I think one reason they are not popular is
that they are not in Stachiw’s
book, nor in PVHO either. Hence although I’ve seen them on subs
like Nekton, I am not aware of good detailed documentation to use in their
design calculations. I know they have worked safely for years on the Nekton,
but personally I would feel quite nervous about the potential concentration of
stress in all those holes near the rim.
Alec
-----Original Message-----
From: Thijs Struijs
[mailto:thijs-struijs@planet.nl]
Sent: Tuesday, June 24, 2003 1:50
PM
To: PSUBS
Subject: [PSUBS-MAILIST] OSS
viewports
When you look at Bill's viewports (http://www.giffordmarineinc.com/sub/sub_5_16_03/Sub_5_16_03.html) you can
see that he uses an acrylic disc bolted to a flange. The Nekton subs use a
similar method. The Delta is probably the most sucsesfull small sub ever built.
Yet i cannot find anything on them in the ABS or Lloyds rules or in
Stachiw's book.
It is a simple and cheap way to
make the viewports. Flanges can be bought of the shelf. No need for a big
lathe and no retainer-rings to make. Can anyone explane me why it is that these
viewports aren't more popular.
Thijs Struijs
The Netherlands