Patent ID: 8210116

Claim:
A watercraft comprising a center hull and a pair of outer side hulls respectively located on opposite sides of the center hull and including outer surfaces forming portions of the outer sides of the watercraft, said center hull having a v-form including varying deadrise from the bow to at least a predetermined point forward of the stem, and said side hulls each having inner surface portions facing the center hull having greater reverse deadrise than the deadrise of the opposing surface of the center hull; said outer surfaces of the side hulls being substantially vertical to the water surface when the hull is at rest and extend to a lower keel; said center hull also having vertical surface portions facing the reverse deadrise surface portions of said outer hulls; and having a vent duct deadrise surface structure between the center hull and side hull forming a flat deadrise surface portion extending from said center hull vertical surface portions and intersecting with the reverse deadrise surface portion of an adjacent outer hull on each side of center hull, whereby said center hull vertical surface portions, side hull reverse deadrise surfaces and vent duct deadrise surface portions define a vent duct on each side of the center hull; and said center hull having at least two transverse steps that extend from the center hull across the vent duct deadrise surface portions on either side of the center hull, to end at the inner surfaces of the side hull; wherein said outer hulls include lower edges extending to a greater depth below the waterline than said vertical surface portions of the center hull.