This and other matters dealing with sizing of rigging, spars, and scantlings
is dealt with quite well in Dave Gerr's "The Nature of Boats." Perhaps you
could take a SWAG at the safety factors which were applied and work
backwards to the loads?

Roger

http://home.earthlink.net/~derbyrm

wrote in message
oups.com...
Hi
Now if what you need is to see if the sail have the right size compared
where the mast are compared the size of the jig ---- the shape of the
sail aso. there are one easy way to find out, the way these things been
"calculated" for centuries. It will not thell you if the sail is big
enough but it will tell you if the boat can sail.
Just draw a sideview of the boat with sails up, then cut it out and
place the cut out pieces on a point needle untill it ballance
------Then you have the geometric center point for the forces of the
sail. Do the same with only the underwater hull and by ballancing it
over an edge, find the center point for that. Now when you have both
the point you can say the sail forces will work from and the point that
tell you how to push the hull sideverts thru the water, it is easy to
point out a point or line to place the mast, so the forces from the
sail effect the hull. In some old books you can find some rules about
what the ideal distance between these two points or lines must be for
the boat to be able to tack.
Cut out a sideview and ballance it over an edge, --- that's
boatbuilding math ) and it work.