----- Original Message -----
Sent: Friday, October 28, 2005 5:36
PM
Subject: [PSUBS-MAILIST] Hard / soft
ballast tanks.
Gents,
Hard / soft ballast tanks....what
exactly are we talking about here ? Hard ones made of...hard material
and soft ones made of inflatable bags or something ?
In contemplating my design for the
fore and aft main ballast tanks, it occured to me that the construction
of these tanks does not have to be up to the same standard as the pressure
hull, even if purged at depth, due to the fact that the forcing of air into
the tanks to purge the water creates an "ambient" enviroment within the tank,
equalizing the pressures put upon it. Is my line of thinking correct
? In other words, as far as the ballast tanks are concerned, it
shouldn't matter if the internal and external pressures are equal due to the
tank being filled with water, or compressed air. As long as your high
pressure air supply has enough psi to force the water out, it should be
possible to blow the tanks at any depth. Again, am I on the right track
with this thinking ? One of the reasons I am enquiring about this is I
am wondering if it's possible to use fore/aft main ballast tanks as trim tanks
as well ? For eg. if I'm at a depth of 50M in my 1ATM sub (with fore/aft
tanks filled with water), and I discover that my trim isn't quite right, that
I require a little lift in the front, can I put a little air into the fore
main ballast tank, or will this damage the tank since the construction of it
is quite light. I suppose if it is possible to blow the tanks at any
depth, you would want some sort of check valve to bleed off the excess
pressure that would occur from surfacing, or risk blowing your ballast tanks
up, sinking, and dying.
Myles.