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Re: [PSUBS-MAILIST] Trim Tanks



Hugh,  Is the pump actually reversible ie , you change the polarity on the motor or is it valves that are changed?  what do they do about the compressing air in the tanks?
 
Brian

On Sun, Feb 13, 2011 at 8:48 PM, Hugh Fulton <hc.fulton@gmail.com> wrote:

Hi Brian,

You can do two tanks with one pump but it needs to be reversible.  This will transfer between the two for fore/aft adjustment.  The Comsub uses a hydraulic pump for the purpose.  Chs, Hugh

 

 

 

From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of ojaivalleybeefarm @dslextreme.com
Sent: Monday, 14 February 2011 4:52 p.m.
To: personal_submersibles
Subject: [PSUBS-MAILIST] Trim Tanks

 

Hi All,

           I've been thinking about my various options for variable ballast / trim tanks.  I'm thinking of having fore and aft hard ballast trim tanks where I transfer seawater back and forth.  I think it would take two separate pumps, unless there is a pump that's reversible, since most pumps just pump one way.  With some plumbing I could pump seawater from the outside and vice versa.  I'm wondering if it would be necessary to evacuate the airspace in the tanks,  that way I could fill the entire tank without the pump having to pressurize the air in the tank.  The hard tanks would have equal straight as the pressure hull.  The pumps would need to be strong enough to pull a vacuum on either of the tanks and would need to hold the water, which could be accomplished by check valves.

 

Brian

 

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