[PSUBS-MAILIST] o-ring hull penetrations

[Alec Smyth <Asmyth@changepoint.com>]

I am in the process of machining mechanical hull penetrations for a couple
of stainless shafts (a weight drop and a hatch dog). But I've run into an
embarrasingly basic question!

The o-rings have to seat against a hull insert that is made of alloy steel
so I can weld it to the hull. Alloy steel is obviously going to need
corrosion protection. So the issue is, do you use some sort of stainless
sleeve in the hull insert, or is it good enough to paint carefully and let
the o-rings seat on paint? So far I have machined these surfaces to a mirror
polish and intended giving them a very fine layer of powder coat once
welded, but it bothers me that paint thickness might not be very precise.

Another approach would be a stainless cup-shaped insert with a static o-ring
at the bottom (hard to explain without a picture), but maybe I'm
over-complicating things again.

What's standard on a K boat for example?


thanks!


- Alec Smyth