A watercraft having propulsion means extending below the water line comprising a pair of flexible fins each adapted to oscillate through an arcurate path in a generally transverse direction across the central longitudinal dimension of the watercraft. As input force is applied, the fins twist to form an angle of attack for providing forward thrust while moving in both directions along the arcurate path. Each of the fins have a generally squared off top and preferably an outer area of harder rubber than the inner area. Each of the fins can be adjusted at the trailing edge to provide adjustable tensioning of the trailing edge.

A water propulsion apparatus operatively connected to a body moving on or through a body of water, may produce a propulsive force by sweeping fins in an oscillating motion in a generally transverse direction relative to a longitudinal axis of the body. The fins may be mounted on opposite sides of a frame and are rotatable about a first axis coplanar to the center longitudinal axis of the frame. Drive members rotatable about a second axis that is canted relative to the first axis may be operatively connected to the fins. The oscillatory motion of the fins may be controlled by torque applied at the canted second axis by reciprocating the drive members in a generally vertical plane parallel to the center longitudinal axis of the frame. The oscillating fins may provide a propulsive force during both oscillating directions of the fins as they sweep back and forth.

A vibration-powered device adapted for flotation and propulsion on an upper surface in a liquid. The device having a body with a top side adapted to be at least partially disposed above the surface of the liquid, and a bottom side adapted to be at least partially submerged below the surface of the liquid. A vibration mechanism is disposed in the body. A propulsion fin is connected to the body. The fin includes a top side adapted to be disposed at least partially above the liquid surface, a bottom side adapted to be disposed at least partially below the surface. The vibration mechanism is adapted to oscillate the free distal end of the propulsion fin upward and downward.

A vibration-powered device adapted for flotation and propulsion on an upper surface in a liquid. The device having a body with a top side adapted to be at least partially disposed above the surface of the liquid, and a bottom side adapted to be at least partially submerged below the surface of the liquid. A vibration mechanism is disposed in the body. A propulsion fin is connected to the body. The fin includes a top side adapted to be disposed at least partially above the liquid surface, a bottom side adapted to be disposed at least partially below the surface. The vibration mechanism is adapted to oscillate the free distal end of the propulsion fin upward and downward.

A watercraft having propulsion means extending below the water line comprising a pair of flexible fins each adapted to oscillate through an arcuate path in a generally transverse direction across the central longitudinal dimension of the watercraft. As input force is applied, the fins twist to form an angle of attack for providing forward thrust while moving in both directions along the arcurate path. Each of the fine have a generally squared off top and preferably an outer area of harder rubber than the inner area. Each of the fins can be adjusted at the trailing edge to provide adjustable tensioning of the trailing edge.

A watercraft having propulsion means extending below the water line comprising a pair of flexible fins each adapted to oscillate through an arcuate path in a generally transverse direction across the central longitudinal dimension of the watercraft. As input force is applied, the fins twist to form an angle of attack for providing forward thrust while moving in both directions along the arcurate path. Each of the fine have a generally squared off top and preferably an outer area of harder rubber than the inner area. Each of the fins can be adjusted at the trailing edge to provide adjustable tensioning of the trailing edge.