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Re: [PSUBS-MAILIST] battery acid? & battery issue follow up



As a trim system, Hg is good. Except you'll more than likely need a hazmat permit for anything over 5 pounds. I may be wrong, as Hg could be a "reportable" hazmat. Two kinds of hazmat- reportable and non-reportable. Reportable means ANY quantity must be reported. Non-reportable is based on quantity. IIRC the limit is 500 pounds.

Don't take my workd for it, as that's the USDOT standards from back when I had a CDL with hazmat endorsements. The rules governing a trim system in a sub could be a lot different. They maybe better, but they could also be worse.
Carl


Brian Cox wrote:

I don't see any problem with using a mercury trim system that's what I was planning to do

Briian Cox
----- Original Message ----- From: "Coalbunny" <coalbunny@vcn.com>
To: <personal_submersibles@psubs.org>
Sent: Tuesday, February 17, 2004 2:49 AM
Subject: Re: [PSUBS-MAILIST] battery acid? & battery issue follow up



Shawn, that is something that I have wondered about- will the ballast shift? I have read how a number of scientific units used lead or steel shot. Is there anything that prohibits that being used? IIRC at one time even mercury was used. Of course we know the environmental implications from that. One thing I thought of using that should be cost effective and would be environmentally friendly is the use of sand or gravel. But since I have no real unit to use that ballast method with, I have no idea if it'll work.
Carl


NeophyteSG@aol.com wrote:

In a message dated 2/16/04 5:47:29 AM Pacific Standard Time, Asmyth@changepoint.com writes:

   Because Solo is intended as a "flying" sub, it's designed to have a
   very small self-righting moment.  [snip]  If Solo had conventional
   stability, she could never roll or fly inverted.

Totally understand. My design is facing similar constraints except that all my nonessentials are fared external to the pressure hull which, Sgt. Pepper-ish, is much smaller than yours appears to be. In my case, I'm juggling axiometric placement of everything in the horizontal and vertical planes through the hull's longitudinal axis, leaving the drop weight(s) placement until near the end to essentially force the righting moment equations to balance. I also liked the idea of essentially being able to use just about everything except the pressure hull as a drop weight should the absolute need arise.

What gave me a worse headache was trying to figure out a functional ballast system for a craft which will hypothetically have six degrees of freedom, won't "slosh" around (changing the center of buoyancy), and will work no matter what the orientation of the craft ... including upside down.
   Given the batteries are snug against the hull "ceiling", I can't
   reach the lugs to connect the cables unless they are upside down.
   Plus, I don't want the lugs shorting out against the hull.  If they
   cannot go upside down, I'll probably have to lower everything by
   about 3". Plus, all the cables will now be a few inches too short.

Aside from simply not having the room, you're making me glad that I chose to mount all but the two emergency reserve batteries outboard ... not meaning to take pleasure from your pain. :)


In a message dated 2/16/04 7:00:24 AM Pacific Standard Time, Asmyth@changepoint.com writes:

   The Lifelines can be used in any position, but only charged upright.
   The Optimas can be used or charged in any position at all.
   Unfortunately, I can't do a straight replacement because Optima
   doesn't make a battery as large as the ones I'm using. So it looks
   like I need to modify my hardware and calculations to turn them
   right side up

FWIW, possible KISS solution: Incorporate a pivot and latch into the mounting hardware whereby you can drop them down into an upright position for charging -- when you won't be occupying that space -- then latch them back upside down and against the hull during dives. If the current cabling reaches the lugs in their upside down position, you won't even have to lengthen them because they'll just need to rotate 180-degrees. Make sense?

Warm Regards
Shawn


*****

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Love not what thou art, but only what thou may become.
Do not pursue pleasure, for thou may have the misfortune to overtake it...
Live in the vision of that one for whom great deeds are done ..."

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Spotted Owl...it's what's for dinner.






--
Spotted Owl...it's what's for dinner.