"Glenn Ashmore" wrote in message
...
Here is where I got the formula on the Harken site. About 2/3 down the
page:
http://www.harken.com/winches/wnchpower.php

In this case I think Harken is just off. They use an example of a 300 sq.
ft headsail (nearly the size of the genoa on my last boat, a 30' cutter) and
conclude you need a 50:1 winch. I don't think so. The winch was a 2 speed
32:1 and was fine. Yes, it was a bit of effort in a stiff breeze - but you
could still wind it in.

The usual formula for sheet loads is

F (lbs) = 0.00431 A(sq. ft) V^2 (knots)

There are some frictional losses through sheet blocks but not that much,
perhaps 10%.

I think 56's would be more than fine for your 505 ft foresail. If they are
self tailers, and you use a 2 handled winch handle, they will be a breeze
for smaller crew members.

by the way in case you were not kidding:
1 N = .0981 kg i.e. about 0.1 kg force or about 0.2 lbs


--
Evan Gatehouse

you'll have to rewrite my email address to get to me
ceilydh AT 3web dot net
(fools the spammers)