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.

The invention relates to an inflatable surfboard having a hull component (2) with a receptacle (4) at the stern end, a drive unit (3) which fits into the receptacle (4) at the stern end in a positively locking manner, and a gap (6) on the underwater surface between the hull component (2) and the drive unit (3), wherein an overlap (8) which covers the gap (6) at least in some sections is arranged on an underwater surface (7) of the hull component (2).

The invention relates to an inflatable surfboard having a hull component (2) with a receptacle (4) at the stern end, a drive unit (3) which fits into the receptacle (4) at the stern end in a positively locking manner, and a gap (6) on the underwater surface between the hull component (2) and the drive unit (3), wherein an overlap (8) which covers the gap (6) at least in some sections is arranged on an underwater surface (7) of the hull component (2).

A method of forming a surf craft includes: providing a bottom section including a surface thereon, wherein at least a portion of the bottom surface section defines a bottom portion of a channel formed on a bottom surface of the surf craft; joining a first side section with the bottom section, the first side section having a shaped wall portion defining a first side wall of the channel formed on the bottom surface of the surf craft; joining a second side section with the bottom section, the second side section having a shaped wall portion defining a second side wall of the channel formed on the bottom surface of the surf craft, the second side wall being opposed to the first side wall; and shaping one or more outer edges of the bottom section, first side section, and second side section into a desired shape of the surf craft.

A method of forming a surf craft includes: providing a bottom section including a surface thereon, wherein at least a portion of the bottom surface section defines a bottom portion of a channel formed on a bottom surface of the surf craft; joining a first side section with the bottom section, the first side section having a shaped wall portion defining a first side wall of the channel formed on the bottom surface of the surf craft; joining a second side section with the bottom section, the second side section having a shaped wall portion defining a second side wall of the channel formed on the bottom surface of the surf craft, the second side wall being opposed to the first side wall; and shaping one or more outer edges of the bottom section, first side section, and second side section into a desired shape of the surf craft.

Embodiments of water activity board 10 that may be configured with several components 210A-H to form a WABS 200, where the components 210A-H may be securely and removably coupled to the board 10 via one or more rail modules 100A-I. Other embodiments may be described and claimed.

Closed cell chitin foam is provided. The closed-cell chitin foam composition does not absorb water, is biodegradable, and is mechanically characterized by a density range of 16 to 800 kg/m3, closed-cell pore sizes ranging from 50 microns to 1 mm, an elastic modulus of 3 to 175 MPa, and a tensile strength of 0.15 to 6.5 MPa. The chitin is at least 70% acetylated. In one aspect, the foam is enclosed in a shell e.g. in the form of a surfboard. Chitin foam according to this invention is fully biodegradable. The chitin foam overcomes the current problems with foams that contain polyurethane and polystyrene, and which are manufactured from petroleum-based sources. Petroleum based foams are not renewable, have an adverse impact on our environment, and pose significant health hazards to those who manufacture them. The chitin foam with its water-based manufacturing process and naturally sourced chitin, solves these problems.

A watersport board includes a board body, two female fasteners, a baseplate, a fin adapter, a fin and two male fasteners. The board body defines a receptacle. The female fasteners are embedded in the board body. Each female fastener has a receiving hole. The baseplate is attached underneath the board body. The baseplate has a first bore and two second bores. The fin adapter has an adapter body and an extension laterally extending from the adapter body. The adapter body passes through the first bore of the baseplate and is engaged in the receptacle of the board body, and the adapter body has a cavity. The fin has a base portion received in the cavity of the adapter body. Each male fastener has one end connected to the extension of the fin adapter, and the other end passing through the second bore of the baseplate and being engaged in the receiving hole of the female fastener.

A fin mounting assembly having a fin box and a cover plate. The fin mounting assembly has a fin box with an upper end that is substantially closed and a lower end that is open with an outer edge. An elongated recess is disposed substantially central along a first axis of the fin box that is adapted to receive and secure a base of a fin. The upper end of the fin box has a flange with an outer border. The flange has a gradually increasing wall height curvature along the first axis, beginning adjacent to the outer edge of the flange and a greatest wall height curvature at a flange central portion. The flange also has a slot cover wall that extends up and away from the flange along the first axis and positioned over the elongated recess. The slot cover wall has an increasing width thickness beginning at the outer edge of the flange that increases in width and has a largest width at a slot cover central portion. A cover plate has an outer border and is adapted to be attached to the outer edge of the fin box.