Another possible solution, is it possible to run a high bridle from a cat rigged boat on a sloop rigged boat in somewhat of a duel bridle configuration, have the high bridle take the tension of the mast and be the actual forestay, and lower jib bridle setup to only take the forces of the jib? or is the jib the main culprit in the sideways forces the hulls encounter?
It's the mainsheet tension which is transfered straight through to the forestay that creates the tension in the bridle. The actual luff tension on the jib is negligible in comparison. The F16s use a system with a high bridle and a solid bar going down from that to the spinnaker pole (about 500-600mm). The jib is attached at the spinnaker pole.
A simpler solution than this, or a beam, is to simply put a longer bridle on the boat. From a performance point of view, the jib does not have to be at the lowest position possible. You could raise the bridle and shorten the forestay by 100mm, which would make an enormous difference to the side loads. You would also need to move the jib sheeting points back some to match (assuming they are in the right place now).
Has anyone ever tried using a spinnaker with the normal cat rigged "dual forestays", how much do the forestays limit the kite? does the kite need to be sheeted in enough that the forestays get in the way? or do they get in the way of or catch the kite during jibes?
Yes, Red Alert had twin forestays. The spinnaker got tangled on the stays when trying to gybe. Peter changed it to a high (cat-rig) bridle and used a separate spectra bridle to hold the chute and pole in place. This worked fine.
I'm still not convinced there is any need to do anything about the bridle loads on a timber Mozzie. There are plenty of timber sloops racing at the top level, some with heavy crews that put a lot of load on the hulls and there really is no problem with hulls breaking.
What causes hulls to break is not so much the amount of time they've spent under load or the size of the loads, but the amount of water and rot that has got into the plywood. Also stringers or frames that have broken free are a problem.
