Simply put, there is enough mass there to work without a vbt system, so why bother.
What difference does the space make outside the boat?
V
-----Original Message-----
From: Brian Cox <
ojaivalleybeefarm@dslextreme.com>
To:
personal_submersibles@psubs.org
Sent: Wed, 4 Feb 2009 8:02 pm
Subject: RE: [PSUBS-MAILIST] hard ballast
The reason I'm contemplating it is to save space. It would be a sphere and if I put it outside in front of my 32" dia pressure hull then I will have the end cap of the pressure hull butting up against the hard ballast sphere so there would be this area where the two spheres come together that would be wasted.
Vance, Does the Aquarius not have hard ballast tanks? Sorry if you already be thru this.
Brian
They probably did not replace the VBT. You just dive a little heavy and ride the bubble. There has been lots of talk here about that, but I'm here to tell you, it works just fine. Aquarius hasn't had a trim system since about 1975, and is working its little buns off all year, every year. You trim the boat carefully during pre-dive, and then you don't need much extra buoyancy. The real issue is in shallow water where that bubble can and does expand rapidly. But if you think about nearly any partially flooded ambient sub on the planet, guess what it uses as primary buoyancy. A bubble. It works just fine. Trust me.
Vance
-----Original Message-----
From: Brent Hartwig <brenthartwig@hotmail.com>
To: PSUBSorg <personal_submersibles@psubs.org>
Sent: Wed, 4 Feb 2009 6:01 pm
Subject: RE: [PSUBS-MAILIST] hard ballast
Brian, I meant to say the K-250 boats generally have short VBT just under the pilots seat, inside. But some like the Great White K-250 have removed them so they can have two people inside. I still don't know exactly what they replaced it with. I'll have to ask Greg Cottrell, or Scott Cassell.
Szybowski
From:
brenthartwig@hotmail.com
To:
personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] hard ballast
Date: Wed, 4 Feb 2009 15:52:29 -0800
Hi Brian, The K boats generally have a short VBT just under the pilots seat. You might also consider using a bladder type that you can let water into with a valve, and then either just dump it out when at the surface, or better yet have a high pressure electric pump that can empty it for you at depth. Another version of this is a box tank, like was used in the S101 that you operate just like the bladder with a pump. The box tank can not take internal or external pressure, it is just a holding tank. Here is a drawing of the S101. The holding tank is just behind the conning tower, and taking up the lower half of the hull.
http://www.msubs.com/Images/S101%20Images/S101%20-%206.jpg
Szybowski
From:
ojaivalleybeefarm@dslextreme.com
To:
personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] hard ballast
Date: Wed, 4 Feb 2009 14:43:01 -0800
Hi All,
I'm contemplating puting a hard ballast tank inside my pressure hull. Do any of the Kittridge subs have this same set up ?
Brian
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