Abstract: A human propelled watercraft having a pair of flexible fins supported by a mast extending into the water each adapted to oscillate through an arcuate path in a generally transverse direction with respect to the central longitudinal dimension of said watercraft. Pedals are provided for applying input force whereby as input force is applied, the flexible fins can twist to form an angle of attack for providing forward thrust with respect to the longitudinal dimension of the watercraft while moving in both directions along the arcuate path. Each of the fins preferably is composed of a layer of stiff and durable material that is wrapped around the mast. The two layers of material touch at the trailing edge and they are free to slide relative to each other. Preferably, each of the fins is provided with adjustable tensioning at the tip of the mast.

Abstract: In one embodiment, a propulsion device for use with a fluid may include a shaft coupled to a drive system that rotates the shaft, one or more cranks rigidly coupled to the shaft, and one or more connecting structures that are movably coupled to one of the one or more cranks. A foil may be rigidly coupled to the one or more connecting structures. One or more slide structures or one or more linkages may be coupled to the foil and arranged to restrain movement of the foil when the foil is actuated by the one or more cranks via the one or more connecting structures, such that rotational motion of the shaft is translated to a combination of motion of the foil between an inner extent and an outer extent and motion of the foil within an angular range between first and second limits.

Abstract: A boat rowing device is disclosed. The device comprises a driving gear secured to a plate. A driven gear is secured with the plate such that to receive rotational movement from the driving gear. A handle is secured with the driving gear to rotate the driving gear. An oar is secured with the driven gear such that to facilitate rowing of the boat.

Abstract: A wheel-type of moving water energy conversion device consists of a limited number of paddles or blades attached to struts, which are secured to a central axis or geared drive shaft. The paddles or blades are hinged to the struts in a unique underneath forward position, allowing the paddle or blade to enter water in an energy conversion, flat plane and exit from water in vertical non-water lifting position. The utilization of extension arms securing paddles, the limitation of engineered positioning of paddles and the design of free paddle exit from water, provide a uniquely efficient energy conversion device for use in moving waters, such as rivers, streams, tidal flows or lake and ocean waves and currents. The device may be engineered as a low profile, rotary barrage type, with paddles or blades positioned on struts with or without telescopic arms.

Abstract: Disclosed herein is an air agitation device that is positioned between two opposite sets of shelves on which the articles to be dried are placed.The device constitutes two identical crankshafts, oriented in the same direction, that rotate in synchrony with respect to axes perpendicular to the opposite surfaces of the said sets of shelves.To the crankpins of the said shafts are articulated, on opposite sides, two ventilation frames, each of which provided with a plurality of fins oriented suitably with respect to the said sets of shelves.The synchronous rotation of the crankshafts renders movable each frame, which oscillates with a harmonic motion in two inter-perpendicular directions, one of which is coincident with the longitudinal axis of the passageway existing between the sets of shelves.