My choice for a voyaging hull was that of a full displacement full keel vessel. Since it was a motor sailor, it had a large rudder. The hull was double ended at the waterline, but had a fairly broad buttock area to give aft buoyancy. The transom went from a narrow point to a full wine glass shape, to give buoyancy as the wave came up from behind. This hull form worked well with seas whose height were close to the length waterline. The prop wash against the rudder, combined with the long full keel, gave exceptional stabilityand control. However this hull form will not surf or go more than about 1.4 x LWL in speed. Again this seems to be an advantage in heavy seas. In my experience a semi displacement or planning hull was more difficult to manage in heavy seas than the full displacement, long keel vessel. However a chinned hull does give more "stability" from rolling--this should not be confused with seaworthiness or tracking ability in heavy conditions Bob Austin