RE: [PSUBS-MAILIST] Impact Calculations..

[Alec Smyth <Asmyth@changepoint.com>]

I haven't actually calculated that one (I don't know how), but I did take
collisions into account somewhat in my design. My dome has a safety factor
of six, which I arrived at per PVHO. But what I'm doing is enclosing that in
a second thinner dome which will be free-flooding. Vance Bradley made a good
suggestion to me once to make the flood holes smallish, so that in case of
an impact the water would exit them slowly and the second dome would act as
a shock absorber. Greg Cottrell also had a suggestion for it, although it is
unrelated to the collision topic... he suggested adding a UV filter to the
acrylic formulation on the second dome so as to protect the thick one inside
from the sun.

cheers,

Alec

-----Original Message-----
From: James Warner [mailto:james@whototake.com]
Sent: Tuesday, July 02, 2002 12:45 AM
To: personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] Impact Calculations..


Has anyone that is currently designing or has designed their sub, calculated
the speed at which they could impact an object while at depth, and not have
to worry about a rupture?  I would think that a sharp impact in a
concentrated area on an acrylic dome or your pressure hull that already has
even pressure distrubuted about it, would cause a rupture fairly easily?  Or
is this just factored into the safety factor of your sub?  Thanks.

James