Charlie: ah, it's the part of the sail that fails first that you are interested in. That's a tough call because modern sails are designed to be stronger where the forces are higher. My tri-radial cut sails even use different weights cloth for different panels
I have no clue what will go first so my guess is that it's at a random location. For old sails it's different, I would say along a seam or fold (folds break the coating).
Talbot: a multihull endures shock loading in the rig that isn't dampened much. On a mono hull
the only shock loading is from slamming into seas, the rest is absorbed by heeling. This is the price
the multihull design pays for not heeling. Shock loading leads to stress (fatigue, hairline cracks) in the stainless parts
incl. the chainplates and their bolts. You don't see that on monohulls: almost all of their chainplate failures are due to crevice corrosion
(lack of oxygen on the steel surface)
Relax, I think you're over-sensitive to my factual pointing out a weak point in the multihull which isn't needed because I would just as easily point out weaknesses in monohulls; I have nothing against initial stability. But the example of a monohull
put in concrete is very similar (for the rig) to a multihull under sail so that's why I brought that up.