David, Matt

The same thoughts occurred to me as well.

First the Bridle seems a little low to me as well considering the hulls were modified A-cat hulls. Personally (as I didn with my own boat) I would have raised the bridle intersection and used a extra 3rd line to keep up the blue snuffer mouth. In altereds case I would have placed the bridle strop some 2 mtr's up from the decks and have it then continue as a single stay.

Having double forestays is not what you want to have on a spi boat as the spi tends to get blown between the stays to often. A single forestay with a high bridle strop seems to be the best compromise.

David. F16 is both sloop and uni-rig. We sail sloop when doublehanding and uni-rig when singlehanding. Gary only sails singlehanded as far as I know and has no jib as a result.

I agree with Matt that the most simple reinforcement against the most likely cause of the failure would be to just laminate an extra skin to the outside of hull that is just inside and in front/below the mainbeam. The failure seems to me to be a compression buckling failure caused by the increased bending stresses due to the bridle strop. You probably have added 400 kg sideways load to the hulls = ALOT.

The fibres can probaly take the laods but not if they become unstable when the hull starts to get out of colom (rimples along the hull) and moves sideways inward and/or outward. Thickening the wall will prevent this rimpling effect and thus induce more strength than would be expect by just adding the cloth.

But we need to be sure that this failure under compression buckling was the case of this. A sub deck is the most effective solutions as that would completely stabilize the walls.

Get up back there on that horse Gary !

Wouter