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

["Dan H." <jmachine@adelphia.net>]

Carl,
Sand or gravel is to light for ballast in a sub.  It's mass is so much more
then lead for the same weight that it's impractical in a compact sub.  A
load of gravel in a pickup truck pretty much fills the box.  If it were
lead, it would be a sheet on the bottom of the floor.
Remember it only the displacement over and above what the same mass of water
weighs that's effective as ballast.

Dan H.
----- Original Message -----
From: "Coalbunny" <coalbunny@vcn.com>
To: <personal_submersibles@psubs.org>
Sent: Tuesday, February 17, 2004 5:49 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
> >
> >
> > *****
> >
> > "Call nothing thy own except thy soul.
> > 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 ..."
> >
> > Man of LaMancha, D. Wasserman
>
> --
> Spotted Owl...it's what's for dinner.
>
>