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Not so. You get practically no advantage of weight when you put the rig on the windward hull. The only thing resisting the boat rotating upside down is the amount of buoyancy in the leeward hull.


Surely this is just phrased badly, Jake. If this were true, there would be no point to trapezing.

Righting moment is determined by the center of bouyancy (CB) for the boat, combined center of gravity (CG) of everything on it, and the distance between the combined CG and CB (moment arm). Moving the mast to windward (towards the right in this diagram) will move the combined CG right, increasing the moment arm, thus increasing the righting moment - same as trapezing (although the mast/rig will have less effect being lighter than the crew).

Why you would want a sliding mast in a practical boat is beyond me. The complexity is surely not worth it. However, ORMA 60 Tris have used mast canting to good advantage.


Agreed. But now look at a similar diagram with the mast on the windward side (and no trapezing) like we were talking about. The large majority of the sail pressure is offset by the buoyancy of the leeward hull, not the boat weight, in that arrangement. There would be very little boat weight on the side of the sail plan that provides the righting moment in your diagram.

Jake Kohl