[PSUBS-MAILIST] onboard gear
T Novak via Personal_Submersibles
personal_submersibles at psubs.org
Fri Apr 26 13:16:19 EDT 2019
These thoughts sound really good, Sean.
This discussion reminds me of the time Nekton Beta, piloted by Richard Slater, was struck at 150 feet by a sinking speed boat, breaking a CT port and causing Beta to crash on the bottom at about 240 feet. Once Beta had flooded enough to equalize to ambient and allow the hatch to open, both Richard and his passenger Larry did a free ascent to the surface. Richard blacked out during the ascent and was found face down on the surface. He was successfully resuscitated. Larry did not survive. Slater probably suffered from shallow water blackout, common to apnea divers. Although he was exhaling all the way up for the two minutes it took, there was likely too low a PPO2 left in his lungs as he approached the surface.
Richard Slater may still hold the record for the deepest unequipped successful ascent from a submarine. He did not mention feeling narked, but he did feel very peaceful, calm, and all was quiet when he deliberately ripped his jeans that were caught as he exited through the hatch. Calm and peaceful are feelings some divers have when they are narked on nitrogen, others may feel anxious and nervous.
I think it would be best to wear a horse collar BCD like Alan suggests, carry a dive mask on board, don the mask as the sub floods. Exit through the hatch where a quick release 60cuft tank and regulator is available along with an emergency float to drag you to the surface, whereupon the float inflates into an emergency raft. All in all, this would likely only be successful for depths not much more than 200 feet, and would also depend on how you personally react to nitrogen narcosis. As some have suggested, the bailout bottle could contain heliox with a lower PPO2.
Tim
From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] On Behalf Of Sean T. Stevenson via Personal_Submersibles
Sent: Friday, April 26, 2019 5:18 AM
To: personal_submersibles at psubs.org
Subject: Re: [PSUBS-MAILIST] onboard gear
Alan - Don't overthink this. A buoyant emergency ascent can get you to the surface in less than 60 seconds if you are not purposefully attempting to limit your ascent rate. How long can you hold your breath (not that you should)? A gas source helps you avoid a hypoxic blackout, but with a hood of any description you shouldn't drown. You'll just end up rebreathing some of the hood gas. As we discussed earlier, hypothermia will be an issue, as will the exposure time - it is actually better to get up from depth ASAP than to spend time messing around at depth and then having a bunch of stuff slowing your ascent while deep. My point about the gas consumption was to illustrate how impractical it would be to carry sufficient gas to enable an ascent as a diver would do it.
Sean
-------- Original Message --------
On Apr 25, 2019, 23:39, Alan via Personal_Submersibles < personal_submersibles at psubs.org> wrote:
More thoughts on escape...
Went in to a couple of dive shops today looking at pony bottles.
The smallest they were selling were 19 cu ft. I did see a 13 cu ft they were
filling. Both looked too big for my intended dual purpose use of a horse shoe
BCD as a life jacked. A bit clutsy getting in to the sub wearing a BCD & large
tank. They make a 6 cu ft pony bottle but I would have to import it & it would
only get me to the surface from about 100ft.
I had the thought of filling a 6 cu ft pony bottle with mixed gas & having an
80 cuft mixed gas tank outside the hull. It could have an octopus regulator
( to avoid free flow) permanently on the 80 & a quick disconnect fitting on it that
a hose attaches to for use as a reserve ballast blow.
So you breath through your pony reg while flooding & escaping, then when
outside use the 80 cu ft tank reg while detaching the ballast hose, attaching
the BCD connection and un latching the tank.
It could be practiced in the garage with your eyes closed & done in about 15
seconds. Any thoughts on this?
Alan
On 26/04/2019, at 1:38 PM, Alan via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:
Thanks Carsten,
I am thinking I may go with something similar; a horse collar BCD with a
13 cu ft pony bottle. (BCD below).
It could double as a life jacket, has manual inflation & push button inflation.
I would have a regulator off the pony bottle as well.
The BCD has an over inflation valve but if you wanted your air to last in an emergency
you could breath expanding air out of the BCD through the manual inflation
mouth piece. With a BCD as apposed to a life jacket you have the chance to
slow your ascent & do a decompression stop.
I am not sure what the maximum depth is that I could come up from with a 13 cu ft
tank.
I could use this for shallow dives or as a supplement for snorkelling, so it won't be
sitting in a sub doing nothing.
Alan
<image1.PNG>
On 25/04/2019, at 7:42 PM, MerlinSub at t-online.de <mailto:MerlinSub at t-online.de> via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:
We figure out that the best escape equipment will be a Steinke hood (hard to get now)
or a traditional scuba west with a small on board air bottle.
Both give you the high lift capacity you need to make an fast rise.
For bigger subs and cold waters light diving suits will help muxh.
Second it will help you a lot if you allready a diver or had make a course.
We make some years ago some exercieces with a semi finish Psub scuttled in a pool .
First go out were really bad feelings and schock about the water rush in and the cold and so.Have these in mind: panic.
But after 3-4 times and with the knowledge it was fun to do the escape exercice.
With training and the right gear I see no problem to get out of a sub even from much greater dephts.
The releasing signal bouy should have a stopper on the reel. Otherwise a 300 m rope bouy will drived far away with a sub sunken in 30 m .
And make the life of the rescue diver much harder. The rope shall resitance the force a human can pull on it - say 150 Kg at least.
Somebody on the surface can come to the conclusion to lift the baot on these rope- better make a mark on the Bouy "Sunken submarine - dont pull on the rope!"
vbr Carsten
-----Original-Nachricht-----
Betreff: Re: [PSUBS-MAILIST] onboard gear
Datum: 2019-04-25T00:07:11+0200
Von: "Alan via Personal_Submersibles" <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> >
An: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> >
Perhaps a Psub plan for escape from down to 100ft, as you could do this
100 times out of 100 if you knew what you were doing.
Also even though most subs are capable of diving deeper there is more
probability that entanglements like ropes & nets are going to be encountered
In shallower depths.
BTW the pressure in the sub is going to increase incrementally quicker as it
floods & you need to keep equalising your ears like mad toward the end or
you'll burst your ear drums, & aside from that pain, will have freezing water
going in to your inner ear. That would increase your chances of failure.
Alan
On 24/04/2019, at 4:12 PM, Stephen Fordyce via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:
Hi all,
This is an interesting discussion I've been meaning to weigh in on - as an experienced tech/deep/cave diver rather than a sub person.
My feel is that unless the escapee is an experienced diver (and even then), the chances of a successful escape from below 50m/150ft depth are so low as to be almost negligible. And I'd suggest having a plan for such is (almost) an entirely false sense of security - and energy should be diverted elsewhere to reduce risk.
A few of the scarier things like narcosis and the bends have had a lot of airtime, but basic stuff like keeping a diving mask clear (and one that's probably fogging up), panic-breathing a soggy SCUBA reg and dealing with the thermal shock of sudden immersion are likely to cause death by drowning much earlier. Don't underestimate the thermal shock and how useless it makes you with no exposure suit. Breathing a regulator without a mask is a skill in itself. You're probably already suffering from fatigue, stress, high CO2 and/or low O2 from waiting for rescue and getting to such a desperate point. All of these cause significant mental impairment before you even start on the escape.
Forget about planning to hold stops on the way up, switch gases or do decompression. Even if you're lucky enough to still be conscious and thinking in the latter stages of the rapid ascent, personal buoyancy control is unlikely to be possible.
So if you're going to attempt to escape, I suggest the best chance for survival is to plan on a very simple setup (per person), buoyancy for a rapid/undignified ascent, and needing urgent medical attention and oxygen on the surface. Maybe carry a cylinder of trimix on board to give yourself a better chance of being able to think, but it's a big weight/cost premium if it's enough to be useful. Use a divers (with closed bottom) "lift bag" and a loop around at the armpits as a quick and easy way to get a person shooting upwards. CO2 inflatable life jacket to keep unconscious head above water on surface. (Inflate at depth while conscious - won't fill much, but will expand on way up) Might be better put towards things like extra life support duration. Consider doing regular practise drills that are as realistic as possible.
Highly skilled divers mess up basic skills in stressful situations and die with sad regularity. Don't imagine your (and passengers) chances of winging it at depth will be anything other than tiny. 30m/90ft and shallower they are a bit better.
I hate to be negative, but perhaps for deep PSUB diving, the inability to escape is just one of those residual risks that can be accepted for a recreational activity.
Cheers,
Steve Fordyce
Melbourne, Australia
On Wed, 24 Apr 2019 10:57 hank pronk via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:
I think all submarines should have an escape pod or jettisoning occupant sphere. I admit I made a mistake with my escape pod by making it only for one. An easy fix that I will likely tackle, and that is to stretch the pod making it big enough for two. E3000 has a jettisoning occupant sphere.
Hank
On Tuesday, April 23, 2019, 5:39:01 PM MDT, TOM WHENT via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:
A compact bail out rebreather might be the most surviveable solution however it would require a significant commitment in training, maintenance as well as the cost of the equipment itself. I personally have not been following the development of bailout rebreathers, although i'm aware that some are working on this. My dive group relies on planning for open circuit bailout in the event of rebreather failure.
If money is no object, I am partial to the ISC Megalodon classic CCR. In terms of robustness and deep water capability, you will find none better.
It will get you home and flies itself. It is an electronic CCR which maintains PPO2 for the user. This is the unit I dive myself and feel very confident in.
KISS classics, which are a simple and reliable mechanical CCR apparatus, often come up on the used market in affordable price ranges.
Both would require significant equipment specific training but would get you out of a 400 ft jam with only two small cylinders and gas to spare. CCR duration is driven by metabolic rate and is the same irrespective of operational depth. Even the lowest end units will give you an hour plus.
On ascent, rebreathers do require the diver to be monitoring the oxygen level display in the breathing loop and very likely adding oxygen manually - particularly in the mCCR type on a fast ascent.
The other benefit of this setup is that an air cell for buoyancy can be integrated easily in one compact package.
It sounds like a lot of effort for the non diver, but it is a functional answer to the risks of a sub disabled in deep water.
What is a life worth?
How much risk can one accept for a hobby?
Food for thought anyhow.
Get Outlook for Android <https://aka.ms/ghei36>
On Tue, Apr 23, 2019 at 7:34 PM -0400, "Alan via Personal_Submersibles" <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:
As an alternative to possible death or even worse, the loss of your submarine,
I am in early stages of designing a buoy release mechanism that is used
for surfacing safely but has an emergency beacon that can be activated
with an electro magnet.
Thoughts are to use 150 lb braid with a tensioning mechanism & have an
automatic boat latch mechanism that can slide down the braid but is fixed
to the buoy with instructions, "tie a long rope to the ring & let down untill
latch attaches to submarine. Pull up"
The automatic latch is a device that Phil described & provided a drawing for,
but there may be a cheap & suitable automatic boat latch ( used on release
& retrieve on boat launching) on the market. I am still searching & if anyone
knows of one that may be suitable I would be interested.
Alan
On 24/04/2019, at 10:51 AM, Sean T. Stevenson via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:
There is a significant difference between submarine escape and a planned SCUBA dive with regard to both the dive profile and the equipment that you can reasonably carry. An escape is more akin to what is known as a buoyant emergency ascent in recreational diving, where you need to get to the surface yesterday and all other considerations are secondary. In this specific case, trying to keep to a slow ascent rate would significantly increase the incurred decompression obligation that you must necessarily then blow off as you ascend through the shallows, introducing an even greater risk. You also have the hypothermia issue to deal with if you are not equipped with exposure protection specifically intended for submersion at depth. Being cold reduces decompression effectiveness. In order to keep to a target ascent rate or perform decompression stops, you would need diving instrumentation (depth gauge and timer), would need the skills and experience to perform gas switches and hold stops, and would need significantly more bulky equipment to have enough gas to perform a proper decompression (slow ascent, gas switches, etc.).
When I dive to these depths on SCUBA, I wear twin cylinders (>100 cu. ft. each) on my back with the bottom gas (10/70 or whatever for the planned depth and time), plus three or four off-board cylinders (80s) carrying the decompression gases (typically 21/35, 35/25, EAN50 and oxygen), plus a small bottle of argon for drysuit inflation. Obviously, as an escapee you are not so equipped. Far better to lockout as quickly as possible and rapidly ascend (with buoyant assist) to get clear of those depths where you are ongassing the most, and if at all possible, to slow the ascent as you approach the surface, and then have your surface support or emergency responders administer oxygen as transport is arranged to recompression. To be clear, an emergency escape from a disabled submarine at these depths is not even remotely a good idea - it is simply a marginally better idea than dying on the bottom.
To illustrate, if you were to attempt a continuous ascent from 300 fsw, the average depth is 150 fsw, which is about 5.5 atmospheres absolute. If you assume a surface air consumption rate of 1 cu. ft. / minute (high, but typical of a diver who is stressed or working hard, which is inevitable in a submarine escape scenario), that corresponds to 5.5 cu. ft. / min at the average depth of the ascent. At a 30 ft/min ascent rate, that's 10 minutes, or 55 cu. ft. of gas consumed just for the continuous ascent with no decompression stops, without consideration for the gas consumed while blowing down and locking out. You can judge for yourself the practicality of carrying an 80 on a PSub sized vessel just for emergency escape purposes.
Sean
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Tuesday, April 23, 2019 12:32 PM, David Colombo via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:
Hi Guys, This topic is fascinating and scary at the same time. Accent rates form the old Navy logs had 60ft / minute max with a recommended max accent rate of 30 ft/ min. At 300ft escape depth, what volume of mixed gases would you need for a 10 minute accent assuming you choose not to swim 60ft/min.
Best Regards,
David Colombo
804 College Ave
Santa Rosa, CA. 95404
(707) 536-1424
www.SeaQuestor.com <http://www.SeaQuestor.com>
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As an alternative to possible death or even worse, the loss of your submarine,
I am in early stages of designing a buoy release mechanism that is used
for surfacing safely but has an emergency beacon that can be activated
with an electro magnet.
Thoughts are to use 150 lb braid with a tensioning mechanism & have an
automatic boat latch mechanism that can slide down the braid but is fixed
to the buoy with instructions, "tie a long rope to the ring & let down untill
latch attaches to submarine. Pull up"
The automatic latch is a device that Phil described & provided a drawing for,
but there may be a cheap & suitable automatic boat latch ( used on release
& retrieve on boat launching) on the market. I am still searching & if anyone
knows of one that may be suitable I would be interested.
Alan
On 24/04/2019, at 10:51 AM, Sean T. Stevenson via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:
There is a significant difference between submarine escape and a planned SCUBA dive with regard to both the dive profile and the equipment that you can reasonably carry. An escape is more akin to what is known as a buoyant emergency ascent in recreational diving, where you need to get to the surface yesterday and all other considerations are secondary. In this specific case, trying to keep to a slow ascent rate would significantly increase the incurred decompression obligation that you must necessarily then blow off as you ascend through the shallows, introducing an even greater risk. You also have the hypothermia issue to deal with if you are not equipped with exposure protection specifically intended for submersion at depth. Being cold reduces decompression effectiveness. In order to keep to a target ascent rate or perform decompression stops, you would need diving instrumentation (depth gauge and timer), would need the skills and experience to perform gas switches and hold stops, and would need significantly more bulky equipment to have enough gas to perform a proper decompression (slow ascent, gas switches, etc.).
When I dive to these depths on SCUBA, I wear twin cylinders (>100 cu. ft. each) on my back with the bottom gas (10/70 or whatever for the planned depth and time), plus three or four off-board cylinders (80s) carrying the decompression gases (typically 21/35, 35/25, EAN50 and oxygen), plus a small bottle of argon for drysuit inflation. Obviously, as an escapee you are not so equipped. Far better to lockout as quickly as possible and rapidly ascend (with buoyant assist) to get clear of those depths where you are ongassing the most, and if at all possible, to slow the ascent as you approach the surface, and then have your surface support or emergency responders administer oxygen as transport is arranged to recompression. To be clear, an emergency escape from a disabled submarine at these depths is not even remotely a good idea - it is simply a marginally better idea than dying on the bottom.
To illustrate, if you were to attempt a continuous ascent from 300 fsw, the average depth is 150 fsw, which is about 5.5 atmospheres absolute. If you assume a surface air consumption rate of 1 cu. ft. / minute (high, but typical of a diver who is stressed or working hard, which is inevitable in a submarine escape scenario), that corresponds to 5.5 cu. ft. / min at the average depth of the ascent. At a 30 ft/min ascent rate, that's 10 minutes, or 55 cu. ft. of gas consumed just for the continuous ascent with no decompression stops, without consideration for the gas consumed while blowing down and locking out. You can judge for yourself the practicality of carrying an 80 on a PSub sized vessel just for emergency escape purposes.
Sean
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Tuesday, April 23, 2019 12:32 PM, David Colombo via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:
Hi Guys, This topic is fascinating and scary at the same time. Accent rates form the old Navy logs had 60ft / minute max with a recommended max accent rate of 30 ft/ min. At 300ft escape depth, what volume of mixed gases would you need for a 10 minute accent assuming you choose not to swim 60ft/min.
Best Regards,
David Colombo
804 College Ave
Santa Rosa, CA. 95404
(707) 536-1424
www.SeaQuestor.com <http://www.SeaQuestor.com>
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