A water propulsion assembly operatively connected to a watercraft 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 watercraft. The fins may be rotatable about a first axis coplanar to the center longitudinal axis of the watercraft. 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 plane generally parallel to the center longitudinal axis of the watercraft. The oscillating fins may provide a propulsive force during both oscillating directions of the fins as they sweep back and forth.

Braking arrangements for inhibiting pedals of a pedal drive system for a watercraft from rotating when an assist drive train of the pedal drive system is activated are provided. Method of preventing pedals of a pedal drive system for a watercraft from rotating when using an assist mode are provided.

A retractable propeller driven pedal system for assembly onto a watercraft is disclosed. The retractable propeller driven pedal system converts an input from a user into a motive force for propelling the watercraft. The system comprises (i) an elongated drive unit having a distal end and a proximal end which comprises a head unit having at least two head unit grooves; (ii) a propeller arm which has a distal end and a proximal end, wherein the proximal end has two circular openings positioned to connect with head unit and the circular openings each have an extension with an aperture configured to receive a latch. The proximal end of the drive unit and proximal end of the propeller arm attach to form an articulation center which pivots around a first pivot point. A method for using a retractable propeller driven system is also disclosed

A watercraft includes a chassis, a drive, a hydrofoil and a drive transfer arm. The drive is operatively connected to a first end of the drive transfer arm. The hydrofoil is pivotably connected to a second end of the drive transfer arm. The watercraft is configured such that operation of the drive causes the hydrofoil to oscillate, to provide thrust. The hydrofoil is pivotably connected to the second end of the drive transfer arm with an adjustable connection mechanism. The adjustable connection mechanism is such that the distance between a leading edge of the hydrofoil and a rotational axis of a pivoting connection point to the drive transfer arm is adjustable.

Examples are disclosed that relate to watercraft with retractable drive mechanisms. One example provides a watercraft including a hull having a receiving compartment, and also having a deck. The watercraft also includes a drive unit extending through the deck and the hull of the watercraft and being configured to receive rotational input. The drive unit includes a driveshaft and propeller moveable between an extended position in which the propeller is positioned underneath the hull and a retracted position in which the propeller is positioned at least partially within the receiving compartment.

A lightweight amphibious vehicle system enables a user to traverse the land or water in the same craft. The wheels have paddles attached on the sides and are powered by a transmission that multiplies the force of a user to enable the system to travel without great effort. The transmission is driven by pedal power input by the user.

A centerless wheel assembly may include a centerless rim configured to rotate about a point. The centerless wheel assembly may also include a centerless flywheel that may be configured to indirectly couple with the centerless rim and to rotate about a point. The centerless wheel assembly may additionally include a device for rotating the centerless rim in a first direction and in a second direction. The centerless wheel assembly may also include a one-way bearing that may be disposed between the centerless rim and the centerless flywheel. The one-way bearing may be positioned such that as the centerless rim may rotate in the first direction, the centerless flywheel may be caused to rotate in the first direction and as the centerless rim may rotate in the second direction, the centerless flywheel may not be caused to rotate.

An improved kayak has a hull of thermoformed ABS plastic having a bow and a seat having a void between the bow and the seat, a top of the hull being a deck with a foam PVC block glued to a bottom face of the deck. A rotomolded polyethylene plastic insert is located in the void and joined to the hull by fasteners that pass through the insert and the deck of the hull and engage the foam PVC block within the hull, with caulking between the hull and the insert. A propulsion device is removably mounted in the rotomolded plastic insert that allows a user of the kayak to propel the kayak.

Disclosed are systems, devices, and methods for swimming using a swimming apparatus that includes an exterior shell, optionally including a top half and bottom half and an opening to accommodate a propulsion system.

The present invention relates to two configurations of structure for a compact, pedal-propelled boat, a recumbent configuration and a conventional configuration, and to two possible propulsion systems, one with rigid transmission system and other with flexible transmission system. Both configurations are used with hulls arranged in parallel, catamaran configuration, preferably inflatable, allowing the volume and size of the assembly to be reduced so as to fit in a car trunk, making it easier to transport and store. In the recumbent configuration, the boat driver is in a sitting position, with his back supported by the seat, and actuates the pedals located in the front part of the structure while maneuvers the boat by means of handlebars located on the sides of the structure. In the conventional configuration, the boat driver is in the same position as the rider of a conventional bicycle, and the seat, pedals and handlebar are arranged in the same positions as in a bicycle. The invention seeks to provide simple solutions and the greatest quantity possible of shared components between these configurations, such that a production plant can produce these configurations through as few production processes as possible and sharing as many production processes as possible.