A passively controlled fluid foil has a span; and a rigid spar extending in the spanwise direction, a cellular material and a flexible outer surface defining a profile of the outer surface of the foil and encapsulating the cellular material and the spar.

A swimming propulsion device. The swimming propulsion device includes a fuselage at least one propulsor pivotally connected to the fuselage, and in some embodiments, at least one stabilizer affixed to the fuselage. The device also includes a swimmer connection mechanism removably attached to the fuselage by a locking mechanism whereby the swimmer connection mechanism connects a swimmer to the device, and a control mechanism installed within the propulsor. A method for efficient swimming is also disclosed.

A hydrofoil may include a starboard support structure and a port support structure. Each structure may be hollow and extend longitudinally in a fore-aft direction and being parallel to one another. The hydrofoil may include an anhedral wing having ends at either side of the wing. The ends may be connected to the starboard and port support structures. The hydrofoil may include a starboard electric propulsor mounted to the starboard support structure and a port electric propulsor mounted to the port support structure. The hydrofoil may also optionally include a front wing having ends at either side of the front wing. The ends of the front may be connected to the starboard and port support structures.

A hydrofoil for a watercraft comprises a mast as well as a front wing and a rear wing, which are arranged, based on the forward travel direction, one behind the other at a free end portion of the mast. The rear wing is designed as an annular wing and, in addition, includes at least one tubular portion, which is oriented to the forward travel direction in such a way that water is able to flow through said tubular portion counter to the forward direction of travel.

A fluid foil has a main fixed portion and a tip portion movably mounted at a tip end of the main fixed portion. The main fixed portion has an upper surface and a lower surface, and the tip portion has an upper surface and a lower surface. The fluid foil is operable in: a) a first configuration in which the upper surface of the tip portion is angled downwardly with respect to the upper surface of the main fixed portion; and b) a second configuration in which the tip portion is rotated upwardly with respect to the first configuration such that the upper surface of the tip portion and the upper surface of the main fixed portion are substantially continuous surfaces. The movement of the tip portion with respect to the main fixed portion is exclusively passively actuated by movement of the foil with respect to a surrounding fluid.

This invention relates generally to hydrofoils. More specifically, this invention relates to a monowing hydrofoil that provides inherent pitch stability during use. The monowing hydrofoil utilizes one or more mast interfaces to facilitate its removable, and optionally angularly adjustable, engagement to a mast.

Various embodiments are disclosed for a stepped cambered planing hull for a boat including a swept back cambered planing surface having a non-linear distribution of camber. The non-linear distribution of camber along the swept back cambered planing surface may enable stepped cambered planing hulls having high deadrise (i.e., greater than 15 degrees). The stepped cambered planing hull may include a shaped hydrofoil that generates further hydrodynamic lift by piercing the free surface wake produced by the swept back cambered planing surface. The stepped cambered planing hull may have external bottom surfaces adapted at the after-body and transom to accommodate a distinctive profile of the free surface wake produced by the swept back cambered planing surface. The stepped cambered planing hull may include an adjustable interceptor blade to regulate hydrodynamic lift at low speeds or to ensure an optimal dynamic trim angle in a wide range of speeds.

The present invention relates generally to underwater wings for providing lift to boats. More particularly, the invention comprises an underwater wing that attaches to the hull or hulls of a pontoon or tri-toon boat. The purpose of the wing is to provide a designated amount of lift to reduce drag and improve performance of the watercraft. This is different from a traditional hydrofoil, which is designed to lift a boat completely out of the water.

In an underwater glider, stability and versatility can be enhanced by the use of a high wing design. In a high wing design, a centerline of the wings extending from the sides of the body of the glider are located above a relative centerline of the body of the glider. The relative centerline of the wings may rise continuously from a region where the wings attach to the body to respective ends of the wings. In particular for a blended wing glider, a top surface of the glider is level in a line extending between ends of each wing.

A watercraft system is provided. The watercraft system includes a lifting body designed to generate dynamic lift during watercraft operation. The lifting body is shaped with a twist from the center to the lateral edges and with a chord and a fore-aft cross-section that both decrease from a center of the lifting body to lateral tips of the lifting body.