Systems, apparatus, and methods for hydrofoil assemblies with planing blades that may be adjusted, and securely maintained in varying tilts with respect to a support member, using a curved indexing system with a curved ridge and a counterpart groove that utilize interacting position retaining elements to retain a desired tilt in different adjustable positions. In one illustrative system, a planing blade may have a convexly curved ridge disposed on a surface thereof with a series of transverse grooves disposed in the curved ridge. A support member may have a counterpart concavely curved receiver with a series of counterpart transverse grooves formed therein. When a user places the planing blade in position with the convex ridge contacting the concave receiver, the blade may be tilted to a desired position. The counterpart transverse grooves interconnect to provide an indexed positive interlock, securely maintaining the blade in the desired position.

A modular, weight-shift controlled watercraft device is disclosed which includes: a modular board removably attachable to a power system. The power system includes a modular power supply system, and a modular propulsion system. The power supply system includes a housing including a battery. The propulsion system includes a modular strut, a modular propulsion pod, and a modular hydrofoil. In one embodiment, the power supply system is removably and mechanically attachable directly to the propulsion system.

A modular, weight-shift controlled watercraft device is disclosed which includes: a modular board removably attachable to a power system. The power system includes a modular power supply system, and a modular propulsion system. The power supply system includes a housing including a battery. The propulsion system includes a modular strut, a modular propulsion pod, and a modular hydrofoil. In one embodiment, the power supply system is removably and mechanically attachable directly to the propulsion system.

A hydrofoil system is disclosed, having a fuselage with a propeller mounted to one end of the fuselage and a wing extending laterally from the fuselage. The fuselage is configured for removable attachment to a mast, so that the mast when attached extends from the fuselage in a direction substantially orthogonal to the longitudinal axis and also substantially orthogonal to the wing. A tail wing is connected to the fuselage by a tail strut, so that the tail wing is positioned beyond the end of the fuselage to which the propeller is attached. A motor is housed in the fuselage and has a cable connected thereto, the cable extending outside the fuselage, wherein a removable sealing system inhibits water ingress to the motor at the location where the cable is connected when the sealing system is installed in the fuselage.

A hydrofoil system is disclosed, having a fuselage with a propeller mounted to one end of the fuselage and a wing extending laterally from the fuselage. The fuselage is configured for removable attachment to a mast, so that the mast when attached extends from the fuselage in a direction substantially orthogonal to the longitudinal axis and also substantially orthogonal to the wing. A tail wing is connected to the fuselage by a tail strut, so that the tail wing is positioned beyond the end of the fuselage to which the propeller is attached. A motor is housed in the fuselage and has a cable connected thereto, the cable extending outside the fuselage, wherein a removable sealing system inhibits water ingress to the motor at the location where the cable is connected when the sealing system is installed in the fuselage.

Disclosed is a method for controlling a hydrofoil board powered by a motor driven propeller. The motor is controlled by a hand controller configured with user selectable operating pre-sets including a first operating pre-set, wherein the board is accelerated to a first speed which is less than that required for the board to hydrofoil, and a second operating pre-set, wherein the board is accelerated to a second speed sufficient for the board to hydrofoil. Alternatively, the operating pre-sets may limit the motor power. A system for operating a hydrofoil board is also disclosed, which includes a propulsion control unit comprising a propulsion source, and a hand controller configured to receive a first user input and a second user input and to transmit the user inputs to the propulsion control unit.

Disclosed is a method for controlling a hydrofoil board powered by a motor driven propeller. The motor is controlled by a hand controller configured with user selectable operating pre-sets including a first operating pre-set, wherein the board is accelerated to a first speed which is less than that required for the board to hydrofoil, and a second operating pre-set, wherein the board is accelerated to a second speed sufficient for the board to hydrofoil. Alternatively, the operating pre-sets may limit the motor power. A system for operating a hydrofoil board is also disclosed, which includes a propulsion control unit comprising a propulsion source, and a hand controller configured to receive a first user input and a second user input and to transmit the user inputs to the propulsion control unit.

An improved support for a fin extending downwardly from the undersurface of a water sport board provides detented rotational positioning of the fin at a selected one of a plurality of angular positions including a vertical position for use, a right side position and a left side position both of which protect the fin from damage during periods of nonuse, transport and storage and which avoid the need for removal and reattachment of the fin between periods of use and periods of nonuse, transport and storage.

An improved support for a fin extending downwardly from the undersurface of a water sport board provides detented rotational positioning of the fin at a selected one of a plurality of angular positions including a vertical position for use, a right side position and a left side position both of which protect the fin from damage during periods of nonuse, transport and storage and which avoid the need for removal and reattachment of the fin between periods of use and periods of nonuse, transport and storage.

Surfboards moved by user power comprises: a surfboard body streamlined, when viewed from a plan view, concave grooves are formed on both sides, respectively; a propulsion body including: a first propulsion body formed with a first propulsion unit that is hinged to one side groove of the surfboard body and is formed inclined with respect to the surfboard body on a lower surface to generate propulsion force according to the movement of the user's feet; and a second propulsion body formed with a second propulsion unit that is hinged to the other side groove of the surfboard body and is formed inclined with respect to the surfboard body on a lower surface to generate propulsion force according to the movement of the user's feet; and a direction change unit including: a rotating shaft passing through the surfboard body; a handle disposed on an upper end of the surfboard body of the rotating shaft to rotate the rotating shaft; and a direction change key that is disposed on a lower part of the surfboard body of the rotating shaft and rotates together with the rotating shaft.