy. Cliff Sent from my iPhone On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles wrote: ?John,I am happy with both air & oil.?Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines.My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity.I think I need to put out a long video once I've finished thisair compensator.From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with.Alan Sent from Yahoo Mail on Android On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Thu Aug 3 15:26:08 2023 From: personal_submersibles at psubs.org (Alan James via Personal_Submersibles) Date: Thu, 3 Aug 2023 19:26:08 +0000 (UTC) Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: <07A09AFA-47F3-4BBA-BDDF-C473219344B3@gmail.com> Message-ID: <1122386630.1777445.1691090768819@mail.yahoo.com> Thanks David,that looks a good price.Cliff and I were looking at the Caroute brushless motor lower unit, 36V 160lb thrust. Cost US $1200 to get to Texas.The big problem was that they had the motor driver in the thruster housing and this had 2 large capacitors in it.These would crush if we equalised the inside of the thruster.Also you can have long leads from the motor controller to the motor but if you have long leads from the battery to the motor controller it is problematic. So by putting the controller in the thruster they are making the battery leads longer.They are bringing out a model with an external motor controller next year.With regard to the brushless Minn Kotta; most brushless motors have 3 wires coming from them, unless they have a hall sensor board or temperature sensor. These can be controlled with a Vesc motor controller & tuned in it's open source program.?Alan Sent from Yahoo Mail on Android On Thu, 3 Aug 2023 at 2:15 pm, David Colombo via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Thu Aug 3 17:27:54 2023 From: personal_submersibles at psubs.org (David Colombo via Personal_Submersibles) Date: Thu, 3 Aug 2023 14:27:54 -0700 Subject: [PSUBS-MAILIST] air compensation In-Reply-To: <1122386630.1777445.1691090768819@mail.yahoo.com> References: <07A09AFA-47F3-4BBA-BDDF-C473219344B3@gmail.com> <1122386630.1777445.1691090768819@mail.yahoo.com> Message-ID: Bernie, so the moisture in the sub where my regulator is located may have been cooling the high humidity moisture in the sub. I hadn't thought of that. Would the cooling effect be the same on both the HP and LP ports. I am considering adding two HP air tanks externally within the lower aft clam shell of the VAST. Being exposed to the water, so the cooling effect would be mitigated by the water mass would eliminate a possible freeze condition? or do I need to add vodka? Best Regards, David Colombo 804 College Ave Santa Rosa, CA. 95404 (707) 536-1424 www.SeaQuestor.com On Thu, Aug 3, 2023 at 12:26?PM Alan James via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Thanks David, > that looks a good price. > Cliff and I were looking at the Caroute brushless motor lower unit, 36V > 160lb thrust. Cost US $1200 to get to Texas. > The big problem was that they had the motor driver in the thruster housing > and this had 2 large capacitors in it. > These would crush if we equalised the inside of the thruster. > Also you can have long leads from the motor controller to the motor but if > you have long leads from the battery to the motor controller it is > problematic. So by putting the controller in the thruster they are making > the battery leads longer. > They are bringing out a model with an external motor controller next year. > With regard to the brushless Minn Kotta; most brushless motors have 3 > wires coming from them, unless they have a hall sensor board or temperature > sensor. These can be controlled with a Vesc motor controller & tuned in > it's open source program. > Alan > > > > Sent from Yahoo Mail on Android > > > On Thu, 3 Aug 2023 at 2:15 pm, David Colombo via Personal_Submersibles > wrote: > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Thu Aug 3 18:13:07 2023 From: personal_submersibles at psubs.org (Bernie Hellstrom via Personal_Submersibles) Date: Thu, 3 Aug 2023 22:13:07 +0000 Subject: [PSUBS-MAILIST] air compensation In-Reply-To: References: <07A09AFA-47F3-4BBA-BDDF-C473219344B3@gmail.com> <1122386630.1777445.1691090768819@mail.yahoo.com> Message-ID: David Yes inside or outside in the water it can freeze too. Environmental kits take this out of the equation. Sent from my iPhone On Aug 3, 2023, at 5:29 PM, David Colombo via Personal_Submersibles wrote: ? Bernie, so the moisture in the sub where my regulator is located may have been cooling the high humidity moisture in the sub. I hadn't thought of that. Would the cooling effect be the same on both the HP and LP ports. I am considering adding two HP air tanks externally within the lower aft clam shell of the VAST. Being exposed to the water, so the cooling effect would be mitigated by the water mass would eliminate a possible freeze condition? or do I need to add vodka? Best Regards, David Colombo [http://static.squarespace.com/static/533310a9e4b0fba62008a464/t/5339c1f2e4b041bac4e25d1b/1396294132055/?format=500w] 804 College Ave Santa Rosa, CA. 95404 (707) 536-1424 www.SeaQuestor.com On Thu, Aug 3, 2023 at 12:26?PM Alan James via Personal_Submersibles > wrote: Thanks David, that looks a good price. Cliff and I were looking at the Caroute brushless motor lower unit, 36V 160lb thrust. Cost US $1200 to get to Texas. The big problem was that they had the motor driver in the thruster housing and this had 2 large capacitors in it. These would crush if we equalised the inside of the thruster. Also you can have long leads from the motor controller to the motor but if you have long leads from the battery to the motor controller it is problematic. So by putting the controller in the thruster they are making the battery leads longer. They are bringing out a model with an external motor controller next year. With regard to the brushless Minn Kotta; most brushless motors have 3 wires coming from them, unless they have a hall sensor board or temperature sensor. These can be controlled with a Vesc motor controller & tuned in it's open source program. Alan Sent from Yahoo Mail on Android On Thu, 3 Aug 2023 at 2:15 pm, David Colombo via Personal_Submersibles > wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Thu Aug 3 21:17:35 2023 From: personal_submersibles at psubs.org (David Colombo via Personal_Submersibles) Date: Thu, 3 Aug 2023 18:17:35 -0700 Subject: [PSUBS-MAILIST] Minn-Kota 101 WD-40 Thruster Teardown In-Reply-To: <1143463933.6869721.1690604886643@mail.yahoo.com> References: <1143463933.6869721.1690604886643.ref@mail.yahoo.com> <1143463933.6869721.1690604886643@mail.yahoo.com> Message-ID: Jon, Looking at those pictures, I think I'm definitely sticking with air compensation. Best Regards, David Colombo 804 College Ave Santa Rosa, CA. 95404 (707) 536-1424 www.SeaQuestor.com On Fri, Jul 28, 2023 at 9:28?PM Jon Wallace via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > > I have added photos of the MK-101 teardown on the website. Use the > following link: > > http://www.psubs.org/projects/1234567801/mk-101oilcompteardown/ > > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Thu Aug 3 22:38:36 2023 From: personal_submersibles at psubs.org (Jon Wallace via Personal_Submersibles) Date: Fri, 4 Aug 2023 02:38:36 +0000 (UTC) Subject: [PSUBS-MAILIST] Minn-Kota 101 WD-40 Thruster Teardown In-Reply-To: References: <1143463933.6869721.1690604886643.ref@mail.yahoo.com> <1143463933.6869721.1690604886643@mail.yahoo.com> Message-ID: <993628908.1946093.1691116716847@mail.yahoo.com> I may end up there as well David, but I'm just stubborn enough to keep experimenting with oil.? I'd be interested to see the results of plain old mineral oil.? I know there might be a power hit from the higher viscosity but maybe that tradeoff is acceptable if the brushes don't disintegrate. Jon On Thursday, August 3, 2023 at 09:19:28 PM EDT, David Colombo via Personal_Submersibles wrote: Jon, Looking at those pictures, I think I'm definitely sticking with air compensation. Best Regards, David Colombo -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Fri Aug 4 09:43:10 2023 From: personal_submersibles at psubs.org (Tim Novak via Personal_Submersibles) Date: Fri, 4 Aug 2023 06:43:10 -0700 Subject: [PSUBS-MAILIST] Minn-Kota 101 WD-40 Thruster Teardown In-Reply-To: <1143463933.6869721.1690604886643@mail.yahoo.com> References: <1143463933.6869721.1690604886643.ref@mail.yahoo.com> <1143463933.6869721.1690604886643@mail.yahoo.com> Message-ID: Hi Jon, How many operating hours were on these motors prior to teardown? Were they used primarily in salt or fresh water? Tim On Fri, Jul 28, 2023 at 9:28?PM Jon Wallace via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > > I have added photos of the MK-101 teardown on the website. Use the > following link: > > http://www.psubs.org/projects/1234567801/mk-101oilcompteardown/ > > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Fri Aug 4 09:52:53 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Fri, 4 Aug 2023 13:52:53 +0000 (UTC) Subject: [PSUBS-MAILIST] Minn-Kota 101 WD-40 Thruster Teardown In-Reply-To: References: <1143463933.6869721.1690604886643.ref@mail.yahoo.com> <1143463933.6869721.1690604886643@mail.yahoo.com> Message-ID: <313944139.2077501.1691157173494@mail.yahoo.com> Tim, these pictures are from the R300 port stern thruster taken during the IS Beaver Island Expedition after the thruster quit working after a two-mile submerged transect.? It had been about 2 years since they were torn down but only an estimated 18-20 operating hour on the unit.? The thruster was hydraulically pressure compensated withe WD-40 and did spend 99% of their life sitting in my shop in Texas exposed to some high temperatures during the summers.? They were used only in Fresh Water, primarily at the Lake Charlevoix Psub event and the recent Beaver Island IS Event. Cliff On Friday, August 4, 2023 at 08:44:11 AM CDT, Tim Novak via Personal_Submersibles wrote: Hi Jon,? How many operating hours were on these motors prior to teardown? Were they used primarily in salt or fresh water? Tim On Fri, Jul 28, 2023 at 9:28?PM Jon Wallace via Personal_Submersibles wrote: I have added photos of the MK-101 teardown on the website.? Use the following link: http://www.psubs.org/projects/1234567801/mk-101oilcompteardown/ _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Fri Aug 4 09:55:08 2023 From: personal_submersibles at psubs.org (Tim Novak via Personal_Submersibles) Date: Fri, 4 Aug 2023 06:55:08 -0700 Subject: [PSUBS-MAILIST] Minn-Kota 101 WD-40 Thruster Teardown In-Reply-To: <313944139.2077501.1691157173494@mail.yahoo.com> References: <1143463933.6869721.1690604886643.ref@mail.yahoo.com> <1143463933.6869721.1690604886643@mail.yahoo.com> <313944139.2077501.1691157173494@mail.yahoo.com> Message-ID: Thanks, Cliff. On Fri, Aug 4, 2023 at 6:53?AM Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Tim, these pictures are from the R300 port stern thruster taken during the > IS Beaver Island Expedition after the thruster quit working after a > two-mile submerged transect. It had been about 2 years since they were > torn down but only an estimated 18-20 operating hour on the unit. The > thruster was hydraulically pressure compensated withe WD-40 and did spend > 99% of their life sitting in my shop in Texas exposed to some high > temperatures during the summers. They were used only in Fresh Water, > primarily at the Lake Charlevoix Psub event and the recent Beaver Island IS > Event. > > Cliff > > On Friday, August 4, 2023 at 08:44:11 AM CDT, Tim Novak via > Personal_Submersibles wrote: > > > Hi Jon, > > How many operating hours were on these motors prior to teardown? Were they > used primarily in salt or fresh water? > > Tim > > On Fri, Jul 28, 2023 at 9:28?PM Jon Wallace via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > > I have added photos of the MK-101 teardown on the website. Use the > following link: > > http://www.psubs.org/projects/1234567801/mk-101oilcompteardown/ > > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sat Aug 5 13:08:10 2023 From: personal_submersibles at psubs.org (Raphael SOULIAC via Personal_Submersibles) Date: Sat, 5 Aug 2023 19:08:10 +0200 Subject: [PSUBS-MAILIST] k250 size Message-ID: Hello, quick question for the k-250 owners/builders. What are the dimensions ( specially the length) of the pressure hull ? Thanks Raphael -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sun Aug 6 17:17:25 2023 From: personal_submersibles at psubs.org (via Personal_Submersibles) Date: Sun, 6 Aug 2023 23:17:25 +0200 Subject: [PSUBS-MAILIST] K250/350 qustion Message-ID: <041801d9c8ab$65c7dc60$31579520$@airesearch.nl> Hi, Can someone provide a sketch of the K350 hardtank piping? Wonder how the venting is done. Thanks in advance Best regards, Emile D.L. van Essen -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Mon Aug 7 11:16:32 2023 From: personal_submersibles at psubs.org (Daniel Lance via Personal_Submersibles) Date: Mon, 7 Aug 2023 11:16:32 -0400 Subject: [PSUBS-MAILIST] k250 size In-Reply-To: References: Message-ID: Rapheal , The cylinder section of the K250 hull is 48" long ( approx. 121.92cm) X 36" (91.44cm) in diameter .Each elliptical head is approximately 14" (35.56cm) deep X 2pcs . For a total pressure hull length of approximately 76" (193.04cm). Dan Lance On Sat, Aug 5, 2023 at 1:08?PM Raphael SOULIAC via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Hello, quick question for the k-250 owners/builders. What are the > dimensions ( specially the length) of the pressure hull ? Thanks > > Raphael > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Mon Aug 7 11:41:06 2023 From: personal_submersibles at psubs.org (Raphael SOULIAC via Personal_Submersibles) Date: Mon, 7 Aug 2023 17:41:06 +0200 Subject: [PSUBS-MAILIST] k250 size In-Reply-To: References: Message-ID: Nice , thank you Daniel. Raphael Le lun. 7 ao?t 2023 ? 17:17, Daniel Lance via Personal_Submersibles < personal_submersibles at psubs.org> a ?crit : > Rapheal , > The cylinder section of the K250 hull is 48" long ( approx. 121.92cm) X > 36" (91.44cm) in diameter .Each elliptical head is approximately 14" > (35.56cm) deep X 2pcs . For a total pressure hull length of > approximately 76" (193.04cm). > Dan Lance > > On Sat, Aug 5, 2023 at 1:08?PM Raphael SOULIAC via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > >> Hello, quick question for the k-250 owners/builders. What are the >> dimensions ( specially the length) of the pressure hull ? Thanks >> >> Raphael >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >> > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Mon Aug 7 12:01:15 2023 From: personal_submersibles at psubs.org (Sean T. Stevenson via Personal_Submersibles) Date: Mon, 07 Aug 2023 16:01:15 +0000 Subject: [PSUBS-MAILIST] k250 size In-Reply-To: References: Message-ID: On a 36" ID cylinder, a mating 2:1 semi-elliptical head would be 9" from the inside center of the head along the major axis to the plane at the curvature break at the end of the cylinder. If you're measuring (or if the plans show) a 14" depth of head, that would seem to indicate either that the head is of a non-standard elliptical form, or is torispherical (not elliptical), or is simply manufactured with a substantially longer (5") length of straight flange than is specified by the rules. I am curious to know which? Sean -------- Original Message -------- On Aug. 7, 2023, 09:16, Daniel Lance via Personal_Submersibles wrote: > Rapheal , > The cylinder section of the K250 hull is 48" long ( approx. 121.92cm) X 36" (91.44cm) in diameter .Each elliptical head is approximately 14" (35.56cm) deep X 2pcs . For a total pressure hull length of approximately 76" (193.04cm). > Dan Lance > > On Sat, Aug 5, 2023 at 1:08?PM Raphael SOULIAC via Personal_Submersibles wrote: > >> Hello, quick question for the k-250 owners/builders. What are the dimensions ( specially the length) of the pressure hull ? Thanks >> >> Raphael >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Mon Aug 7 12:34:00 2023 From: personal_submersibles at psubs.org (Jon Wallace via Personal_Submersibles) Date: Mon, 7 Aug 2023 16:34:00 +0000 (UTC) Subject: [PSUBS-MAILIST] k250 size In-Reply-To: References: Message-ID: <589435526.982403.1691426040928@mail.yahoo.com> All Kittredge subs use 2:1 semi-elliptical.? The length of the straight flange would be the only variation and the plans do not specify that dimension. Jon On Monday, August 7, 2023 at 12:03:40 PM EDT, Sean T. Stevenson via Personal_Submersibles wrote: On a 36" ID cylinder, a mating 2:1 semi-elliptical head would be 9" from the inside center of the head along the major axis to the plane at the curvature break at the end of the cylinder. If you're measuring (or if the plans show) a 14" depth of head, that would seem to indicate either that the head is of a non-standard elliptical form, or is torispherical (not elliptical), or is simply manufactured with a substantially longer (5") length of straight flange than is specified by the rules. I am curious to know which? Sean -------- Original Message -------- On Aug. 7, 2023, 09:16, Daniel Lance via Personal_Submersibles < personal_submersibles at psubs.org> wrote: Rapheal ,The cylinder section of the K250 hull is 48" long ( approx. 121.92cm) X 36" (91.44cm) in diameter .Each elliptical head is approximately 14" (35.56cm) deep? X? 2pcs? . For a total pressure hull length of approximately 76" (193.04cm).Dan Lance On Sat, Aug 5, 2023 at 1:08?PM Raphael SOULIAC via Personal_Submersibles wrote: Hello, quick question for the k-250 owners/builders. What are the dimensions ( specially the length) of the pressure hull ? Thanks Raphael_______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Mon Aug 7 12:39:25 2023 From: personal_submersibles at psubs.org (Daniel Lance via Personal_Submersibles) Date: Mon, 7 Aug 2023 12:39:25 -0400 Subject: [PSUBS-MAILIST] k250 size In-Reply-To: References: Message-ID: Sean , You're correct . A 36" diameter 2 to 1 elliptical head is 9 inches (22.86cm)deep. I made the mistake of referring to the K250 drawing . I should know better ...both the K250 and K350 drawings are full of mistakes and inaccuracies. I did what I should have done in the first place....I went out and measured a head on my K350....9 inches ! Imagine that ! So that revises down the overall length of a K250 hull to 66inches (167.64cm). Dan On Mon, Aug 7, 2023, 12:02 PM Sean T. Stevenson via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > On a 36" ID cylinder, a mating 2:1 semi-elliptical head would be 9" from > the inside center of the head along the major axis to the plane at the > curvature break at the end of the cylinder. If you're measuring (or if the > plans show) a 14" depth of head, that would seem to indicate either that > the head is of a non-standard elliptical form, or is torispherical (not > elliptical), or is simply manufactured with a substantially longer (5") > length of straight flange than is specified by the rules. > > I am curious to know which? > > Sean > > > > -------- Original Message -------- > On Aug. 7, 2023, 09:16, Daniel Lance via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > > Rapheal , > The cylinder section of the K250 hull is 48" long ( approx. 121.92cm) X > 36" (91.44cm) in diameter .Each elliptical head is approximately 14" > (35.56cm) deep X 2pcs . For a total pressure hull length of > approximately 76" (193.04cm). > Dan Lance > > On Sat, Aug 5, 2023 at 1:08?PM Raphael SOULIAC via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > >> Hello, quick question for the k-250 owners/builders. What are the >> dimensions ( specially the length) of the pressure hull ? Thanks >> >> Raphael >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >> > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Mon Aug 7 12:42:47 2023 From: personal_submersibles at psubs.org (Daniel Lance via Personal_Submersibles) Date: Mon, 7 Aug 2023 12:42:47 -0400 Subject: [PSUBS-MAILIST] k250 size In-Reply-To: References: Message-ID: Just so it's clear....66 inches (167.64cm) is the length of just the pressure hull . On Mon, Aug 7, 2023, 12:39 PM Daniel Lance wrote: > Sean , > You're correct . A 36" diameter 2 to 1 elliptical head is 9 inches > (22.86cm)deep. I made the mistake of referring to the K250 drawing . I > should know better ...both the K250 and K350 drawings are full of mistakes > and inaccuracies. I did what I should have done in the first place....I > went out and measured a head on my K350....9 inches ! Imagine that ! > So that revises down the overall length of a K250 hull to 66inches > (167.64cm). > Dan > On Mon, Aug 7, 2023, 12:02 PM Sean T. Stevenson via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > >> On a 36" ID cylinder, a mating 2:1 semi-elliptical head would be 9" from >> the inside center of the head along the major axis to the plane at the >> curvature break at the end of the cylinder. If you're measuring (or if the >> plans show) a 14" depth of head, that would seem to indicate either that >> the head is of a non-standard elliptical form, or is torispherical (not >> elliptical), or is simply manufactured with a substantially longer (5") >> length of straight flange than is specified by the rules. >> >> I am curious to know which? >> >> Sean >> >> >> >> -------- Original Message -------- >> On Aug. 7, 2023, 09:16, Daniel Lance via Personal_Submersibles < >> personal_submersibles at psubs.org> wrote: >> >> >> Rapheal , >> The cylinder section of the K250 hull is 48" long ( approx. 121.92cm) X >> 36" (91.44cm) in diameter .Each elliptical head is approximately 14" >> (35.56cm) deep X 2pcs . For a total pressure hull length of >> approximately 76" (193.04cm). >> Dan Lance >> >> On Sat, Aug 5, 2023 at 1:08?PM Raphael SOULIAC via Personal_Submersibles < >> personal_submersibles at psubs.org> wrote: >> >>> Hello, quick question for the k-250 owners/builders. What are the >>> dimensions ( specially the length) of the pressure hull ? Thanks >>> >>> Raphael >>> _______________________________________________ >>> Personal_Submersibles mailing list >>> Personal_Submersibles at psubs.org >>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >>> >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >> >> -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 8 09:47:00 2023 From: personal_submersibles at psubs.org (James Frankland via Personal_Submersibles) Date: Tue, 8 Aug 2023 14:47:00 +0100 Subject: [PSUBS-MAILIST] K250/350 qustion In-Reply-To: <041801d9c8ab$65c7dc60$31579520$@airesearch.nl> References: <041801d9c8ab$65c7dc60$31579520$@airesearch.nl> Message-ID: Hi Emile. Here you are. More or less. Shown without the bends around the hull. The vent acts as both vent and high pressure inlet. PS: I am meeting up with Antoine tonight. He is here in Guernsey. Regards James [image: image.png] On Sun, 6 Aug 2023 at 22:16, via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Hi, > > > > Can someone provide a sketch of the K350 hardtank piping? Wonder how the > venting is done. > > Thanks in advance > > > > Best regards, > > > > Emile D.L. van Essen > > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: image.png Type: image/png Size: 221422 bytes Desc: not available URL: From personal_submersibles at psubs.org Tue Aug 8 15:20:31 2023 From: personal_submersibles at psubs.org (via Personal_Submersibles) Date: Tue, 8 Aug 2023 21:20:31 +0200 Subject: [PSUBS-MAILIST] K250/350 qustion In-Reply-To: References: <041801d9c8ab$65c7dc60$31579520$@airesearch.nl> Message-ID: <04e401d9ca2d$65c0bf10$31423d30$@airesearch.nl> Thanks James! Was wondering how the venting was done. Please give greetings to Antoine (for the others: the guy from the human powered pilotfish project) BR, Emile Van: Personal_Submersibles Namens James Frankland via Personal_Submersibles Verzonden: dinsdag 8 augustus 2023 15:47 Aan: Personal Submersibles General Discussion Onderwerp: Re: [PSUBS-MAILIST] K250/350 qustion Hi Emile. Here you are. More or less. Shown without the bends around the hull. The vent acts as both vent and high pressure inlet. PS: I am meeting up with Antoine tonight. He is here in Guernsey. Regards James On Sun, 6 Aug 2023 at 22:16, via Personal_Submersibles > wrote: Hi, Can someone provide a sketch of the K350 hardtank piping? Wonder how the venting is done. Thanks in advance Best regards, Emile D.L. van Essen _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: image001.png Type: image/png Size: 221422 bytes Desc: not available URL: From personal_submersibles at psubs.org Wed Aug 9 04:16:54 2023 From: personal_submersibles at psubs.org (Antoine Delafargue via Personal_Submersibles) Date: Wed, 9 Aug 2023 09:16:54 +0100 Subject: [PSUBS-MAILIST] K250/350 qustion In-Reply-To: <04e401d9ca2d$65c0bf10$31423d30$@airesearch.nl> References: <041801d9c8ab$65c7dc60$31579520$@airesearch.nl> <04e401d9ca2d$65c0bf10$31423d30$@airesearch.nl> Message-ID: Hi Emile Thanks, it was great to meet James at last and have a look at his beautiful k350! Guernsey really is not far. Cheers Antoine Le mar. 8 ao?t 2023 ? 20:19, via Personal_Submersibles < personal_submersibles at psubs.org> a ?crit : > Thanks James! > > > > Was wondering how the venting was done. > > > > Please give greetings to Antoine (for the others: the guy from the human > powered pilotfish project) > > > > BR, Emile > > > > *Van:* Personal_Submersibles *Namens > *James Frankland via Personal_Submersibles > *Verzonden:* dinsdag 8 augustus 2023 15:47 > *Aan:* Personal Submersibles General Discussion < > personal_submersibles at psubs.org> > *Onderwerp:* Re: [PSUBS-MAILIST] K250/350 qustion > > > > Hi Emile. Here you are. More or less. Shown without the bends around the > hull. > > > > The vent acts as both vent and high pressure inlet. > > > > PS: I am meeting up with Antoine tonight. He is here in Guernsey. > > > Regards > > James > > > > > > On Sun, 6 Aug 2023 at 22:16, via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > Hi, > > > > Can someone provide a sketch of the K350 hardtank piping? Wonder how the > venting is done. > > Thanks in advance > > > > Best regards, > > > > Emile D.L. van Essen > > > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: image001.png Type: image/png Size: 221422 bytes Desc: not available URL: From personal_submersibles at psubs.org Fri Aug 11 16:41:03 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Fri, 11 Aug 2023 13:41:03 -0700 Subject: [PSUBS-MAILIST] Air comp References: <55323B80-52D2-41AF-89CF-A6B73D32BE82.ref@yahoo.ca> Message-ID: <55323B80-52D2-41AF-89CF-A6B73D32BE82@yahoo.ca> Hi all just did 400 feet for one hr and no water intrusion in motors. Decent rate was 5 min for 400 feet and 4 motors on one reg and one OP valve. Also 4 to 5 min to surface Hank Sent from my iPhone From personal_submersibles at psubs.org Fri Aug 11 17:33:00 2023 From: personal_submersibles at psubs.org (Alan James via Personal_Submersibles) Date: Fri, 11 Aug 2023 21:33:00 +0000 (UTC) Subject: [PSUBS-MAILIST] Air comp In-Reply-To: <55323B80-52D2-41AF-89CF-A6B73D32BE82@yahoo.ca> References: <55323B80-52D2-41AF-89CF-A6B73D32BE82.ref@yahoo.ca> <55323B80-52D2-41AF-89CF-A6B73D32BE82@yahoo.ca> Message-ID: <1514779292.3425674.1691789580198@mail.yahoo.com> Hank, well done.What pressure did you set the regulator & the over-pressure valve at.?Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 8:52 am, hank pronk via Personal_Submersibles wrote: Hi all just did 400 feet for one hr and no water intrusion in motors.? Decent rate was 5 min for 400 feet and 4 motors on one reg and one OP valve.? Also 4 to 5 min to surface Hank Sent from my iPhone _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Fri Aug 11 18:20:38 2023 From: personal_submersibles at psubs.org (Alec Smyth via Personal_Submersibles) Date: Fri, 11 Aug 2023 18:20:38 -0400 Subject: [PSUBS-MAILIST] Air comp In-Reply-To: <1514779292.3425674.1691789580198@mail.yahoo.com> References: <55323B80-52D2-41AF-89CF-A6B73D32BE82.ref@yahoo.ca> <55323B80-52D2-41AF-89CF-A6B73D32BE82@yahoo.ca> <1514779292.3425674.1691789580198@mail.yahoo.com> Message-ID: Outstanding, Hank! That's serious depths, but you certainly have the hull for ultimate peace of mind. Best, Alec On Fri, Aug 11, 2023 at 5:33?PM Alan James via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Hank, well done. > What pressure did you set the regulator & the over-pressure valve at. > Alan > > Sent from Yahoo Mail on Android > > > On Sat, 12 Aug 2023 at 8:52 am, hank pronk via Personal_Submersibles > wrote: > > Hi all just did 400 feet for one hr and no water intrusion in motors. > Decent rate was 5 min for 400 feet and 4 motors on one reg and one OP > valve. Also 4 to 5 min to surface > Hank > Sent from my iPhone > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Fri Aug 11 21:39:19 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Sat, 12 Aug 2023 01:39:19 +0000 (UTC) Subject: [PSUBS-MAILIST] Air comp In-Reply-To: References: <55323B80-52D2-41AF-89CF-A6B73D32BE82.ref@yahoo.ca> <55323B80-52D2-41AF-89CF-A6B73D32BE82@yahoo.ca> <1514779292.3425674.1691789580198@mail.yahoo.com> Message-ID: <844873419.3488839.1691804359477@mail.yahoo.com> ?Alec, yes, my concern was sure not with the DW hulls. ?It was really a test for my high amp penetrators etc.Hank On Friday, August 11, 2023, 04:21:05 PM MDT, Alec Smyth via Personal_Submersibles wrote: Outstanding, Hank! That's serious depths, but you certainly have the hull for ultimate peace of mind.? Best,Alec On Fri, Aug 11, 2023 at 5:33?PM Alan James via Personal_Submersibles wrote: Hank, well done.What pressure did you set the regulator & the over-pressure valve at.?Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 8:52 am, hank pronk via Personal_Submersibles wrote: Hi all just did 400 feet for one hr and no water intrusion in motors.? Decent rate was 5 min for 400 feet and 4 motors on one reg and one OP valve.? Also 4 to 5 min to surface Hank Sent from my iPhone _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Fri Aug 11 21:39:58 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Sat, 12 Aug 2023 01:39:58 +0000 (UTC) Subject: [PSUBS-MAILIST] Air comp In-Reply-To: <1514779292.3425674.1691789580198@mail.yahoo.com> References: <55323B80-52D2-41AF-89CF-A6B73D32BE82.ref@yahoo.ca> <55323B80-52D2-41AF-89CF-A6B73D32BE82@yahoo.ca> <1514779292.3425674.1691789580198@mail.yahoo.com> Message-ID: <876106235.3480608.1691804398964@mail.yahoo.com> Alan,?I would guess 2 psi over, but again thats a guess.Hank On Friday, August 11, 2023, 03:33:22 PM MDT, Alan James via Personal_Submersibles wrote: Hank, well done.What pressure did you set the regulator & the over-pressure valve at.?Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 8:52 am, hank pronk via Personal_Submersibles wrote: Hi all just did 400 feet for one hr and no water intrusion in motors.? Decent rate was 5 min for 400 feet and 4 motors on one reg and one OP valve.? Also 4 to 5 min to surface Hank Sent from my iPhone _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Fri Aug 11 21:51:05 2023 From: personal_submersibles at psubs.org (Alan James via Personal_Submersibles) Date: Sat, 12 Aug 2023 01:51:05 +0000 (UTC) Subject: [PSUBS-MAILIST] Air comp In-Reply-To: <876106235.3480608.1691804398964@mail.yahoo.com> References: <55323B80-52D2-41AF-89CF-A6B73D32BE82.ref@yahoo.ca> <55323B80-52D2-41AF-89CF-A6B73D32BE82@yahoo.ca> <1514779292.3425674.1691789580198@mail.yahoo.com> <876106235.3480608.1691804398964@mail.yahoo.com> Message-ID: <639532452.3496302.1691805065566@mail.yahoo.com> Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sat Aug 12 11:46:24 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Sat, 12 Aug 2023 09:46:24 -0600 Subject: [PSUBS-MAILIST] Air comp In-Reply-To: <639532452.3496302.1691805065566@mail.yahoo.com> References: <639532452.3496302.1691805065566@mail.yahoo.com> Message-ID: <002BCF2F-91CB-4CD3-9145-CA33FB321728@yahoo.ca> An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sat Aug 12 11:52:43 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Sat, 12 Aug 2023 09:52:43 -0600 Subject: [PSUBS-MAILIST] Air comp In-Reply-To: <639532452.3496302.1691805065566@mail.yahoo.com> References: <639532452.3496302.1691805065566@mail.yahoo.com> Message-ID: <9C08AE0F-8818-4DE7-8B99-9E7EF23B9E3D@yahoo.ca> An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sat Aug 12 12:29:45 2023 From: personal_submersibles at psubs.org (Rick Patton via Personal_Submersibles) Date: Sat, 12 Aug 2023 09:29:45 -0700 Subject: [PSUBS-MAILIST] Air comp In-Reply-To: <876106235.3480608.1691804398964@mail.yahoo.com> References: <876106235.3480608.1691804398964@mail.yahoo.com> Message-ID: An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sat Aug 12 13:06:46 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Sat, 12 Aug 2023 17:06:46 +0000 (UTC) Subject: [PSUBS-MAILIST] Air comp In-Reply-To: <002BCF2F-91CB-4CD3-9145-CA33FB321728@yahoo.ca> References: <639532452.3496302.1691805065566@mail.yahoo.com> <002BCF2F-91CB-4CD3-9145-CA33FB321728@yahoo.ca> Message-ID: <723664355.3647360.1691860006286@mail.yahoo.com> That's interesting.? I calculated you would I would go from 3000 psig to 2,832 psig from a 80 scf tank at 400 feet for four MD-101 thrusters alone.? 2,250 is a bit lower than expected.? Are these MK 101's ?? Are you using the air in this scuba tank for anything else?? My calc does not take into account tubing connecting the regulator to thrusters.? How many liner feet of tubing do you have and what size? Best On Saturday, August 12, 2023 at 10:47:16 AM CDT, hank pronk via Personal_Submersibles wrote: Cliff, the pressure in my 80 cu tank dropped to 2250 from 3000 to supply the 4 motors to 400 feet. ?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sat Aug 12 13:07:06 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Sat, 12 Aug 2023 17:07:06 +0000 (UTC) Subject: [PSUBS-MAILIST] Air comp In-Reply-To: <9C08AE0F-8818-4DE7-8B99-9E7EF23B9E3D@yahoo.ca> References: <639532452.3496302.1691805065566@mail.yahoo.com> <9C08AE0F-8818-4DE7-8B99-9E7EF23B9E3D@yahoo.ca> Message-ID: <1423558626.724066.1691860026585@mail.yahoo.com> Excellent! Cliff On Saturday, August 12, 2023 at 10:53:29 AM CDT, hank pronk via Personal_Submersibles wrote: Also to confirm, all four motors are water free.?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sat Aug 12 13:16:39 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Sat, 12 Aug 2023 17:16:39 +0000 (UTC) Subject: [PSUBS-MAILIST] Air comp In-Reply-To: References: <876106235.3480608.1691804398964@mail.yahoo.com> Message-ID: <96011130.3642237.1691860599794@mail.yahoo.com> Rick, the sub was maybe 15 lb heavy. ?As a rule I try to be close to neutral, then have weights on ropes to add as needed.Make it at least 15 or 20 lb or you will be all day waiting for it to dive.Hank On Saturday, August 12, 2023, 10:30:22 AM MDT, Rick Patton via Personal_Submersibles wrote: Excellent test. I am going ?air comp? and would rather not change horses in the middle of the stream so been watching people?s results closely. How negative did you set your bouncy at? Sent from my iPhone On Aug 11, 2023, at 6:40 PM, hank pronk via Personal_Submersibles wrote: ? Alan,?I would guess 2 psi over, but again thats a guess.Hank On Friday, August 11, 2023, 03:33:22 PM MDT, Alan James via Personal_Submersibles wrote: Hank, well done.What pressure did you set the regulator & the over-pressure valve at.?Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 8:52 am, hank pronk via Personal_Submersibles wrote: Hi all just did 400 feet for one hr and no water intrusion in motors.? Decent rate was 5 min for 400 feet and 4 motors on one reg and one OP valve.? Also 4 to 5 min to surface Hank Sent from my iPhone _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sat Aug 12 13:25:21 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Sat, 12 Aug 2023 17:25:21 +0000 (UTC) Subject: [PSUBS-MAILIST] Air comp In-Reply-To: <723664355.3647360.1691860006286@mail.yahoo.com> References: <639532452.3496302.1691805065566@mail.yahoo.com> <002BCF2F-91CB-4CD3-9145-CA33FB321728@yahoo.ca> <723664355.3647360.1691860006286@mail.yahoo.com> Message-ID: <1574114254.3653300.1691861121249@mail.yahoo.com> Cliff, my thrusters are 3 inch housings, so smaller than yours. I have two scuba second stage hoses ?and about 12 feet of 5\16 hose going to the aft motors. ?The whips are 1\4, but I wanted bigger to compensate for the length. ?The tank may have been a bit under also. ?The system is pretty tight because this morning when I checked the aft motors, they gave off a puff of air, and the tank was shut off when I loaded the sub.Hank On Saturday, August 12, 2023, 11:07:05 AM MDT, Cliff Redus via Personal_Submersibles wrote: That's interesting.? I calculated you would I would go from 3000 psig to 2,832 psig from a 80 scf tank at 400 feet for four MD-101 thrusters alone.? 2,250 is a bit lower than expected.? Are these MK 101's ?? Are you using the air in this scuba tank for anything else?? My calc does not take into account tubing connecting the regulator to thrusters.? How many liner feet of tubing do you have and what size? Best On Saturday, August 12, 2023 at 10:47:16 AM CDT, hank pronk via Personal_Submersibles wrote: Cliff, the pressure in my 80 cu tank dropped to 2250 from 3000 to supply the 4 motors to 400 feet. ?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sat Aug 12 13:35:46 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Sat, 12 Aug 2023 17:35:46 +0000 (UTC) Subject: [PSUBS-MAILIST] Air comp In-Reply-To: <723664355.3647360.1691860006286@mail.yahoo.com> References: <639532452.3496302.1691805065566@mail.yahoo.com> <002BCF2F-91CB-4CD3-9145-CA33FB321728@yahoo.ca> <723664355.3647360.1691860006286@mail.yahoo.com> Message-ID: <1911000381.3647135.1691861746281@mail.yahoo.com> Cliff, ?on the test, it was strictly the motors, on the tank.I think it is pretty safe to say this is working out. ?I will be diving to 300 feet in October, so I can check if the system works with the motors running.Hank On Saturday, August 12, 2023, 11:07:05 AM MDT, Cliff Redus via Personal_Submersibles wrote: That's interesting.? I calculated you would I would go from 3000 psig to 2,832 psig from a 80 scf tank at 400 feet for four MD-101 thrusters alone.? 2,250 is a bit lower than expected.? Are these MK 101's ?? Are you using the air in this scuba tank for anything else?? My calc does not take into account tubing connecting the regulator to thrusters.? How many liner feet of tubing do you have and what size? Best On Saturday, August 12, 2023 at 10:47:16 AM CDT, hank pronk via Personal_Submersibles wrote: Cliff, the pressure in my 80 cu tank dropped to 2250 from 3000 to supply the 4 motors to 400 feet. ?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sat Aug 12 13:53:12 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Sat, 12 Aug 2023 17:53:12 +0000 (UTC) Subject: [PSUBS-MAILIST] Air comp In-Reply-To: <1911000381.3647135.1691861746281@mail.yahoo.com> References: <639532452.3496302.1691805065566@mail.yahoo.com> <002BCF2F-91CB-4CD3-9145-CA33FB321728@yahoo.ca> <723664355.3647360.1691860006286@mail.yahoo.com> <1911000381.3647135.1691861746281@mail.yahoo.com> Message-ID: <427249940.3638327.1691862792404@mail.yahoo.com> Cliff, I just double checked and my old eyes failed me. ?The pressure is actually at 2300 psi.Hank On Saturday, August 12, 2023, 11:36:03 AM MDT, hank pronk via Personal_Submersibles wrote: Cliff, ?on the test, it was strictly the motors, on the tank.I think it is pretty safe to say this is working out. ?I will be diving to 300 feet in October, so I can check if the system works with the motors running.Hank On Saturday, August 12, 2023, 11:07:05 AM MDT, Cliff Redus via Personal_Submersibles wrote: That's interesting.? I calculated you would I would go from 3000 psig to 2,832 psig from a 80 scf tank at 400 feet for four MD-101 thrusters alone.? 2,250 is a bit lower than expected.? Are these MK 101's ?? Are you using the air in this scuba tank for anything else?? My calc does not take into account tubing connecting the regulator to thrusters.? How many liner feet of tubing do you have and what size? Best On Saturday, August 12, 2023 at 10:47:16 AM CDT, hank pronk via Personal_Submersibles wrote: Cliff, the pressure in my 80 cu tank dropped to 2250 from 3000 to supply the 4 motors to 400 feet. ?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sat Aug 12 14:31:26 2023 From: personal_submersibles at psubs.org (Jon Wallace via Personal_Submersibles) Date: Sat, 12 Aug 2023 18:31:26 +0000 (UTC) Subject: [PSUBS-MAILIST] Air comp In-Reply-To: <1574114254.3653300.1691861121249@mail.yahoo.com> References: <639532452.3496302.1691805065566@mail.yahoo.com> <002BCF2F-91CB-4CD3-9145-CA33FB321728@yahoo.ca> <723664355.3647360.1691860006286@mail.yahoo.com> <1574114254.3653300.1691861121249@mail.yahoo.com> Message-ID: <1668944863.3663505.1691865087254@mail.yahoo.com> It does kind of confirm the air consumption issue Cliff was concerned about which would make replacement of the air-tank a primary design consideration as well as planning for extra tanks.? Calculates to a max of 4 dives to 400 feet per tank assuming a 3000psi start, maybe three dives for 4 inch diameter 101's.? Folks with 1000 foot capability are going to use a lot more air.? Also demonstrates we can't simply calculate the volume of the motors.? All the hoses and parts that make up the plumbing have to be considered. Jon On Saturday, August 12, 2023 at 01:26:58 PM EDT, hank pronk via Personal_Submersibles wrote: Cliff, my thrusters are 3 inch housings, so smaller than yours. I have two scuba second stage hoses ?and about 12 feet of 5\16 hose going to the aft motors. ?The whips are 1\4, but I wanted bigger to compensate for the length. ?The tank may have been a bit under also. ?The system is pretty tight because this morning when I checked the aft motors, they gave off a puff of air, and the tank was shut off when I loaded the sub.Hank On Saturday, August 12, 2023, 11:07:05 AM MDT, Cliff Redus via Personal_Submersibles wrote: That's interesting.? I calculated you would I would go from 3000 psig to 2,832 psig from a 80 scf tank at 400 feet for four MD-101 thrusters alone.? 2,250 is a bit lower than expected.? Are these MK 101's ?? Are you using the air in this scuba tank for anything else?? My calc does not take into account tubing connecting the regulator to thrusters.? How many liner feet of tubing do you have and what size? Best On Saturday, August 12, 2023 at 10:47:16 AM CDT, hank pronk via Personal_Submersibles wrote: Cliff, the pressure in my 80 cu tank dropped to 2250 from 3000 to supply the 4 motors to 400 feet. ?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sat Aug 12 16:10:05 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Sat, 12 Aug 2023 20:10:05 +0000 (UTC) Subject: [PSUBS-MAILIST] Air comp In-Reply-To: <1668944863.3663505.1691865087254@mail.yahoo.com> References: <639532452.3496302.1691805065566@mail.yahoo.com> <002BCF2F-91CB-4CD3-9145-CA33FB321728@yahoo.ca> <723664355.3647360.1691860006286@mail.yahoo.com> <1574114254.3653300.1691861121249@mail.yahoo.com> <1668944863.3663505.1691865087254@mail.yahoo.com> Message-ID: <637453623.768598.1691871005503@mail.yahoo.com> Jon, I wish I thought about this volume test before the dive, I would have made sure it was accurate. ?I think it was 3000 psi, but can't guarantee it. ?More testing is needed. ?Hank On Saturday, August 12, 2023, 12:31:43 PM MDT, Jon Wallace via Personal_Submersibles wrote: It does kind of confirm the air consumption issue Cliff was concerned about which would make replacement of the air-tank a primary design consideration as well as planning for extra tanks.? Calculates to a max of 4 dives to 400 feet per tank assuming a 3000psi start, maybe three dives for 4 inch diameter 101's.? Folks with 1000 foot capability are going to use a lot more air.? Also demonstrates we can't simply calculate the volume of the motors.? All the hoses and parts that make up the plumbing have to be considered. Jon On Saturday, August 12, 2023 at 01:26:58 PM EDT, hank pronk via Personal_Submersibles wrote: Cliff, my thrusters are 3 inch housings, so smaller than yours. I have two scuba second stage hoses ?and about 12 feet of 5\16 hose going to the aft motors. ?The whips are 1\4, but I wanted bigger to compensate for the length. ?The tank may have been a bit under also. ?The system is pretty tight because this morning when I checked the aft motors, they gave off a puff of air, and the tank was shut off when I loaded the sub.Hank On Saturday, August 12, 2023, 11:07:05 AM MDT, Cliff Redus via Personal_Submersibles wrote: That's interesting.? I calculated you would I would go from 3000 psig to 2,832 psig from a 80 scf tank at 400 feet for four MD-101 thrusters alone.? 2,250 is a bit lower than expected.? Are these MK 101's ?? Are you using the air in this scuba tank for anything else?? My calc does not take into account tubing connecting the regulator to thrusters.? How many liner feet of tubing do you have and what size? Best On Saturday, August 12, 2023 at 10:47:16 AM CDT, hank pronk via Personal_Submersibles wrote: Cliff, the pressure in my 80 cu tank dropped to 2250 from 3000 to supply the 4 motors to 400 feet. ?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sun Aug 13 17:56:39 2023 From: personal_submersibles at psubs.org (via Personal_Submersibles) Date: Mon, 14 Aug 2023 09:56:39 +1200 Subject: [PSUBS-MAILIST] FW: VBT pump In-Reply-To: References: Message-ID: <014301d9ce31$0b36a430$21a3ec90$@gmail.com> Hi Guys What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze. These are only rated for 10 bar. I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. Regards, Hugh -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sun Aug 13 18:37:35 2023 From: personal_submersibles at psubs.org (David Colombo via Personal_Submersibles) Date: Sun, 13 Aug 2023 15:37:35 -0700 Subject: [PSUBS-MAILIST] Air comp In-Reply-To: <002BCF2F-91CB-4CD3-9145-CA33FB321728@yahoo.ca> References: <639532452.3496302.1691805065566@mail.yahoo.com> <002BCF2F-91CB-4CD3-9145-CA33FB321728@yahoo.ca> Message-ID: Hank do you have a diagram on your air comp system you could share. I'm adding external hp air tanks to the VAST and trying to figure out the plumbing and where the second stage reg would be located. David On Sat, Aug 12, 2023, 8:47 AM hank pronk via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Cliff, the pressure in my 80 cu tank dropped to 2250 from 3000 to supply > the 4 motors to 400 feet. > Hank > > Sent from my iPhone > > On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > ?Thanks Hank, look forward to any videos. > Alan > > Sent from Yahoo Mail on Android > > > On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles > wrote: > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sun Aug 13 18:56:09 2023 From: personal_submersibles at psubs.org (via Personal_Submersibles) Date: Mon, 14 Aug 2023 10:56:09 +1200 Subject: [PSUBS-MAILIST] Air Comp In-Reply-To: References: Message-ID: <014f01d9ce39$5b6406c0$122c1440$@gmail.com> Regarding hose/tube I have found that there is a DN2 hose 1/12" ID nom. (.083" 2.1mm) WP 630 bar which is 0.2" OD (5mm OD) that is really good for so many purposes as it has low volume for air comp, easy to bend in tight places etc etc. We used to use 3/16" 5,000 psi but in many cases we have changed over. Chs, Hugh. -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Sunday, August 13, 2023 5:07 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 30 Send Personal_Submersibles mailing list submissions to personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to personal_submersibles-request at psubs.org You can reach the person managing the list at personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: 1. Re: Air comp (Rick Patton via Personal_Submersibles) 2. Re: Air comp (Cliff Redus via Personal_Submersibles) 3. Re: Air comp (Cliff Redus via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Sat, 12 Aug 2023 09:29:45 -0700 From: Rick Patton via Personal_Submersibles To: Personal Submersibles General Discussion Subject: Re: [PSUBS-MAILIST] Air comp Message-ID: Content-Type: text/plain; charset="us-ascii" An HTML attachment was scrubbed... URL: ------------------------------ Message: 2 Date: Sat, 12 Aug 2023 17:06:46 +0000 (UTC) From: Cliff Redus via Personal_Submersibles To: hank pronk via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] Air comp Message-ID: <723664355.3647360.1691860006286 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" That's interesting.? I calculated you would I would go from 3000 psig to 2,832 psig from a 80 scf tank at 400 feet for four MD-101 thrusters alone.? 2,250 is a bit lower than expected.? Are these MK 101's ?? Are you using the air in this scuba tank for anything else?? My calc does not take into account tubing connecting the regulator to thrusters.? How many liner feet of tubing do you have and what size? Best On Saturday, August 12, 2023 at 10:47:16 AM CDT, hank pronk via Personal_Submersibles wrote: Cliff, the pressure in my 80 cu tank dropped to 2250 from 3000 to supply the 4 motors to 400 feet. ?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Sat, 12 Aug 2023 17:07:06 +0000 (UTC) From: Cliff Redus via Personal_Submersibles To: hank pronk via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] Air comp Message-ID: <1423558626.724066.1691860026585 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Excellent! Cliff On Saturday, August 12, 2023 at 10:53:29 AM CDT, hank pronk via Personal_Submersibles wrote: Also to confirm, all four motors are water free.?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 30 ****************************************************** From personal_submersibles at psubs.org Sun Aug 13 19:06:49 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Sun, 13 Aug 2023 23:06:49 +0000 (UTC) Subject: [PSUBS-MAILIST] Air comp In-Reply-To: References: <639532452.3496302.1691805065566@mail.yahoo.com> <002BCF2F-91CB-4CD3-9145-CA33FB321728@yahoo.ca> Message-ID: <214124219.3977766.1691968009548@mail.yahoo.com> David, I will send you pictures of the system connections on FB messenger.Hank On Sunday, August 13, 2023, 04:38:01 PM MDT, David Colombo via Personal_Submersibles wrote: Hank do you have a diagram on your air comp system you could share. I'm adding external hp air tanks to the VAST and trying to figure out the plumbing and where the second stage reg would be located.David On Sat, Aug 12, 2023, 8:47 AM hank pronk via Personal_Submersibles wrote: Cliff, the pressure in my 80 cu tank dropped to 2250 from 3000 to supply the 4 motors to 400 feet. ?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Mon Aug 14 04:17:23 2023 From: personal_submersibles at psubs.org (Alan James via Personal_Submersibles) Date: Mon, 14 Aug 2023 08:17:23 +0000 (UTC) Subject: [PSUBS-MAILIST] FW: VBT pump In-Reply-To: <014301d9ce31$0b36a430$21a3ec90$@gmail.com> References: <014301d9ce31$0b36a430$21a3ec90$@gmail.com> Message-ID: <501348157.4080278.1692001043729@mail.yahoo.com> Hugh,Years ago I bought a Karcher 36V battery powered car wash water blaster with a piston pump that is touted as being corrosion resistant.I think the pressure was 750psi.I saw this item with a higher psi but not sure if its corrosion resistant.https://www.kaercher.com/int/overview-battery-products.html It may be a product you mightn't have thought of.Ali may have the pump for this unit.Alan? Sent from Yahoo Mail on Android On Mon, 14 Aug 2023 at 9:58 am, via Personal_Submersibles wrote: Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Mon Aug 14 22:05:40 2023 From: personal_submersibles at psubs.org (Rick Patton via Personal_Submersibles) Date: Mon, 14 Aug 2023 19:05:40 -0700 Subject: [PSUBS-MAILIST] Air comp In-Reply-To: <1423558626.724066.1691860026585@mail.yahoo.com> References: <1423558626.724066.1691860026585@mail.yahoo.com> Message-ID: <647AFD30-D84F-4B3C-A9AC-D0983842532D@gmail.com> An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Tue Aug 15 17:41:56 2023 From: personal_submersibles at psubs.org (via Personal_Submersibles) Date: Wed, 16 Aug 2023 09:41:56 +1200 Subject: [PSUBS-MAILIST] VBT Pump In-Reply-To: References: Message-ID: <031601d9cfc1$532742e0$f975c8a0$@gmail.com> Alan, karcher water pump is very low lpm I am wanting 40 lpm at 200 psi for 1.5kw motor at 1800 rpm. Pump hp simple calc = rpm x 15/63000+psi x gpm/1460 I am wanting to know if anyone has actually done it with a pump for VBT and what works best. As back-up I have air but my VBT tanks are 40 ltr each fore and aft. Vance? Any comments? -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Monday, August 14, 2023 8:18 PM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 34 Send Personal_Submersibles mailing list submissions to personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to personal_submersibles-request at psubs.org You can reach the person managing the list at personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: 1. Re: Air Comp (via Personal_Submersibles) 2. Re: Air comp (hank pronk via Personal_Submersibles) 3. Re: FW: VBT pump (Alan James via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Mon, 14 Aug 2023 10:56:09 +1200 From: via Personal_Submersibles To: Subject: Re: [PSUBS-MAILIST] Air Comp Message-ID: <014f01d9ce39$5b6406c0$122c1440$@gmail.com> Content-Type: text/plain; charset="us-ascii" Regarding hose/tube I have found that there is a DN2 hose 1/12" ID nom. (.083" 2.1mm) WP 630 bar which is 0.2" OD (5mm OD) that is really good for so many purposes as it has low volume for air comp, easy to bend in tight places etc etc. We used to use 3/16" 5,000 psi but in many cases we have changed over. Chs, Hugh. -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Sunday, August 13, 2023 5:07 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 30 Send Personal_Submersibles mailing list submissions to personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to personal_submersibles-request at psubs.org You can reach the person managing the list at personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: 1. Re: Air comp (Rick Patton via Personal_Submersibles) 2. Re: Air comp (Cliff Redus via Personal_Submersibles) 3. Re: Air comp (Cliff Redus via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Sat, 12 Aug 2023 09:29:45 -0700 From: Rick Patton via Personal_Submersibles To: Personal Submersibles General Discussion Subject: Re: [PSUBS-MAILIST] Air comp Message-ID: Content-Type: text/plain; charset="us-ascii" An HTML attachment was scrubbed... URL: ------------------------------ Message: 2 Date: Sat, 12 Aug 2023 17:06:46 +0000 (UTC) From: Cliff Redus via Personal_Submersibles To: hank pronk via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] Air comp Message-ID: <723664355.3647360.1691860006286 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" That's interesting.? I calculated you would I would go from 3000 psig to 2,832 psig from a 80 scf tank at 400 feet for four MD-101 thrusters alone.? 2,250 is a bit lower than expected.? Are these MK 101's ?? Are you using the air in this scuba tank for anything else?? My calc does not take into account tubing connecting the regulator to thrusters.? How many liner feet of tubing do you have and what size? Best On Saturday, August 12, 2023 at 10:47:16 AM CDT, hank pronk via Personal_Submersibles wrote: Cliff, the pressure in my 80 cu tank dropped to 2250 from 3000 to supply the 4 motors to 400 feet. ?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Sat, 12 Aug 2023 17:07:06 +0000 (UTC) From: Cliff Redus via Personal_Submersibles To: hank pronk via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] Air comp Message-ID: <1423558626.724066.1691860026585 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Excellent! Cliff On Saturday, August 12, 2023 at 10:53:29 AM CDT, hank pronk via Personal_Submersibles wrote: Also to confirm, all four motors are water free.?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 30 ****************************************************** ------------------------------ Message: 2 Date: Sun, 13 Aug 2023 23:06:49 +0000 (UTC) From: hank pronk via Personal_Submersibles To: David Colombo via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] Air comp Message-ID: <214124219.3977766.1691968009548 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" David, I will send you pictures of the system connections on FB messenger.Hank On Sunday, August 13, 2023, 04:38:01 PM MDT, David Colombo via Personal_Submersibles wrote: Hank do you have a diagram on your air comp system you could share. I'm adding external hp air tanks to the VAST and trying to figure out the plumbing and where the second stage reg would be located.David On Sat, Aug 12, 2023, 8:47 AM hank pronk via Personal_Submersibles wrote: Cliff, the pressure in my 80 cu tank dropped to 2250 from 3000 to supply the 4 motors to 400 feet. ?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Mon, 14 Aug 2023 08:17:23 +0000 (UTC) From: Alan James via Personal_Submersibles To: Personal Submersibles General Discussion Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <501348157.4080278.1692001043729 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh,Years ago I bought a Karcher 36V battery powered car wash water blaster with a piston pump that is touted as being corrosion resistant.I think the pressure was 750psi.I saw this item with a higher psi but not sure if its corrosion resistant.https://www.kaercher.com/int/overview-battery-products.html It may be a product you mightn't have thought of.Ali may have the pump for this unit.Alan? Sent from Yahoo Mail on Android On Mon, 14 Aug 2023 at 9:58 am, via Personal_Submersibles wrote: Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 34 ****************************************************** From personal_submersibles at psubs.org Wed Aug 16 05:35:48 2023 From: personal_submersibles at psubs.org (Alan James via Personal_Submersibles) Date: Wed, 16 Aug 2023 09:35:48 +0000 (UTC) Subject: [PSUBS-MAILIST] VBT Pump In-Reply-To: <031601d9cfc1$532742e0$f975c8a0$@gmail.com> References: <031601d9cfc1$532742e0$f975c8a0$@gmail.com> Message-ID: <1899392452.313553.1692178548654@mail.yahoo.com> Hugh,I can remember Paul Moorhouse sourcing a pump & motor for ballasting as he commented on my post when I bought the Karcher.?Paul is either on the Submersibles or Psub facebook site.I was getting about 11 LPM with the wand off the pressure washer.Alan Sent from Yahoo Mail on Android On Wed, 16 Aug 2023 at 9:44 am, via Personal_Submersibles wrote: Alan, karcher water pump is very low lpm? I am wanting 40 lpm at 200 psi for 1.5kw motor at 1800 rpm. Pump hp simple calc = rpm x 15/63000+psi x gpm/1460? I am wanting to know if anyone has actually done it with a pump for VBT and what works best.? As back-up I have air but my VBT tanks are 40 ltr each fore and aft.? Vance? Any comments? -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Monday, August 14, 2023 8:18 PM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 34 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: Air Comp (via Personal_Submersibles) ? 2. Re: Air comp (hank pronk via Personal_Submersibles) ? 3. Re: FW: VBT pump (Alan James via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Mon, 14 Aug 2023 10:56:09 +1200 From: via Personal_Submersibles To: Subject: Re: [PSUBS-MAILIST] Air Comp Message-ID: <014f01d9ce39$5b6406c0$122c1440$@gmail.com> Content-Type: text/plain;??? charset="us-ascii" Regarding hose/tube I have found that there is a DN2 hose 1/12" ID nom. (.083" 2.1mm) WP 630 bar which is 0.2" OD (5mm OD) that is really good for so many purposes as it has low volume for air comp, easy to bend in tight places etc etc.? We used to use 3/16"? 5,000 psi but in many cases we have changed over.? Chs, Hugh. -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Sunday, August 13, 2023 5:07 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 30 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: Air comp (Rick Patton via Personal_Submersibles) ? 2. Re: Air comp (Cliff Redus via Personal_Submersibles) ? 3. Re: Air comp (Cliff Redus via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Sat, 12 Aug 2023 09:29:45 -0700 From: Rick Patton via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] Air comp Message-ID: Content-Type: text/plain; charset="us-ascii" An HTML attachment was scrubbed... URL: ------------------------------ Message: 2 Date: Sat, 12 Aug 2023 17:06:46 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: hank pronk via Personal_Submersibles ??? Subject: Re: [PSUBS-MAILIST] Air comp Message-ID: <723664355.3647360.1691860006286 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" That's interesting.? I calculated you would I would go from 3000 psig to 2,832 psig from a 80 scf tank at 400 feet for four MD-101 thrusters alone.? 2,250 is a bit lower than expected.? Are these MK 101's ?? Are you using the air in this scuba tank for anything else?? My calc does not take into account tubing connecting the regulator to thrusters.? How many liner feet of tubing do you have and what size? Best ? ? On Saturday, August 12, 2023 at 10:47:16 AM CDT, hank pronk via Personal_Submersibles wrote:? Cliff, the pressure in my 80 cu tank dropped to 2250 from 3000 to supply the 4 motors to 400 feet. ?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android ? On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Sat, 12 Aug 2023 17:07:06 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: hank pronk via Personal_Submersibles ??? Subject: Re: [PSUBS-MAILIST] Air comp Message-ID: <1423558626.724066.1691860026585 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Excellent! Cliff ? ? On Saturday, August 12, 2023 at 10:53:29 AM CDT, hank pronk via Personal_Submersibles wrote:? Also to confirm, all four motors are water free.?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android ? On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 30 ****************************************************** ------------------------------ Message: 2 Date: Sun, 13 Aug 2023 23:06:49 +0000 (UTC) From: hank pronk via Personal_Submersibles ??? To: David Colombo via Personal_Submersibles ??? Subject: Re: [PSUBS-MAILIST] Air comp Message-ID: <214124219.3977766.1691968009548 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" David, I will send you pictures of the system connections on FB messenger.Hank ? ? On Sunday, August 13, 2023, 04:38:01 PM MDT, David Colombo via Personal_Submersibles wrote:? Hank do you have a diagram on your air comp system you could share. I'm adding external hp air tanks to the VAST and trying to figure out the plumbing and where the second stage reg would be located.David On Sat, Aug 12, 2023, 8:47 AM hank pronk via Personal_Submersibles wrote: Cliff, the pressure in my 80 cu tank dropped to 2250 from 3000 to supply the 4 motors to 400 feet. ?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android ? On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Mon, 14 Aug 2023 08:17:23 +0000 (UTC) From: Alan James via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <501348157.4080278.1692001043729 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh,Years ago I bought a Karcher 36V battery powered car wash water blaster with a piston pump that is touted as being corrosion resistant.I think the pressure was 750psi.I saw this item with a higher psi but not sure if its corrosion resistant.https://www.kaercher.com/int/overview-battery-products.html It may be a product you mightn't have thought of.Ali may have the pump for this unit.Alan? Sent from Yahoo Mail on Android ? On Mon, 14 Aug 2023 at 9:58 am, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 34 ****************************************************** _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 16 09:29:07 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) Subject: [PSUBS-MAILIST] FW: VBT pump In-Reply-To: <014301d9ce31$0b36a430$21a3ec90$@gmail.com> References: <014301d9ce31$0b36a430$21a3ec90$@gmail.com> Message-ID: <536726240.403633.1692192547749@mail.yahoo.com> Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat negatively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote: Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 16 09:41:53 2023 From: personal_submersibles at psubs.org (Alec Smyth via Personal_Submersibles) Date: Wed, 16 Aug 2023 09:41:53 -0400 Subject: [PSUBS-MAILIST] FW: VBT pump In-Reply-To: <536726240.403633.1692192547749@mail.yahoo.com> References: <014301d9ce31$0b36a430$21a3ec90$@gmail.com> <536726240.403633.1692192547749@mail.yahoo.com> Message-ID: I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify, and it worked so well I never thought of using any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best, Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Hugh, on my original design for the R300 I had a hard VBT just aft of the > pilot. At the time I had a small HPU in the boat. My plan was to use a > Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water > in and out of the VBT. I don't remember the specs on the pump. I had > motorized ball valves on the vent and flood side of the VBT. Prior to > using this set up, I did some testing of this gear pump which I still > have. What I found was an unacceptable amount of flow slippage at my max > design depth. There was so much slippage that the pump could not blow the > VBT at max depth. At that point I abandoned using a pump and vent to > blowing the VBT with air. I eventually abandoned the VBT altogether for > operability reasons. When I used this hard VBT to get neutral on the > surface, the pressure in the tank was low. When at depth if I ever tried > to use the VBT, water would rush in until the pressure equalized with > ambient water pressure. This made the boat negatively buoyant until air > was added. The other thing that bugged me was I had a float style level > sensor in the VBT. The water level in the VBT was always moving around so > you never trust the reading. I eventually abandoned the VBT and now just > add ballast at the boat CG where the VBT was located. I find this works > great. The other issue is the VBT restricted access to equipment aft of > the VBT so to work on any of this equipment, I had to remove the VBT. All > in all, I found the VBT to be a pain in butt. > > Cliff > > Oberdorfer 944 Bronze > > On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > > > Hi Guys > > > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze. These are only > rated for 10 bar. I tried an hydraulic gear pump 30cc where I had a > stainless and bronze gear set made up but the aluminium body corroded form > the trials and I just found that they had used steel backed sleeve bearings. > > > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 16 11:20:44 2023 From: personal_submersibles at psubs.org (Jon Wallace via Personal_Submersibles) Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) Subject: [PSUBS-MAILIST] FW: VBT pump In-Reply-To: References: <014301d9ce31$0b36a430$21a3ec90$@gmail.com> <536726240.403633.1692192547749@mail.yahoo.com> Message-ID: <1959084270.469930.1692199244774@mail.yahoo.com> I'll chime in here...I removed the VBT from the K600 because it was fairly well rusted inside and needed to be replaced, however I am planning on using the ballast/float method instead and forgoing the VBT altogether for many of the reasons Alec and Cliff cited.? I will say that it can be challenging to change ballast on-station since the weight/floatation has to be transferred somewhere and by somebody, however I see the K600 being trimmed for specific missions prior to launch and not being trimmed dynamically on-station to embark/disembark passengers or equipment. Jon On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via Personal_Submersibles wrote: I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify,?and it worked so well I never thought of using?any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best,Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles wrote: Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat negatively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote: Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 16 12:36:45 2023 From: personal_submersibles at psubs.org (vbra676539@aol.com via Personal_Submersibles) Date: Wed, 16 Aug 2023 16:36:45 +0000 (UTC) Subject: [PSUBS-MAILIST] VBT Pump In-Reply-To: <031601d9cfc1$532742e0$f975c8a0$@gmail.com> References: <031601d9cfc1$532742e0$f975c8a0$@gmail.com> Message-ID: <9017999.279546.1692203805654@mail.yahoo.com> A bronze Oberdorfer gear pump is pretty much bulletproof, and the 2000 series will give you an advertised 2.2 gpm at 1800 rpm (they specify .68 hp for the motor). Same pump Kittredge recommended. It would take a little poking around to insure sufficient psi at the output to deliver that flow rate against external pressure. A K350 at 350 fsw, for instance is what, 160 psi, give or take??Vance On Tuesday, August 15, 2023, 05:42:23 PM EDT, via Personal_Submersibles wrote: Alan, karcher water pump is very low lpm? I am wanting 40 lpm at 200 psi for 1.5kw motor at 1800 rpm. Pump hp simple calc = rpm x 15/63000+psi x gpm/1460? I am wanting to know if anyone has actually done it with a pump for VBT and what works best.? As back-up I have air but my VBT tanks are 40 ltr each fore and aft.? Vance? Any comments? -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Monday, August 14, 2023 8:18 PM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 34 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: Air Comp (via Personal_Submersibles) ? 2. Re: Air comp (hank pronk via Personal_Submersibles) ? 3. Re: FW: VBT pump (Alan James via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Mon, 14 Aug 2023 10:56:09 +1200 From: via Personal_Submersibles To: Subject: Re: [PSUBS-MAILIST] Air Comp Message-ID: <014f01d9ce39$5b6406c0$122c1440$@gmail.com> Content-Type: text/plain;??? charset="us-ascii" Regarding hose/tube I have found that there is a DN2 hose 1/12" ID nom. (.083" 2.1mm) WP 630 bar which is 0.2" OD (5mm OD) that is really good for so many purposes as it has low volume for air comp, easy to bend in tight places etc etc.? We used to use 3/16"? 5,000 psi but in many cases we have changed over.? Chs, Hugh. -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Sunday, August 13, 2023 5:07 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 30 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: Air comp (Rick Patton via Personal_Submersibles) ? 2. Re: Air comp (Cliff Redus via Personal_Submersibles) ? 3. Re: Air comp (Cliff Redus via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Sat, 12 Aug 2023 09:29:45 -0700 From: Rick Patton via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] Air comp Message-ID: Content-Type: text/plain; charset="us-ascii" An HTML attachment was scrubbed... URL: ------------------------------ Message: 2 Date: Sat, 12 Aug 2023 17:06:46 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: hank pronk via Personal_Submersibles ??? Subject: Re: [PSUBS-MAILIST] Air comp Message-ID: <723664355.3647360.1691860006286 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" That's interesting.? I calculated you would I would go from 3000 psig to 2,832 psig from a 80 scf tank at 400 feet for four MD-101 thrusters alone.? 2,250 is a bit lower than expected.? Are these MK 101's ?? Are you using the air in this scuba tank for anything else?? My calc does not take into account tubing connecting the regulator to thrusters.? How many liner feet of tubing do you have and what size? Best ? ? On Saturday, August 12, 2023 at 10:47:16 AM CDT, hank pronk via Personal_Submersibles wrote:? Cliff, the pressure in my 80 cu tank dropped to 2250 from 3000 to supply the 4 motors to 400 feet. ?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android ? On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Sat, 12 Aug 2023 17:07:06 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: hank pronk via Personal_Submersibles ??? Subject: Re: [PSUBS-MAILIST] Air comp Message-ID: <1423558626.724066.1691860026585 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Excellent! Cliff ? ? On Saturday, August 12, 2023 at 10:53:29 AM CDT, hank pronk via Personal_Submersibles wrote:? Also to confirm, all four motors are water free.?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android ? On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 30 ****************************************************** ------------------------------ Message: 2 Date: Sun, 13 Aug 2023 23:06:49 +0000 (UTC) From: hank pronk via Personal_Submersibles ??? To: David Colombo via Personal_Submersibles ??? Subject: Re: [PSUBS-MAILIST] Air comp Message-ID: <214124219.3977766.1691968009548 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" David, I will send you pictures of the system connections on FB messenger.Hank ? ? On Sunday, August 13, 2023, 04:38:01 PM MDT, David Colombo via Personal_Submersibles wrote:? Hank do you have a diagram on your air comp system you could share. I'm adding external hp air tanks to the VAST and trying to figure out the plumbing and where the second stage reg would be located.David On Sat, Aug 12, 2023, 8:47 AM hank pronk via Personal_Submersibles wrote: Cliff, the pressure in my 80 cu tank dropped to 2250 from 3000 to supply the 4 motors to 400 feet. ?Hank Sent from my iPhone On Aug 11, 2023, at 7:51 PM, Alan James via Personal_Submersibles wrote: ?Thanks Hank, look forward to any videos.Alan Sent from Yahoo Mail on Android ? On Sat, 12 Aug 2023 at 1:41 pm, hank pronk via Personal_Submersibles wrote: _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Mon, 14 Aug 2023 08:17:23 +0000 (UTC) From: Alan James via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <501348157.4080278.1692001043729 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh,Years ago I bought a Karcher 36V battery powered car wash water blaster with a piston pump that is touted as being corrosion resistant.I think the pressure was 750psi.I saw this item with a higher psi but not sure if its corrosion resistant.https://www.kaercher.com/int/overview-battery-products.html It may be a product you mightn't have thought of.Ali may have the pump for this unit.Alan? Sent from Yahoo Mail on Android ? On Mon, 14 Aug 2023 at 9:58 am, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 34 ****************************************************** _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 16 12:54:41 2023 From: personal_submersibles at psubs.org (vbra676539@aol.com via Personal_Submersibles) Date: Wed, 16 Aug 2023 16:54:41 +0000 (UTC) Subject: [PSUBS-MAILIST] FW: VBT pump In-Reply-To: <536726240.403633.1692192547749@mail.yahoo.com> References: <014301d9ce31$0b36a430$21a3ec90$@gmail.com> <536726240.403633.1692192547749@mail.yahoo.com> Message-ID: <886051092.283168.1692204881545@mail.yahoo.com> It's all about the usage. A VBT was handy when working a PC12 (for instance) mid-water or alongside some kind of structure. ?That said, I ran Aquarius quite successfully using the forward (smallest of 3) MBT to hang on the bubble, as we called it. You have to be quick on the adjustments, but it worked fine that way. The JSLs have a dandy pressure compensated system for the VBTs, but you may notice how many T bottles are hung on those things. They were air hungry by definition. The little boats we mess with respond much more quickly to the bubble trim, but smaller volumes of air are involved, so are reasonably manageable. The Nektons, for instnce, ran on the bubble and fit into our sort of portable category (4400 to 5200 pounds crane weight). An 8 to 10 ton Perry or Hyco sub, however, is much happier trimmed neutral, or very close to it. In relatively shallow water (call it down to 500 feet or so) I could easily run those subs a little heavy, and then fine trim with the MBT bubble. Not always, but it was nice to have the options.Vance On Wednesday, August 16, 2023, 09:30:02 AM EDT, Cliff Redus via Personal_Submersibles wrote: Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat negatively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote: Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 16 13:13:32 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Wed, 16 Aug 2023 11:13:32 -0600 Subject: [PSUBS-MAILIST] FW: VBT pump In-Reply-To: <886051092.283168.1692204881545@mail.yahoo.com> References: <886051092.283168.1692204881545@mail.yahoo.com> Message-ID: An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 16 13:44:39 2023 From: personal_submersibles at psubs.org (Rick Patton via Personal_Submersibles) Date: Wed, 16 Aug 2023 10:44:39 -0700 Subject: [PSUBS-MAILIST] FW: VBT pump In-Reply-To: References: Message-ID: <81DC6835-5791-4DD0-9953-BA270D73ADC8@gmail.com> An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 16 19:42:59 2023 From: personal_submersibles at psubs.org (via Personal_Submersibles) Date: Thu, 17 Aug 2023 11:42:59 +1200 Subject: [PSUBS-MAILIST] Re VBT Pump In-Reply-To: References: Message-ID: <035f01d9d09b$653a05f0$2fae11d0$@gmail.com> Thanks, Cliff, Alec, Vance, Jon. The model I was looking at, correction, was the Oberdorfer 994 which is same as a 2000 series but 3/8" - 1/2" and direct mounted not foot mounted as per the 2000 series. The other pump I liked was the Wanner D10 which is diaphragm and can do no slippage and 250 -300 psi etc but it is not bidirectional. However that can be fixed with valves. I am making some progress with my Q-Sub but made the mistake of going too complex and trying to do everything. I have had issues with --- 1. BMS systems for the LiFePO4 batteries and had to replace these. 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. 3. Gear cable kinking for the mercruiser sternlegs. 4. Inaccessible fuses and not motor rated. 5. Mechanical seal leakage on the hydraulics. 6. Joystick pot issues. 7. Canbus systems at different voltages. 8. Rotary sensors too coarse required op amp addition to amplify signals for small rotary movements with steering. 9. Port Engine starting issues. 10. Oil compensation line fittings leaks. 11. Software issues. Still plugging along. IN the meantime I have built a test pool same-same Hank 8 ft deep 12 wide x 27 long, and another gantry crane for PVHO removal, as well as a shed just for the sub. This year it has to be finished. Has not even been in the pool yet!! Regards, Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 3:21 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 36 Send Personal_Submersibles mailing list submissions to personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to personal_submersibles-request at psubs.org You can reach the person managing the list at personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) 2. Re: FW: VBT pump (Alec Smyth via Personal_Submersibles) 3. Re: FW: VBT pump (Jon Wallace via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) From: Cliff Redus via Personal_Submersibles To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote: Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 2 Date: Wed, 16 Aug 2023 09:41:53 -0400 From: Alec Smyth via Personal_Submersibles To: Personal Submersibles General Discussion Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: Content-Type: text/plain; charset="utf-8" I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify, and it worked so well I never thought of using any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best, Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat. My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT. I don't remember the specs on the > pump. I had motorized ball valves on the vent and flood side of the > VBT. Prior to using this set up, I did some testing of this gear pump > which I still have. What I found was an unacceptable amount of flow > slippage at my max design depth. There was so much slippage that the > pump could not blow the VBT at max depth. At that point I abandoned > using a pump and vent to blowing the VBT with air. I eventually > abandoned the VBT altogether for operability reasons. When I used > this hard VBT to get neutral on the surface, the pressure in the tank > was low. When at depth if I ever tried to use the VBT, water would > rush in until the pressure equalized with ambient water pressure. > This made the boat negatively buoyant until air was added. The other > thing that bugged me was I had a float style level sensor in the VBT. > The water level in the VBT was always moving around so you never trust > the reading. I eventually abandoned the VBT and now just add ballast > at the boat CG where the VBT was located. I find this works great. The other issue is the VBT restricted access to equipment aft of > the VBT so to work on any of this equipment, I had to remove the VBT. All > in all, I found the VBT to be a pain in butt. > > Cliff > > Oberdorfer 944 Bronze > > On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles < personal_submersibles at psubs.org> wrote: > > > Hi Guys > > > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze. These are > only rated for 10 bar. I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel backed sleeve bearings. > > > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) From: Jon Wallace via Personal_Submersibles To: Personal Submersibles General Discussion Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" I'll chime in here...I removed the VBT from the K600 because it was fairly well rusted inside and needed to be replaced, however I am planning on using the ballast/float method instead and forgoing the VBT altogether for many of the reasons Alec and Cliff cited.? I will say that it can be challenging to change ballast on-station since the weight/floatation has to be transferred somewhere and by somebody, however I see the K600 being trimmed for specific missions prior to launch and not being trimmed dynamically on-station to embark/disembark passengers or equipment. Jon On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via Personal_Submersibles wrote: I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify,?and it worked so well I never thought of using?any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best,Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles wrote: Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote: Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 36 ****************************************************** From personal_submersibles at psubs.org Wed Aug 16 19:43:53 2023 From: personal_submersibles at psubs.org (via Personal_Submersibles) Date: Thu, 17 Aug 2023 11:43:53 +1200 Subject: [PSUBS-MAILIST] RE VBT Pump. In-Reply-To: References: Message-ID: <036001d9d09b$869e7460$93db5d20$@gmail.com> Hi Vance, Cliff, Thanks for the feedback. Correction of the pump I am looking at it is an Oberdorfer 994 but also comparing a piston diaphragm. Vance experience looks as though it was much deeper than the 50-400 ft I am looking at with the NZ coastline. 150 feet is the max in most places with coastal access. -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 5:45 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 38 Send Personal_Submersibles mailing list submissions to personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to personal_submersibles-request at psubs.org You can reach the person managing the list at personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: 1. Re: FW: VBT pump (vbra676539 at aol.com via Personal_Submersibles) 2. Re: FW: VBT pump (hank pronk via Personal_Submersibles) 3. Re: FW: VBT pump (Rick Patton via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Wed, 16 Aug 2023 16:54:41 +0000 (UTC) From: "vbra676539 at aol.com via Personal_Submersibles" To: Cliff Redus via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <886051092.283168.1692204881545 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" It's all about the usage. A VBT was handy when working a PC12 (for instance) mid-water or alongside some kind of structure. ?That said, I ran Aquarius quite successfully using the forward (smallest of 3) MBT to hang on the bubble, as we called it. You have to be quick on the adjustments, but it worked fine that way. The JSLs have a dandy pressure compensated system for the VBTs, but you may notice how many T bottles are hung on those things. They were air hungry by definition. The little boats we mess with respond much more quickly to the bubble trim, but smaller volumes of air are involved, so are reasonably manageable. The Nektons, for instnce, ran on the bubble and fit into our sort of portable category (4400 to 5200 pounds crane weight). An 8 to 10 ton Perry or Hyco sub, however, is much happier trimmed neutral, or very close to it. In relatively shallow water (call it down to 500 feet or so) I could easily run those subs a little heavy, and then fine trim with the MBT ! bubble. Not always, but it was nice to have the options.Vance On Wednesday, August 16, 2023, 09:30:02 AM EDT, Cliff Redus via Personal_Submersibles wrote: Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat neg! atively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote: Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 2 Date: Wed, 16 Aug 2023 11:13:32 -0600 From: hank pronk via Personal_Submersibles To: Personal Submersibles General Discussion Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: Content-Type: text/plain; charset="us-ascii" An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Wed, 16 Aug 2023 10:44:39 -0700 From: Rick Patton via Personal_Submersibles To: Personal Submersibles General Discussion Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <81DC6835-5791-4DD0-9953-BA270D73ADC8 at gmail.com> Content-Type: text/plain; charset="us-ascii" An HTML attachment was scrubbed... URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 38 ****************************************************** From personal_submersibles at psubs.org Wed Aug 16 20:19:35 2023 From: personal_submersibles at psubs.org (Alan James via Personal_Submersibles) Date: Thu, 17 Aug 2023 00:19:35 +0000 (UTC) Subject: [PSUBS-MAILIST] Re VBT Pump In-Reply-To: <035f01d9d09b$653a05f0$2fae11d0$@gmail.com> References: <035f01d9d09b$653a05f0$2fae11d0$@gmail.com> Message-ID: <1177223314.746294.1692231575096@mail.yahoo.com> Good on you Hugh,?Sounds like you are getting through all the issues.It will be quite an achievement when the Qsub isoperational. "Can't wait."With my ballast / trim system I am intending to have?external flexible bags to pump water in and out of.Alan? Sent from Yahoo Mail on Android On Thu, 17 Aug 2023 at 11:44 am, via Personal_Submersibles wrote: Thanks, Cliff, Alec, Vance, Jon. The model I was looking at, correction, was the Oberdorfer 994 which is same as a 2000 series but 3/8" - 1/2"? and direct mounted not foot mounted as per the 2000 series. The other pump I liked was the Wanner D10 which is diaphragm and can do no slippage and 250 -300 psi etc but it is not bidirectional.? However that can be fixed with valves. I am making some progress with my Q-Sub but made the mistake of going too complex and trying to do everything.? I? have had issues with --- 1. BMS systems for the LiFePO4 batteries and had to replace these. 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. 3. Gear cable kinking for the mercruiser sternlegs. 4. Inaccessible fuses and not motor rated. 5. Mechanical seal leakage on the hydraulics. 6. Joystick pot issues. 7. Canbus systems at different voltages. 8. Rotary sensors too coarse required op amp addition to amplify signals for small rotary movements with steering. 9. Port Engine starting issues. 10. Oil compensation line fittings leaks. 11. Software issues. Still plugging along.? IN the meantime I have built a test pool same-same Hank 8 ft deep 12 wide x 27 long, and another gantry crane for PVHO removal, as well as a shed just for the sub.? This year it has to be finished.? Has not even been in the pool yet!! Regards,? Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 3:21 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 36 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) ? 2. Re: FW: VBT pump (Alec Smyth via Personal_Submersibles) ? 3. Re: FW: VBT pump (Jon Wallace via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 2 Date: Wed, 16 Aug 2023 09:41:53 -0400 From: Alec Smyth via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: ??? Content-Type: text/plain; charset="utf-8" I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify, and it worked so well I never thought of using any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best, Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat.? My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT.? I don't remember the specs on the > pump.? I had motorized ball valves on the vent and flood side of the > VBT.? Prior to using this set up, I did some testing of this gear pump > which I still have.? What I found was an unacceptable amount of flow > slippage at my max design depth.? There was so much slippage that the > pump could not blow the VBT at max depth.? At that point I abandoned > using a pump and vent to blowing the VBT with air.? I eventually > abandoned the VBT altogether for operability reasons.? When I used > this hard VBT to get neutral on the surface, the pressure in the tank > was low.? When at depth if I ever tried to use the VBT, water would > rush in until the pressure equalized with ambient water pressure.? > This made the boat negatively buoyant until air was added.? The other > thing that bugged me was I had a float style level sensor in the VBT.? > The water level in the VBT was always moving around so you never trust > the reading.? I eventually abandoned the VBT and now just add ballast > at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of > the VBT so to work on any of this equipment, I had to remove the VBT. All > in all, I found the VBT to be a pain in butt. > > Cliff > > Oberdorfer 944 Bronze > > On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles < personal_submersibles at psubs.org> wrote: > > > Hi Guys > > > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are > only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel backed sleeve bearings. > > > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) From: Jon Wallace via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" I'll chime in here...I removed the VBT from the K600 because it was fairly well rusted inside and needed to be replaced, however I am planning on using the ballast/float method instead and forgoing the VBT altogether for many of the reasons Alec and Cliff cited.? I will say that it can be challenging to change ballast on-station since the weight/floatation has to be transferred somewhere and by somebody, however I see the K600 being trimmed for specific missions prior to launch and not being trimmed dynamically on-station to embark/disembark passengers or equipment. Jon ? ? On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via Personal_Submersibles wrote:? I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify,?and it worked so well I never thought of using?any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best,Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles wrote: Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... 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URL: From personal_submersibles at psubs.org Wed Aug 16 21:01:56 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Thu, 17 Aug 2023 01:01:56 +0000 (UTC) Subject: [PSUBS-MAILIST] Re VBT Pump In-Reply-To: <035f01d9d09b$653a05f0$2fae11d0$@gmail.com> References: <035f01d9d09b$653a05f0$2fae11d0$@gmail.com> Message-ID: <2137621386.758356.1692234116222@mail.yahoo.com> Hugh, thanks for update on QSub.? I am looking forward to her dunk test in your new test pool. I quite enjoyed sitting in her pressure hull in your shop in New Zealand a few years back.? She will be quite something when complete. Best On Wednesday, August 16, 2023 at 06:43:41 PM CDT, via Personal_Submersibles wrote: Thanks, Cliff, Alec, Vance, Jon. The model I was looking at, correction, was the Oberdorfer 994 which is same as a 2000 series but 3/8" - 1/2"? and direct mounted not foot mounted as per the 2000 series. The other pump I liked was the Wanner D10 which is diaphragm and can do no slippage and 250 -300 psi etc but it is not bidirectional.? However that can be fixed with valves. I am making some progress with my Q-Sub but made the mistake of going too complex and trying to do everything.? I? have had issues with --- 1. BMS systems for the LiFePO4 batteries and had to replace these. 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. 3. Gear cable kinking for the mercruiser sternlegs. 4. Inaccessible fuses and not motor rated. 5. Mechanical seal leakage on the hydraulics. 6. Joystick pot issues. 7. Canbus systems at different voltages. 8. Rotary sensors too coarse required op amp addition to amplify signals for small rotary movements with steering. 9. Port Engine starting issues. 10. Oil compensation line fittings leaks. 11. Software issues. Still plugging along.? IN the meantime I have built a test pool same-same Hank 8 ft deep 12 wide x 27 long, and another gantry crane for PVHO removal, as well as a shed just for the sub.? This year it has to be finished.? Has not even been in the pool yet!! Regards,? Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 3:21 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 36 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) ? 2. Re: FW: VBT pump (Alec Smyth via Personal_Submersibles) ? 3. Re: FW: VBT pump (Jon Wallace via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 2 Date: Wed, 16 Aug 2023 09:41:53 -0400 From: Alec Smyth via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: ??? Content-Type: text/plain; charset="utf-8" I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify, and it worked so well I never thought of using any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best, Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat.? My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT.? I don't remember the specs on the > pump.? I had motorized ball valves on the vent and flood side of the > VBT.? Prior to using this set up, I did some testing of this gear pump > which I still have.? What I found was an unacceptable amount of flow > slippage at my max design depth.? There was so much slippage that the > pump could not blow the VBT at max depth.? At that point I abandoned > using a pump and vent to blowing the VBT with air.? I eventually > abandoned the VBT altogether for operability reasons.? When I used > this hard VBT to get neutral on the surface, the pressure in the tank > was low.? When at depth if I ever tried to use the VBT, water would > rush in until the pressure equalized with ambient water pressure.? > This made the boat negatively buoyant until air was added.? The other > thing that bugged me was I had a float style level sensor in the VBT.? > The water level in the VBT was always moving around so you never trust > the reading.? I eventually abandoned the VBT and now just add ballast > at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of > the VBT so to work on any of this equipment, I had to remove the VBT. All > in all, I found the VBT to be a pain in butt. > > Cliff > > Oberdorfer 944 Bronze > > On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles < personal_submersibles at psubs.org> wrote: > > > Hi Guys > > > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are > only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel backed sleeve bearings. > > > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) From: Jon Wallace via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" I'll chime in here...I removed the VBT from the K600 because it was fairly well rusted inside and needed to be replaced, however I am planning on using the ballast/float method instead and forgoing the VBT altogether for many of the reasons Alec and Cliff cited.? I will say that it can be challenging to change ballast on-station since the weight/floatation has to be transferred somewhere and by somebody, however I see the K600 being trimmed for specific missions prior to launch and not being trimmed dynamically on-station to embark/disembark passengers or equipment. Jon ? ? On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via Personal_Submersibles wrote:? I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify,?and it worked so well I never thought of using?any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best,Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles wrote: Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 36 ****************************************************** _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 16 22:25:12 2023 From: personal_submersibles at psubs.org (via Personal_Submersibles) Date: Thu, 17 Aug 2023 14:25:12 +1200 Subject: [PSUBS-MAILIST] Personal_Submersibles Digest, Vol 120, Issue 40 In-Reply-To: References: Message-ID: <037801d9d0b2$0e871470$2b953d50$@gmail.com> Hi Cliff, I am interested in your comments re the pump slippage etc and operation of the VBTs when you were using them. My approach, untried and purely theoretical, was that most of the VBT adjustment would be done just below the surface and only minor adjustment for compression of vessels etc would be done at depth. I do appreciate that weight balance appears more foolproof. Regards, Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 1:02 PM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 40 Send Personal_Submersibles mailing list submissions to personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to personal_submersibles-request at psubs.org You can reach the person managing the list at personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: 1. Re: Re VBT Pump (Cliff Redus via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Thu, 17 Aug 2023 01:01:56 +0000 (UTC) From: Cliff Redus via Personal_Submersibles To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] Re VBT Pump Message-ID: <2137621386.758356.1692234116222 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, thanks for update on QSub.? I am looking forward to her dunk test in your new test pool. I quite enjoyed sitting in her pressure hull in your shop in New Zealand a few years back.? She will be quite something when complete. Best On Wednesday, August 16, 2023 at 06:43:41 PM CDT, via Personal_Submersibles wrote: Thanks, Cliff, Alec, Vance, Jon. The model I was looking at, correction, was the Oberdorfer 994 which is same as a 2000 series but 3/8" - 1/2"? and direct mounted not foot mounted as per the 2000 series. The other pump I liked was the Wanner D10 which is diaphragm and can do no slippage and 250 -300 psi etc but it is not bidirectional.? However that can be fixed with valves. I am making some progress with my Q-Sub but made the mistake of going too complex and trying to do everything.? I? have had issues with --- 1. BMS systems for the LiFePO4 batteries and had to replace these. 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. 3. Gear cable kinking for the mercruiser sternlegs. 4. Inaccessible fuses and not motor rated. 5. Mechanical seal leakage on the hydraulics. 6. Joystick pot issues. 7. Canbus systems at different voltages. 8. Rotary sensors too coarse required op amp addition to amplify signals for small rotary movements with steering. 9. Port Engine starting issues. 10. Oil compensation line fittings leaks. 11. Software issues. Still plugging along.? IN the meantime I have built a test pool same-same Hank 8 ft deep 12 wide x 27 long, and another gantry crane for PVHO removal, as well as a shed just for the sub.? This year it has to be finished.? Has not even been in the pool yet!! Regards,? Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 3:21 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 36 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) ? 2. Re: FW: VBT pump (Alec Smyth via Personal_Submersibles) ? 3. Re: FW: VBT pump (Jon Wallace via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 2 Date: Wed, 16 Aug 2023 09:41:53 -0400 From: Alec Smyth via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: ??? Content-Type: text/plain; charset="utf-8" I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify, and it worked so well I never thought of using any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best, Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat.? My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT.? I don't remember the specs on the > pump.? I had motorized ball valves on the vent and flood side of the > VBT.? Prior to using this set up, I did some testing of this gear pump > which I still have.? What I found was an unacceptable amount of flow > slippage at my max design depth.? There was so much slippage that the > pump could not blow the VBT at max depth.? At that point I abandoned > using a pump and vent to blowing the VBT with air.? I eventually > abandoned the VBT altogether for operability reasons.? When I used > this hard VBT to get neutral on the surface, the pressure in the tank > was low.? When at depth if I ever tried to use the VBT, water would > rush in until the pressure equalized with ambient water pressure.? > This made the boat negatively buoyant until air was added.? The other > thing that bugged me was I had a float style level sensor in the VBT.? > The water level in the VBT was always moving around so you never trust > the reading.? I eventually abandoned the VBT and now just add ballast > at the boat CG where the VBT was located.? I find this works great.? > The other issue is the VBT restricted access to equipment aft of > the VBT so to work on any of this equipment, I had to remove the VBT. All > in all, I found the VBT to be a pain in butt. > > Cliff > > Oberdorfer 944 Bronze > > On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles < personal_submersibles at psubs.org> wrote: > > > Hi Guys > > > > What make of pump is best for VBT water transfer in/out for 250 psi > 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are > only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel > backed sleeve bearings. > > > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) From: Jon Wallace via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" I'll chime in here...I removed the VBT from the K600 because it was fairly well rusted inside and needed to be replaced, however I am planning on using the ballast/float method instead and forgoing the VBT altogether for many of the reasons Alec and Cliff cited.? I will say that it can be challenging to change ballast on-station since the weight/floatation has to be transferred somewhere and by somebody, however I see the K600 being trimmed for specific missions prior to launch and not being trimmed dynamically on-station to embark/disembark passengers or equipment. Jon ? ? On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via Personal_Submersibles wrote:? I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify,?and it worked so well I never thought of using?any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best,Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles wrote: Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... 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URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 40 ****************************************************** From personal_submersibles at psubs.org Wed Aug 16 23:18:46 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Thu, 17 Aug 2023 03:18:46 +0000 (UTC) Subject: [PSUBS-MAILIST] Personal_Submersibles Digest, Vol 120, Issue 40 In-Reply-To: <037801d9d0b2$0e871470$2b953d50$@gmail.com> References: <037801d9d0b2$0e871470$2b953d50$@gmail.com> Message-ID: <1628568723.807762.1692242326936@mail.yahoo.com> Hugh, I understand the attraction of using VBT for QSub.? With a mission profile to be able to do long ocean surface transects to a dive location, submerge, dive, surface and then transect back.? It is not practical to haul excess ballast since the Qsub is operating more like a submarine than a submersible.? If you can find a positive displacement pump that does not have a lot of slippage at your maximum depth, then the issue I mentioned about opening the VBT at depth and getting negatively buoyant goes away because the pump itself is preventing a large inrush of water.? When this happened on my boat, I had already switched to air for blowing VBT. I would, as you note, adjust the water in the VBT just below the surface after flooding the MBTs.? This was the NOP but sometimes the unexpected happens and you need to add buoyancy at depth with the VBT.? I was diving the R300 about seven years ago at Lake Amistad on the border between Mexico and Texas.? I submerged to about 150 ft in old river bottom. When I lifted of the bottom to start the ascent using my vertical thrusters at an altitude of about 10ft, the boat stopped ascending even with full vertical thrusters.? I was watching the depth gage and I was just going up.? I did not realize it but I was being dragged along by a 5-knot current and was not accenting at a rate I was comfortable with.? The boat at the time was neutrally buoyant.? To increase the rate of ascent, I decided to blow the VBT at depth. The depth was about 140 ft at the time.? When I opened the motorized ball valve on the vent side of the VBT, the boat started descending even though air was being introduced because of this sudden influx of water.? Eventually, the water in the VBT was displaced with air and the boat started to ascend.? When I surfaced, I was about a mile downstream from the tender vessel.? Because the water visibly was so bad, I did not realize I was being dragged by the current so much.?? Cliff On Wednesday, August 16, 2023 at 09:25:55 PM CDT, via Personal_Submersibles wrote: Hi Cliff, I am interested in your comments re the pump slippage etc and operation of the VBTs when you were using them. My approach, untried and purely theoretical, was that most of the VBT adjustment would be done just below the surface and only minor adjustment for compression of vessels etc would be done at depth.? I do appreciate that weight balance appears more foolproof.? Regards, Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 1:02 PM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 40 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: Re VBT Pump (Cliff Redus via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Thu, 17 Aug 2023 01:01:56 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] Re VBT Pump Message-ID: <2137621386.758356.1692234116222 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, thanks for update on QSub.? I am looking forward to her dunk test in your new test pool. I quite enjoyed sitting in her pressure hull in your shop in New Zealand a few years back.? She will be quite something when complete. Best ? ? On Wednesday, August 16, 2023 at 06:43:41 PM CDT, via Personal_Submersibles wrote:? Thanks, Cliff, Alec, Vance, Jon. The model I was looking at, correction, was the Oberdorfer 994 which is same as a 2000 series but 3/8" - 1/2"? and direct mounted not foot mounted as per the 2000 series. The other pump I liked was the Wanner D10 which is diaphragm and can do no slippage and 250 -300 psi etc but it is not bidirectional.? However that can be fixed with valves. I am making some progress with my Q-Sub but made the mistake of going too complex and trying to do everything.? I? have had issues with --- 1. BMS systems for the LiFePO4 batteries and had to replace these. 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. 3. Gear cable kinking for the mercruiser sternlegs. 4. Inaccessible fuses and not motor rated. 5. Mechanical seal leakage on the hydraulics. 6. Joystick pot issues. 7. Canbus systems at different voltages. 8. Rotary sensors too coarse required op amp addition to amplify signals for small rotary movements with steering. 9. Port Engine starting issues. 10. Oil compensation line fittings leaks. 11. Software issues. Still plugging along.? IN the meantime I have built a test pool same-same Hank 8 ft deep 12 wide x 27 long, and another gantry crane for PVHO removal, as well as a shed just for the sub.? This year it has to be finished.? Has not even been in the pool yet!! Regards,? Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 3:21 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 36 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) ? 2. Re: FW: VBT pump (Alec Smyth via Personal_Submersibles) ? 3. Re: FW: VBT pump (Jon Wallace via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 2 Date: Wed, 16 Aug 2023 09:41:53 -0400 From: Alec Smyth via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: ??? Content-Type: text/plain; charset="utf-8" I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify, and it worked so well I never thought of using any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best, Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat.? My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT.? I don't remember the specs on the > pump.? I had motorized ball valves on the vent and flood side of the > VBT.? Prior to using this set up, I did some testing of this gear pump > which I still have.? What I found was an unacceptable amount of flow > slippage at my max design depth.? There was so much slippage that the > pump could not blow the VBT at max depth.? At that point I abandoned > using a pump and vent to blowing the VBT with air.? I eventually > abandoned the VBT altogether for operability reasons.? When I used > this hard VBT to get neutral on the surface, the pressure in the tank > was low.? When at depth if I ever tried to use the VBT, water would > rush in until the pressure equalized with ambient water pressure.? > This made the boat negatively buoyant until air was added.? The other > thing that bugged me was I had a float style level sensor in the VBT.? > The water level in the VBT was always moving around so you never trust > the reading.? I eventually abandoned the VBT and now just add ballast > at the boat CG where the VBT was located.? I find this works great.? > The other issue is the VBT restricted access to equipment aft of > the VBT so to work on any of this equipment, I had to remove the VBT. All > in all, I found the VBT to be a pain in butt. > > Cliff > > Oberdorfer 944 Bronze > > On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles < personal_submersibles at psubs.org> wrote: > > > Hi Guys > > > > What make of pump is best for VBT water transfer in/out for 250 psi > 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are > only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel > backed sleeve bearings. > > > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) From: Jon Wallace via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" I'll chime in here...I removed the VBT from the K600 because it was fairly well rusted inside and needed to be replaced, however I am planning on using the ballast/float method instead and forgoing the VBT altogether for many of the reasons Alec and Cliff cited.? I will say that it can be challenging to change ballast on-station since the weight/floatation has to be transferred somewhere and by somebody, however I see the K600 being trimmed for specific missions prior to launch and not being trimmed dynamically on-station to embark/disembark passengers or equipment. Jon ? ? On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via Personal_Submersibles wrote:? I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify,?and it worked so well I never thought of using?any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best,Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles wrote: Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... 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URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 40 ****************************************************** _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 16 23:28:06 2023 From: personal_submersibles at psubs.org (Sean T. Stevenson via Personal_Submersibles) Date: Thu, 17 Aug 2023 03:28:06 +0000 Subject: [PSUBS-MAILIST] Personal_Submersibles Digest, Vol 120, Issue 40 In-Reply-To: <1628568723.807762.1692242326936@mail.yahoo.com> References: <037801d9d0b2$0e871470$2b953d50$@gmail.com> <1628568723.807762.1692242326936@mail.yahoo.com> Message-ID: I think Sent from Proton Mail mobile -------- Original Message -------- On Aug. 16, 2023, 21:18, Cliff Redus via Personal_Submersibles wrote: > Hugh, I understand the attraction of using VBT for QSub. With a mission profile to be able to do long ocean surface transects to a dive location, submerge, dive, surface and then transect back. It is not practical to haul excess ballast since the Qsub is operating more like a submarine than a submersible. If you can find a positive displacement pump that does not have a lot of slippage at your maximum depth, then the issue I mentioned about opening the VBT at depth and getting negatively buoyant goes away because the pump itself is preventing a large inrush of water. When this happened on my boat, I had already switched to air for blowing VBT. I would, as you note, adjust the water in the VBT just below the surface after flooding the MBTs. This was the NOP but sometimes the unexpected happens and you need to add buoyancy at depth with the VBT. I was diving the R300 about seven years ago at Lake Amistad on the border between Mexico and Texas. I submerged to about 150 ft in old river bottom. When I lifted of the bottom to start the ascent using my vertical thrusters at an altitude of about 10ft, the boat stopped ascending even with full vertical thrusters. I was watching the depth gage and I was just going up. I did not realize it but I was being dragged along by a 5-knot current and was not accenting at a rate I was comfortable with. The boat at the time was neutrally buoyant. To increase the rate of ascent, I decided to blow the VBT at depth. The depth was about 140 ft at the time. When I opened the motorized ball valve on the vent side of the VBT, the boat started descending even though air was being introduced because of this sudden influx of water. Eventually, the water in the VBT was displaced with air and the boat started to ascend. When I surfaced, I was about a mile downstream from the tender vessel. Because the water visibly was so bad, I did not realize I was being dragged by the current so much. > > Cliff > > On Wednesday, August 16, 2023 at 09:25:55 PM CDT, via Personal_Submersibles wrote: > > Hi Cliff, > I am interested in your comments re the pump slippage etc and operation of > the VBTs when you were using them. > My approach, untried and purely theoretical, was that most of the VBT > adjustment would be done just below the surface and only minor adjustment > for compression of vessels etc would be done at depth. > I do appreciate that weight balance appears more foolproof. Regards, Hugh > > -----Original Message----- > From: Personal_Submersibles On > Behalf Of via Personal_Submersibles > Sent: Thursday, August 17, 2023 1:02 PM > To: personal_submersibles at psubs.org > Subject: Personal_Submersibles Digest, Vol 120, Issue 40 > > Send Personal_Submersibles mailing list submissions to > personal_submersibles at psubs.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > or, via email, send a message with subject or body 'help' to > personal_submersibles-request at psubs.org > > You can reach the person managing the list at > personal_submersibles-owner at psubs.org > > When replying, please edit your Subject line so it is more specific than > "Re: Contents of Personal_Submersibles digest..." > > Today's Topics: > > 1. Re: Re VBT Pump (Cliff Redus via Personal_Submersibles) > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 17 Aug 2023 01:01:56 +0000 (UTC) > From: Cliff Redus via Personal_Submersibles > > To: via Personal_Submersibles > Subject: Re: [PSUBS-MAILIST] Re VBT Pump > Message-ID: <2137621386.758356.1692234116222 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > Hugh, thanks for update on QSub.? I am looking forward to her dunk test in > your new test pool. I quite enjoyed sitting in her pressure hull in your > shop in New Zealand a few years back.? She will be quite something when > complete. > Best > On Wednesday, August 16, 2023 at 06:43:41 PM CDT, via > Personal_Submersibles wrote: > > Thanks, Cliff, Alec, Vance, Jon. > > The model I was looking at, correction, was the Oberdorfer 994 which is same > as a 2000 series but 3/8" - 1/2"? and direct mounted not foot mounted as per > the 2000 series. > > The other pump I liked was the Wanner D10 which is diaphragm and can do no > slippage and 250 -300 psi etc but it is not bidirectional.? However that can > be fixed with valves. > > I am making some progress with my Q-Sub but made the mistake of going too > complex and trying to do everything.? I? have had issues with --- 1. BMS > systems for the LiFePO4 batteries and had to replace these. > 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. > 3. Gear cable kinking for the mercruiser sternlegs. > 4. Inaccessible fuses and not motor rated. > 5. Mechanical seal leakage on the hydraulics. > 6. Joystick pot issues. > 7. Canbus systems at different voltages. > 8. Rotary sensors too coarse required op amp addition to amplify signals for > small rotary movements with steering. > 9. Port Engine starting issues. > 10. Oil compensation line fittings leaks. > 11. Software issues. > > Still plugging along.? IN the meantime I have built a test pool same-same > Hank 8 ft deep 12 wide x 27 long, and another gantry crane for PVHO removal, > as well as a shed just for the sub.? This year it has to be finished.? Has > not even been in the pool yet!! > Regards,? Hugh > > -----Original Message----- > From: Personal_Submersibles On > Behalf Of via Personal_Submersibles > Sent: Thursday, August 17, 2023 3:21 AM > To: personal_submersibles at psubs.org > Subject: Personal_Submersibles Digest, Vol 120, Issue 36 > > Send Personal_Submersibles mailing list submissions to ??? > personal_submersibles at psubs.org > > To subscribe or unsubscribe via the World Wide Web, visit ??? > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > or, via email, send a message with subject or body 'help' to ??? > personal_submersibles-request at psubs.org > > You can reach the person managing the list at ??? > personal_submersibles-owner at psubs.org > > When replying, please edit your Subject line so it is more specific than > "Re: Contents of Personal_Submersibles digest..." > > Today's Topics: > > ? 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) ? 2. Re: FW: > VBT pump (Alec Smyth via Personal_Submersibles) ? 3. Re: FW: VBT pump (Jon > Wallace via Personal_Submersibles) > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) > From: Cliff Redus via Personal_Submersibles ??? > > To: via Personal_Submersibles > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > Hugh, on my original design for the R300 I had a hard VBT just aft of the > pilot. At the time I had a small HPU in the boat.? My plan was to use a > Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water > in and out of the VBT.? I don't remember the specs on the pump.? I had > motorized ball valves on the vent and flood side of the VBT.? Prior to using > this set up, I did some testing of this gear pump which I still have.? What > I found was an unacceptable amount of flow slippage at my max design depth.? > There was so much slippage that the pump could not blow the VBT at max > depth.? At that point I abandoned using a pump and vent to blowing the VBT > with air.? I eventually abandoned the VBT altogether for operability > reasons.? When I used this hard VBT to get neutral on the surface, the > pressure in the tank was low.? When at depth if I ever tried to use the VBT, > water would rush in until the pressure equalized with ambient water > pressure.? This made the boat nega! > tively buoyant until air was added.? The other thing that bugged me was I > had a float style level sensor in the VBT.? The water level in the VBT was > always moving around so you never trust the reading.? I eventually abandoned > the VBT and now just add ballast at the boat CG where the VBT was located.? > I find this works great.? The other issue is the VBT restricted access to > equipment aft of the VBT so to work on any of this equipment, I had to > remove the VBT.? ?All in all, I found the VBT to be a pain in butt. > Cliff > Oberdorfer 944 Bronze > > ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles > wrote:? > > Hi Guys > > ? > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only > rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a > stainless and bronze gear set made up but the aluminium body corroded form > the trials and I just found that they had used steel backed sleeve bearings. > > ? > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > ? > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > b13a39c1/attachment-0001.html> > > ------------------------------ > > Message: 2 > Date: Wed, 16 Aug 2023 09:41:53 -0400 > From: Alec Smyth via Personal_Submersibles ??? > > To: Personal Submersibles General Discussion ??? > > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: > ??? > Content-Type: text/plain; charset="utf-8" > > I second that (getting rid of VBT). I got rid of the VBT in my K250 years > ago to make space and turn it into a 2-person and to try and to simplify, > and it worked so well I never thought of using any other method on the > current sub. The only difference with Cliff's method is that I add or remove > floats, while he uses ballast. But either way, once you have a reference > point for how much ballast/buoyancy you need for a given crew weight, you > just make incremental changes and it never fails. You may be off neutral by > just a few pounds, but if you have vertical thrusters they're usually just > ticking over at slow RPMs to compensate. > > Best, > Alec > > On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > >> Hugh, on my original design for the R300 I had a hard VBT just aft of >> the pilot. At the time I had a small HPU in the boat.? My plan was to >> use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to >> move water in and out of the VBT.? I don't remember the specs on the >> pump.? I had motorized ball valves on the vent and flood side of the >> VBT.? Prior to using this set up, I did some testing of this gear pump >> which I still have.? What I found was an unacceptable amount of flow >> slippage at my max design depth.? There was so much slippage that the >> pump could not blow the VBT at max depth.? At that point I abandoned >> using a pump and vent to blowing the VBT with air.? I eventually >> abandoned the VBT altogether for operability reasons.? When I used >> this hard VBT to get neutral on the surface, the pressure in the tank >> was low.? When at depth if I ever tried to use the VBT, water would >> rush in until the pressure equalized with ambient water pressure.? >> This made the boat negatively buoyant until air was added.? The other >> thing that bugged me was I had a float style level sensor in the VBT.? >> The water level in the VBT was always moving around so you never trust >> the reading.? I eventually abandoned the VBT and now just add ballast >> at the boat CG where the VBT was located.? I find this works great.? >> The > other issue is the VBT restricted access to equipment aft of >> the VBT so to work on any of this equipment, I had to remove the VBT. > All >> in all, I found the VBT to be a pain in butt. >> >> Cliff >> >> Oberdorfer 944 Bronze >> >> On Sunday, August 13, 2023 at 04:57:24 PM CDT, via >> Personal_Submersibles < personal_submersibles at psubs.org> wrote: >> >> >> Hi Guys >> >> >> >> What make of pump is best for VBT water transfer in/out for 250 psi >> 1.5 > kw. >> >> I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are >> only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I >> had a stainless and bronze gear set made up but the aluminium body >> corroded form the trials and I just found that they had used steel >> backed > sleeve bearings. >> >> >> >> Regards, >> >> Hugh >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >> > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > b5338913/attachment-0001.html> > > ------------------------------ > > Message: 3 > Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) > From: Jon Wallace via Personal_Submersibles ??? > > To: Personal Submersibles General Discussion ??? > > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > I'll chime in here...I removed the VBT from the K600 because it was fairly > well rusted inside and needed to be replaced, however I am planning on using > the ballast/float method instead and forgoing the VBT altogether for many of > the reasons Alec and Cliff cited.? I will say that it can be challenging to > change ballast on-station since the weight/floatation has to be transferred > somewhere and by somebody, however I see the K600 being trimmed for specific > missions prior to launch and not being trimmed dynamically on-station to > embark/disembark passengers or equipment. > Jon > > ? ? On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via > Personal_Submersibles wrote:? > > I second that (getting rid of VBT). I got rid of the VBT in my K250 years > ago to make space and turn it into a 2-person and to try and to > simplify,?and it worked so well I never thought of using?any other method on > the current sub. The only difference with Cliff's method is that I add or > remove floats, while he uses ballast. But either way, once you have a > reference point for how much ballast/buoyancy you need for a given crew > weight, you just make incremental changes and it never fails. You may be off > neutral by just a few pounds, but if you have vertical thrusters they're > usually just ticking over at slow RPMs to compensate. > > Best,Alec > On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles > wrote: > > Hugh, on my original design for the R300 I had a hard VBT just aft of the > pilot. At the time I had a small HPU in the boat.? My plan was to use a > Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water > in and out of the VBT.? I don't remember the specs on the pump.? I had > motorized ball valves on the vent and flood side of the VBT.? Prior to using > this set up, I did some testing of this gear pump which I still have.? What > I found was an unacceptable amount of flow slippage at my max design depth.? > There was so much slippage that the pump could not blow the VBT at max > depth.? At that point I abandoned using a pump and vent to blowing the VBT > with air.? I eventually abandoned the VBT altogether for operability > reasons.? When I used this hard VBT to get neutral on the surface, the > pressure in the tank was low.? When at depth if I ever tried to use the VBT, > water would rush in until the pressure equalized with ambient water > pressure.? This made the boat nega! > tively buoyant until air was added.? The other thing that bugged me was I > had a float style level sensor in the VBT.? The water level in the VBT was > always moving around so you never trust the reading.? I eventually abandoned > the VBT and now just add ballast at the boat CG where the VBT was located.? > I find this works great.? The other issue is the VBT restricted access to > equipment aft of the VBT so to work on any of this equipment, I had to > remove the VBT.? ?All in all, I found the VBT to be a pain in butt. > Cliff > Oberdorfer 944 Bronze > > ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles > wrote:? > > Hi Guys > > ? > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only > rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a > stainless and bronze gear set made up but the aluminium body corroded form > the trials and I just found that they had used steel backed sleeve bearings. > > ? > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > ? _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > ? > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > 301b6d76/attachment.html> > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > > ------------------------------ > > End of Personal_Submersibles Digest, Vol 120, Issue 36 > ****************************************************** > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > b598be5b/attachment.html> > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > > ------------------------------ > > End of Personal_Submersibles Digest, Vol 120, Issue 40 > ****************************************************** > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 16 23:58:34 2023 From: personal_submersibles at psubs.org (Sean T. Stevenson via Personal_Submersibles) Date: Thu, 17 Aug 2023 03:58:34 +0000 Subject: [PSUBS-MAILIST] Personal_Submersibles Digest, Vol 120, Issue 40 In-Reply-To: <1628568723.807762.1692242326936@mail.yahoo.com> References: <037801d9d0b2$0e871470$2b953d50$@gmail.com> <1628568723.807762.1692242326936@mail.yahoo.com> Message-ID: I think I may have offered this the last time the VBT discussion came up, but I always thought that a good control scheme for the VBT would be to automate it within a slave loop to the vertical thruster control. So, for example, you have a position setpoint in the vertical direction which is either auto-depth or auto-altitude, and have your vertical thrusters programmed to respond accordingly to maintain that setpoint. Separately, you monitor the instantaneous output to the vertical thrusters that results from that control loop, filtered on a longer time base, and operate one of two valves via a slower acting control loop to either admit water to the VBT, or open the pump discharge to let water out, as necessary in order to null out that thruster input. This way, external disturbances such as vertical currents, or buoyancy changes due to hull deflection at depth etc., would be compensated for automatically, and the system would also act to conserve energy by minimizing power consumption to the vertical thrusters, by always dialing the boat to neutral. When not holding an altitude or depth, the system could also activate whenever the manual thruster command was saturated at 100% in either direction, in order to hasten a long ascent or descent, or possibly to respond to the condition where the available vertical thrust is insufficient. The only caveat would be to make sure that you don't allow so much VBT volume that you couldn't manually counter the resultant buoyant force with opposing thrust in an emergency. Such an embodiment would require a check valve based reciprocating pump, like a Sprague, that could be deadheaded against the discharge valve at full outlet pressure. Opening the discharge valve would cause it to stroke, while closing the discharge valve would deadhead it again. This is possibly a safety feature, because as as long as the pump is not stroking with the discharge valve closed, you know it can develop pressure, and again, having a pump that just stops when pressure builds downstream will conserve the HP air or electrical power used to drive it, in contrast to a pump that must be explicitly run. Just a thought. Sean -------- Original Message -------- On Aug. 16, 2023, 21:18, Cliff Redus via Personal_Submersibles wrote: > Hugh, I understand the attraction of using VBT for QSub. With a mission profile to be able to do long ocean surface transects to a dive location, submerge, dive, surface and then transect back. It is not practical to haul excess ballast since the Qsub is operating more like a submarine than a submersible. If you can find a positive displacement pump that does not have a lot of slippage at your maximum depth, then the issue I mentioned about opening the VBT at depth and getting negatively buoyant goes away because the pump itself is preventing a large inrush of water. When this happened on my boat, I had already switched to air for blowing VBT. I would, as you note, adjust the water in the VBT just below the surface after flooding the MBTs. This was the NOP but sometimes the unexpected happens and you need to add buoyancy at depth with the VBT. I was diving the R300 about seven years ago at Lake Amistad on the border between Mexico and Texas. I submerged to about 150 ft in old river bottom. When I lifted of the bottom to start the ascent using my vertical thrusters at an altitude of about 10ft, the boat stopped ascending even with full vertical thrusters. I was watching the depth gage and I was just going up. I did not realize it but I was being dragged along by a 5-knot current and was not accenting at a rate I was comfortable with. The boat at the time was neutrally buoyant. To increase the rate of ascent, I decided to blow the VBT at depth. The depth was about 140 ft at the time. When I opened the motorized ball valve on the vent side of the VBT, the boat started descending even though air was being introduced because of this sudden influx of water. Eventually, the water in the VBT was displaced with air and the boat started to ascend. When I surfaced, I was about a mile downstream from the tender vessel. Because the water visibly was so bad, I did not realize I was being dragged by the current so much. > > Cliff > > On Wednesday, August 16, 2023 at 09:25:55 PM CDT, via Personal_Submersibles wrote: > > Hi Cliff, > I am interested in your comments re the pump slippage etc and operation of > the VBTs when you were using them. > My approach, untried and purely theoretical, was that most of the VBT > adjustment would be done just below the surface and only minor adjustment > for compression of vessels etc would be done at depth. > I do appreciate that weight balance appears more foolproof. Regards, Hugh > > -----Original Message----- > From: Personal_Submersibles On > Behalf Of via Personal_Submersibles > Sent: Thursday, August 17, 2023 1:02 PM > To: personal_submersibles at psubs.org > Subject: Personal_Submersibles Digest, Vol 120, Issue 40 > > Send Personal_Submersibles mailing list submissions to > personal_submersibles at psubs.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > or, via email, send a message with subject or body 'help' to > personal_submersibles-request at psubs.org > > You can reach the person managing the list at > personal_submersibles-owner at psubs.org > > When replying, please edit your Subject line so it is more specific than > "Re: Contents of Personal_Submersibles digest..." > > Today's Topics: > > 1. Re: Re VBT Pump (Cliff Redus via Personal_Submersibles) > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 17 Aug 2023 01:01:56 +0000 (UTC) > From: Cliff Redus via Personal_Submersibles > > To: via Personal_Submersibles > Subject: Re: [PSUBS-MAILIST] Re VBT Pump > Message-ID: <2137621386.758356.1692234116222 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > Hugh, thanks for update on QSub.? I am looking forward to her dunk test in > your new test pool. I quite enjoyed sitting in her pressure hull in your > shop in New Zealand a few years back.? She will be quite something when > complete. > Best > On Wednesday, August 16, 2023 at 06:43:41 PM CDT, via > Personal_Submersibles wrote: > > Thanks, Cliff, Alec, Vance, Jon. > > The model I was looking at, correction, was the Oberdorfer 994 which is same > as a 2000 series but 3/8" - 1/2"? and direct mounted not foot mounted as per > the 2000 series. > > The other pump I liked was the Wanner D10 which is diaphragm and can do no > slippage and 250 -300 psi etc but it is not bidirectional.? However that can > be fixed with valves. > > I am making some progress with my Q-Sub but made the mistake of going too > complex and trying to do everything.? I? have had issues with --- 1. BMS > systems for the LiFePO4 batteries and had to replace these. > 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. > 3. Gear cable kinking for the mercruiser sternlegs. > 4. Inaccessible fuses and not motor rated. > 5. Mechanical seal leakage on the hydraulics. > 6. Joystick pot issues. > 7. Canbus systems at different voltages. > 8. Rotary sensors too coarse required op amp addition to amplify signals for > small rotary movements with steering. > 9. Port Engine starting issues. > 10. Oil compensation line fittings leaks. > 11. Software issues. > > Still plugging along.? IN the meantime I have built a test pool same-same > Hank 8 ft deep 12 wide x 27 long, and another gantry crane for PVHO removal, > as well as a shed just for the sub.? This year it has to be finished.? Has > not even been in the pool yet!! > Regards,? Hugh > > -----Original Message----- > From: Personal_Submersibles On > Behalf Of via Personal_Submersibles > Sent: Thursday, August 17, 2023 3:21 AM > To: personal_submersibles at psubs.org > Subject: Personal_Submersibles Digest, Vol 120, Issue 36 > > Send Personal_Submersibles mailing list submissions to ??? > personal_submersibles at psubs.org > > To subscribe or unsubscribe via the World Wide Web, visit ??? > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > or, via email, send a message with subject or body 'help' to ??? > personal_submersibles-request at psubs.org > > You can reach the person managing the list at ??? > personal_submersibles-owner at psubs.org > > When replying, please edit your Subject line so it is more specific than > "Re: Contents of Personal_Submersibles digest..." > > Today's Topics: > > ? 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) ? 2. Re: FW: > VBT pump (Alec Smyth via Personal_Submersibles) ? 3. Re: FW: VBT pump (Jon > Wallace via Personal_Submersibles) > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) > From: Cliff Redus via Personal_Submersibles ??? > > To: via Personal_Submersibles > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > Hugh, on my original design for the R300 I had a hard VBT just aft of the > pilot. At the time I had a small HPU in the boat.? My plan was to use a > Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water > in and out of the VBT.? I don't remember the specs on the pump.? I had > motorized ball valves on the vent and flood side of the VBT.? Prior to using > this set up, I did some testing of this gear pump which I still have.? What > I found was an unacceptable amount of flow slippage at my max design depth.? > There was so much slippage that the pump could not blow the VBT at max > depth.? At that point I abandoned using a pump and vent to blowing the VBT > with air.? I eventually abandoned the VBT altogether for operability > reasons.? When I used this hard VBT to get neutral on the surface, the > pressure in the tank was low.? When at depth if I ever tried to use the VBT, > water would rush in until the pressure equalized with ambient water > pressure.? This made the boat nega! > tively buoyant until air was added.? The other thing that bugged me was I > had a float style level sensor in the VBT.? The water level in the VBT was > always moving around so you never trust the reading.? I eventually abandoned > the VBT and now just add ballast at the boat CG where the VBT was located.? > I find this works great.? The other issue is the VBT restricted access to > equipment aft of the VBT so to work on any of this equipment, I had to > remove the VBT.? ?All in all, I found the VBT to be a pain in butt. > Cliff > Oberdorfer 944 Bronze > > ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles > wrote:? > > Hi Guys > > ? > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only > rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a > stainless and bronze gear set made up but the aluminium body corroded form > the trials and I just found that they had used steel backed sleeve bearings. > > ? > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > ? > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > b13a39c1/attachment-0001.html> > > ------------------------------ > > Message: 2 > Date: Wed, 16 Aug 2023 09:41:53 -0400 > From: Alec Smyth via Personal_Submersibles ??? > > To: Personal Submersibles General Discussion ??? > > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: > ??? > Content-Type: text/plain; charset="utf-8" > > I second that (getting rid of VBT). I got rid of the VBT in my K250 years > ago to make space and turn it into a 2-person and to try and to simplify, > and it worked so well I never thought of using any other method on the > current sub. The only difference with Cliff's method is that I add or remove > floats, while he uses ballast. But either way, once you have a reference > point for how much ballast/buoyancy you need for a given crew weight, you > just make incremental changes and it never fails. You may be off neutral by > just a few pounds, but if you have vertical thrusters they're usually just > ticking over at slow RPMs to compensate. > > Best, > Alec > > On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > >> Hugh, on my original design for the R300 I had a hard VBT just aft of >> the pilot. At the time I had a small HPU in the boat.? My plan was to >> use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to >> move water in and out of the VBT.? I don't remember the specs on the >> pump.? I had motorized ball valves on the vent and flood side of the >> VBT.? Prior to using this set up, I did some testing of this gear pump >> which I still have.? What I found was an unacceptable amount of flow >> slippage at my max design depth.? There was so much slippage that the >> pump could not blow the VBT at max depth.? At that point I abandoned >> using a pump and vent to blowing the VBT with air.? I eventually >> abandoned the VBT altogether for operability reasons.? When I used >> this hard VBT to get neutral on the surface, the pressure in the tank >> was low.? When at depth if I ever tried to use the VBT, water would >> rush in until the pressure equalized with ambient water pressure.? >> This made the boat negatively buoyant until air was added.? The other >> thing that bugged me was I had a float style level sensor in the VBT.? >> The water level in the VBT was always moving around so you never trust >> the reading.? I eventually abandoned the VBT and now just add ballast >> at the boat CG where the VBT was located.? I find this works great.? >> The > other issue is the VBT restricted access to equipment aft of >> the VBT so to work on any of this equipment, I had to remove the VBT. > All >> in all, I found the VBT to be a pain in butt. >> >> Cliff >> >> Oberdorfer 944 Bronze >> >> On Sunday, August 13, 2023 at 04:57:24 PM CDT, via >> Personal_Submersibles < personal_submersibles at psubs.org> wrote: >> >> >> Hi Guys >> >> >> >> What make of pump is best for VBT water transfer in/out for 250 psi >> 1.5 > kw. >> >> I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are >> only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I >> had a stainless and bronze gear set made up but the aluminium body >> corroded form the trials and I just found that they had used steel >> backed > sleeve bearings. >> >> >> >> Regards, >> >> Hugh >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >> > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > b5338913/attachment-0001.html> > > ------------------------------ > > Message: 3 > Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) > From: Jon Wallace via Personal_Submersibles ??? > > To: Personal Submersibles General Discussion ??? > > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > I'll chime in here...I removed the VBT from the K600 because it was fairly > well rusted inside and needed to be replaced, however I am planning on using > the ballast/float method instead and forgoing the VBT altogether for many of > the reasons Alec and Cliff cited.? I will say that it can be challenging to > change ballast on-station since the weight/floatation has to be transferred > somewhere and by somebody, however I see the K600 being trimmed for specific > missions prior to launch and not being trimmed dynamically on-station to > embark/disembark passengers or equipment. > Jon > > ? ? On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via > Personal_Submersibles wrote:? > > I second that (getting rid of VBT). I got rid of the VBT in my K250 years > ago to make space and turn it into a 2-person and to try and to > simplify,?and it worked so well I never thought of using?any other method on > the current sub. The only difference with Cliff's method is that I add or > remove floats, while he uses ballast. But either way, once you have a > reference point for how much ballast/buoyancy you need for a given crew > weight, you just make incremental changes and it never fails. You may be off > neutral by just a few pounds, but if you have vertical thrusters they're > usually just ticking over at slow RPMs to compensate. > > Best,Alec > On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles > wrote: > > Hugh, on my original design for the R300 I had a hard VBT just aft of the > pilot. At the time I had a small HPU in the boat.? My plan was to use a > Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water > in and out of the VBT.? I don't remember the specs on the pump.? I had > motorized ball valves on the vent and flood side of the VBT.? Prior to using > this set up, I did some testing of this gear pump which I still have.? What > I found was an unacceptable amount of flow slippage at my max design depth.? > There was so much slippage that the pump could not blow the VBT at max > depth.? At that point I abandoned using a pump and vent to blowing the VBT > with air.? I eventually abandoned the VBT altogether for operability > reasons.? When I used this hard VBT to get neutral on the surface, the > pressure in the tank was low.? When at depth if I ever tried to use the VBT, > water would rush in until the pressure equalized with ambient water > pressure.? This made the boat nega! > tively buoyant until air was added.? The other thing that bugged me was I > had a float style level sensor in the VBT.? The water level in the VBT was > always moving around so you never trust the reading.? I eventually abandoned > the VBT and now just add ballast at the boat CG where the VBT was located.? > I find this works great.? The other issue is the VBT restricted access to > equipment aft of the VBT so to work on any of this equipment, I had to > remove the VBT.? ?All in all, I found the VBT to be a pain in butt. > Cliff > Oberdorfer 944 Bronze > > ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles > wrote:? > > Hi Guys > > ? > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only > rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a > stainless and bronze gear set made up but the aluminium body corroded form > the trials and I just found that they had used steel backed sleeve bearings. > > ? > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > ? _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > ? > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > 301b6d76/attachment.html> > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > > ------------------------------ > > End of Personal_Submersibles Digest, Vol 120, Issue 36 > ****************************************************** > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > b598be5b/attachment.html> > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > > ------------------------------ > > End of Personal_Submersibles Digest, Vol 120, Issue 40 > ****************************************************** > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Thu Aug 17 08:17:17 2023 From: personal_submersibles at psubs.org (hank pronk via Personal_Submersibles) Date: Thu, 17 Aug 2023 12:17:17 +0000 (UTC) Subject: [PSUBS-MAILIST] Re VBT Pump In-Reply-To: <2137621386.758356.1692234116222@mail.yahoo.com> References: <035f01d9d09b$653a05f0$2fae11d0$@gmail.com> <2137621386.758356.1692234116222@mail.yahoo.com> Message-ID: <461193146.900097.1692274637765@mail.yahoo.com> Hugh,You mentioned a long time ago, you were going to use a sea can for a pool. ?Is that what you did? ?My pool cost me about 3,500 dollars, but has paid for itself easily. ?Plus it is much safer.Hank On Wednesday, August 16, 2023, 07:02:15 PM MDT, Cliff Redus via Personal_Submersibles wrote: Hugh, thanks for update on QSub.? I am looking forward to her dunk test in your new test pool. I quite enjoyed sitting in her pressure hull in your shop in New Zealand a few years back.? She will be quite something when complete. Best On Wednesday, August 16, 2023 at 06:43:41 PM CDT, via Personal_Submersibles wrote: Thanks, Cliff, Alec, Vance, Jon. The model I was looking at, correction, was the Oberdorfer 994 which is same as a 2000 series but 3/8" - 1/2"? and direct mounted not foot mounted as per the 2000 series. The other pump I liked was the Wanner D10 which is diaphragm and can do no slippage and 250 -300 psi etc but it is not bidirectional.? However that can be fixed with valves. I am making some progress with my Q-Sub but made the mistake of going too complex and trying to do everything.? I? have had issues with --- 1. BMS systems for the LiFePO4 batteries and had to replace these. 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. 3. Gear cable kinking for the mercruiser sternlegs. 4. Inaccessible fuses and not motor rated. 5. Mechanical seal leakage on the hydraulics. 6. Joystick pot issues. 7. Canbus systems at different voltages. 8. Rotary sensors too coarse required op amp addition to amplify signals for small rotary movements with steering. 9. Port Engine starting issues. 10. Oil compensation line fittings leaks. 11. Software issues. Still plugging along.? IN the meantime I have built a test pool same-same Hank 8 ft deep 12 wide x 27 long, and another gantry crane for PVHO removal, as well as a shed just for the sub.? This year it has to be finished.? Has not even been in the pool yet!! Regards,? Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 3:21 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 36 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) ? 2. Re: FW: VBT pump (Alec Smyth via Personal_Submersibles) ? 3. Re: FW: VBT pump (Jon Wallace via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 2 Date: Wed, 16 Aug 2023 09:41:53 -0400 From: Alec Smyth via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: ??? Content-Type: text/plain; charset="utf-8" I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify, and it worked so well I never thought of using any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best, Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat.? My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT.? I don't remember the specs on the > pump.? I had motorized ball valves on the vent and flood side of the > VBT.? Prior to using this set up, I did some testing of this gear pump > which I still have.? What I found was an unacceptable amount of flow > slippage at my max design depth.? There was so much slippage that the > pump could not blow the VBT at max depth.? At that point I abandoned > using a pump and vent to blowing the VBT with air.? I eventually > abandoned the VBT altogether for operability reasons.? When I used > this hard VBT to get neutral on the surface, the pressure in the tank > was low.? When at depth if I ever tried to use the VBT, water would > rush in until the pressure equalized with ambient water pressure.? > This made the boat negatively buoyant until air was added.? The other > thing that bugged me was I had a float style level sensor in the VBT.? > The water level in the VBT was always moving around so you never trust > the reading.? I eventually abandoned the VBT and now just add ballast > at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of > the VBT so to work on any of this equipment, I had to remove the VBT. All > in all, I found the VBT to be a pain in butt. > > Cliff > > Oberdorfer 944 Bronze > > On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles < personal_submersibles at psubs.org> wrote: > > > Hi Guys > > > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are > only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel backed sleeve bearings. > > > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) From: Jon Wallace via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" I'll chime in here...I removed the VBT from the K600 because it was fairly well rusted inside and needed to be replaced, however I am planning on using the ballast/float method instead and forgoing the VBT altogether for many of the reasons Alec and Cliff cited.? I will say that it can be challenging to change ballast on-station since the weight/floatation has to be transferred somewhere and by somebody, however I see the K600 being trimmed for specific missions prior to launch and not being trimmed dynamically on-station to embark/disembark passengers or equipment. Jon ? ? On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via Personal_Submersibles wrote:? I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify,?and it worked so well I never thought of using?any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best,Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles wrote: Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 36 ****************************************************** _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Thu Aug 17 10:24:03 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Thu, 17 Aug 2023 14:24:03 +0000 (UTC) Subject: [PSUBS-MAILIST] Personal_Submersibles Digest, Vol 120, Issue 40 In-Reply-To: References: <037801d9d0b2$0e871470$2b953d50$@gmail.com> <1628568723.807762.1692242326936@mail.yahoo.com> Message-ID: <311293821.973720.1692282243195@mail.yahoo.com> Sean, I think this control strategy could work.? To utilize, you would need a PLC or microprocessor to implement a PID loop.? It would be easy to test by putting the sub in shallow test tank to test depth station keeping capability.? You could then upset the system by adding some lead ballast to the boat and see how well the VBT/Thrusters handle the upset. My guess is that those in our group that like the KISS strategy would deems this as too complicated while those that like this kind of approach would see some nice benefits of this control strategy.? My experience with Psubs is that someone try's something new and if it works incrementally better than what they were using, they adopt.? For me it would have to be modified as I don't have a VBT, i.e., I could implement a depth/altitude station keeping PLC function with a PID loop controlling either depth or altitude with vertical thrusters alone. Cliff On Wednesday, August 16, 2023 at 10:59:28 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: I think I may have offered this the last time the VBT discussion came up, but I always thought that a good control scheme for the VBT would be to automate it within a slave loop to the vertical thruster control. So, for example, you have a position setpoint in the vertical direction which is either auto-depth or auto-altitude, and have your vertical thrusters programmed to respond accordingly to maintain that setpoint. Separately, you monitor the instantaneous output to the vertical thrusters that results from that control loop, filtered on a longer time base, and operate one of two valves via a slower acting control loop to either admit water to the VBT, or open the pump discharge to let water out, as necessary in order to null out that thruster input. This way, external disturbances such as vertical currents, or buoyancy changes due to hull deflection at depth etc., would be compensated for automatically, and the system would also act to conserve energy by minimizing power consumption to the vertical thrusters, by always dialing the boat to neutral. When not holding an altitude or depth, the system could also activate whenever the manual thruster command was saturated at 100% in either direction, in order to hasten a long ascent or descent, or possibly to respond to the condition where the available vertical thrust is insufficient. The only caveat would be to make sure that you don't allow so much VBT volume that you couldn't manually counter the resultant buoyant force with opposing thrust in an emergency. Such an embodiment would require a check valve based reciprocating pump, like a Sprague, that could be deadheaded against the discharge valve at full outlet pressure. Opening the discharge valve would cause it to stroke, while closing the discharge valve would deadhead it again. This is possibly a safety feature, because as as long as the pump is not stroking with the discharge valve closed, you know it can develop pressure, and again, having a pump that just stops when pressure builds downstream will conserve the HP air or electrical power used to drive it, in contrast to a pump that must be explicitly run. Just a thought. Sean -------- Original Message -------- On Aug. 16, 2023, 21:18, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: Hugh, I understand the attraction of using VBT for QSub.? With a mission profile to be able to do long ocean surface transects to a dive location, submerge, dive, surface and then transect back.? It is not practical to haul excess ballast since the Qsub is operating more like a submarine than a submersible.? If you can find a positive displacement pump that does not have a lot of slippage at your maximum depth, then the issue I mentioned about opening the VBT at depth and getting negatively buoyant goes away because the pump itself is preventing a large inrush of water.? When this happened on my boat, I had already switched to air for blowing VBT. I would, as you note, adjust the water in the VBT just below the surface after flooding the MBTs.? This was the NOP but sometimes the unexpected happens and you need to add buoyancy at depth with the VBT.? I was diving the R300 about seven years ago at Lake Amistad on the border between Mexico and Texas.? I submerged to about 150 ft in old river bottom. When I lifted of the bottom to start the ascent using my vertical thrusters at an altitude of about 10ft, the boat stopped ascending even with full vertical thrusters.? I was watching the depth gage and I was just going up.? I did not realize it but I was being dragged along by a 5-knot current and was not accenting at a rate I was comfortable with.? The boat at the time was neutrally buoyant.? To increase the rate of ascent, I decided to blow the VBT at depth. The depth was about 140 ft at the time.? When I opened the motorized ball valve on the vent side of the VBT, the boat started descending even though air was being introduced because of this sudden influx of water.? Eventually, the water in the VBT was displaced with air and the boat started to ascend.? When I surfaced, I was about a mile downstream from the tender vessel.? Because the water visibly was so bad, I did not realize I was being dragged by the current so much.?? Cliff On Wednesday, August 16, 2023 at 09:25:55 PM CDT, via Personal_Submersibles wrote: Hi Cliff, I am interested in your comments re the pump slippage etc and operation of the VBTs when you were using them. My approach, untried and purely theoretical, was that most of the VBT adjustment would be done just below the surface and only minor adjustment for compression of vessels etc would be done at depth.? I do appreciate that weight balance appears more foolproof.? Regards, Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 1:02 PM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 40 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: Re VBT Pump (Cliff Redus via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Thu, 17 Aug 2023 01:01:56 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] Re VBT Pump Message-ID: <2137621386.758356.1692234116222 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, thanks for update on QSub.? I am looking forward to her dunk test in your new test pool. I quite enjoyed sitting in her pressure hull in your shop in New Zealand a few years back.? She will be quite something when complete. Best ? ? On Wednesday, August 16, 2023 at 06:43:41 PM CDT, via Personal_Submersibles wrote:? Thanks, Cliff, Alec, Vance, Jon. The model I was looking at, correction, was the Oberdorfer 994 which is same as a 2000 series but 3/8" - 1/2"? and direct mounted not foot mounted as per the 2000 series. The other pump I liked was the Wanner D10 which is diaphragm and can do no slippage and 250 -300 psi etc but it is not bidirectional.? However that can be fixed with valves. I am making some progress with my Q-Sub but made the mistake of going too complex and trying to do everything.? I? have had issues with --- 1. BMS systems for the LiFePO4 batteries and had to replace these. 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. 3. Gear cable kinking for the mercruiser sternlegs. 4. Inaccessible fuses and not motor rated. 5. Mechanical seal leakage on the hydraulics. 6. Joystick pot issues. 7. Canbus systems at different voltages. 8. Rotary sensors too coarse required op amp addition to amplify signals for small rotary movements with steering. 9. Port Engine starting issues. 10. Oil compensation line fittings leaks. 11. Software issues. Still plugging along.? IN the meantime I have built a test pool same-same Hank 8 ft deep 12 wide x 27 long, and another gantry crane for PVHO removal, as well as a shed just for the sub.? This year it has to be finished.? Has not even been in the pool yet!! Regards,? Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 3:21 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 36 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) ? 2. Re: FW: VBT pump (Alec Smyth via Personal_Submersibles) ? 3. Re: FW: VBT pump (Jon Wallace via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 2 Date: Wed, 16 Aug 2023 09:41:53 -0400 From: Alec Smyth via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: ??? Content-Type: text/plain; charset="utf-8" I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify, and it worked so well I never thought of using any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best, Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat.? My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT.? I don't remember the specs on the > pump.? I had motorized ball valves on the vent and flood side of the > VBT.? Prior to using this set up, I did some testing of this gear pump > which I still have.? What I found was an unacceptable amount of flow > slippage at my max design depth.? There was so much slippage that the > pump could not blow the VBT at max depth.? At that point I abandoned > using a pump and vent to blowing the VBT with air.? I eventually > abandoned the VBT altogether for operability reasons.? When I used > this hard VBT to get neutral on the surface, the pressure in the tank > was low.? When at depth if I ever tried to use the VBT, water would > rush in until the pressure equalized with ambient water pressure.? > This made the boat negatively buoyant until air was added.? The other > thing that bugged me was I had a float style level sensor in the VBT.? > The water level in the VBT was always moving around so you never trust > the reading.? I eventually abandoned the VBT and now just add ballast > at the boat CG where the VBT was located.? I find this works great.? > The other issue is the VBT restricted access to equipment aft of > the VBT so to work on any of this equipment, I had to remove the VBT. All > in all, I found the VBT to be a pain in butt. > > Cliff > > Oberdorfer 944 Bronze > > On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles < personal_submersibles at psubs.org> wrote: > > > Hi Guys > > > > What make of pump is best for VBT water transfer in/out for 250 psi > 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are > only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel > backed sleeve bearings. > > > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) From: Jon Wallace via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" I'll chime in here...I removed the VBT from the K600 because it was fairly well rusted inside and needed to be replaced, however I am planning on using the ballast/float method instead and forgoing the VBT altogether for many of the reasons Alec and Cliff cited.? I will say that it can be challenging to change ballast on-station since the weight/floatation has to be transferred somewhere and by somebody, however I see the K600 being trimmed for specific missions prior to launch and not being trimmed dynamically on-station to embark/disembark passengers or equipment. Jon ? ? On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via Personal_Submersibles wrote:? I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify,?and it worked so well I never thought of using?any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best,Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles wrote: Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... 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URL: From personal_submersibles at psubs.org Thu Aug 17 11:50:13 2023 From: personal_submersibles at psubs.org (Jon Wallace via Personal_Submersibles) Date: Thu, 17 Aug 2023 15:50:13 +0000 (UTC) Subject: [PSUBS-MAILIST] Personal_Submersibles Digest, Vol 120, Issue 40 In-Reply-To: <311293821.973720.1692282243195@mail.yahoo.com> References: <037801d9d0b2$0e871470$2b953d50$@gmail.com> <1628568723.807762.1692242326936@mail.yahoo.com> <311293821.973720.1692282243195@mail.yahoo.com> Message-ID: <1852172581.1034074.1692287413417@mail.yahoo.com> Conceptually it's a great idea for automation and likely not a big deal to implement via software code.? I think working out the dynamics in actual practice would require a bit of time.? Assuming you wanted more buoyancy the biggest issue would be the description Cliff gave of adding air to the VBT without the inrush of water because of the pressure difference at depth.? The only solution I see to that is adding a pressure sensor to the VBT and adding air first to counter the outside water pressure, then opening the outside valve to the VBT.? That means another sensor, more software code, and more potential things that could go wrong, which is why I like the simplicity of removing the VBT entirely and just relying on weight control to obtain neutral buoyancy.? BUT...it would be a good project if somebody wanted to implement it. Jon On Thursday, August 17, 2023 at 10:25:56 AM EDT, Cliff Redus via Personal_Submersibles wrote: Sean, I think this control strategy could work.? To utilize, you would need a PLC or microprocessor to implement a PID loop.? It would be easy to test by putting the sub in shallow test tank to test depth station keeping capability.? You could then upset the system by adding some lead ballast to the boat and see how well the VBT/Thrusters handle the upset. My guess is that those in our group that like the KISS strategy would deems this as too complicated while those that like this kind of approach would see some nice benefits of this control strategy.? My experience with Psubs is that someone try's something new and if it works incrementally better than what they were using, they adopt.? For me it would have to be modified as I don't have a VBT, i.e., I could implement a depth/altitude station keeping PLC function with a PID loop controlling either depth or altitude with vertical thrusters alone. Cliff On Wednesday, August 16, 2023 at 10:59:28 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: I think I may have offered this the last time the VBT discussion came up, but I always thought that a good control scheme for the VBT would be to automate it within a slave loop to the vertical thruster control. So, for example, you have a position setpoint in the vertical direction which is either auto-depth or auto-altitude, and have your vertical thrusters programmed to respond accordingly to maintain that setpoint. Separately, you monitor the instantaneous output to the vertical thrusters that results from that control loop, filtered on a longer time base, and operate one of two valves via a slower acting control loop to either admit water to the VBT, or open the pump discharge to let water out, as necessary in order to null out that thruster input. This way, external disturbances such as vertical currents, or buoyancy changes due to hull deflection at depth etc., would be compensated for automatically, and the system would also act to conserve energy by minimizing power consumption to the vertical thrusters, by always dialing the boat to neutral. When not holding an altitude or depth, the system could also activate whenever the manual thruster command was saturated at 100% in either direction, in order to hasten a long ascent or descent, or possibly to respond to the condition where the available vertical thrust is insufficient. The only caveat would be to make sure that you don't allow so much VBT volume that you couldn't manually counter the resultant buoyant force with opposing thrust in an emergency. Such an embodiment would require a check valve based reciprocating pump, like a Sprague, that could be deadheaded against the discharge valve at full outlet pressure. Opening the discharge valve would cause it to stroke, while closing the discharge valve would deadhead it again. This is possibly a safety feature, because as as long as the pump is not stroking with the discharge valve closed, you know it can develop pressure, and again, having a pump that just stops when pressure builds downstream will conserve the HP air or electrical power used to drive it, in contrast to a pump that must be explicitly run. Just a thought. Sean -------- Original Message -------- On Aug. 16, 2023, 21:18, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: Hugh, I understand the attraction of using VBT for QSub.? With a mission profile to be able to do long ocean surface transects to a dive location, submerge, dive, surface and then transect back.? It is not practical to haul excess ballast since the Qsub is operating more like a submarine than a submersible.? If you can find a positive displacement pump that does not have a lot of slippage at your maximum depth, then the issue I mentioned about opening the VBT at depth and getting negatively buoyant goes away because the pump itself is preventing a large inrush of water.? When this happened on my boat, I had already switched to air for blowing VBT. I would, as you note, adjust the water in the VBT just below the surface after flooding the MBTs.? This was the NOP but sometimes the unexpected happens and you need to add buoyancy at depth with the VBT.? I was diving the R300 about seven years ago at Lake Amistad on the border between Mexico and Texas.? I submerged to about 150 ft in old river bottom. When I lifted of the bottom to start the ascent using my vertical thrusters at an altitude of about 10ft, the boat stopped ascending even with full vertical thrusters.? I was watching the depth gage and I was just going up.? I did not realize it but I was being dragged along by a 5-knot current and was not accenting at a rate I was comfortable with.? The boat at the time was neutrally buoyant.? To increase the rate of ascent, I decided to blow the VBT at depth. The depth was about 140 ft at the time.? When I opened the motorized ball valve on the vent side of the VBT, the boat started descending even though air was being introduced because of this sudden influx of water.? Eventually, the water in the VBT was displaced with air and the boat started to ascend.? When I surfaced, I was about a mile downstream from the tender vessel.? Because the water visibly was so bad, I did not realize I was being dragged by the current so much.?? Cliff On Wednesday, August 16, 2023 at 09:25:55 PM CDT, via Personal_Submersibles wrote: Hi Cliff, I am interested in your comments re the pump slippage etc and operation of the VBTs when you were using them. My approach, untried and purely theoretical, was that most of the VBT adjustment would be done just below the surface and only minor adjustment for compression of vessels etc would be done at depth.? I do appreciate that weight balance appears more foolproof.? Regards, Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 1:02 PM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 40 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: Re VBT Pump (Cliff Redus via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Thu, 17 Aug 2023 01:01:56 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] Re VBT Pump Message-ID: <2137621386.758356.1692234116222 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, thanks for update on QSub.? I am looking forward to her dunk test in your new test pool. I quite enjoyed sitting in her pressure hull in your shop in New Zealand a few years back.? She will be quite something when complete. Best ? ? On Wednesday, August 16, 2023 at 06:43:41 PM CDT, via Personal_Submersibles wrote:? Thanks, Cliff, Alec, Vance, Jon. The model I was looking at, correction, was the Oberdorfer 994 which is same as a 2000 series but 3/8" - 1/2"? and direct mounted not foot mounted as per the 2000 series. The other pump I liked was the Wanner D10 which is diaphragm and can do no slippage and 250 -300 psi etc but it is not bidirectional.? However that can be fixed with valves. I am making some progress with my Q-Sub but made the mistake of going too complex and trying to do everything.? I? have had issues with --- 1. BMS systems for the LiFePO4 batteries and had to replace these. 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. 3. Gear cable kinking for the mercruiser sternlegs. 4. Inaccessible fuses and not motor rated. 5. Mechanical seal leakage on the hydraulics. 6. Joystick pot issues. 7. Canbus systems at different voltages. 8. Rotary sensors too coarse required op amp addition to amplify signals for small rotary movements with steering. 9. Port Engine starting issues. 10. Oil compensation line fittings leaks. 11. Software issues. Still plugging along.? IN the meantime I have built a test pool same-same Hank 8 ft deep 12 wide x 27 long, and another gantry crane for PVHO removal, as well as a shed just for the sub.? This year it has to be finished.? Has not even been in the pool yet!! Regards,? Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 3:21 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 36 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) ? 2. Re: FW: VBT pump (Alec Smyth via Personal_Submersibles) ? 3. Re: FW: VBT pump (Jon Wallace via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 2 Date: Wed, 16 Aug 2023 09:41:53 -0400 From: Alec Smyth via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: ??? Content-Type: text/plain; charset="utf-8" I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify, and it worked so well I never thought of using any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best, Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat.? My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT.? I don't remember the specs on the > pump.? I had motorized ball valves on the vent and flood side of the > VBT.? Prior to using this set up, I did some testing of this gear pump > which I still have.? What I found was an unacceptable amount of flow > slippage at my max design depth.? There was so much slippage that the > pump could not blow the VBT at max depth.? At that point I abandoned > using a pump and vent to blowing the VBT with air.? I eventually > abandoned the VBT altogether for operability reasons.? When I used > this hard VBT to get neutral on the surface, the pressure in the tank > was low.? When at depth if I ever tried to use the VBT, water would > rush in until the pressure equalized with ambient water pressure.? > This made the boat negatively buoyant until air was added.? The other > thing that bugged me was I had a float style level sensor in the VBT.? > The water level in the VBT was always moving around so you never trust > the reading.? I eventually abandoned the VBT and now just add ballast > at the boat CG where the VBT was located.? I find this works great.? > The other issue is the VBT restricted access to equipment aft of > the VBT so to work on any of this equipment, I had to remove the VBT. All > in all, I found the VBT to be a pain in butt. > > Cliff > > Oberdorfer 944 Bronze > > On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles < personal_submersibles at psubs.org> wrote: > > > Hi Guys > > > > What make of pump is best for VBT water transfer in/out for 250 psi > 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are > only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel > backed sleeve bearings. > > > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) From: Jon Wallace via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" I'll chime in here...I removed the VBT from the K600 because it was fairly well rusted inside and needed to be replaced, however I am planning on using the ballast/float method instead and forgoing the VBT altogether for many of the reasons Alec and Cliff cited.? I will say that it can be challenging to change ballast on-station since the weight/floatation has to be transferred somewhere and by somebody, however I see the K600 being trimmed for specific missions prior to launch and not being trimmed dynamically on-station to embark/disembark passengers or equipment. Jon ? ? On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via Personal_Submersibles wrote:? I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify,?and it worked so well I never thought of using?any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best,Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles wrote: Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... 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URL: From personal_submersibles at psubs.org Thu Aug 17 12:41:37 2023 From: personal_submersibles at psubs.org (Cliff Redus via Personal_Submersibles) Date: Thu, 17 Aug 2023 16:41:37 +0000 (UTC) Subject: [PSUBS-MAILIST] Personal_Submersibles Digest, Vol 120, Issue 40 In-Reply-To: <1852172581.1034074.1692287413417@mail.yahoo.com> References: <037801d9d0b2$0e871470$2b953d50$@gmail.com> <1628568723.807762.1692242326936@mail.yahoo.com> <311293821.973720.1692282243195@mail.yahoo.com> <1852172581.1034074.1692287413417@mail.yahoo.com> Message-ID: <10223209.1074837.1692290497024@mail.yahoo.com> Jon, if I am understanding Sean correctly, he is advocating using a PD pump with a check valve to move water out of the VBT instead of air pressure so issue of in rush of water when the flood valve is opened goes away. I do agree "working out the dynamics in actual practice would require a bit of time".? Constants for PID controller would have to be experimented with. Cliff On Thursday, August 17, 2023 at 10:51:19 AM CDT, Jon Wallace via Personal_Submersibles wrote: Conceptually it's a great idea for automation and likely not a big deal to implement via software code.? I think working out the dynamics in actual practice would require a bit of time.? Assuming you wanted more buoyancy the biggest issue would be the description Cliff gave of adding air to the VBT without the inrush of water because of the pressure difference at depth.? The only solution I see to that is adding a pressure sensor to the VBT and adding air first to counter the outside water pressure, then opening the outside valve to the VBT.? That means another sensor, more software code, and more potential things that could go wrong, which is why I like the simplicity of removing the VBT entirely and just relying on weight control to obtain neutral buoyancy.? BUT...it would be a good project if somebody wanted to implement it. Jon On Thursday, August 17, 2023 at 10:25:56 AM EDT, Cliff Redus via Personal_Submersibles wrote: Sean, I think this control strategy could work.? To utilize, you would need a PLC or microprocessor to implement a PID loop.? It would be easy to test by putting the sub in shallow test tank to test depth station keeping capability.? You could then upset the system by adding some lead ballast to the boat and see how well the VBT/Thrusters handle the upset. My guess is that those in our group that like the KISS strategy would deems this as too complicated while those that like this kind of approach would see some nice benefits of this control strategy.? My experience with Psubs is that someone try's something new and if it works incrementally better than what they were using, they adopt.? For me it would have to be modified as I don't have a VBT, i.e., I could implement a depth/altitude station keeping PLC function with a PID loop controlling either depth or altitude with vertical thrusters alone. Cliff On Wednesday, August 16, 2023 at 10:59:28 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: I think I may have offered this the last time the VBT discussion came up, but I always thought that a good control scheme for the VBT would be to automate it within a slave loop to the vertical thruster control. So, for example, you have a position setpoint in the vertical direction which is either auto-depth or auto-altitude, and have your vertical thrusters programmed to respond accordingly to maintain that setpoint. Separately, you monitor the instantaneous output to the vertical thrusters that results from that control loop, filtered on a longer time base, and operate one of two valves via a slower acting control loop to either admit water to the VBT, or open the pump discharge to let water out, as necessary in order to null out that thruster input. This way, external disturbances such as vertical currents, or buoyancy changes due to hull deflection at depth etc., would be compensated for automatically, and the system would also act to conserve energy by minimizing power consumption to the vertical thrusters, by always dialing the boat to neutral. When not holding an altitude or depth, the system could also activate whenever the manual thruster command was saturated at 100% in either direction, in order to hasten a long ascent or descent, or possibly to respond to the condition where the available vertical thrust is insufficient. The only caveat would be to make sure that you don't allow so much VBT volume that you couldn't manually counter the resultant buoyant force with opposing thrust in an emergency. Such an embodiment would require a check valve based reciprocating pump, like a Sprague, that could be deadheaded against the discharge valve at full outlet pressure. Opening the discharge valve would cause it to stroke, while closing the discharge valve would deadhead it again. This is possibly a safety feature, because as as long as the pump is not stroking with the discharge valve closed, you know it can develop pressure, and again, having a pump that just stops when pressure builds downstream will conserve the HP air or electrical power used to drive it, in contrast to a pump that must be explicitly run. Just a thought. Sean -------- Original Message -------- On Aug. 16, 2023, 21:18, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: Hugh, I understand the attraction of using VBT for QSub.? With a mission profile to be able to do long ocean surface transects to a dive location, submerge, dive, surface and then transect back.? It is not practical to haul excess ballast since the Qsub is operating more like a submarine than a submersible.? If you can find a positive displacement pump that does not have a lot of slippage at your maximum depth, then the issue I mentioned about opening the VBT at depth and getting negatively buoyant goes away because the pump itself is preventing a large inrush of water.? When this happened on my boat, I had already switched to air for blowing VBT. I would, as you note, adjust the water in the VBT just below the surface after flooding the MBTs.? This was the NOP but sometimes the unexpected happens and you need to add buoyancy at depth with the VBT.? I was diving the R300 about seven years ago at Lake Amistad on the border between Mexico and Texas.? I submerged to about 150 ft in old river bottom. When I lifted of the bottom to start the ascent using my vertical thrusters at an altitude of about 10ft, the boat stopped ascending even with full vertical thrusters.? I was watching the depth gage and I was just going up.? I did not realize it but I was being dragged along by a 5-knot current and was not accenting at a rate I was comfortable with.? The boat at the time was neutrally buoyant.? To increase the rate of ascent, I decided to blow the VBT at depth. The depth was about 140 ft at the time.? When I opened the motorized ball valve on the vent side of the VBT, the boat started descending even though air was being introduced because of this sudden influx of water.? Eventually, the water in the VBT was displaced with air and the boat started to ascend.? When I surfaced, I was about a mile downstream from the tender vessel.? Because the water visibly was so bad, I did not realize I was being dragged by the current so much.?? Cliff On Wednesday, August 16, 2023 at 09:25:55 PM CDT, via Personal_Submersibles wrote: Hi Cliff, I am interested in your comments re the pump slippage etc and operation of the VBTs when you were using them. My approach, untried and purely theoretical, was that most of the VBT adjustment would be done just below the surface and only minor adjustment for compression of vessels etc would be done at depth.? I do appreciate that weight balance appears more foolproof.? Regards, Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 1:02 PM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 40 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: Re VBT Pump (Cliff Redus via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Thu, 17 Aug 2023 01:01:56 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] Re VBT Pump Message-ID: <2137621386.758356.1692234116222 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, thanks for update on QSub.? I am looking forward to her dunk test in your new test pool. I quite enjoyed sitting in her pressure hull in your shop in New Zealand a few years back.? She will be quite something when complete. Best ? ? On Wednesday, August 16, 2023 at 06:43:41 PM CDT, via Personal_Submersibles wrote:? Thanks, Cliff, Alec, Vance, Jon. The model I was looking at, correction, was the Oberdorfer 994 which is same as a 2000 series but 3/8" - 1/2"? and direct mounted not foot mounted as per the 2000 series. The other pump I liked was the Wanner D10 which is diaphragm and can do no slippage and 250 -300 psi etc but it is not bidirectional.? However that can be fixed with valves. I am making some progress with my Q-Sub but made the mistake of going too complex and trying to do everything.? I? have had issues with --- 1. BMS systems for the LiFePO4 batteries and had to replace these. 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. 3. Gear cable kinking for the mercruiser sternlegs. 4. Inaccessible fuses and not motor rated. 5. Mechanical seal leakage on the hydraulics. 6. Joystick pot issues. 7. Canbus systems at different voltages. 8. Rotary sensors too coarse required op amp addition to amplify signals for small rotary movements with steering. 9. Port Engine starting issues. 10. Oil compensation line fittings leaks. 11. Software issues. Still plugging along.? IN the meantime I have built a test pool same-same Hank 8 ft deep 12 wide x 27 long, and another gantry crane for PVHO removal, as well as a shed just for the sub.? This year it has to be finished.? Has not even been in the pool yet!! Regards,? Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 3:21 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 36 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) ? 2. Re: FW: VBT pump (Alec Smyth via Personal_Submersibles) ? 3. Re: FW: VBT pump (Jon Wallace via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 2 Date: Wed, 16 Aug 2023 09:41:53 -0400 From: Alec Smyth via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: ??? Content-Type: text/plain; charset="utf-8" I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify, and it worked so well I never thought of using any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best, Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat.? My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT.? I don't remember the specs on the > pump.? I had motorized ball valves on the vent and flood side of the > VBT.? Prior to using this set up, I did some testing of this gear pump > which I still have.? What I found was an unacceptable amount of flow > slippage at my max design depth.? There was so much slippage that the > pump could not blow the VBT at max depth.? At that point I abandoned > using a pump and vent to blowing the VBT with air.? I eventually > abandoned the VBT altogether for operability reasons.? When I used > this hard VBT to get neutral on the surface, the pressure in the tank > was low.? When at depth if I ever tried to use the VBT, water would > rush in until the pressure equalized with ambient water pressure.? > This made the boat negatively buoyant until air was added.? The other > thing that bugged me was I had a float style level sensor in the VBT.? > The water level in the VBT was always moving around so you never trust > the reading.? I eventually abandoned the VBT and now just add ballast > at the boat CG where the VBT was located.? I find this works great.? > The other issue is the VBT restricted access to equipment aft of > the VBT so to work on any of this equipment, I had to remove the VBT. All > in all, I found the VBT to be a pain in butt. > > Cliff > > Oberdorfer 944 Bronze > > On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles < personal_submersibles at psubs.org> wrote: > > > Hi Guys > > > > What make of pump is best for VBT water transfer in/out for 250 psi > 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are > only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel > backed sleeve bearings. > > > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) From: Jon Wallace via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" I'll chime in here...I removed the VBT from the K600 because it was fairly well rusted inside and needed to be replaced, however I am planning on using the ballast/float method instead and forgoing the VBT altogether for many of the reasons Alec and Cliff cited.? I will say that it can be challenging to change ballast on-station since the weight/floatation has to be transferred somewhere and by somebody, however I see the K600 being trimmed for specific missions prior to launch and not being trimmed dynamically on-station to embark/disembark passengers or equipment. Jon ? ? On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via Personal_Submersibles wrote:? I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify,?and it worked so well I never thought of using?any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best,Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles wrote: Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... 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URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 40 ****************************************************** _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Thu Aug 17 13:18:20 2023 From: personal_submersibles at psubs.org (Sean T. Stevenson via Personal_Submersibles) Date: Thu, 17 Aug 2023 17:18:20 +0000 Subject: [PSUBS-MAILIST] Personal_Submersibles Digest, Vol 120, Issue 40 In-Reply-To: <10223209.1074837.1692290497024@mail.yahoo.com> References: <037801d9d0b2$0e871470$2b953d50$@gmail.com> <1628568723.807762.1692242326936@mail.yahoo.com> <311293821.973720.1692282243195@mail.yahoo.com> <1852172581.1034074.1692287413417@mail.yahoo.com> <10223209.1074837.1692290497024@mail.yahoo.com> Message-ID: Exactly. You never want the tank to contain stored energy in the form of gas pressure. The only part of the system that would see constant pressure is the line between the PD pump discharge and the discharge isolator valve. When the pump is operating, the tank should be relieved by a process air line at 1 atm or some other low pressure to maintain some positive suction head against the pump inlet. The only time the VBT would see internal pressure is when the inlet isolator valve is open, and in that case for safety's sake you would probably have an orifice or something to throttle that flow to something manageable at the deepest operating depth. If the VBT is a hard tank, as it fills the gas cap above the water inside will compress, and will need to be vented off. This can either be done continuously or discretely, but at the end of the addition operation, the VBT should be returned to LP internally. If it is a soft tank, that is a non-issue. Sean -------- Original Message -------- On Aug. 17, 2023, 10:41, Cliff Redus via Personal_Submersibles wrote: > Jon, if I am understanding Sean correctly, he is advocating using a PD pump with a check valve to move water out of the VBT instead of air pressure so issue of in rush of water when the flood valve is opened goes away. > > I do agree "working out the dynamics in actual practice would require a bit of time". Constants for PID controller would have to be experimented with. > > Cliff > > On Thursday, August 17, 2023 at 10:51:19 AM CDT, Jon Wallace via Personal_Submersibles wrote: > > Conceptually it's a great idea for automation and likely not a big deal to implement via software code. I think working out the dynamics in actual practice would require a bit of time. Assuming you wanted more buoyancy the biggest issue would be the description Cliff gave of adding air to the VBT without the inrush of water because of the pressure difference at depth. The only solution I see to that is adding a pressure sensor to the VBT and adding air first to counter the outside water pressure, then opening the outside valve to the VBT. That means another sensor, more software code, and more potential things that could go wrong, which is why I like the simplicity of removing the VBT entirely and just relying on weight control to obtain neutral buoyancy. BUT...it would be a good project if somebody wanted to implement it. > > Jon > > On Thursday, August 17, 2023 at 10:25:56 AM EDT, Cliff Redus via Personal_Submersibles wrote: > > Sean, I think this control strategy could work. To utilize, you would need a PLC or microprocessor to implement a PID loop. It would be easy to test by putting the sub in shallow test tank to test depth station keeping capability. You could then upset the system by adding some lead ballast to the boat and see how well the VBT/Thrusters handle the upset. > > My guess is that those in our group that like the KISS strategy would deems this as too complicated while those that like this kind of approach would see some nice benefits of this control strategy. My experience with Psubs is that someone try's something new and if it works incrementally better than what they were using, they adopt. For me it would have to be modified as I don't have a VBT, i.e., I could implement a depth/altitude station keeping PLC function with a PID loop controlling either depth or altitude with vertical thrusters alone. > > Cliff > > On Wednesday, August 16, 2023 at 10:59:28 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: > > I think I may have offered this the last time the VBT discussion came up, but I always thought that a good control scheme for the VBT would be to automate it within a slave loop to the vertical thruster control. So, for example, you have a position setpoint in the vertical direction which is either auto-depth or auto-altitude, and have your vertical thrusters programmed to respond accordingly to maintain that setpoint. Separately, you monitor the instantaneous output to the vertical thrusters that results from that control loop, filtered on a longer time base, and operate one of two valves via a slower acting control loop to either admit water to the VBT, or open the pump discharge to let water out, as necessary in order to null out that thruster input. This way, external disturbances such as vertical currents, or buoyancy changes due to hull deflection at depth etc., would be compensated for automatically, and the system would also act to conserve energy by minimizing power consumption to the vertical thrusters, by always dialing the boat to neutral. > > When not holding an altitude or depth, the system could also activate whenever the manual thruster command was saturated at 100% in either direction, in order to hasten a long ascent or descent, or possibly to respond to the condition where the available vertical thrust is insufficient. The only caveat would be to make sure that you don't allow so much VBT volume that you couldn't manually counter the resultant buoyant force with opposing thrust in an emergency. > > Such an embodiment would require a check valve based reciprocating pump, like a Sprague, that could be deadheaded against the discharge valve at full outlet pressure. Opening the discharge valve would cause it to stroke, while closing the discharge valve would deadhead it again. This is possibly a safety feature, because as as long as the pump is not stroking with the discharge valve closed, you know it can develop pressure, and again, having a pump that just stops when pressure builds downstream will conserve the HP air or electrical power used to drive it, in contrast to a pump that must be explicitly run. > > Just a thought. > > Sean > > -------- Original Message -------- > On Aug. 16, 2023, 21:18, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > >> > > Hugh, I understand the attraction of using VBT for QSub. With a mission profile to be able to do long ocean surface transects to a dive location, submerge, dive, surface and then transect back. It is not practical to haul excess ballast since the Qsub is operating more like a submarine than a submersible. If you can find a positive displacement pump that does not have a lot of slippage at your maximum depth, then the issue I mentioned about opening the VBT at depth and getting negatively buoyant goes away because the pump itself is preventing a large inrush of water. When this happened on my boat, I had already switched to air for blowing VBT. I would, as you note, adjust the water in the VBT just below the surface after flooding the MBTs. This was the NOP but sometimes the unexpected happens and you need to add buoyancy at depth with the VBT. I was diving the R300 about seven years ago at Lake Amistad on the border between Mexico and Texas. I submerged to about 150 ft in old river bottom. When I lifted of the bottom to start the ascent using my vertical thrusters at an altitude of about 10ft, the boat stopped ascending even with full vertical thrusters. I was watching the depth gage and I was just going up. I did not realize it but I was being dragged along by a 5-knot current and was not accenting at a rate I was comfortable with. The boat at the time was neutrally buoyant. To increase the rate of ascent, I decided to blow the VBT at depth. The depth was about 140 ft at the time. When I opened the motorized ball valve on the vent side of the VBT, the boat started descending even though air was being introduced because of this sudden influx of water. Eventually, the water in the VBT was displaced with air and the boat started to ascend. When I surfaced, I was about a mile downstream from the tender vessel. Because the water visibly was so bad, I did not realize I was being dragged by the current so much. > > Cliff > > On Wednesday, August 16, 2023 at 09:25:55 PM CDT, via Personal_Submersibles wrote: > > Hi Cliff, > I am interested in your comments re the pump slippage etc and operation of > the VBTs when you were using them. > My approach, untried and purely theoretical, was that most of the VBT > adjustment would be done just below the surface and only minor adjustment > for compression of vessels etc would be done at depth. > I do appreciate that weight balance appears more foolproof. Regards, Hugh > > -----Original Message----- > From: Personal_Submersibles On > Behalf Of via Personal_Submersibles > Sent: Thursday, August 17, 2023 1:02 PM > To: personal_submersibles at psubs.org > > Subject: Personal_Submersibles Digest, Vol 120, Issue 40 > > Send Personal_Submersibles mailing list submissions to > personal_submersibles at psubs.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > > or, via email, send a message with subject or body 'help' to > personal_submersibles-request at psubs.org > > You can reach the person managing the list at > personal_submersibles-owner at psubs.org > > When replying, please edit your Subject line so it is more specific than > "Re: Contents of Personal_Submersibles digest..." > > Today's Topics: > > 1. Re: Re VBT Pump (Cliff Redus via Personal_Submersibles) > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 17 Aug 2023 01:01:56 +0000 (UTC) > From: Cliff Redus via Personal_Submersibles > > To: via Personal_Submersibles > Subject: Re: [PSUBS-MAILIST] Re VBT Pump > Message-ID: <2137621386.758356.1692234116222 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > Hugh, thanks for update on QSub.? I am looking forward to her dunk test in > your new test pool. I quite enjoyed sitting in her pressure hull in your > shop in New Zealand a few years back.? She will be quite something when > complete. > Best > On Wednesday, August 16, 2023 at 06:43:41 PM CDT, via > Personal_Submersibles wrote: > > Thanks, Cliff, Alec, Vance, Jon. > > The model I was looking at, correction, was the Oberdorfer 994 which is same > as a 2000 series but 3/8" - 1/2"? and direct mounted not foot mounted as per > the 2000 series. > > The other pump I liked was the Wanner D10 which is diaphragm and can do no > slippage and 250 -300 psi etc but it is not bidirectional.? However that can > be fixed with valves. > > I am making some progress with my Q-Sub but made the mistake of going too > complex and trying to do everything.? I? have had issues with --- 1. BMS > systems for the LiFePO4 batteries and had to replace these. > 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. > 3. Gear cable kinking for the mercruiser sternlegs. > 4. Inaccessible fuses and not motor rated. > 5. Mechanical seal leakage on the hydraulics. > 6. Joystick pot issues. > 7. Canbus systems at different voltages. > 8. Rotary sensors too coarse required op amp addition to amplify signals for > small rotary movements with steering. > 9. Port Engine starting issues. > 10. Oil compensation line fittings leaks. > 11. Software issues. > > Still plugging along.? IN the meantime I have built a test pool same-same > Hank 8 ft deep 12 wide x 27 long, and another gantry crane for PVHO removal, > as well as a shed just for the sub.? This year it has to be finished.? Has > not even been in the pool yet!! > Regards,? Hugh > > -----Original Message----- > From: Personal_Submersibles On > Behalf Of via Personal_Submersibles > Sent: Thursday, August 17, 2023 3:21 AM > To: personal_submersibles at psubs.org > > Subject: Personal_Submersibles Digest, Vol 120, Issue 36 > > Send Personal_Submersibles mailing list submissions to ??? > personal_submersibles at psubs.org > > To subscribe or unsubscribe via the World Wide Web, visit ??? > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > > or, via email, send a message with subject or body 'help' to ??? > personal_submersibles-request at psubs.org > > You can reach the person managing the list at ??? > personal_submersibles-owner at psubs.org > > When replying, please edit your Subject line so it is more specific than > "Re: Contents of Personal_Submersibles digest..." > > Today's Topics: > > ? 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) ? 2. Re: FW: > VBT pump (Alec Smyth via Personal_Submersibles) ? 3. Re: FW: VBT pump (Jon > Wallace via Personal_Submersibles) > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) > From: Cliff Redus via Personal_Submersibles ??? > > To: via Personal_Submersibles > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > Hugh, on my original design for the R300 I had a hard VBT just aft of the > pilot. At the time I had a small HPU in the boat.? My plan was to use a > Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water > in and out of the VBT.? I don't remember the specs on the pump.? I had > motorized ball valves on the vent and flood side of the VBT.? Prior to using > this set up, I did some testing of this gear pump which I still have.? What > I found was an unacceptable amount of flow slippage at my max design depth.? > There was so much slippage that the pump could not blow the VBT at max > depth.? At that point I abandoned using a pump and vent to blowing the VBT > with air.? I eventually abandoned the VBT altogether for operability > reasons.? When I used this hard VBT to get neutral on the surface, the > pressure in the tank was low.? When at depth if I ever tried to use the VBT, > water would rush in until the pressure equalized with ambient water > pressure.? This made the boat nega! > tively buoyant until air was added.? The other thing that bugged me was I > had a float style level sensor in the VBT.? The water level in the VBT was > always moving around so you never trust the reading.? I eventually abandoned > the VBT and now just add ballast at the boat CG where the VBT was located.? > I find this works great.? The other issue is the VBT restricted access to > equipment aft of the VBT so to work on any of this equipment, I had to > remove the VBT.? ?All in all, I found the VBT to be a pain in butt. > Cliff > Oberdorfer 944 Bronze > > ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles > wrote:? > > Hi Guys > > ? > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only > rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a > stainless and bronze gear set made up but the aluminium body corroded form > the trials and I just found that they had used steel backed sleeve bearings. > > ? > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > ? > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > > b13a39c1/attachment-0001.html> > > ------------------------------ > > Message: 2 > Date: Wed, 16 Aug 2023 09:41:53 -0400 > From: Alec Smyth via Personal_Submersibles ??? > > To: Personal Submersibles General Discussion ??? > > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: > ??? > Content-Type: text/plain; charset="utf-8" > > I second that (getting rid of VBT). I got rid of the VBT in my K250 years > ago to make space and turn it into a 2-person and to try and to simplify, > and it worked so well I never thought of using any other method on the > current sub. The only difference with Cliff's method is that I add or remove > floats, while he uses ballast. But either way, once you have a reference > point for how much ballast/buoyancy you need for a given crew weight, you > just make incremental changes and it never fails. You may be off neutral by > just a few pounds, but if you have vertical thrusters they're usually just > ticking over at slow RPMs to compensate. > > Best, > Alec > > On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles < > personal_submersibles at psubs.org> wrote: > >> Hugh, on my original design for the R300 I had a hard VBT just aft of >> the pilot. At the time I had a small HPU in the boat.? My plan was to >> use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to >> move water in and out of the VBT.? I don't remember the specs on the >> pump.? I had motorized ball valves on the vent and flood side of the >> VBT.? Prior to using this set up, I did some testing of this gear pump >> which I still have.? What I found was an unacceptable amount of flow >> slippage at my max design depth.? There was so much slippage that the >> pump could not blow the VBT at max depth.? At that point I abandoned >> using a pump and vent to blowing the VBT with air.? I eventually >> abandoned the VBT altogether for operability reasons.? When I used >> this hard VBT to get neutral on the surface, the pressure in the tank >> was low.? When at depth if I ever tried to use the VBT, water would >> rush in until the pressure equalized with ambient water pressure.? >> This made the boat negatively buoyant until air was added.? The other >> thing that bugged me was I had a float style level sensor in the VBT.? >> The water level in the VBT was always moving around so you never trust >> the reading.? I eventually abandoned the VBT and now just add ballast >> at the boat CG where the VBT was located.? I find this works great.? >> The > other issue is the VBT restricted access to equipment aft of >> the VBT so to work on any of this equipment, I had to remove the VBT. > All >> in all, I found the VBT to be a pain in butt. >> >> Cliff >> >> Oberdorfer 944 Bronze >> >> On Sunday, August 13, 2023 at 04:57:24 PM CDT, via >> Personal_Submersibles < personal_submersibles at psubs.org> wrote: >> >> >> Hi Guys >> >> >> >> What make of pump is best for VBT water transfer in/out for 250 psi >> 1.5 > kw. >> >> I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are >> only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I >> had a stainless and bronze gear set made up but the aluminium body >> corroded form the trials and I just found that they had used steel >> backed > sleeve bearings. >> >> >> >> Regards, >> >> Hugh >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org > >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org > >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > >> > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > > b5338913/attachment-0001.html> > > ------------------------------ > > Message: 3 > Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) > From: Jon Wallace via Personal_Submersibles ??? > > To: Personal Submersibles General Discussion ??? > > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > I'll chime in here...I removed the VBT from the K600 because it was fairly > well rusted inside and needed to be replaced, however I am planning on using > the ballast/float method instead and forgoing the VBT altogether for many of > the reasons Alec and Cliff cited.? I will say that it can be challenging to > change ballast on-station since the weight/floatation has to be transferred > somewhere and by somebody, however I see the K600 being trimmed for specific > missions prior to launch and not being trimmed dynamically on-station to > embark/disembark passengers or equipment. > Jon > > ? ? On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via > Personal_Submersibles wrote:? > > I second that (getting rid of VBT). I got rid of the VBT in my K250 years > ago to make space and turn it into a 2-person and to try and to > simplify,?and it worked so well I never thought of using?any other method on > the current sub. The only difference with Cliff's method is that I add or > remove floats, while he uses ballast. But either way, once you have a > reference point for how much ballast/buoyancy you need for a given crew > weight, you just make incremental changes and it never fails. You may be off > neutral by just a few pounds, but if you have vertical thrusters they're > usually just ticking over at slow RPMs to compensate. > > Best,Alec > On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles > wrote: > > Hugh, on my original design for the R300 I had a hard VBT just aft of the > pilot. At the time I had a small HPU in the boat.? My plan was to use a > Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water > in and out of the VBT.? I don't remember the specs on the pump.? I had > motorized ball valves on the vent and flood side of the VBT.? Prior to using > this set up, I did some testing of this gear pump which I still have.? What > I found was an unacceptable amount of flow slippage at my max design depth.? > There was so much slippage that the pump could not blow the VBT at max > depth.? At that point I abandoned using a pump and vent to blowing the VBT > with air.? I eventually abandoned the VBT altogether for operability > reasons.? When I used this hard VBT to get neutral on the surface, the > pressure in the tank was low.? When at depth if I ever tried to use the VBT, > water would rush in until the pressure equalized with ambient water > pressure.? This made the boat nega! > tively buoyant until air was added.? The other thing that bugged me was I > had a float style level sensor in the VBT.? The water level in the VBT was > always moving around so you never trust the reading.? I eventually abandoned > the VBT and now just add ballast at the boat CG where the VBT was located.? > I find this works great.? The other issue is the VBT restricted access to > equipment aft of the VBT so to work on any of this equipment, I had to > remove the VBT.? ?All in all, I found the VBT to be a pain in butt. > Cliff > Oberdorfer 944 Bronze > > ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles > wrote:? > > Hi Guys > > ? > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only > rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a > stainless and bronze gear set made up but the aluminium body corroded form > the trials and I just found that they had used steel backed sleeve bearings. > > ? > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > ? _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > ? > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > > 301b6d76/attachment.html> > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > > ------------------------------ > > End of Personal_Submersibles Digest, Vol 120, Issue 36 > ****************************************************** > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > > b598be5b/attachment.html> > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > > ------------------------------ > > End of Personal_Submersibles Digest, Vol 120, Issue 40 > ****************************************************** > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Thu Aug 17 14:39:16 2023 From: personal_submersibles at psubs.org (Jon Wallace via Personal_Submersibles) Date: Thu, 17 Aug 2023 18:39:16 +0000 (UTC) Subject: [PSUBS-MAILIST] Personal_Submersibles Digest, Vol 120, Issue 40 In-Reply-To: <10223209.1074837.1692290497024@mail.yahoo.com> References: <037801d9d0b2$0e871470$2b953d50$@gmail.com> <1628568723.807762.1692242326936@mail.yahoo.com> <311293821.973720.1692282243195@mail.yahoo.com> <1852172581.1034074.1692287413417@mail.yahoo.com> <10223209.1074837.1692290497024@mail.yahoo.com> Message-ID: <64068358.1131692.1692297556435@mail.yahoo.com> Yeah, I missed that part.? :) Jon On Thursday, August 17, 2023 at 12:44:07 PM EDT, Cliff Redus via Personal_Submersibles wrote: Jon, if I am understanding Sean correctly, he is advocating using a PD pump with a check valve to move water out of the VBT instead of air pressure so issue of in rush of water when the flood valve is opened goes away. I do agree "working out the dynamics in actual practice would require a bit of time".? Constants for PID controller would have to be experimented with. Cliff On Thursday, August 17, 2023 at 10:51:19 AM CDT, Jon Wallace via Personal_Submersibles wrote: Conceptually it's a great idea for automation and likely not a big deal to implement via software code.? I think working out the dynamics in actual practice would require a bit of time.? Assuming you wanted more buoyancy the biggest issue would be the description Cliff gave of adding air to the VBT without the inrush of water because of the pressure difference at depth.? The only solution I see to that is adding a pressure sensor to the VBT and adding air first to counter the outside water pressure, then opening the outside valve to the VBT.? That means another sensor, more software code, and more potential things that could go wrong, which is why I like the simplicity of removing the VBT entirely and just relying on weight control to obtain neutral buoyancy.? BUT...it would be a good project if somebody wanted to implement it. Jon On Thursday, August 17, 2023 at 10:25:56 AM EDT, Cliff Redus via Personal_Submersibles wrote: Sean, I think this control strategy could work.? To utilize, you would need a PLC or microprocessor to implement a PID loop.? It would be easy to test by putting the sub in shallow test tank to test depth station keeping capability.? You could then upset the system by adding some lead ballast to the boat and see how well the VBT/Thrusters handle the upset. My guess is that those in our group that like the KISS strategy would deems this as too complicated while those that like this kind of approach would see some nice benefits of this control strategy.? My experience with Psubs is that someone try's something new and if it works incrementally better than what they were using, they adopt.? For me it would have to be modified as I don't have a VBT, i.e., I could implement a depth/altitude station keeping PLC function with a PID loop controlling either depth or altitude with vertical thrusters alone. Cliff On Wednesday, August 16, 2023 at 10:59:28 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: I think I may have offered this the last time the VBT discussion came up, but I always thought that a good control scheme for the VBT would be to automate it within a slave loop to the vertical thruster control. So, for example, you have a position setpoint in the vertical direction which is either auto-depth or auto-altitude, and have your vertical thrusters programmed to respond accordingly to maintain that setpoint. Separately, you monitor the instantaneous output to the vertical thrusters that results from that control loop, filtered on a longer time base, and operate one of two valves via a slower acting control loop to either admit water to the VBT, or open the pump discharge to let water out, as necessary in order to null out that thruster input. This way, external disturbances such as vertical currents, or buoyancy changes due to hull deflection at depth etc., would be compensated for automatically, and the system would also act to conserve energy by minimizing power consumption to the vertical thrusters, by always dialing the boat to neutral. When not holding an altitude or depth, the system could also activate whenever the manual thruster command was saturated at 100% in either direction, in order to hasten a long ascent or descent, or possibly to respond to the condition where the available vertical thrust is insufficient. The only caveat would be to make sure that you don't allow so much VBT volume that you couldn't manually counter the resultant buoyant force with opposing thrust in an emergency. Such an embodiment would require a check valve based reciprocating pump, like a Sprague, that could be deadheaded against the discharge valve at full outlet pressure. Opening the discharge valve would cause it to stroke, while closing the discharge valve would deadhead it again. This is possibly a safety feature, because as as long as the pump is not stroking with the discharge valve closed, you know it can develop pressure, and again, having a pump that just stops when pressure builds downstream will conserve the HP air or electrical power used to drive it, in contrast to a pump that must be explicitly run. Just a thought. Sean -------- Original Message -------- On Aug. 16, 2023, 21:18, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: Hugh, I understand the attraction of using VBT for QSub.? With a mission profile to be able to do long ocean surface transects to a dive location, submerge, dive, surface and then transect back.? It is not practical to haul excess ballast since the Qsub is operating more like a submarine than a submersible.? If you can find a positive displacement pump that does not have a lot of slippage at your maximum depth, then the issue I mentioned about opening the VBT at depth and getting negatively buoyant goes away because the pump itself is preventing a large inrush of water.? When this happened on my boat, I had already switched to air for blowing VBT. I would, as you note, adjust the water in the VBT just below the surface after flooding the MBTs.? This was the NOP but sometimes the unexpected happens and you need to add buoyancy at depth with the VBT.? I was diving the R300 about seven years ago at Lake Amistad on the border between Mexico and Texas.? I submerged to about 150 ft in old river bottom. When I lifted of the bottom to start the ascent using my vertical thrusters at an altitude of about 10ft, the boat stopped ascending even with full vertical thrusters.? I was watching the depth gage and I was just going up.? I did not realize it but I was being dragged along by a 5-knot current and was not accenting at a rate I was comfortable with.? The boat at the time was neutrally buoyant.? To increase the rate of ascent, I decided to blow the VBT at depth. The depth was about 140 ft at the time.? When I opened the motorized ball valve on the vent side of the VBT, the boat started descending even though air was being introduced because of this sudden influx of water.? Eventually, the water in the VBT was displaced with air and the boat started to ascend.? When I surfaced, I was about a mile downstream from the tender vessel.? Because the water visibly was so bad, I did not realize I was being dragged by the current so much.?? Cliff On Wednesday, August 16, 2023 at 09:25:55 PM CDT, via Personal_Submersibles wrote: Hi Cliff, I am interested in your comments re the pump slippage etc and operation of the VBTs when you were using them. My approach, untried and purely theoretical, was that most of the VBT adjustment would be done just below the surface and only minor adjustment for compression of vessels etc would be done at depth.? I do appreciate that weight balance appears more foolproof.? Regards, Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 1:02 PM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 40 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: Re VBT Pump (Cliff Redus via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Thu, 17 Aug 2023 01:01:56 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] Re VBT Pump Message-ID: <2137621386.758356.1692234116222 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, thanks for update on QSub.? I am looking forward to her dunk test in your new test pool. I quite enjoyed sitting in her pressure hull in your shop in New Zealand a few years back.? She will be quite something when complete. Best ? ? On Wednesday, August 16, 2023 at 06:43:41 PM CDT, via Personal_Submersibles wrote:? Thanks, Cliff, Alec, Vance, Jon. The model I was looking at, correction, was the Oberdorfer 994 which is same as a 2000 series but 3/8" - 1/2"? and direct mounted not foot mounted as per the 2000 series. The other pump I liked was the Wanner D10 which is diaphragm and can do no slippage and 250 -300 psi etc but it is not bidirectional.? However that can be fixed with valves. I am making some progress with my Q-Sub but made the mistake of going too complex and trying to do everything.? I? have had issues with --- 1. BMS systems for the LiFePO4 batteries and had to replace these. 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. 3. Gear cable kinking for the mercruiser sternlegs. 4. Inaccessible fuses and not motor rated. 5. Mechanical seal leakage on the hydraulics. 6. Joystick pot issues. 7. Canbus systems at different voltages. 8. Rotary sensors too coarse required op amp addition to amplify signals for small rotary movements with steering. 9. Port Engine starting issues. 10. Oil compensation line fittings leaks. 11. Software issues. Still plugging along.? IN the meantime I have built a test pool same-same Hank 8 ft deep 12 wide x 27 long, and another gantry crane for PVHO removal, as well as a shed just for the sub.? This year it has to be finished.? Has not even been in the pool yet!! Regards,? Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 3:21 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 36 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) ? 2. Re: FW: VBT pump (Alec Smyth via Personal_Submersibles) ? 3. Re: FW: VBT pump (Jon Wallace via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 2 Date: Wed, 16 Aug 2023 09:41:53 -0400 From: Alec Smyth via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: ??? Content-Type: text/plain; charset="utf-8" I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify, and it worked so well I never thought of using any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best, Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat.? My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT.? I don't remember the specs on the > pump.? I had motorized ball valves on the vent and flood side of the > VBT.? Prior to using this set up, I did some testing of this gear pump > which I still have.? What I found was an unacceptable amount of flow > slippage at my max design depth.? There was so much slippage that the > pump could not blow the VBT at max depth.? At that point I abandoned > using a pump and vent to blowing the VBT with air.? I eventually > abandoned the VBT altogether for operability reasons.? When I used > this hard VBT to get neutral on the surface, the pressure in the tank > was low.? When at depth if I ever tried to use the VBT, water would > rush in until the pressure equalized with ambient water pressure.? > This made the boat negatively buoyant until air was added.? The other > thing that bugged me was I had a float style level sensor in the VBT.? > The water level in the VBT was always moving around so you never trust > the reading.? I eventually abandoned the VBT and now just add ballast > at the boat CG where the VBT was located.? I find this works great.? > The other issue is the VBT restricted access to equipment aft of > the VBT so to work on any of this equipment, I had to remove the VBT. All > in all, I found the VBT to be a pain in butt. > > Cliff > > Oberdorfer 944 Bronze > > On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles < personal_submersibles at psubs.org> wrote: > > > Hi Guys > > > > What make of pump is best for VBT water transfer in/out for 250 psi > 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are > only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel > backed sleeve bearings. > > > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) From: Jon Wallace via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" I'll chime in here...I removed the VBT from the K600 because it was fairly well rusted inside and needed to be replaced, however I am planning on using the ballast/float method instead and forgoing the VBT altogether for many of the reasons Alec and Cliff cited.? I will say that it can be challenging to change ballast on-station since the weight/floatation has to be transferred somewhere and by somebody, however I see the K600 being trimmed for specific missions prior to launch and not being trimmed dynamically on-station to embark/disembark passengers or equipment. Jon ? ? On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via Personal_Submersibles wrote:? I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify,?and it worked so well I never thought of using?any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best,Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles wrote: Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... 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URL: From personal_submersibles at psubs.org Thu Aug 17 17:28:09 2023 From: personal_submersibles at psubs.org (via Personal_Submersibles) Date: Fri, 18 Aug 2023 09:28:09 +1200 Subject: [PSUBS-MAILIST] Personal_Submersibles Digest, Vol 120, Issue 42 In-Reply-To: References: Message-ID: <03ba01d9d151$b9e29250$2da7b6f0$@gmail.com> Hi Cliff, Thanks for that. Glad to have you with us with an episode like that. An exciting day to say the least. I have 2 valves on my VBT that can open to either the pump or to sea water, so hopefully avoid slippage etc but the human factor comes in. Regards, Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 3:29 PM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 42 Send Personal_Submersibles mailing list submissions to personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to personal_submersibles-request at psubs.org You can reach the person managing the list at personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: 1. Re: Personal_Submersibles Digest, Vol 120, Issue 40 (Sean T. Stevenson via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Thu, 17 Aug 2023 03:28:06 +0000 From: "Sean T. Stevenson via Personal_Submersibles" To: personal_submersibles at psubs.org Subject: Re: [PSUBS-MAILIST] Personal_Submersibles Digest, Vol 120, Issue 40 Message-ID: Content-Type: text/plain; charset="utf-8" I think Sent from Proton Mail mobile -------- Original Message -------- On Aug. 16, 2023, 21:18, Cliff Redus via Personal_Submersibles wrote: > Hugh, I understand the attraction of using VBT for QSub. With a mission profile to be able to do long ocean surface transects to a dive location, submerge, dive, surface and then transect back. It is not practical to haul excess ballast since the Qsub is operating more like a submarine than a submersible. If you can find a positive displacement pump that does not have a lot of slippage at your maximum depth, then the issue I mentioned about opening the VBT at depth and getting negatively buoyant goes away because the pump itself is preventing a large inrush of water. When this happened on my boat, I had already switched to air for blowing VBT. I would, as you note, adjust the water in the VBT just below the surface after flooding the MBTs. This was the NOP but sometimes the unexpected happens and you need to add buoyancy at depth with the VBT. I was diving the R300 about seven years ago at Lake Amistad on the border between Mexico and Texas. I submerged to about 150 ft in ! old river bottom. When I lifted of the bottom to start the ascent using my vertical thrusters at an altitude of about 10ft, the boat stopped ascending even with full vertical thrusters. I was watching the depth gage and I was just going up. I did not realize it but I was being dragged along by a 5-knot current and was not accenting at a rate I was comfortable with. The boat at the time was neutrally buoyant. To increase the rate of ascent, I decided to blow the VBT at depth. The depth was about 140 ft at the time. When I opened the motorized ball valve on the vent side of the VBT, the boat started descending even though air was being introduced because of this sudden influx of water. Eventually, the water in the VBT was displaced with air and the boat started to ascend. When I surfaced, I was about a mile downstream from the tender vessel. Because the water visibly was so bad, I did not realize I was being dragged by the current so much. > > Cliff > > On Wednesday, August 16, 2023 at 09:25:55 PM CDT, via Personal_Submersibles wrote: > > Hi Cliff, > I am interested in your comments re the pump slippage etc and > operation of the VBTs when you were using them. > My approach, untried and purely theoretical, was that most of the VBT > adjustment would be done just below the surface and only minor > adjustment for compression of vessels etc would be done at depth. > I do appreciate that weight balance appears more foolproof. Regards, > Hugh > > -----Original Message----- > From: Personal_Submersibles > On Behalf Of via Personal_Submersibles > Sent: Thursday, August 17, 2023 1:02 PM > To: personal_submersibles at psubs.org > Subject: Personal_Submersibles Digest, Vol 120, Issue 40 > > Send Personal_Submersibles mailing list submissions to > personal_submersibles at psubs.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > or, via email, send a message with subject or body 'help' to > personal_submersibles-request at psubs.org > > You can reach the person managing the list at > personal_submersibles-owner at psubs.org > > When replying, please edit your Subject line so it is more specific > than > "Re: Contents of Personal_Submersibles digest..." > > Today's Topics: > > 1. Re: Re VBT Pump (Cliff Redus via Personal_Submersibles) > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 17 Aug 2023 01:01:56 +0000 (UTC) > From: Cliff Redus via Personal_Submersibles > > To: via Personal_Submersibles > Subject: Re: [PSUBS-MAILIST] Re VBT Pump > Message-ID: <2137621386.758356.1692234116222 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > Hugh, thanks for update on QSub.? I am looking forward to her dunk > test in your new test pool. I quite enjoyed sitting in her pressure > hull in your shop in New Zealand a few years back.? She will be quite > something when complete. > Best > On Wednesday, August 16, 2023 at 06:43:41 PM CDT, via > Personal_Submersibles wrote: > > Thanks, Cliff, Alec, Vance, Jon. > > The model I was looking at, correction, was the Oberdorfer 994 which > is same as a 2000 series but 3/8" - 1/2"? and direct mounted not foot > mounted as per the 2000 series. > > The other pump I liked was the Wanner D10 which is diaphragm and can > do no slippage and 250 -300 psi etc but it is not bidirectional.? > However that can be fixed with valves. > > I am making some progress with my Q-Sub but made the mistake of going > too complex and trying to do everything.? I? have had issues with --- > 1. BMS systems for the LiFePO4 batteries and had to replace these. > 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. > 3. Gear cable kinking for the mercruiser sternlegs. > 4. Inaccessible fuses and not motor rated. > 5. Mechanical seal leakage on the hydraulics. > 6. Joystick pot issues. > 7. Canbus systems at different voltages. > 8. Rotary sensors too coarse required op amp addition to amplify > signals for small rotary movements with steering. > 9. Port Engine starting issues. > 10. Oil compensation line fittings leaks. > 11. Software issues. > > Still plugging along.? IN the meantime I have built a test pool > same-same Hank 8 ft deep 12 wide x 27 long, and another gantry crane > for PVHO removal, as well as a shed just for the sub.? This year it > has to be finished.? Has not even been in the pool yet!! > Regards,? Hugh > > -----Original Message----- > From: Personal_Submersibles > On Behalf Of via Personal_Submersibles > Sent: Thursday, August 17, 2023 3:21 AM > To: personal_submersibles at psubs.org > Subject: Personal_Submersibles Digest, Vol 120, Issue 36 > > Send Personal_Submersibles mailing list submissions to ??? > personal_submersibles at psubs.org > > To subscribe or unsubscribe via the World Wide Web, visit ??? > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > or, via email, send a message with subject or body 'help' to ??? > personal_submersibles-request at psubs.org > > You can reach the person managing the list at ??? > personal_submersibles-owner at psubs.org > > When replying, please edit your Subject line so it is more specific > than > "Re: Contents of Personal_Submersibles digest..." > > Today's Topics: > > ? 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) ? 2. Re: FW: > VBT pump (Alec Smyth via Personal_Submersibles) ? 3. Re: FW: VBT pump > (Jon Wallace via Personal_Submersibles) > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) > From: Cliff Redus via Personal_Submersibles ??? > > To: via Personal_Submersibles > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat.? My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT.? I don't remember the specs on the > pump.? I had motorized ball valves on the vent and flood side of the > VBT.? Prior to using this set up, I did some testing of this gear pump > which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? > There was so much slippage that the pump could not blow the VBT at max > depth.? At that point I abandoned using a pump and vent to blowing the > VBT with air.? I eventually abandoned the VBT altogether for > operability reasons.? When I used this hard VBT to get neutral on the > surface, the pressure in the tank was low.? When at depth if I ever > tried to use the VBT, water would rush in until the pressure equalized > with ambient water pressure.? This made the boat nega! > tively buoyant until air was added.? The other thing that bugged me > was I had a float style level sensor in the VBT.? The water level in > the VBT was always moving around so you never trust the reading.? I > eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? > I find this works great.? The other issue is the VBT restricted access > to equipment aft of the VBT so to work on any of this equipment, I had > to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. > Cliff > Oberdorfer 944 Bronze > > ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles wrote:? > > Hi Guys > > ? > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are > only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel backed sleeve bearings. > > ? > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > ? > -------------- next part -------------- An HTML attachment was > scrubbed... > URL: > 30816/ > b13a39c1/attachment-0001.html> > > ------------------------------ > > Message: 2 > Date: Wed, 16 Aug 2023 09:41:53 -0400 > From: Alec Smyth via Personal_Submersibles ??? > > To: Personal Submersibles General Discussion ??? > > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: > ??? > > Content-Type: text/plain; charset="utf-8" > > I second that (getting rid of VBT). I got rid of the VBT in my K250 > years ago to make space and turn it into a 2-person and to try and to > simplify, and it worked so well I never thought of using any other > method on the current sub. The only difference with Cliff's method is > that I add or remove floats, while he uses ballast. But either way, > once you have a reference point for how much ballast/buoyancy you need > for a given crew weight, you just make incremental changes and it > never fails. You may be off neutral by just a few pounds, but if you > have vertical thrusters they're usually just ticking over at slow RPMs to compensate. > > Best, > Alec > > On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles > < personal_submersibles at psubs.org> wrote: > >> Hugh, on my original design for the R300 I had a hard VBT just aft of >> the pilot. At the time I had a small HPU in the boat.? My plan was to >> use a Oberdorfer Bronze gear pump driven by a small hydraulic motor >> to move water in and out of the VBT.? I don't remember the specs on >> the pump.? I had motorized ball valves on the vent and flood side of >> the VBT.? Prior to using this set up, I did some testing of this gear >> pump which I still have.? What I found was an unacceptable amount of >> flow slippage at my max design depth.? There was so much slippage >> that the pump could not blow the VBT at max depth.? At that point I >> abandoned using a pump and vent to blowing the VBT with air.? I >> eventually abandoned the VBT altogether for operability reasons.? >> When I used this hard VBT to get neutral on the surface, the pressure >> in the tank was low.? When at depth if I ever tried to use the VBT, >> water would rush in until the pressure equalized with ambient water pressure.? >> This made the boat negatively buoyant until air was added.? The other >> thing that bugged me was I had a float style level sensor in the VBT.? >> The water level in the VBT was always moving around so you never >> trust the reading.? I eventually abandoned the VBT and now just add >> ballast at the boat CG where the VBT was located.? I find this works great.? >> The > other issue is the VBT restricted access to equipment aft of >> the VBT so to work on any of this equipment, I had to remove the VBT. > All >> in all, I found the VBT to be a pain in butt. >> >> Cliff >> >> Oberdorfer 944 Bronze >> >> On Sunday, August 13, 2023 at 04:57:24 PM CDT, via >> Personal_Submersibles < personal_submersibles at psubs.org> wrote: >> >> >> Hi Guys >> >> >> >> What make of pump is best for VBT water transfer in/out for 250 psi >> 1.5 > kw. >> >> I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are >> only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I >> had a stainless and bronze gear set made up but the aluminium body >> corroded form the trials and I just found that they had used steel >> backed > sleeve bearings. >> >> >> >> Regards, >> >> Hugh >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >> > -------------- next part -------------- An HTML attachment was > scrubbed... > URL: > 30816/ > b5338913/attachment-0001.html> > > ------------------------------ > > Message: 3 > Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) > From: Jon Wallace via Personal_Submersibles ??? > > To: Personal Submersibles General Discussion ??? > > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > I'll chime in here...I removed the VBT from the K600 because it was > fairly well rusted inside and needed to be replaced, however I am > planning on using the ballast/float method instead and forgoing the > VBT altogether for many of the reasons Alec and Cliff cited.? I will > say that it can be challenging to change ballast on-station since the > weight/floatation has to be transferred somewhere and by somebody, > however I see the K600 being trimmed for specific missions prior to > launch and not being trimmed dynamically on-station to embark/disembark passengers or equipment. > Jon > > ? ? On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via > Personal_Submersibles wrote:? > > I second that (getting rid of VBT). I got rid of the VBT in my K250 > years ago to make space and turn it into a 2-person and to try and to > simplify,?and it worked so well I never thought of using?any other > method on the current sub. The only difference with Cliff's method is > that I add or remove floats, while he uses ballast. But either way, > once you have a reference point for how much ballast/buoyancy you need > for a given crew weight, you just make incremental changes and it > never fails. You may be off neutral by just a few pounds, but if you > have vertical thrusters they're usually just ticking over at slow RPMs to compensate. > > Best,Alec > On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles > wrote: > > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat.? My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT.? I don't remember the specs on the > pump.? I had motorized ball valves on the vent and flood side of the > VBT.? Prior to using this set up, I did some testing of this gear pump > which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? > There was so much slippage that the pump could not blow the VBT at max > depth.? At that point I abandoned using a pump and vent to blowing the > VBT with air.? I eventually abandoned the VBT altogether for > operability reasons.? When I used this hard VBT to get neutral on the > surface, the pressure in the tank was low.? When at depth if I ever > tried to use the VBT, water would rush in until the pressure equalized > with ambient water pressure.? This made the boat nega! > tively buoyant until air was added.? The other thing that bugged me > was I had a float style level sensor in the VBT.? The water level in > the VBT was always moving around so you never trust the reading.? I > eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? > I find this works great.? The other issue is the VBT restricted access > to equipment aft of the VBT so to work on any of this equipment, I had > to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. > Cliff > Oberdorfer 944 Bronze > > ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles wrote:? > > Hi Guys > > ? > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are > only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel backed sleeve bearings. > > ? > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > ? _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > ? > -------------- next part -------------- An HTML attachment was > scrubbed... > URL: > 30816/ > 301b6d76/attachment.html> > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > > ------------------------------ > > End of Personal_Submersibles Digest, Vol 120, Issue 36 > ****************************************************** > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > -------------- next part -------------- An HTML attachment was > scrubbed... > URL: > 30817/ > b598be5b/attachment.html> > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > > ------------------------------ > > End of Personal_Submersibles Digest, Vol 120, Issue 40 > ****************************************************** > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 42 ****************************************************** From personal_submersibles at psubs.org Thu Aug 17 17:30:56 2023 From: personal_submersibles at psubs.org (via Personal_Submersibles) Date: Fri, 18 Aug 2023 09:30:56 +1200 Subject: [PSUBS-MAILIST] Personal_Submersibles Digest, Vol 120, Issue 43 In-Reply-To: References: Message-ID: <03bb01d9d152$1df21c70$59d65550$@gmail.com> Hi Sean, That is my original goal but at this stage I just want to get it in the water. I will keep that explanation. Thanks Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 3:59 PM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 43 Send Personal_Submersibles mailing list submissions to personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to personal_submersibles-request at psubs.org You can reach the person managing the list at personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: 1. Re: Personal_Submersibles Digest, Vol 120, Issue 40 (Sean T. Stevenson via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Thu, 17 Aug 2023 03:58:34 +0000 From: "Sean T. Stevenson via Personal_Submersibles" To: personal_submersibles at psubs.org Subject: Re: [PSUBS-MAILIST] Personal_Submersibles Digest, Vol 120, Issue 40 Message-ID: Content-Type: text/plain; charset="utf-8" I think I may have offered this the last time the VBT discussion came up, but I always thought that a good control scheme for the VBT would be to automate it within a slave loop to the vertical thruster control. So, for example, you have a position setpoint in the vertical direction which is either auto-depth or auto-altitude, and have your vertical thrusters programmed to respond accordingly to maintain that setpoint. Separately, you monitor the instantaneous output to the vertical thrusters that results from that control loop, filtered on a longer time base, and operate one of two valves via a slower acting control loop to either admit water to the VBT, or open the pump discharge to let water out, as necessary in order to null out that thruster input. This way, external disturbances such as vertical currents, or buoyancy changes due to hull deflection at depth etc., would be compensated for automatically, and the system would also act to conserve energy by minimizing power! consumption to the vertical thrusters, by always dialing the boat to neutral. When not holding an altitude or depth, the system could also activate whenever the manual thruster command was saturated at 100% in either direction, in order to hasten a long ascent or descent, or possibly to respond to the condition where the available vertical thrust is insufficient. The only caveat would be to make sure that you don't allow so much VBT volume that you couldn't manually counter the resultant buoyant force with opposing thrust in an emergency. Such an embodiment would require a check valve based reciprocating pump, like a Sprague, that could be deadheaded against the discharge valve at full outlet pressure. Opening the discharge valve would cause it to stroke, while closing the discharge valve would deadhead it again. This is possibly a safety feature, because as as long as the pump is not stroking with the discharge valve closed, you know it can develop pressure, and again, having a pump that just stops when pressure builds downstream will conserve the HP air or electrical power used to drive it, in contrast to a pump that must be explicitly run. Just a thought. Sean -------- Original Message -------- On Aug. 16, 2023, 21:18, Cliff Redus via Personal_Submersibles wrote: > Hugh, I understand the attraction of using VBT for QSub. With a mission profile to be able to do long ocean surface transects to a dive location, submerge, dive, surface and then transect back. It is not practical to haul excess ballast since the Qsub is operating more like a submarine than a submersible. If you can find a positive displacement pump that does not have a lot of slippage at your maximum depth, then the issue I mentioned about opening the VBT at depth and getting negatively buoyant goes away because the pump itself is preventing a large inrush of water. When this happened on my boat, I had already switched to air for blowing VBT. I would, as you note, adjust the water in the VBT just below the surface after flooding the MBTs. This was the NOP but sometimes the unexpected happens and you need to add buoyancy at depth with the VBT. I was diving the R300 about seven years ago at Lake Amistad on the border between Mexico and Texas. I submerged to about 150 ft in ! old river bottom. When I lifted of the bottom to start the ascent using my vertical thrusters at an altitude of about 10ft, the boat stopped ascending even with full vertical thrusters. I was watching the depth gage and I was just going up. I did not realize it but I was being dragged along by a 5-knot current and was not accenting at a rate I was comfortable with. The boat at the time was neutrally buoyant. To increase the rate of ascent, I decided to blow the VBT at depth. The depth was about 140 ft at the time. When I opened the motorized ball valve on the vent side of the VBT, the boat started descending even though air was being introduced because of this sudden influx of water. Eventually, the water in the VBT was displaced with air and the boat started to ascend. When I surfaced, I was about a mile downstream from the tender vessel. Because the water visibly was so bad, I did not realize I was being dragged by the current so much. > > Cliff > > On Wednesday, August 16, 2023 at 09:25:55 PM CDT, via Personal_Submersibles wrote: > > Hi Cliff, > I am interested in your comments re the pump slippage etc and > operation of the VBTs when you were using them. > My approach, untried and purely theoretical, was that most of the VBT > adjustment would be done just below the surface and only minor > adjustment for compression of vessels etc would be done at depth. > I do appreciate that weight balance appears more foolproof. Regards, > Hugh > > -----Original Message----- > From: Personal_Submersibles > On Behalf Of via Personal_Submersibles > Sent: Thursday, August 17, 2023 1:02 PM > To: personal_submersibles at psubs.org > Subject: Personal_Submersibles Digest, Vol 120, Issue 40 > > Send Personal_Submersibles mailing list submissions to > personal_submersibles at psubs.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > or, via email, send a message with subject or body 'help' to > personal_submersibles-request at psubs.org > > You can reach the person managing the list at > personal_submersibles-owner at psubs.org > > When replying, please edit your Subject line so it is more specific > than > "Re: Contents of Personal_Submersibles digest..." > > Today's Topics: > > 1. Re: Re VBT Pump (Cliff Redus via Personal_Submersibles) > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 17 Aug 2023 01:01:56 +0000 (UTC) > From: Cliff Redus via Personal_Submersibles > > To: via Personal_Submersibles > Subject: Re: [PSUBS-MAILIST] Re VBT Pump > Message-ID: <2137621386.758356.1692234116222 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > Hugh, thanks for update on QSub.? I am looking forward to her dunk > test in your new test pool. I quite enjoyed sitting in her pressure > hull in your shop in New Zealand a few years back.? She will be quite > something when complete. > Best > On Wednesday, August 16, 2023 at 06:43:41 PM CDT, via > Personal_Submersibles wrote: > > Thanks, Cliff, Alec, Vance, Jon. > > The model I was looking at, correction, was the Oberdorfer 994 which > is same as a 2000 series but 3/8" - 1/2"? and direct mounted not foot > mounted as per the 2000 series. > > The other pump I liked was the Wanner D10 which is diaphragm and can > do no slippage and 250 -300 psi etc but it is not bidirectional.? > However that can be fixed with valves. > > I am making some progress with my Q-Sub but made the mistake of going > too complex and trying to do everything.? I? have had issues with --- > 1. BMS systems for the LiFePO4 batteries and had to replace these. > 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. > 3. Gear cable kinking for the mercruiser sternlegs. > 4. Inaccessible fuses and not motor rated. > 5. Mechanical seal leakage on the hydraulics. > 6. Joystick pot issues. > 7. Canbus systems at different voltages. > 8. Rotary sensors too coarse required op amp addition to amplify > signals for small rotary movements with steering. > 9. Port Engine starting issues. > 10. Oil compensation line fittings leaks. > 11. Software issues. > > Still plugging along.? IN the meantime I have built a test pool > same-same Hank 8 ft deep 12 wide x 27 long, and another gantry crane > for PVHO removal, as well as a shed just for the sub.? This year it > has to be finished.? Has not even been in the pool yet!! > Regards,? Hugh > > -----Original Message----- > From: Personal_Submersibles > On Behalf Of via Personal_Submersibles > Sent: Thursday, August 17, 2023 3:21 AM > To: personal_submersibles at psubs.org > Subject: Personal_Submersibles Digest, Vol 120, Issue 36 > > Send Personal_Submersibles mailing list submissions to ??? > personal_submersibles at psubs.org > > To subscribe or unsubscribe via the World Wide Web, visit ??? > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > or, via email, send a message with subject or body 'help' to ??? > personal_submersibles-request at psubs.org > > You can reach the person managing the list at ??? > personal_submersibles-owner at psubs.org > > When replying, please edit your Subject line so it is more specific > than > "Re: Contents of Personal_Submersibles digest..." > > Today's Topics: > > ? 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) ? 2. Re: FW: > VBT pump (Alec Smyth via Personal_Submersibles) ? 3. Re: FW: VBT pump > (Jon Wallace via Personal_Submersibles) > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) > From: Cliff Redus via Personal_Submersibles ??? > > To: via Personal_Submersibles > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat.? My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT.? I don't remember the specs on the > pump.? I had motorized ball valves on the vent and flood side of the > VBT.? Prior to using this set up, I did some testing of this gear pump > which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? > There was so much slippage that the pump could not blow the VBT at max > depth.? At that point I abandoned using a pump and vent to blowing the > VBT with air.? I eventually abandoned the VBT altogether for > operability reasons.? When I used this hard VBT to get neutral on the > surface, the pressure in the tank was low.? When at depth if I ever > tried to use the VBT, water would rush in until the pressure equalized > with ambient water pressure.? This made the boat nega! > tively buoyant until air was added.? The other thing that bugged me > was I had a float style level sensor in the VBT.? The water level in > the VBT was always moving around so you never trust the reading.? I > eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? > I find this works great.? The other issue is the VBT restricted access > to equipment aft of the VBT so to work on any of this equipment, I had > to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. > Cliff > Oberdorfer 944 Bronze > > ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles wrote:? > > Hi Guys > > ? > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are > only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel backed sleeve bearings. > > ? > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > ? > -------------- next part -------------- An HTML attachment was > scrubbed... > URL: > 30816/ > b13a39c1/attachment-0001.html> > > ------------------------------ > > Message: 2 > Date: Wed, 16 Aug 2023 09:41:53 -0400 > From: Alec Smyth via Personal_Submersibles ??? > > To: Personal Submersibles General Discussion ??? > > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: > ??? > > Content-Type: text/plain; charset="utf-8" > > I second that (getting rid of VBT). I got rid of the VBT in my K250 > years ago to make space and turn it into a 2-person and to try and to > simplify, and it worked so well I never thought of using any other > method on the current sub. The only difference with Cliff's method is > that I add or remove floats, while he uses ballast. But either way, > once you have a reference point for how much ballast/buoyancy you need > for a given crew weight, you just make incremental changes and it > never fails. You may be off neutral by just a few pounds, but if you > have vertical thrusters they're usually just ticking over at slow RPMs to compensate. > > Best, > Alec > > On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles > < personal_submersibles at psubs.org> wrote: > >> Hugh, on my original design for the R300 I had a hard VBT just aft of >> the pilot. At the time I had a small HPU in the boat.? My plan was to >> use a Oberdorfer Bronze gear pump driven by a small hydraulic motor >> to move water in and out of the VBT.? I don't remember the specs on >> the pump.? I had motorized ball valves on the vent and flood side of >> the VBT.? Prior to using this set up, I did some testing of this gear >> pump which I still have.? What I found was an unacceptable amount of >> flow slippage at my max design depth.? There was so much slippage >> that the pump could not blow the VBT at max depth.? At that point I >> abandoned using a pump and vent to blowing the VBT with air.? I >> eventually abandoned the VBT altogether for operability reasons.? >> When I used this hard VBT to get neutral on the surface, the pressure >> in the tank was low.? When at depth if I ever tried to use the VBT, >> water would rush in until the pressure equalized with ambient water pressure.? >> This made the boat negatively buoyant until air was added.? The other >> thing that bugged me was I had a float style level sensor in the VBT.? >> The water level in the VBT was always moving around so you never >> trust the reading.? I eventually abandoned the VBT and now just add >> ballast at the boat CG where the VBT was located.? I find this works great.? >> The > other issue is the VBT restricted access to equipment aft of >> the VBT so to work on any of this equipment, I had to remove the VBT. > All >> in all, I found the VBT to be a pain in butt. >> >> Cliff >> >> Oberdorfer 944 Bronze >> >> On Sunday, August 13, 2023 at 04:57:24 PM CDT, via >> Personal_Submersibles < personal_submersibles at psubs.org> wrote: >> >> >> Hi Guys >> >> >> >> What make of pump is best for VBT water transfer in/out for 250 psi >> 1.5 > kw. >> >> I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are >> only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I >> had a stainless and bronze gear set made up but the aluminium body >> corroded form the trials and I just found that they had used steel >> backed > sleeve bearings. >> >> >> >> Regards, >> >> Hugh >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles >> > -------------- next part -------------- An HTML attachment was > scrubbed... > URL: > 30816/ > b5338913/attachment-0001.html> > > ------------------------------ > > Message: 3 > Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) > From: Jon Wallace via Personal_Submersibles ??? > > To: Personal Submersibles General Discussion ??? > > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > I'll chime in here...I removed the VBT from the K600 because it was > fairly well rusted inside and needed to be replaced, however I am > planning on using the ballast/float method instead and forgoing the > VBT altogether for many of the reasons Alec and Cliff cited.? I will > say that it can be challenging to change ballast on-station since the > weight/floatation has to be transferred somewhere and by somebody, > however I see the K600 being trimmed for specific missions prior to > launch and not being trimmed dynamically on-station to embark/disembark passengers or equipment. > Jon > > ? ? On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via > Personal_Submersibles wrote:? > > I second that (getting rid of VBT). I got rid of the VBT in my K250 > years ago to make space and turn it into a 2-person and to try and to > simplify,?and it worked so well I never thought of using?any other > method on the current sub. The only difference with Cliff's method is > that I add or remove floats, while he uses ballast. But either way, > once you have a reference point for how much ballast/buoyancy you need > for a given crew weight, you just make incremental changes and it > never fails. You may be off neutral by just a few pounds, but if you > have vertical thrusters they're usually just ticking over at slow RPMs to compensate. > > Best,Alec > On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles > wrote: > > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat.? My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT.? I don't remember the specs on the > pump.? I had motorized ball valves on the vent and flood side of the > VBT.? Prior to using this set up, I did some testing of this gear pump > which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? > There was so much slippage that the pump could not blow the VBT at max > depth.? At that point I abandoned using a pump and vent to blowing the > VBT with air.? I eventually abandoned the VBT altogether for > operability reasons.? When I used this hard VBT to get neutral on the > surface, the pressure in the tank was low.? When at depth if I ever > tried to use the VBT, water would rush in until the pressure equalized > with ambient water pressure.? This made the boat nega! > tively buoyant until air was added.? The other thing that bugged me > was I had a float style level sensor in the VBT.? The water level in > the VBT was always moving around so you never trust the reading.? I > eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? > I find this works great.? The other issue is the VBT restricted access > to equipment aft of the VBT so to work on any of this equipment, I had > to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. > Cliff > Oberdorfer 944 Bronze > > ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles wrote:? > > Hi Guys > > ? > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are > only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel backed sleeve bearings. > > ? > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > ? _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > ? > -------------- next part -------------- An HTML attachment was > scrubbed... > URL: > 30816/ > 301b6d76/attachment.html> > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > > ------------------------------ > > End of Personal_Submersibles Digest, Vol 120, Issue 36 > ****************************************************** > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > -------------- next part -------------- An HTML attachment was > scrubbed... > URL: > 30817/ > b598be5b/attachment.html> > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > > ------------------------------ > > End of Personal_Submersibles Digest, Vol 120, Issue 40 > ****************************************************** > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 43 ****************************************************** From personal_submersibles at psubs.org Thu Aug 17 17:57:08 2023 From: personal_submersibles at psubs.org (via Personal_Submersibles) Date: Fri, 18 Aug 2023 09:57:08 +1200 Subject: [PSUBS-MAILIST] Re VBT pump. In-Reply-To: References: Message-ID: <03d501d9d155$c65c8dc0$5315a940$@gmail.com> I have pressure transducer, relief valve and level gauge in both VBT tanks and expect the pump to pressurise the air to some degree in certain circumstances to assist the pump at depth. So VBT can be air pressurised, vented or filled/emptied with water via the pump or transferred from aft tank to forward tank. Hopefully at some stage I will be able to do auto depth and compression compensation automatically. With my pool I could do the Cliff test but I don't think it would be sensitive enough for the small depth variation allowed. I would have to deepen the tank. Depth is 2.5 meters only. I can send a drawing of the setup I have built if I can paste it on this or is this only text compatible. Chs Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Friday, August 18, 2023 6:40 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 49 Send Personal_Submersibles mailing list submissions to personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to personal_submersibles-request at psubs.org You can reach the person managing the list at personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: 1. Re: Personal_Submersibles Digest, Vol 120, Issue 40 (Jon Wallace via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Thu, 17 Aug 2023 18:39:16 +0000 (UTC) From: Jon Wallace via Personal_Submersibles To: Jon Wallace via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] Personal_Submersibles Digest, Vol 120, Issue 40 Message-ID: <64068358.1131692.1692297556435 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Yeah, I missed that part.? :) Jon On Thursday, August 17, 2023 at 12:44:07 PM EDT, Cliff Redus via Personal_Submersibles wrote: Jon, if I am understanding Sean correctly, he is advocating using a PD pump with a check valve to move water out of the VBT instead of air pressure so issue of in rush of water when the flood valve is opened goes away. I do agree "working out the dynamics in actual practice would require a bit of time".? Constants for PID controller would have to be experimented with. Cliff On Thursday, August 17, 2023 at 10:51:19 AM CDT, Jon Wallace via Personal_Submersibles wrote: Conceptually it's a great idea for automation and likely not a big deal to implement via software code.? I think working out the dynamics in actual practice would require a bit of time.? Assuming you wanted more buoyancy the biggest issue would be the description Cliff gave of adding air to the VBT without the inrush of water because of the pressure difference at depth.? The only solution I see to that is adding a pressure sensor to the VBT and adding air first to counter the outside water pressure, then opening the outside valve to the VBT.? That means another sensor, more software code, and more potential things that could go wrong, which is why I like the simplicity of removing the VBT entirely and just relying on weight control to obtain neutral buoyancy.? BUT...it would be a good project if somebody wanted to implement it. Jon On Thursday, August 17, 2023 at 10:25:56 AM EDT, Cliff Redus via Personal_Submersibles wrote: Sean, I think this control strategy could work.? To utilize, you would need a PLC or microprocessor to implement a PID loop.? It would be easy to test by putting the sub in shallow test tank to test depth station keeping capability.? You could then upset the system by adding some lead ballast to the boat and see how well the VBT/Thrusters handle the upset. My guess is that those in our group that like the KISS strategy would deems this as too complicated while those that like this kind of approach would see some nice benefits of this control strategy.? My experience with Psubs is that someone try's something new and if it works incrementally better than what they were using, they adopt.? For me it would have to be modified as I don't have a VBT, i.e., I could implement a depth/altitude station keeping PLC function with a PID loop controlling either depth or altitude with vertical thrusters alone. Cliff On Wednesday, August 16, 2023 at 10:59:28 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: I think I may have offered this the last time the VBT discussion came up, but I always thought that a good control scheme for the VBT would be to automate it within a slave loop to the vertical thruster control. So, for example, you have a position setpoint in the vertical direction which is either auto-depth or auto-altitude, and have your vertical thrusters programmed to respond accordingly to maintain that setpoint. Separately, you monitor the instantaneous output to the vertical thrusters that results from that control loop, filtered on a longer time base, and operate one of two valves via a slower acting control loop to either admit water to the VBT, or open the pump discharge to let water out, as necessary in order to null out that thruster input. This way, external disturbances such as vertical currents, or buoyancy changes due to hull deflection at depth etc., would be compensated for automatically, and the system would also act to conserve energy by minimizing powe! r consumption to the vertical thrusters, by always dialing the boat to neutral. When not holding an altitude or depth, the system could also activate whenever the manual thruster command was saturated at 100% in either direction, in order to hasten a long ascent or descent, or possibly to respond to the condition where the available vertical thrust is insufficient. The only caveat would be to make sure that you don't allow so much VBT volume that you couldn't manually counter the resultant buoyant force with opposing thrust in an emergency. Such an embodiment would require a check valve based reciprocating pump, like a Sprague, that could be deadheaded against the discharge valve at full outlet pressure. Opening the discharge valve would cause it to stroke, while closing the discharge valve would deadhead it again. This is possibly a safety feature, because as as long as the pump is not stroking with the discharge valve closed, you know it can develop pressure, and again, having a pump that just stops when pressure builds downstream will conserve the HP air or electrical power used to drive it, in contrast to a pump that must be explicitly run. Just a thought. Sean -------- Original Message -------- On Aug. 16, 2023, 21:18, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: Hugh, I understand the attraction of using VBT for QSub.? With a mission profile to be able to do long ocean surface transects to a dive location, submerge, dive, surface and then transect back.? It is not practical to haul excess ballast since the Qsub is operating more like a submarine than a submersible.? If you can find a positive displacement pump that does not have a lot of slippage at your maximum depth, then the issue I mentioned about opening the VBT at depth and getting negatively buoyant goes away because the pump itself is preventing a large inrush of water.? When this happened on my boat, I had already switched to air for blowing VBT. I would, as you note, adjust the water in the VBT just below the surface after flooding the MBTs.? This was the NOP but sometimes the unexpected happens and you need to add buoyancy at depth with the VBT.? I was diving the R300 about seven years ago at Lake Amistad on the border between Mexico and Texas.? I submerged to about 150 ! ft in old river bottom. When I lifted of the bottom to start the ascent using my vertical thrusters at an altitude of about 10ft, the boat stopped ascending even with full vertical thrusters.? I was watching the depth gage and I was just going up.? I did not realize it but I was being dragged along by a 5-knot current and was not accenting at a rate I was comfortable with.? The boat at the time was neutrally buoyant.? To increase the rate of ascent, I decided to blow the VBT at depth. The depth was about 140 ft at the time.? When I opened the motorized ball valve on the vent side of the VBT, the boat started descending even though air was being introduced because of this sudden influx of water.? Eventually, the water in the VBT was displaced with air and the boat started to ascend.? When I surfaced, I was about a mile downstream from the tender vessel.? Because the water visibly was so bad, I did not realize I was being dragged by the current so much.?? Cliff On Wednesday, August 16, 2023 at 09:25:55 PM CDT, via Personal_Submersibles wrote: Hi Cliff, I am interested in your comments re the pump slippage etc and operation of the VBTs when you were using them. My approach, untried and purely theoretical, was that most of the VBT adjustment would be done just below the surface and only minor adjustment for compression of vessels etc would be done at depth.? I do appreciate that weight balance appears more foolproof.? Regards, Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 1:02 PM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 40 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: Re VBT Pump (Cliff Redus via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Thu, 17 Aug 2023 01:01:56 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] Re VBT Pump Message-ID: <2137621386.758356.1692234116222 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, thanks for update on QSub.? I am looking forward to her dunk test in your new test pool. I quite enjoyed sitting in her pressure hull in your shop in New Zealand a few years back.? She will be quite something when complete. Best ? ? On Wednesday, August 16, 2023 at 06:43:41 PM CDT, via Personal_Submersibles wrote:? Thanks, Cliff, Alec, Vance, Jon. The model I was looking at, correction, was the Oberdorfer 994 which is same as a 2000 series but 3/8" - 1/2"? and direct mounted not foot mounted as per the 2000 series. The other pump I liked was the Wanner D10 which is diaphragm and can do no slippage and 250 -300 psi etc but it is not bidirectional.? However that can be fixed with valves. I am making some progress with my Q-Sub but made the mistake of going too complex and trying to do everything.? I? have had issues with --- 1. BMS systems for the LiFePO4 batteries and had to replace these. 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. 3. Gear cable kinking for the mercruiser sternlegs. 4. Inaccessible fuses and not motor rated. 5. Mechanical seal leakage on the hydraulics. 6. Joystick pot issues. 7. Canbus systems at different voltages. 8. Rotary sensors too coarse required op amp addition to amplify signals for small rotary movements with steering. 9. Port Engine starting issues. 10. Oil compensation line fittings leaks. 11. Software issues. Still plugging along.? IN the meantime I have built a test pool same-same Hank 8 ft deep 12 wide x 27 long, and another gantry crane for PVHO removal, as well as a shed just for the sub.? This year it has to be finished.? Has not even been in the pool yet!! Regards,? Hugh -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Thursday, August 17, 2023 3:21 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 36 Send Personal_Submersibles mailing list submissions to ??? personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit ??? http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to ??? personal_submersibles-request at psubs.org You can reach the person managing the list at ??? personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: ? 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) ? 2. Re: FW: VBT pump (Alec Smyth via Personal_Submersibles) ? 3. Re: FW: VBT pump (Jon Wallace via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) From: Cliff Redus via Personal_Submersibles ??? To: via Personal_Submersibles Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 2 Date: Wed, 16 Aug 2023 09:41:53 -0400 From: Alec Smyth via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: ??? Content-Type: text/plain; charset="utf-8" I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify, and it worked so well I never thought of using any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best, Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat.? My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT.? I don't remember the specs on the > pump.? I had motorized ball valves on the vent and flood side of the > VBT.? Prior to using this set up, I did some testing of this gear pump > which I still have.? What I found was an unacceptable amount of flow > slippage at my max design depth.? There was so much slippage that the > pump could not blow the VBT at max depth.? At that point I abandoned > using a pump and vent to blowing the VBT with air.? I eventually > abandoned the VBT altogether for operability reasons.? When I used > this hard VBT to get neutral on the surface, the pressure in the tank > was low.? When at depth if I ever tried to use the VBT, water would > rush in until the pressure equalized with ambient water pressure.? > This made the boat negatively buoyant until air was added.? The other > thing that bugged me was I had a float style level sensor in the VBT.? > The water level in the VBT was always moving around so you never trust > the reading.? I eventually abandoned the VBT and now just add ballast > at the boat CG where the VBT was located.? I find this works great.? > The other issue is the VBT restricted access to equipment aft of > the VBT so to work on any of this equipment, I had to remove the VBT. All > in all, I found the VBT to be a pain in butt. > > Cliff > > Oberdorfer 944 Bronze > > On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles < personal_submersibles at psubs.org> wrote: > > > Hi Guys > > > > What make of pump is best for VBT water transfer in/out for 250 psi > 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are > only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel > backed sleeve bearings. > > > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Message: 3 Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) From: Jon Wallace via Personal_Submersibles ??? To: Personal Submersibles General Discussion ??? Subject: Re: [PSUBS-MAILIST] FW: VBT pump Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> Content-Type: text/plain; charset="utf-8" I'll chime in here...I removed the VBT from the K600 because it was fairly well rusted inside and needed to be replaced, however I am planning on using the ballast/float method instead and forgoing the VBT altogether for many of the reasons Alec and Cliff cited.? I will say that it can be challenging to change ballast on-station since the weight/floatation has to be transferred somewhere and by somebody, however I see the K600 being trimmed for specific missions prior to launch and not being trimmed dynamically on-station to embark/disembark passengers or equipment. Jon ? ? On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via Personal_Submersibles wrote:? I second that (getting rid of VBT). I got rid of the VBT in my K250 years ago to make space and turn it into a 2-person and to try and to simplify,?and it worked so well I never thought of using?any other method on the current sub. The only difference with Cliff's method is that I add or remove floats, while he uses ballast. But either way, once you have a reference point for how much ballast/buoyancy you need for a given crew weight, you just make incremental changes and it never fails. You may be off neutral by just a few pounds, but if you have vertical thrusters they're usually just ticking over at slow RPMs to compensate. Best,Alec On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles wrote: Hugh, on my original design for the R300 I had a hard VBT just aft of the pilot. At the time I had a small HPU in the boat.? My plan was to use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to move water in and out of the VBT.? I don't remember the specs on the pump.? I had motorized ball valves on the vent and flood side of the VBT.? Prior to using this set up, I did some testing of this gear pump which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? There was so much slippage that the pump could not blow the VBT at max depth.? At that point I abandoned using a pump and vent to blowing the VBT with air.? I eventually abandoned the VBT altogether for operability reasons.? When I used this hard VBT to get neutral on the surface, the pressure in the tank was low.? When at depth if I ever tried to use the VBT, water would rush in until the pressure equalized with ambient water pressure.? This made the boat nega! tively buoyant until air was added.? The other thing that bugged me was I had a float style level sensor in the VBT.? The water level in the VBT was always moving around so you never trust the reading.? I eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? I find this works great.? The other issue is the VBT restricted access to equipment aft of the VBT so to work on any of this equipment, I had to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. Cliff Oberdorfer 944 Bronze ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via Personal_Submersibles wrote:? Hi Guys ? What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I had a stainless and bronze gear set made up but the aluminium body corroded form the trials and I just found that they had used steel backed sleeve bearings. ? Regards, Hugh _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles ? -------------- next part -------------- An HTML attachment was scrubbed... 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URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 49 ****************************************************** From personal_submersibles at psubs.org Thu Aug 17 18:31:56 2023 From: personal_submersibles at psubs.org (via Personal_Submersibles) Date: Fri, 18 Aug 2023 10:31:56 +1200 Subject: [PSUBS-MAILIST] Personal_Submersibles Digest, Vol 120, Issue 48 In-Reply-To: References: Message-ID: <03f201d9d15a$a3aaec90$eb00c5b0$@gmail.com> Aha, just spotted a flaw in my system, dumb--s. I have the relief valve on the water side. Should be on the air vent side and I need to vent it to not under the MBT catchment but through the hull so the relief vented air doesn't add to an MBT bubble situation. -----Original Message----- From: Personal_Submersibles On Behalf Of via Personal_Submersibles Sent: Friday, August 18, 2023 5:19 AM To: personal_submersibles at psubs.org Subject: Personal_Submersibles Digest, Vol 120, Issue 48 Send Personal_Submersibles mailing list submissions to personal_submersibles at psubs.org To subscribe or unsubscribe via the World Wide Web, visit http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles or, via email, send a message with subject or body 'help' to personal_submersibles-request at psubs.org You can reach the person managing the list at personal_submersibles-owner at psubs.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Personal_Submersibles digest..." Today's Topics: 1. Re: Personal_Submersibles Digest, Vol 120, Issue 40 (Sean T. Stevenson via Personal_Submersibles) ---------------------------------------------------------------------- Message: 1 Date: Thu, 17 Aug 2023 17:18:20 +0000 From: "Sean T. Stevenson via Personal_Submersibles" To: personal_submersibles at psubs.org Subject: Re: [PSUBS-MAILIST] Personal_Submersibles Digest, Vol 120, Issue 40 Message-ID: Content-Type: text/plain; charset="utf-8" Exactly. You never want the tank to contain stored energy in the form of gas pressure. The only part of the system that would see constant pressure is the line between the PD pump discharge and the discharge isolator valve. When the pump is operating, the tank should be relieved by a process air line at 1 atm or some other low pressure to maintain some positive suction head against the pump inlet. The only time the VBT would see internal pressure is when the inlet isolator valve is open, and in that case for safety's sake you would probably have an orifice or something to throttle that flow to something manageable at the deepest operating depth. If the VBT is a hard tank, as it fills the gas cap above the water inside will compress, and will need to be vented off. This can either be done continuously or discretely, but at the end of the addition operation, the VBT should be returned to LP internally. If it is a soft tank, that is a non-issue. Sean -------- Original Message -------- On Aug. 17, 2023, 10:41, Cliff Redus via Personal_Submersibles wrote: > Jon, if I am understanding Sean correctly, he is advocating using a PD pump with a check valve to move water out of the VBT instead of air pressure so issue of in rush of water when the flood valve is opened goes away. > > I do agree "working out the dynamics in actual practice would require a bit of time". Constants for PID controller would have to be experimented with. > > Cliff > > On Thursday, August 17, 2023 at 10:51:19 AM CDT, Jon Wallace via Personal_Submersibles wrote: > > Conceptually it's a great idea for automation and likely not a big deal to implement via software code. I think working out the dynamics in actual practice would require a bit of time. Assuming you wanted more buoyancy the biggest issue would be the description Cliff gave of adding air to the VBT without the inrush of water because of the pressure difference at depth. The only solution I see to that is adding a pressure sensor to the VBT and adding air first to counter the outside water pressure, then opening the outside valve to the VBT. That means another sensor, more software code, and more potential things that could go wrong, which is why I like the simplicity of removing the VBT entirely and just relying on weight control to obtain neutral buoyancy. BUT...it would be a good project if somebody wanted to implement it. > > Jon > > On Thursday, August 17, 2023 at 10:25:56 AM EDT, Cliff Redus via Personal_Submersibles wrote: > > Sean, I think this control strategy could work. To utilize, you would need a PLC or microprocessor to implement a PID loop. It would be easy to test by putting the sub in shallow test tank to test depth station keeping capability. You could then upset the system by adding some lead ballast to the boat and see how well the VBT/Thrusters handle the upset. > > My guess is that those in our group that like the KISS strategy would deems this as too complicated while those that like this kind of approach would see some nice benefits of this control strategy. My experience with Psubs is that someone try's something new and if it works incrementally better than what they were using, they adopt. For me it would have to be modified as I don't have a VBT, i.e., I could implement a depth/altitude station keeping PLC function with a PID loop controlling either depth or altitude with vertical thrusters alone. > > Cliff > > On Wednesday, August 16, 2023 at 10:59:28 PM CDT, Sean T. Stevenson via Personal_Submersibles wrote: > > I think I may have offered this the last time the VBT discussion came up, but I always thought that a good control scheme for the VBT would be to automate it within a slave loop to the vertical thruster control. So, for example, you have a position setpoint in the vertical direction which is either auto-depth or auto-altitude, and have your vertical thrusters programmed to respond accordingly to maintain that setpoint. Separately, you monitor the instantaneous output to the vertical thrusters that results from that control loop, filtered on a longer time base, and operate one of two valves via a slower acting control loop to either admit water to the VBT, or open the pump discharge to let water out, as necessary in order to null out that thruster input. This way, external disturbances such as vertical currents, or buoyancy changes due to hull deflection at depth etc., would be compensated for automatically, and the system would also act to conserve energy by minimizing pow! er consumption to the vertical thrusters, by always dialing the boat to neutral. > > When not holding an altitude or depth, the system could also activate whenever the manual thruster command was saturated at 100% in either direction, in order to hasten a long ascent or descent, or possibly to respond to the condition where the available vertical thrust is insufficient. The only caveat would be to make sure that you don't allow so much VBT volume that you couldn't manually counter the resultant buoyant force with opposing thrust in an emergency. > > Such an embodiment would require a check valve based reciprocating pump, like a Sprague, that could be deadheaded against the discharge valve at full outlet pressure. Opening the discharge valve would cause it to stroke, while closing the discharge valve would deadhead it again. This is possibly a safety feature, because as as long as the pump is not stroking with the discharge valve closed, you know it can develop pressure, and again, having a pump that just stops when pressure builds downstream will conserve the HP air or electrical power used to drive it, in contrast to a pump that must be explicitly run. > > Just a thought. > > Sean > > -------- Original Message -------- > On Aug. 16, 2023, 21:18, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > >> > > Hugh, I understand the attraction of using VBT for QSub. With a mission profile to be able to do long ocean surface transects to a dive location, submerge, dive, surface and then transect back. It is not practical to haul excess ballast since the Qsub is operating more like a submarine than a submersible. If you can find a positive displacement pump that does not have a lot of slippage at your maximum depth, then the issue I mentioned about opening the VBT at depth and getting negatively buoyant goes away because the pump itself is preventing a large inrush of water. When this happened on my boat, I had already switched to air for blowing VBT. I would, as you note, adjust the water in the VBT just below the surface after flooding the MBTs. This was the NOP but sometimes the unexpected happens and you need to add buoyancy at depth with the VBT. I was diving the R300 about seven years ago at Lake Amistad on the border between Mexico and Texas. I submerged to about 150 ft in ! old river bottom. When I lifted of the bottom to start the ascent using my vertical thrusters at an altitude of about 10ft, the boat stopped ascending even with full vertical thrusters. I was watching the depth gage and I was just going up. I did not realize it but I was being dragged along by a 5-knot current and was not accenting at a rate I was comfortable with. The boat at the time was neutrally buoyant. To increase the rate of ascent, I decided to blow the VBT at depth. The depth was about 140 ft at the time. When I opened the motorized ball valve on the vent side of the VBT, the boat started descending even though air was being introduced because of this sudden influx of water. Eventually, the water in the VBT was displaced with air and the boat started to ascend. When I surfaced, I was about a mile downstream from the tender vessel. Because the water visibly was so bad, I did not realize I was being dragged by the current so much. > > Cliff > > On Wednesday, August 16, 2023 at 09:25:55 PM CDT, via Personal_Submersibles wrote: > > Hi Cliff, > I am interested in your comments re the pump slippage etc and > operation of the VBTs when you were using them. > My approach, untried and purely theoretical, was that most of the VBT > adjustment would be done just below the surface and only minor > adjustment for compression of vessels etc would be done at depth. > I do appreciate that weight balance appears more foolproof. Regards, > Hugh > > -----Original Message----- > From: Personal_Submersibles > On Behalf Of via Personal_Submersibles > Sent: Thursday, August 17, 2023 1:02 PM > To: personal_submersibles at psubs.org > > Subject: Personal_Submersibles Digest, Vol 120, Issue 40 > > Send Personal_Submersibles mailing list submissions to > personal_submersibles at psubs.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > > or, via email, send a message with subject or body 'help' to > personal_submersibles-request at psubs.org > > You can reach the person managing the list at > personal_submersibles-owner at psubs.org > > When replying, please edit your Subject line so it is more specific > than > "Re: Contents of Personal_Submersibles digest..." > > Today's Topics: > > 1. Re: Re VBT Pump (Cliff Redus via Personal_Submersibles) > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 17 Aug 2023 01:01:56 +0000 (UTC) > From: Cliff Redus via Personal_Submersibles > > To: via Personal_Submersibles > Subject: Re: [PSUBS-MAILIST] Re VBT Pump > Message-ID: <2137621386.758356.1692234116222 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > Hugh, thanks for update on QSub.? I am looking forward to her dunk > test in your new test pool. I quite enjoyed sitting in her pressure > hull in your shop in New Zealand a few years back.? She will be quite > something when complete. > Best > On Wednesday, August 16, 2023 at 06:43:41 PM CDT, via > Personal_Submersibles wrote: > > Thanks, Cliff, Alec, Vance, Jon. > > The model I was looking at, correction, was the Oberdorfer 994 which > is same as a 2000 series but 3/8" - 1/2"? and direct mounted not foot > mounted as per the 2000 series. > > The other pump I liked was the Wanner D10 which is diaphragm and can > do no slippage and 250 -300 psi etc but it is not bidirectional.? > However that can be fixed with valves. > > I am making some progress with my Q-Sub but made the mistake of going > too complex and trying to do everything.? I? have had issues with --- > 1. BMS systems for the LiFePO4 batteries and had to replace these. > 2. Precharge systems for the 72 v and 144 volt electrics and voltage spikes. > 3. Gear cable kinking for the mercruiser sternlegs. > 4. Inaccessible fuses and not motor rated. > 5. Mechanical seal leakage on the hydraulics. > 6. Joystick pot issues. > 7. Canbus systems at different voltages. > 8. Rotary sensors too coarse required op amp addition to amplify > signals for small rotary movements with steering. > 9. Port Engine starting issues. > 10. Oil compensation line fittings leaks. > 11. Software issues. > > Still plugging along.? IN the meantime I have built a test pool > same-same Hank 8 ft deep 12 wide x 27 long, and another gantry crane > for PVHO removal, as well as a shed just for the sub.? This year it > has to be finished.? Has not even been in the pool yet!! > Regards,? Hugh > > -----Original Message----- > From: Personal_Submersibles > On Behalf Of via Personal_Submersibles > Sent: Thursday, August 17, 2023 3:21 AM > To: personal_submersibles at psubs.org > > Subject: Personal_Submersibles Digest, Vol 120, Issue 36 > > Send Personal_Submersibles mailing list submissions to ??? > personal_submersibles at psubs.org > > To subscribe or unsubscribe via the World Wide Web, visit ??? > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > > or, via email, send a message with subject or body 'help' to ??? > personal_submersibles-request at psubs.org > > You can reach the person managing the list at ??? > personal_submersibles-owner at psubs.org > > When replying, please edit your Subject line so it is more specific > than > "Re: Contents of Personal_Submersibles digest..." > > Today's Topics: > > ? 1. Re: FW: VBT pump (Cliff Redus via Personal_Submersibles) ? 2. Re: FW: > VBT pump (Alec Smyth via Personal_Submersibles) ? 3. Re: FW: VBT pump > (Jon Wallace via Personal_Submersibles) > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 16 Aug 2023 13:29:07 +0000 (UTC) > From: Cliff Redus via Personal_Submersibles ??? > > To: via Personal_Submersibles > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: <536726240.403633.1692192547749 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat.? My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT.? I don't remember the specs on the > pump.? I had motorized ball valves on the vent and flood side of the > VBT.? Prior to using this set up, I did some testing of this gear pump > which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? > There was so much slippage that the pump could not blow the VBT at max > depth.? At that point I abandoned using a pump and vent to blowing the > VBT with air.? I eventually abandoned the VBT altogether for > operability reasons.? When I used this hard VBT to get neutral on the > surface, the pressure in the tank was low.? When at depth if I ever > tried to use the VBT, water would rush in until the pressure equalized > with ambient water pressure.? This made the boat nega! > tively buoyant until air was added.? The other thing that bugged me > was I had a float style level sensor in the VBT.? The water level in > the VBT was always moving around so you never trust the reading.? I > eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? > I find this works great.? The other issue is the VBT restricted access > to equipment aft of the VBT so to work on any of this equipment, I had > to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. > Cliff > Oberdorfer 944 Bronze > > ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles wrote:? > > Hi Guys > > ? > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are > only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel backed sleeve bearings. > > ? > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > ? > -------------- next part -------------- An HTML attachment was > scrubbed... > URL: > 30816/ > > b13a39c1/attachment-0001.html> > > ------------------------------ > > Message: 2 > Date: Wed, 16 Aug 2023 09:41:53 -0400 > From: Alec Smyth via Personal_Submersibles ??? > > To: Personal Submersibles General Discussion ??? > > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: > ??? > > Content-Type: text/plain; charset="utf-8" > > I second that (getting rid of VBT). I got rid of the VBT in my K250 > years ago to make space and turn it into a 2-person and to try and to > simplify, and it worked so well I never thought of using any other > method on the current sub. The only difference with Cliff's method is > that I add or remove floats, while he uses ballast. But either way, > once you have a reference point for how much ballast/buoyancy you need > for a given crew weight, you just make incremental changes and it > never fails. You may be off neutral by just a few pounds, but if you > have vertical thrusters they're usually just ticking over at slow RPMs to compensate. > > Best, > Alec > > On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles > < personal_submersibles at psubs.org> wrote: > >> Hugh, on my original design for the R300 I had a hard VBT just aft of >> the pilot. At the time I had a small HPU in the boat.? My plan was to >> use a Oberdorfer Bronze gear pump driven by a small hydraulic motor >> to move water in and out of the VBT.? I don't remember the specs on >> the pump.? I had motorized ball valves on the vent and flood side of >> the VBT.? Prior to using this set up, I did some testing of this gear >> pump which I still have.? What I found was an unacceptable amount of >> flow slippage at my max design depth.? There was so much slippage >> that the pump could not blow the VBT at max depth.? At that point I >> abandoned using a pump and vent to blowing the VBT with air.? I >> eventually abandoned the VBT altogether for operability reasons.? >> When I used this hard VBT to get neutral on the surface, the pressure >> in the tank was low.? When at depth if I ever tried to use the VBT, >> water would rush in until the pressure equalized with ambient water pressure.? >> This made the boat negatively buoyant until air was added.? The other >> thing that bugged me was I had a float style level sensor in the VBT.? >> The water level in the VBT was always moving around so you never >> trust the reading.? I eventually abandoned the VBT and now just add >> ballast at the boat CG where the VBT was located.? I find this works great.? >> The > other issue is the VBT restricted access to equipment aft of >> the VBT so to work on any of this equipment, I had to remove the VBT. > All >> in all, I found the VBT to be a pain in butt. >> >> Cliff >> >> Oberdorfer 944 Bronze >> >> On Sunday, August 13, 2023 at 04:57:24 PM CDT, via >> Personal_Submersibles < personal_submersibles at psubs.org> wrote: >> >> >> Hi Guys >> >> >> >> What make of pump is best for VBT water transfer in/out for 250 psi >> 1.5 > kw. >> >> I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are >> only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I >> had a stainless and bronze gear set made up but the aluminium body >> corroded form the trials and I just found that they had used steel >> backed > sleeve bearings. >> >> >> >> Regards, >> >> Hugh >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org > >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > >> _______________________________________________ >> Personal_Submersibles mailing list >> Personal_Submersibles at psubs.org > >> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > >> > -------------- next part -------------- An HTML attachment was > scrubbed... > URL: > 30816/ > > b5338913/attachment-0001.html> > > ------------------------------ > > Message: 3 > Date: Wed, 16 Aug 2023 15:20:44 +0000 (UTC) > From: Jon Wallace via Personal_Submersibles ??? > > To: Personal Submersibles General Discussion ??? > > Subject: Re: [PSUBS-MAILIST] FW: VBT pump > Message-ID: <1959084270.469930.1692199244774 at mail.yahoo.com> > Content-Type: text/plain; charset="utf-8" > > I'll chime in here...I removed the VBT from the K600 because it was > fairly well rusted inside and needed to be replaced, however I am > planning on using the ballast/float method instead and forgoing the > VBT altogether for many of the reasons Alec and Cliff cited.? I will > say that it can be challenging to change ballast on-station since the > weight/floatation has to be transferred somewhere and by somebody, > however I see the K600 being trimmed for specific missions prior to > launch and not being trimmed dynamically on-station to embark/disembark passengers or equipment. > Jon > > ? ? On Wednesday, August 16, 2023 at 09:43:35 AM EDT, Alec Smyth via > Personal_Submersibles wrote:? > > I second that (getting rid of VBT). I got rid of the VBT in my K250 > years ago to make space and turn it into a 2-person and to try and to > simplify,?and it worked so well I never thought of using?any other > method on the current sub. The only difference with Cliff's method is > that I add or remove floats, while he uses ballast. But either way, > once you have a reference point for how much ballast/buoyancy you need > for a given crew weight, you just make incremental changes and it > never fails. You may be off neutral by just a few pounds, but if you > have vertical thrusters they're usually just ticking over at slow RPMs to compensate. > > Best,Alec > On Wed, Aug 16, 2023 at 9:30?AM Cliff Redus via Personal_Submersibles > wrote: > > Hugh, on my original design for the R300 I had a hard VBT just aft of > the pilot. At the time I had a small HPU in the boat.? My plan was to > use a Oberdorfer Bronze gear pump driven by a small hydraulic motor to > move water in and out of the VBT.? I don't remember the specs on the > pump.? I had motorized ball valves on the vent and flood side of the > VBT.? Prior to using this set up, I did some testing of this gear pump > which I still have.? What I found was an unacceptable amount of flow slippage at my max design depth.? > There was so much slippage that the pump could not blow the VBT at max > depth.? At that point I abandoned using a pump and vent to blowing the > VBT with air.? I eventually abandoned the VBT altogether for > operability reasons.? When I used this hard VBT to get neutral on the > surface, the pressure in the tank was low.? When at depth if I ever > tried to use the VBT, water would rush in until the pressure equalized > with ambient water pressure.? This made the boat nega! > tively buoyant until air was added.? The other thing that bugged me > was I had a float style level sensor in the VBT.? The water level in > the VBT was always moving around so you never trust the reading.? I > eventually abandoned the VBT and now just add ballast at the boat CG where the VBT was located.? > I find this works great.? The other issue is the VBT restricted access > to equipment aft of the VBT so to work on any of this equipment, I had > to remove the VBT.? ?All in all, I found the VBT to be a pain in butt. > Cliff > Oberdorfer 944 Bronze > > ? ? On Sunday, August 13, 2023 at 04:57:24 PM CDT, via > Personal_Submersibles wrote:? > > Hi Guys > > ? > > What make of pump is best for VBT water transfer in/out for 250 psi 1.5 kw. > > I am looking at a gear pump 1.5kw Oberdorfer 944 Bronze.? These are > only rated for 10 bar.? I tried an hydraulic gear pump 30cc where I > had a stainless and bronze gear set made up but the aluminium body > corroded form the trials and I just found that they had used steel backed sleeve bearings. > > ? > > Regards, > > Hugh > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > ? _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > ? > -------------- next part -------------- An HTML attachment was > scrubbed... > URL: > 30816/ > > 301b6d76/attachment.html> > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > > ------------------------------ > > End of Personal_Submersibles Digest, Vol 120, Issue 36 > ****************************************************** > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > -------------- next part -------------- An HTML attachment was > scrubbed... > URL: > 30817/ > > b598be5b/attachment.html> > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > > http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles > > ------------------------------ > > End of Personal_Submersibles Digest, Vol 120, Issue 40 > ****************************************************** > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: ------------------------------ Subject: Digest Footer _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.whoweb.com/mailman/listinfo.cgi/personal_submersibles ------------------------------ End of Personal_Submersibles Digest, Vol 120, Issue 48 ****************************************************** From personal_submersibles at psubs.org Fri Aug 18 04:24:53 2023 From: personal_submersibles at psubs.org (irox via Personal_Submersibles) Date: Fri, 18 Aug 2023 08:24:53 +0000 Subject: [PSUBS-MAILIST] Maui fire Message-ID: <2a04f259-b003-b78b-f0ef-4c4ad3fbd0da@ix.netcom.com> Absolute tragedy on Maui. My heart goes out to all there. In some footage of the fire damage I briefly saw the 48 person Atlantis Submarines tourist sub: https://www.youtube.com/watch?v=Y_sjw5ex9z8&t=110s Lying on its side just outside the harbor. Looks like most of the fiberglass ballast tanks and fairings have burn off. From personal_submersibles at psubs.org Fri Aug 18 09:07:54 2023 From: personal_submersibles at psubs.org (Jon Wallace via Personal_Submersibles) Date: Fri, 18 Aug 2023 13:07:54 +0000 (UTC) Subject: [PSUBS-MAILIST] Maui fire In-Reply-To: <2a04f259-b003-b78b-f0ef-4c4ad3fbd0da@ix.netcom.com> References: <2a04f259-b003-b78b-f0ef-4c4ad3fbd0da@ix.netcom.com> Message-ID: <201967263.1478767.1692364075002@mail.yahoo.com> Their website says they have a 48 and 64 passenger vessel.??At 1:41 it looks like the bigger one is still floating. Jon On Friday, August 18, 2023 at 04:26:24 AM EDT, irox via Personal_Submersibles wrote: Absolute tragedy on Maui. My heart goes out to all there. In some footage of the fire damage I briefly saw the 48 person Atlantis Submarines tourist sub: https://www.youtube.com/watch?v=Y_sjw5ex9z8&t=110s Lying on its side just outside the harbor. Looks like most of the fiberglass ballast tanks and fairings have burn off. _______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sat Aug 19 13:45:01 2023 From: personal_submersibles at psubs.org (Jon Wallace via Personal_Submersibles) Date: Sat, 19 Aug 2023 17:45:01 +0000 (UTC) Subject: [PSUBS-MAILIST] I've got a Potato in my sub References: <1460814352.1966819.1692467101532.ref@mail.yahoo.com> Message-ID: <1460814352.1966819.1692467101532@mail.yahoo.com> Le Potato, to be specific.? It's a potential SBC replacement for the Raspberry Pi which is still difficult to obtain here in the USA due to chip shortages causing prices of the PI to soar over $100.? At $35 the Potato has the same form-factor but a 64 bit processor as well as some other hardware upgrades that match or exceed the Raspberry Pi.? Last year I spent many frustrating hours trying to get the Potato to work with a USB WIFI and configured as necessary to interface with my sensor inputs.? This year a new OS revision has resolved all those issues and I have gotten the Potato configured as necessary rather easily using UBUNTU 22.04, making it a potential alternative to the PI.? The only real negative I ran into was that it comes with GNOME desktop which is way too bulky, fat, and slow for the 2GB of memory that comes on the Potato board.? I resolved that by installing Xfce instead which is a light-weight no frills GUI desktop. https://libre.computer/products/aml-s905x-cc/ Jon -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sat Aug 19 15:30:31 2023 From: personal_submersibles at psubs.org (Alan James via Personal_Submersibles) Date: Sat, 19 Aug 2023 19:30:31 +0000 (UTC) Subject: [PSUBS-MAILIST] I've got a Potato in my sub In-Reply-To: <1460814352.1966819.1692467101532@mail.yahoo.com> References: <1460814352.1966819.1692467101532.ref@mail.yahoo.com> <1460814352.1966819.1692467101532@mail.yahoo.com> Message-ID: <104252972.1993388.1692473431763@mail.yahoo.com> Jon,If the Gnome was too bulky & fat you should keep him off the raspberry Pi & give him potato instead.There are a few PLC type arduino products coming out & other plc like Controllino that are arduino compatible that look quite interesting. More bulky but the connections would be more robust. Around NZ $400.Alan Sent from Yahoo Mail on Android On Sun, 20 Aug 2023 at 5:46 am, Jon Wallace via Personal_Submersibles wrote: Le Potato, to be specific.? It's a potential SBC replacement for the Raspberry Pi which is still difficult to obtain here in the USA due to chip shortages causing prices of the PI to soar over $100.? At $35 the Potato has the same form-factor but a 64 bit processor as well as some other hardware upgrades that match or exceed the Raspberry Pi.? Last year I spent many frustrating hours trying to get the Potato to work with a USB WIFI and configured as necessary to interface with my sensor inputs.? This year a new OS revision has resolved all those issues and I have gotten the Potato configured as necessary rather easily using UBUNTU 22.04, making it a potential alternative to the PI.? The only real negative I ran into was that it comes with GNOME desktop which is way too bulky, fat, and slow for the 2GB of memory that comes on the Potato board.? I resolved that by installing Xfce instead which is a light-weight no frills GUI desktop. https://libre.computer/products/aml-s905x-cc/ Jon_______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Sat Aug 19 18:01:06 2023 From: personal_submersibles at psubs.org (irox via Personal_Submersibles) Date: Sat, 19 Aug 2023 22:01:06 +0000 Subject: [PSUBS-MAILIST] I've got a Potato in my sub Message-ID: <8c1666fa-e372-06f2-b994-bdf4d7c94126@ix.netcom.com> Hi Jon, thanks for reporting back on your experiences there. I've also played around with the Raspberry Pi as the main interface for sub controls and monitoring. Rather than go using a standard desktop distribution I built my own based on the Automotive Grade Linux (), which is making its way into many car brands. Here's a shot of the UI with mocked up data: https://photos.app.goo.gl/YLqRpgRkBHLrrb3W8 (https://www.automotivelinux.org/) Its a low priority upgrade, but it would be nice to have a Tesla/SpaceX type user interface. Cheers, Ian. -----Original Message----- From: Personal Submersibles General Discussion Sent: Aug 19, 2023 10:45 AM To: Personal Submersibles General Discussion Subject: [PSUBS-MAILIST] I've got a Potato in my sub Le Potato, to be specific. It's a potential SBC replacement for the Raspberry Pi which is still difficult to obtain here in the USA due to chip shortages causing prices of the PI to soar over $100. At $35 the Potato has the same form-factor but a 64 bit processor as well as some other hardware upgrades that match or exceed the Raspberry Pi. Last year I spent many frustrating hours trying to get the Potato to work with a USB WIFI and configured as necessary to interface with my sensor inputs. This year a new OS revision has resolved all those issues and I have gotten the Potato configured as necessary rather easily using UBUNTU 22.04, making it a potential alternative to the PI. The only real negative I ran into was that it comes with GNOME desktop which is way too bulky, fat, and slow for the 2GB of memory that comes on the Potato board. I resolved that by installing Xfce instead which is a light-weight no frills GUI desktop. https://libre.computer/products/aml-s905x-cc/ Jon -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 30 05:47:40 2023 From: personal_submersibles at psubs.org (James Frankland via Personal_Submersibles) Date: Wed, 30 Aug 2023 10:47:40 +0100 Subject: [PSUBS-MAILIST] message yesterday Message-ID: did anyone see my message yesterday re conductor thickness? I think i sent it to members board by mistake. Or maybe the attachments got it stopped. ? Thanks James -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 30 06:33:25 2023 From: personal_submersibles at psubs.org (Jon Wallace via Personal_Submersibles) Date: Wed, 30 Aug 2023 10:33:25 +0000 (UTC) Subject: [PSUBS-MAILIST] message yesterday In-Reply-To: References: Message-ID: <1741920393.2462217.1693391605444@mail.yahoo.com> Probably the attachment size which is limited to 5mb. ?Can you shrink it? Jon On Wednesday, August 30, 2023 at 03:49:29 AM MDT, James Frankland via Personal_Submersibles wrote: did anyone see my message yesterday re conductor thickness?? I think i sent it to members board by mistake.? Or maybe the attachments got it stopped. ? ThanksJames_______________________________________________ Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 30 10:14:32 2023 From: personal_submersibles at psubs.org (James Frankland via Personal_Submersibles) Date: Wed, 30 Aug 2023 15:14:32 +0100 Subject: [PSUBS-MAILIST] message yesterday In-Reply-To: <1741920393.2462217.1693391605444@mail.yahoo.com> References: <1741920393.2462217.1693391605444@mail.yahoo.com> Message-ID: Ill past in what i said and resend the pictures. somehow. Hi All Im designing a penetrator for my new boat. This is to go through from the battery pod to hull, so no water involved unless a pod floods. Ive got several options but the one i am mostly considering now is this one. I am trying to balance making it as small as possible while having 2 penetrators in the unit. This one is using a 60mm body but that leaves the small end of the electrode at diameter 8mm. It doesn't feel thick enough to me. Also bearing in mind that im not quite sure what motors or even batteries ill be using yet. I suspect Min Kota 40's at 12v. There will be 4 of these. I know i should know the voltage and peak current to work this out correctly, but i dont know, so its just a sort of rough idea. Any thoughts? (Hank i know youve sent me you method, which is still an option. Actually what thickness wire do you use?) Drawing attached. (in next message..i hope) On Wed, 30 Aug 2023 at 11:34, Jon Wallace via Personal_Submersibles < personal_submersibles at psubs.org> wrote: > Probably the attachment size which is limited to 5mb. Can you shrink it? > > Jon > > On Wednesday, August 30, 2023 at 03:49:29 AM MDT, James Frankland via > Personal_Submersibles wrote: > > > did anyone see my message yesterday re conductor thickness? I think i > sent it to members board by mistake. Or maybe the attachments got it > stopped. > > ? > Thanks > James > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > _______________________________________________ > Personal_Submersibles mailing list > Personal_Submersibles at psubs.org > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles > -------------- next part -------------- An HTML attachment was scrubbed... URL: From personal_submersibles at psubs.org Wed Aug 30 10:15:13 2023 From: personal_submersibles at psubs.org (James Frankland via Personal_Submersibles) Date: Wed, 30 Aug 2023 15:15:13 +0100 Subject: [PSUBS-MAILIST] Drawing 1 Message-ID: -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: 8 Electrical Penetrator Drawing v4.pdf Type: application/pdf Size: 209092 bytes Desc: not available URL: From personal_submersibles at psubs.org Wed Aug 30 10:15:37 2023 From: personal_submersibles at psubs.org (James Frankland via Personal_Submersibles) Date: Wed, 30 Aug 2023 15:15:37 +0100 Subject: [PSUBS-MAILIST] Drawing 2 Message-ID: -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: 9 EP Rod Assembly Drawing v2.pdf Type: application/pdf Size: 167756 bytes Desc: not available URL: