Re: [PSUBS-MAILIST] Hard / soft ballast tanks.

[Paul Kreemer <paulkreemer@gmail.com>]

Hmm, so do people use a pressure compensating system to keep the ballast tanks pressurized to ambient? Otherwise, depending on when this theoretical tank valve is closed, the ballast tank might be overpressured by ascending, or compressed by descending.  ??

My understanding was that a
hard tank was an independent pressure vessel strong enough to take the
pressure changes between the surface and max operating depth.  No?

thanks for any help-
Paul

On 10/31/05, atozed@juno.com <atozed@juno.com> wrote:

Yes, its pressure will vary. I'm going to use an old carbon dioxide fire extingusher.

Peter K

 

On Mon, 31 Oct 2005 14:07:50 -0700 Paul Kreemer <paulkreemer@gmail.com> writes:

Adding a valve to a soft ballast tank does change the tank from an ambient to a potentially 1atm chamber.  By closing that valve you allow a pressure differential to be created when your sub changes depth.  So you'd have to build it much stronger than a more simple soft ballast tank.  Right?

Paul

On 10/29/05, Myles Hall <myles.h@sasktel.net> wrote:

Bill,

 

   To make a "soft" tank into a "hard" tank, do I simply need to install a valve to let in the water as opposed to just an open flood hole ?  This valve, of course, would keep the water from coming in while the sub gains depth (pressure).

 

Myles.