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Fw: [PSUBS-MAILIST] Re: Blowing ballast (was: question about general design?)
Through the wonders of modern electronics, this posting was lost in the
ether. It's old and musty, but here it is, for what it's worth. - Joe
----- Original Message -----
From: Marsee Skidmore <heyred@email.msn.com>
To: <personal_submersibles@psubs.org>
Sent: Tuesday, August 14, 2001 8:27 PM
Subject: Re: [PSUBS-MAILIST] Re: Blowing ballast (was: question about
general design?)
> I've been considering using gravel ballast, out of
> granola-eatin'-Birkenstock-wearin'-tree-huggin' environmental
sensibilities.
> Besides, it's cheap. But Vance speaks a mouthful. Lead has a density of
> 710 lb/cu ft, compared to stone (basalt, granite, gneiss) at 96 lb/cu ft.
> Please excuse my English units, but this is bad news in any language.
> Trieste, by the way, used steel shot (490 lb/cu ft), not lead. A mondo
ring
> electromagnet at the mouth of the shot hopper froze the shot into a lump.
> Pretty clever, but not clever enough for anyone to have stolen the idea.
I
> remember reading that they couldn't get it to work with Good American
> Bethlehem Steel shot, and had to import Italian shot.
>
> Joe
>
> ----- Original Message -----
> From: <VBra676539@aol.com>
> To: <personal_submersibles@psubs.org>
> Sent: Monday, August 13, 2001 3:27 PM
> Subject: Re: [PSUBS-MAILIST] Re: Blowing ballast (was: question about
> general design?)
>
>
> > In a message dated 8/13/2001 3:19:50 PM Eastern Daylight Time,
> > mholt@richmond.edu writes:
> >
> > << Long ago, I was actually thinking about using gravel as emergency
> > ballast. I had the idea that a thick trash bag nested in a frame
> > of metal would survive most normal operations, and I'd drop the
> > ballast by having a blade that would tear the bag. The gravel
> > would cascade out of the frame, tearing the bag to shreds.
> > >>
> > You might want to do some experiments about weight before making any
> > decisions along the "detachable gravel" line. You might be surprised
just
> how
> > much volume it takes to equal a chunk of lead the size of a shoe box.
> > Vance
> >
>
>