[PSUBS-MAILIST] cable fittings

Mon Jun 8 18:49:43 EDT 2020

I bought these for use on my stern thruster so I could easily remove it for
maintenance or replacement.
Rick

On Mon, Jun 8, 2020 at 12:46 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
>
> [image: 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
>> _______________________________________________
>> 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: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20200608/cecfa0b9/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image1.JPG
Type: image/jpeg
Size: 1786328 bytes
Desc: not available
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20200608/cecfa0b9/attachment-0001.jpe>