On Mon, 21 Jun 2010 22:24:27 -0400, W1TEF
wrote:

The A-7 Polyform bouy holds 161.6 gallons of air which ~~ mumble -
mumble - carry the six, add four, times 12, price of tea in China ~~
works out to...24.8 something or other cubic feet? That right?

I'm getting about 20 cubic feet assuming 8 gallons per cube, or about
1200 pounds of buoyancy. That's a big-un, should do the trick if we
can get the chain to slip and have enough static engine thrust. Nice
solution if you've got the room for a big buoy like that. Any idea
what they cost, and what the deflated size is? A couple of them might
be useful as hurricane fenders.

http://www.polyformus.com/doc/product_a7.htm

My personal solution is to use a chain hook led to a 3,000 lb
Come-a-Long. I've tested it enough to know that it works but it would
take a while to bring up the anchor from 40 ft. The nice thing is
that Come-a-Longs are relatively cheap and don't take up a lot of
space. A multi-part block and tackle led to a chain hook or rolling
hitch should be workable also if you have enough mechanical advantage.