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Antoine,
I agree with Frank.
Keep it simple.
For through hulls that are a permanent part of the sub, something you must
have to operate and will never move, just drill through your hull and weld in
schedule 80 stainless steel pipe nipples (male thread). On the interior,
install an emergency valve on each of them where they pass into the
hull.
For through hulls you may later change or for room to add more, install a
stainless steel disk in a housing similar to what a view port would be.
That way any changes you want to do later can be done on the disk and your not
burning and welding on the finished hull.
Dan H.
----- Original Message -----
Sent: Sunday, January 13, 2008 2:57
AM
Subject: Re: [PSUBS-MAILIST] gas piping
through hull
Hello Antoine. I prefer the '' welded pipe'' design but have seen the
''threaded hole'' design and both seem to work fine. I am using 3/4 inch
stainless nipples welded into the hull, with a ball valve on the inside, and
compression fittings leading to the inside manifold or outside ballast
tanks.
My thought is that the fewer connections, the lower the risk of
leakage.
Depending on the anticipated depth, the nipples can be sized to withstand
whatever pressure you have.
A schedule 80 fitting can take lots of pressure, and should it be
necessary later to replace it, it can either be re-threaded or cut out and
replaced quite easily and cheaply, versus a female thread assembly which would
be a little harder to fix. Frank D.
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