A water ski system includes an elongate ski body member having an aft end portion with a mounting face. Interchangeable tail members having an engagement face are configured to be selectively mounted to the ski body such that the engagement face of the tail member abut the mounting face of the ski body member. Attachment hardware removably fixes the selected tail member to the ski body member. The interchangeable tail members may have a variety of shapes and lengths, allowing a skier to customize the water ski to accommodate differing water ski styles, water, conditions, and skill levels.

A water ski system includes an elongate ski body member having an aft end portion with a mounting face. Interchangeable tail members having an engagement face are configured to be selectively mounted to the ski body such that the engagement face of the tail member abut the mounting face of the ski body member. Attachment hardware removably fixes the selected tail member to the ski body member. The interchangeable tail members may have a variety of shapes and lengths, allowing a skier to customize the water ski to accommodate differing water ski styles, water, conditions, and skill levels.

This invention is directed toward a fin box capable of accepting either a Futures or an FCS fin without the need for any additional products being added to either the fins or the fin box. The box has an internally-adjustable wedge that can force the bottom of a fin into an indent, thereby giving it a cant or angle. The box also has channels for both FCS and Futures fins, such that a user can easily exchange either brand of fin without adding or subtracting items from the fins or fin boxes. Another embodiment of the invention provides a fin base with a wedge angle that compresses an underlying wedge, thereby wedging the fin in the fin box. A further embodiment has a button on the fin that compresses a springy material as it passes over a fin box lip, thereby removably securing the fin in the fin box.

A surfboard fin assembly for the flush incorporation into a surfboard body that allows for adjusting the depth the fin extends below the surfboard. It has a biasing means that maintains the fin in the down position yet allows upward movement upon the application of upward force such as when the fin is struck from below. The fin is perpendicularly affixed to a hinge body that is pivotally housed in an open ended fin box that is integrated into the volume of the surfboard body. A means for tensioning is releasably attached at a distal end to the hinge body and at a proximal end to the surfer's ankle. The height of the fin is adjustable through the means for tensioning and sets the performance of the surfboard to the surfer's desired level of directional control depending on their type of surfing. The fin or fin and hinge body are interchangeable with other design of fins.

A surfboard fin assembly for the flush incorporation into a surfboard body that allows for adjusting the depth the fin extends below the surfboard. It has a biasing means that maintains the fin in the down position yet allows upward movement upon the application of upward force such as when the fin is struck from below. The fin is perpendicularly affixed to a hinge body that is pivotally housed in an open ended fin box that is integrated into the volume of the surfboard body. A means for tensioning is releasably attached at a distal end to the hinge body and at a proximal end to the surfer's ankle. The height of the fin is adjustable through the means for tensioning and sets the performance of the surfboard to the surfer's desired level of directional control depending on their type of surfing. The fin or fin and hinge body are interchangeable with other design of fins.

A Kinetic Infinity Mount System (KIMS) comprises an outer housing, first and second outer gears, first and second inner gears, two pins, two screws, two mechanical collars, and a fin box. The KIMS allows different reusable and removable fins to be mounted onto a surfboard or other waterborne vessels. The KIMS provides dynamic, simultaneous adjustment and setting of a toe angle and a camber angle of the fin. The fin box includes two screw holes at each end and four screw holes along the side. Users choose from multiple settings of positive or negative toe angle or camber angle for each fin mounted into the surfboard. Camber and toe angles, in both positive or negative directions, can be adjusted simultaneously or separately to the user's preference. The KIMS allows different types of fins by FCS, Futures or similar, rectangular based fins to be mounted into the fin box and adjusted to desired configuration.

A hydrofoil (1) includes a mast (2), with an incoming flow edge (3), a discharge edge (4), lateral surfaces (5) and an upper mast end (6) with a holder (7) to be fastened to a watersports board. A fuselage (8) has front (10) and rear wings (11) are arranged on opposite sides. The mast and the fuselage are configured as separate components and are connected to one another via a screw connection (12). An adapter (13) is connected to the mast and to the fuselage and is arranged in a recess (14) of the fuselage. A positive locking is established between an adapter outer surface (15) and the recess of the fuselage. An adapter mount (16) receives a lower mast end (9). A positive locking is formed between the mast and the adapter such that the lower mast end is arranged within the fuselage.

A hydrofoil (1) includes a mast (2), with an incoming flow edge (3), a discharge edge (4), lateral surfaces (5) and an upper mast end (6) with a holder (7) to be fastened to a watersports board. A fuselage (8) has front (10) and rear wings (11) are arranged on opposite sides. The mast and the fuselage are configured as separate components and are connected to one another via a screw connection (12). An adapter (13) is connected to the mast and to the fuselage and is arranged in a recess (14) of the fuselage. A positive locking is established between an adapter outer surface (15) and the recess of the fuselage. An adapter mount (16) receives a lower mast end (9). A positive locking is formed between the mast and the adapter such that the lower mast end is arranged within the fuselage.

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.

The invention relates to a movable fin assembly, which includes a housing attachable to an underside of a watercraft and a rotation and pivoting mechanism. The mechanism positioned inside the housing and movable about two axes of rotation. The mechanism further has a fin locating position, thereby a fin provided at the fin locating position is capable of moving about the two axes of rotation via the mechanism, such that the fin's toe angle and camber angle changes when moving through the water. The invention further extends to an interchangeable self-aligning fin and static fin kit which includes a rotation and pivoting mechanism and a static member shaped and dimensioned to correspond with an interior of the housing. The static member and the rotation and pivoting mechanism interchangeably receivable by the housing in order to selectively provide a dynamic or static fin on the underside of the watercraft.