----- Original Message -----
Sent: Saturday, October 29, 2005 5:56
PM
Subject: Re: [PSUBS-MAILIST] Hard / soft
ballast tanks.
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.
----- Original Message -----
Sent: Saturday, October 29, 2005 1:54
PM
Subject: Re: [PSUBS-MAILIST] Hard /
soft ballast tanks.
Ah yes! Brian is right Myles. I totally forgot
about the compression of the air by the water at depth in the open bottom
ballast tanks. That is another reason to use non open to the water hard
ballast trim tanks
to adjust the attitude and neutral buoyancy of
the sub at depth.
Bill.
----- Original Message -----
Sent: Saturday, October 29, 2005 9:20
AM
Subject: Re: [PSUBS-MAILIST] Hard /
soft ballast tanks.
The reason is that as the air gets compressed
( in a soft ballast) as you descend the volume shrinks and you have
less lift, making you sink faster. This gets you into a situation
where you are constantly readjusting to maintain a steady accent or
descent. I believe this is all in the busby book which can be bought
on the psubs web store.
Thank you
Brian