It seems that the "flood and escape" scenario presumes that the sub is in a stable position that won't be altered by sacrificing the bouyancy provided by the air in the hull. Might be feasible if sitting on a level bottom but not if caught in rigging above a wreck, etc.
If the hull is already leaking or some other circumstance is compelling evacuation, then go for it. Otherwise I'd put my efforts into equipping the sub to increase survival time.
We've had some discussions on "escape" before and I think it was pointed
out that to flood the sub quickly the risk of breaking your ear drums was very
likely. If you wait too long to fill the sub slowly your chances of survival
decreased so it was a trade-off.
Flooding a sub is just plain SCARY !!!
It's dark, cold, very high pressure, in an enclosed space with limited
egress, and a long way to the top IF you manage to get out.
Jay did a bit of study on the subject and gave a presentation on the risks
involved. Anyway you look at it, it's dangerous and your chances of survival are
not good. The second one out has little chance of survival.
Phil's procedure was designed for a sub where your head stays inside the
bubble. That seems like a good approach to me.
If a builder was contemplating the escape scenario, I think it might be a
good idea to design the hatch area with a little extra room.
If you start with imagining just how the whole procedure would be
carried out, a method of procedure ( M.O.P. ) could be developed, and then
trained for.
Good dive lights inside would be essential. Scuba tanks with regulators.
I'm using the skinny 40 cu. ft. ones that can fit through the hatch on your
chest, and "horse collar" buoyancy vests with inflators. These lay flat against
your body before inflation, and hold your face above the surface if you're
unconsious.
A valve to release the last bit of air would help if you have a metal
hatch. Phil's use of a "break-away"
dome hatch sounds good.
Just some random thoughts.
Frank D.