By my quick calculation, the shroud would see a little over 5000lb upwind. This is assuming that the shrouds connect to the amas and that the windward ama and main hull are flying just above the water (i.e., all weight on leeward hull) and that there is 500lb of crew weight on the windward hull. Downwind with a big spinnaker up, it may be more, but at least this gives you an order of magnitude.

sm