Abstract: A personal marine transporter capable of offering the rider the exhilarating feeling of steering a very maneuverable water craft by the direction of his body motion. Additional features consisting of a handle bar collapsible downward into its housing, a seat with its back rotatable backward and two armrests rotatable forward, reduce the height of the water craft for easy land transportation.

Abstract: Water craft achieving better hydrodynamic performance, greater stability and increased versatility. The improvement over the water craft in the U.S. Pat. No. 6,595,815 is achieved by the use of a new configuration of the active hulls and the stationary hull, the modification of the active hulls and the stationary hulls and the addition of a pair of the modified active hulls.

Abstract: Water craft achieving better hydrodynamic performance, greater stability and increased versatility. The improvement over the water craft in the U.S. Pat. No. 6,595,815 is achieved by the use of a new configuration of the active hulls and the stationary hull, the modification of the active hulls and the stationary hulls and the addition of a pair of the modified active hulls.

Abstract: Watercrafts comprising rotatable hulls that serve as propulsors. The hulls are rotors with paddle surfaces and are arranged three-dimensionally to gain the capability of actively diverting water toward the side and the rear, for the purpose of drastically reducing frontal drag and the capability of minimizing friction drag on their wetted surfaces. Watercrafts with rotatable hulls are essentially amphibious.

Abstract: Watercrafts comprising rotatable hulls that serve as propulsors. The hulls are rotors with paddle surfaces and are arranged three-dimensionally to gain the capability of actively diverting water toward the side and the rear, for the purpose of drastically reducing frontal drag and the capability of minimizing friction drag on their wetted surfaces. Watercrafts with rotatable hulls are essentially amphibious.

Abstract: A fluid forcing device comprising many rotatable slender elements that converts mechanical energy into fluid energy by mechanically arranging and maintaining, at all time, the rotatable slender elements in a predetermined wave form and by mechanically moving the wave form in a direction normal to the rotation of the elements by an improved drive comprising two fluted rollers. The new drive reduces the weight and complexity of the entire fluid forcing device and renders it more mechanically rigid and less vibration prone.