Re: [PSUBS-MAILIST] VBT's

[irox <irox@ix.netcom.com>]

Another conderations is how you are filling/emptying the VBT.
If it's inside the pressure hull, it's probably best to avoid using high
pressure air, since a failure of the VBT (remember, in most cases you
can't inspect the inside of VBT for problems after installation) could
result in pressurization of the human occupied space.  If the VBT is
outside the pressure hull, then high pressure air should be ok.
For internal VBTs, either a hand or electic pump would be best, since
they don't require the pressurization of the tank.

Ian.

-----Original Message-----
>From: Joseph Perkel <joeperkel@hotmail.com>
>Sent: May 24, 2007 11:30 PM
>To: personal_submersibles@psubs.org
>Subject: Re: [PSUBS-MAILIST] VBT's
>
>
>
>Ken,
>
>......A reasonable question.
>
>VBT's inside will reduce outside overall displacement, less weight to carry in lead ballast. But...Takes up big time room as you note, and potential for leaks / failure if not sufficiently hardened. If I do the NR-2 concept, it would have two outside VBT's along centerline. Ben Franklin had an interesting internal trim system up high on the extreme ends, but had the space for it....take a look at it.
>
>Diver lock out. Yes you must compensate or "overcompensate" as the case may be. Take a close look at Peters Kraka. Note the structure beneath the divers hatch. I suspect Peter employs a "Negative" tank somewhere,... lands the sub on the bottom and balances her with trim to deploy the diver. Doing this mid-water would take the size and complexity of Euronaut.
>
>Joe
>
>
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>
>From:  Ken F <syber_psubber@yahoo.com>
>Reply-To:  personal_submersibles@psubs.org
>To:  personal_submersibles@psubs.org
>Subject:  Re: [PSUBS-MAILIST] VBT's
>Date:  Thu, 24 May 2007 18:20:32 -0700 (PDT)
>
>
>Can someone give me some pro's and con's for having VBT's either inside, or outside of the hull?  (besides the obvious fact that if it's outside, there's more room inside.)
>  
>
>Also, about using small VBT's in specific locations to provide normal trim, or for purposefull offset trim.  Has anyone done this?  Does anyone recommend it?
>  
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>  
>Thirdly....
>If a diver leaves the sub via diver lock-out...the sub has just lost that person's bodyweight in ballast.  Any comments on my idea of using a VBT which has been carefully measured and marked on the outside, with some type of magnetic float on the inside, running along a vertical composite track so as not to stick to the side of the VBT, which moves a marker on the outside of the VBT so that you can take on a *specific* weight in water, possibly to negate the effects of a diver leaving the sub.
>  
> 
>  
>Thanks to any replies,
> 
>  
>Ken
>
>      Building a website is a piece of cake. 
>Yahoo! Small Business gives you all the tools to get online.
>
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