Patent ID: 7040244

Claim:
A watercraft comprising: at least first and second hulls, each hull including at least one electrical motor and a propulsion device coupled to the electrical motor, each hull having a stern, a bow and a bottom surface extending in a forward direction between the stern and the bow, each of the hulls floating on a water surface during operation with a lower portion of each hull displacing water to provide buoyancy; a structure supported by the first and second hulls; a first passive flotation device positioned below and parallel to the first hull, the first passive flotation device mechanically coupled to the first hull by at least a first interconnection member, the first passive flotation device being entirely submerged during operation to provide additional buoyancy, the first passive flotation device comprising a sealed substantially hollow body, the first passive flotation device having no equipment within the body and having no access ports on the body; and a second passive flotation device positioned below and parallel to the second hull, the second passive flotation device mechanically coupled to the second hull by at least a second interconnection member, the second passive flotation device being entirely submerged during operation to provide additional buoyancy, the second passive flotation device comprising a sealed substantially hollow body, the second passive flotation device having no equipment within the body and having no access ports on the body.