[PSUBS-MAILIST] VBT positioning

["Harry Spillett" <harry.spillett@bigfoot.com>]

Hello, I am new to the group so please excuses any errors in protocol I may
make!

I live in Surrey England and have been doing my own research into
submersibles and ROV's for some time. I have almost finished my first
prototype ROV which I hope to get wet in the near future.

However in tandem with my ROV I am also sketching out preliminary designs
for a single person submersible.

My question is:

I have noticed that on all most all existing designs I have seen the
variable buoyancy tank is sited inside the pressure hull.
Is this so that it does not have to withstand diving pressure? Ore is there
another reason perhaps to do with the internal volume of the pressure hull.

Following on from this, when the VBT is flooded is the air released vented
into the pressure hull or to the sea.

Once again I hope I have followed correct procedure and look forward to your
thoughts. It is comforting to know there is a pool of like minded people I
can turn to for advice rather than pull my hair out alone!

Regards

Harry Spillett