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Re: [PSUBS-MAILIST] Electrical thru-hulls



Work on my sub has been going steady lately, and I was getting ready to start wacking holes in the hull for the wires.
Well, I was re-thinking my simplified thru-hull design and decided it was a maintenance nightmare.
My latest solution is this........
Still use the simple stainless nipple welded into the hull, with a ball valve threaded onto the inside.
( You know me.....EVERY hole gets a ball valve.)
Here's the new part.....instead of welding shoulder stops into the inside of the nipple, and potting the conductor rods in epoxy in the welded nipple, put the rods and epoxy in a bell reducer, and screw it onto the outside of the nipple. This makes the epoxy plug a wedge shape so it can't be forced into the smaller diameter nipple, and it makes the task of potting with the rods in place much simpler as it can be done on the bench, rather than trying to glue the rods into the nipple that's already welded into the hull.
The biggest advantage here is that if there's a problem with the assembly, it can be unscrewed and replaced with just a pipe wrench, rather than having to drill out and re-pot the welded nipple.
Maintenance and repair are a couple of the biggest factors when I'm pondering how to accomplish something. I don't want to be far afield on a dive trip and have a simple part break and take days to fix.
This thru-hull design makes it simpler to do the first time, and replacement MUCH faster and easier. This way I can carry spare potted reducers and affect a repair in minutes rather than taking all day to drill, re-pot with epoxy, and wait for it all to cure before going back out.
Anybody got any thoughts on this newest design? I welcome criticism. Frank D.