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RE: [PSUBS-MAILIST] RE: payload



Correct.  The weight of the sub remains the same, it is the bouyancy that is affected.  But why oil and not water?  Water would weigh more and allow a smaller VBT for the same amount of bouyancy.  I'm guessing that would be more beneficial overall than any bouyancy advantage obtained strictly between the different densities of oil and water.
 
Jon
-----Original Message-----
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org]On Behalf Of Paul Kreemer
Sent: Tuesday, December 05, 2006 6:05 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] RE: payload

Well, the weight of the sub wouldn't change.  The oil would be either in the bladder or the internal tank but either way it's a part of the sub and contributes to the weight.  Right?

And air would work about the same and could be used to inflate that external bladder.  It's the change in displacement that's important, not the fact that you're using air, or olive oil or mercury to pump up that bladder.  :-)


Paul

On 12/5/06, Brian Cox <ojaivalleybeefarm@dslextreme.com> wrote:
Hi Ray,
              You would still be losing the weight of the oil from inside the sub.  And you would realize positive buoyancy from the oil ( in a badder) in a open tank connected to the sub.  You would have to use way more oil than you would just using air.    I'm not sure I am comprehending the though on this.

Brian

----- Original Message -----
From: "Ray Keefer" <psubs2001@yahoo.com>
To: <personal_submersibles@psubs.org >
Sent: Tuesday, December 05, 2006 11:15
Subject: Re: [PSUBS-MAILIST] RE: payload


> Hi Brian,
>
> I think the idea is to change the amount of
> displacement instead of changing the amount of weight.
> Pump the oil into the bladder and more water is
> displaced with the same weight of sub. Making the sub
> more bouyant. Pump the water out of the bladder,
> bladder collaspes causing less displacement for the
> weight, causing the sub to become less bouyant.
>
> Regards,
> Ray
>