Wayne.B wrote:
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.


Whether you go with a come-along or block/tackle make sure it works.
The cheap block/tackles are sometime just plain worthless, coming with
ready-made frozen pulleys and cheap binding rope.
I threw away a bubble packaged 1/4 ton half a minute after I opened it.
Even a cheap come-along usually works well enough.
Here's a U.S. made come-along and block/tackle which look a couple
quality cuts above the typical Chinese crap.

http://www.garrettwade.com/come-alon...er/p/60R05.01/

http://www.garrettwade.com/product.a...cd2=1277183447

I'm not endorsing any of those. I'm just putting these links in for
DePlume, because she might be serious about this, and probably hasn't
seen any of this gear. This place could use a new young boater who
knows where to put the doilies. The old farts here are dying off.
That block/tackle above has 4:1 advantage.
The come-along might be 8:1. Hard to tell, just going by experience.
I was closer than far - looks like this one is +12:1.
https://www.aceindustries.com/p-8230...ome-along.aspx



You can get even more with the lever if put a pipe on in.
But you only want to do that if you're weak, otherwise you'll exceed its
capacity and likely break it.
Easy to break your boat in half with some of this gear.
https://www.aceindustries.com/c-24-h...ll-models.aspx
With the block/tackle more pulleys will increase the advantage, but that
takes wider blocks and more rope.
I had a heavy chain come-alone but it weighed about 70 pounds.
All drop forged and very heavy chain.
Lost it off Nantucket when a shackle broke pulling in a humpback.
A chain fall is a great pulley hoist, but again they're heavy.
Here's an example.
https://www.aceindustries.com/p-8240...chainfall.aspx
See how you pull 172 feet to lift a foot?
Don't know what the advantage ratio is, but I've hoisted +1000 lbs many
times with them, and it's almost effortless strength-wise.
Rope or chain is the only practical "line" for manual pulley hoists.
But for a light come-along on a non-whaling boat I'd go with cable.
If I had a davit without a manual winch and expected I might have to
manually hoist using it, I would have a good quality rope block/tackle
rated to the davit capacity. Then all your rigging is right at the action.
But a come-along cable run through a snatch block on the davit hook
could do the job.
Wayne might give us his preference and needs from his "big boat"
perspective.
I hung up my whaling gear some years ago when I moved to Florida, so I'm
out of the big boat loop now.

Jim - Reminiscing sure can change history.