On Tue, 09 Oct 2007 02:50:57 GMT, Brian Whatcott
wrote:

How would an engineer want to specify the rigging for a sailboat?
He might want to consider the peak loads applied to the rigging.
What could that be?
Perhaps it would be the gale that puts the main mast and sail parallel
to the water? The rigging forces could hardly get greater, possibly?

Except for a roll over and no rig is designed to withstand that.

Professional experts and engineers use the righting moment of the boat
to determine rig loads. Sail area is largely irrelevant. A fudge
factor for shock loads and a safety factor is also necessary of
course.

I don't know how rigging wire is specified but I do know that anchor
chain and rode is usually specified with a Safe Working Load (SWL) of
approximately 20 to 25% of breaking strength. Sometime after SWL is
exceeded, but before breaking, the material in question will exceed
its elastic limit and permanent elongation will occur. That's a
particularly bad thing for chain which is sized to fit the pockets in
the windlass gypsy. It would also be a bad thing for rigging wire
because it would leave the mast badly out of tune.