viewport mounting and electrolysis.

[shawl@torchlake.com (Jonathan Shawl)]

protek@shreve.net wrote:

> ..... you can use proven
> designs.  The book is "Acrylic Plastic Viewports", by Jerry D. Stachiw.
> The publisher is Marcel Dekker in New York.  It is about $100, or was when
> I bought mine years ago.  It covers all thicknesses and unsupported areas
> that you can use in a sub window design.  It even shows you where to put
> the seals and how thick etc. etc.  The book was well worth it to me.  There
> is one thing in window design that has not been mentioned on here.  If you
> machine a metal seat for the window (concrete, or plywood for some) and
> then weld it to the conning tower some warping will occur.  You can not
> weld a piece of metal without having some warpage.  There is a tolorance
> for this explained in the book.  I welded round rings into my conning tower
> before I welded the conning tower to the sub body.  I then had the rings
> milled before welding to the sub.  This minimized the warpage at the window
> locations.  I machined separate seats for all my windows and attached them
> to the machined portions of the conning tower with O-ring seals and bolts
> (not welding).  This is probably too elaborate, but the windows seats are
> difficult to machine as an installed part of the sub.
>
> Gary Boucher
>

Hi Gary and all Psubers

I'm finally getting around to responding to some older mail.
No doubt about it, Gary and I do think allot alike. I used almost the same
mounting method as Gary described above.
Except I used the ASME  PVHO guidelines for the lens and seat design. Also, I
did not need to machine the flat rings after welding them to the hull, as the
warpage was within an acceptable amount for a metal to metal o-ring seal. I then
bolted up the separate aluminum lens seats (using a o-ring seal) to the rings
welded in place in the hull.
Electrolysis could be a big problem if I used it in salt water. I will add, all
parts are painted and I only use the sub in fresh water for a day or two at a
time. I also use 2 sacrificial magnesium anodes, the type found in most hot
water heaters, to help control the electrolysis problem. As a result,
electrolysis has not been a problem (yet).

Jon Shawl