RE: [PSUBS-MAILIST] Nice Sub Bill!

[Alec Smyth <Asmyth@changepoint.com>]

Bill,

Great project! May I point out a couple of possible structural issues? Sorry
to back seat drive.

The hull stiffeners look like they're a rectangular profile with the long
side against the hull. The effectiveness of stiffeners is a function of the
moment of inertia of the profile. So while using flat rings allows them to
be formed easily, maybe even inside the hull, it GREATLY diminishes their
strength. You would want the rings to make contact with the hull on one of
the thin sides. Even better, make them Ts with the base of the T against the
hull. My guess is you've gone with the "flat" rings so as to form them
inside the hull, because the endcaps were already on. I don't see a way to
introduce ready-made rings into a capped cylinder, but somewhere in the
literature I remember reading its acceptable to make each ring out of
several angular sections as opposed to a one-piece ring. 

The hull opening for the coning tower seems to have rounded corners, but
this would still be less than optimal... the best would be a perfectly round
opening to distribute stress evenly. Perhaps you're planning on a heavy duty
overlay with a circular opening in it?

Again, this is a really impressive large-scale project!

rgds,

- Alec