[PSUBS-MAILIST] cable fittings

Tue Jun 9 11:59:21 EDT 2020

Ian,
https://www.macartney.com/what-we-offer/systems-and-products/connectors/subconn/
I'm not sure how you get Psub discount. I got some through Jon the facilitator / owner 
of the group a long time ago.
He normally reads the emails & will comment if you have a question.
There may be an email link to Jon, or more info on the Psub web site.
He's based in NY, so just a submarine ride away!
Cheers Alan

> On 10/06/2020, at 1:07 AM, Ian Juby via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> :O  That's them!  Subcon eh? I'll look them up. Psubs gets a discount? How does that work?
> 
> Ian
> 
> 
>> On Mon, Jun 8, 2020 at 6:46 PM Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> Thanks Ian,
>> I have those type of penetrators (below). Psubs gets a discount from subConn
>> that makes them.
>> Would be a bit difficult making them yourself & the bought ones have a securing
>> device so they can't pull apart ( orange thing in photo).
>> I agree that there wouldn't be much call for wet mating them, & that it would just
>> be an opportunity for corrosion.
>> Alan
>> 
>> <image1.JPG>
>> 
>>> On 9/06/2020, at 5:43 AM, Ian Juby via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>> 
>>> Hi Rick,
>>> I saw your post and wanted to ask if you meant electrical or plumbing through hull connections. So I'm glad you reposted because I haven't been able to follow the thread, nor have I had the time to go back and look stuff up. 
>>> When I was working R&D on our diver heater system, we used a watertight bulkhead connector for the shot line and remote control. Unfortunately, this was over 20 years ago and I was not the one who actually ordered the connector. So I innernets'd some pictures to try and hopefully find it again because I remember quite well what it looked like, its design and construction. The closest thing I could find was Teledyne Marine's "Wet mate" connectors:  http://www.teledynemarine.com/electrical-wet-mate-connectors/
>>> I couldn't tell you the price, but I'm sure they weren't cheap. For my ROV project, I'm still in the rough design phase and I keep increasing its depth capabilities. So I'm just going to make my own through-hull connectors, and they will be similar to this design.
>>> The through-hull seal is accomplished by a simple and reliable o-ring (which doesn't appear in teledyne's picture). Basically, the rubber connector body is mounted to a brass threaded tube that goes through the bulkhead. The brass threaded tube has a seat for an o-ring which gets compressed by both the nut and external water pressure. Here, I drew a pretty picture:
>>> 
>>> <bulkhead connector.jpg>
>>> I just realized I didn't mark the brass tube, but it's the part that goes through the bulkhead.
>>> The particular connector we were using only needed to go to like, 300 feet. I believe we tested the heater unit to 300 psi and ironically, it was the swagelock fittings inside the unit that leaked - that electrical connector never leaked. We had I think 8 electrical connections passing through that? We could get the identical connector as a straight-through connector, and not an angled connector like my drawing.
>>> The pins and sockets were the solid style - in other words there was no splits to allow for expansion or contraction of the sockets or pins. This further added to the waterproof nature as now the wire (a possible leak point) was buried in solid rubber, behind a solid metal socket which itself was buried in solid rubber. Any water wicking along would have to travel 1/2" along the metal/rubber just to get past the socket.
>>> The connector body was a hard rubber, both the through-bulkhead block and the male connector. Under high pressures, the water can wick along the inside of the wires (between the copper and the outer insulation) or if you pass the wire through say, silicone rubber, it can wick along the junction of the outside of the wire and the encasing rubber. So the longer that travel distance is, the higher the pressure needs to be to force water through those avenues. That rubber block was only maybe 2 inches left to right in my drawing. I don't remember what pressures or depths it was rated for, but I guarantee you it could take a LOT of pressure. Mechanically  (because the bulkhead hole was small) and in keeping watertight. The biggest risk for a leak was if the bulkhead got a scratch where the o-ring seated against it. I have no doubt that connector could have taken hydraulic pressures (thousands of PSI).
>>> I did not draw this in my pretty picture, but the head of the brass tube probably had multiple rings inside the rubber, both to get good mechanical locking between the rubber body and the brass body, and to make the greatest distance the water would have to travel to get around from outside to inside the tube, if it were to wick along the junction between brass and rubber. But I'm speculating there because I didn't cut one of those connector$ open to find out. Lest I get fired and stuff for destroying a connector worth hundreds of dollars, you know.  :D Just, when I go to make my own connectors, I'll be making the mounting tube like that, for those reasons. The rubber that made up the connector body filled everything, including right to the bottom of the brass tube.
>>> The nice thing about making your own connector as well is that you can make the electrical pins, sockets and wires any size you want to match your electrical current needs.
>>> 
>>> These particular connectors could be plugged and unplugged underwater, but I suspect it would be very difficult to do as it would have to displace water or vacuum from the connector holes. But as you can see, the male pins had insulating rubber for a part of their length to maximize the distance the electricity would have to travel from pin to pin, thus maximizing the electrical resistance from pin to pin as well.
>>> Hope that helps,
>>> Ian
>>> 
>>> 
>>>> On Mon, Jun 8, 2020 at 12:09 PM Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>> I posted the other day about cable threw hull water tight fittings and only got one response back and was hoping for more feed back as I know most of you probably don't make your own so for the ones that buy them, is Blue Globe the only player out there besides sealcon? 
>>>> Thanks 
>>>> Rick
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