Not exactly. The "percentage" is LP (the distance perpendicular from
the luff to the clew) divided my J (The horozontal distance from the
tack to the front of the mast. Because LP is at an angle to J, a 100%
jib will not quite reach the mast.

Matt Koch wrote:
Stephen

In a nutshell, the percentages are arrived at as follows. Assume a sail
that "goes to the top of the mast".

Measue the horizontal distance from where the forestay attaches to the bow
to the mast.

A sail that extends exaclty to the mast (i.e. the distance you measured when
it;s sheeted tight is called a 100% or a working jib. A sail that extends
half again, the distance you measured, beyond the mast when sheeted in tight
is called a 150%.

Matt


"Stephen Trapani" wrote in message
...

jdmarchand wrote:


Stephen:

I would first get myself a good book on the theory and practise of

sailin

and learn a bit about sail performance and terminology. You seem to be a

bit

mixed up in your terms.

A 135% genoa (any good sailing theory book will explain how this is
measured) is generally the best all around compromise. If you generally

sail

in light air, a 150% might be better. If you routinely sail in heavy

wind, a

100-120% would be better.

David



Thanks, I'll get one of those books right away. In fact I have a friend
who has one. I'll need to borrow it if I want to beat him racing.

But I need to make this sail decision day after tomorrow, for the free
storm jib, and I thought someone might have a quick forumula for the
measurements a storm jib should be, or any jib/genoa if someone can.
That will be in the book? I can get it right away, I guess.

I'll know the height of my mast, the length of the boom, etc. I'll
investigate much further before buying any sails later.

Stephen




--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
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