A foil displacement system includes one or more foils that can be deployed and stowed. When deployed, each foil can exert downforce or uplift depending on its orientation. For example, each foil may be positioned to have an angle of attack that creates a downward force effectively transmitted to the hull to pull the hull deeper within the water to, for example, create a larger wake. Use of the foil displacement system can enhance or replace the use of a ballast tank system, can be integrated into a new boat or retrofitted to existing boats, can be electronically or manually positioned, can enhance activities such as wake surfing, wake boarding, water skiing or other similar or related water sports.

A hydrofoil craft includes a hull including a bottom that spreads from a bow to a stern; and a hydrofoil mechanism provided on the bow side of the hull. The hull further includes an accommodating recess formed therein, and the accommodating recess is recessed toward the stern side between the bow and the bottom to accommodate the hydrofoil mechanism. A retreat surface is formed between the bottom and a recess main surface facing the bow side in the accommodating recess, and the retreat surface extends toward the stern side in a downward direction and is connected to the bottom.

A linear drive system adapted for repetitive driving using a linear motor. The drive system may be used to power pumping hydrofoils which drive a boat or ship. Linkages are used to maintain the driven portion in linear motion. A coupled dual drive system in which two driven portions are coupled such that their coupled motions travel at the same velocity in opposed directions. The coupled linear drive system which may be used as a mechanical power source for drive systems used in transportation and industry. A boat with dual pumping hydrofoils adapted for propel a boat using the hydrofoils for both lift and propulsion.

Safety strut assembly (9) for a hydrofoil craft (1) comprising a strut (12), which is attached to the hull (10) of the craft by means of a transverse oriented strut axle (40) for pivotal movement with respect to the hull, the assembly further comprising: a control rod (33) passing down through the strut (12); a linear actuator assembly (28); a hydrofoil (13) pivotally mounted to the bottom portion of the strut (12) about a transverse oriented foil axle (35); first linkage means (34) connecting the hydrofoil (13) to the control rod (33); wherein the first linkage means (34) comprises a first drive ring (48) mounted around the foil axle (35), wherein the first drive ring is provided with one first ring cam element (45), and wherein the foil axle (35) is provided with one foil axle cam element (46).

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.

A foil, such as an aerofoil, having a leading edge and a trailing edge, of which at least a portion of one or both of the leading edge and trailing edge has a serrated profile comprising a plurality of adjoining teeth, each tooth having a tip point that represents a local maximum chord-wise extent of the tooth and, on each side span-wise of the tip point, a root point that represents a local minimum chord-wise extent of the tooth and at which the tooth adjoins a respective adjacent tooth, wherein the tooth edge profile varies with an ogee-like curve between tip point and root point such that the tooth is sharper in the neighbourhood of the tip point and in the neighbourhood of the root point than at locations in between.

A hydrofoiling watercraft including a board for supporting a user includes a plurality of masts extending downwardly to connect one or more hydrofoil wings to the board. Examples of the watercraft include a fuselage mounted to each mast wherein a forward portion of each fuselage extends toward a direction of travel for the watercraft. A hydrofoil wing is mounted to the forward portion of each fuselage. A tail wing may be mounted to a rearward portion of the respective fuselages.

This disclosure extends to systems, apparatus, and methods for quick release mast mounting assemblies for board mounted hydrofoil assemblies. In one exemplary system, a quick release mounting assembly may include board mountable base receiver for mounting to a sports board, which defines a longitudinal receiving recess. A resilient locking member is disposed at a front end of the base receiver. A separate mast connection member formed as a body configured for connection to an upper end of a hydrofoil mast, corresponds to the longitudinal receiving recess, and includes a counterpart structure for forming a secure connection with the resilient locking member. The mast connection member may include opposite shoulder or wing members that extend laterally orthogonal to the longitudinal axis thereof and the receiving recess may include counterpart slots for receiving these members. The resilient locking member may include a separate spring assembly or be a unitary member.

The present invention is directed broadly to an underwater appendage assembly (10) of a marine vessel (12). The underwater appendage assembly (10) is in the form of a rudder assembly fitted to a bow section (14) of the vessel (12). The rudder assembly comprises an appendage in the form of a rudder foil (18) connected to a flapper member (20). The flapper member (20) is arranged whereby movement and more particularly pitching, of the vessel (12) induces deflection of the flapper member (20) relative to the rudder foil (18). This deflection in the flapper member (20) provides an oscillating movement of the flapper member (20) in a flapping action which is substantially synchronised with movement of the vessel (12) upward and downward. The flapping action of the flapper member (20) is effective in promoting forward propulsion of the vessel (12).

A centerboard for a boat, having a body with a head disposed at its proximal end and an arm emanating therefrom. The centerboard is of unitary construction, namely wherein the body, the arm, and the various specific features associated therewith, all consist of a single piece or portion of uniform material.