In one example, a method includes positioning, within a mold, a device with a movable element that defines a portion of a volume, and the volume is contained within the mold, as part of a molding process, at least partly defining a molded watercraft by introducing plastic into the mold, disposing the plastic about the movable element, and with the movable element, excluding the plastic from the portion of the volume that is defined by the movable element so as to define a recess and an undercut that are integral with the watercraft and extend lengthwise with respect to a centerline of the watercraft, and the recess and undercut are integral, and communicate, with each other.

In one example, a method includes positioning, within a mold, a device with a movable element that defines a portion of a volume, and the volume is contained within the mold, as part of a molding process, at least partly defining a molded watercraft by introducing plastic into the mold, disposing the plastic about the movable element, and with the movable element, excluding the plastic from the portion of the volume that is defined by the movable element so as to define a recess and an undercut that are integral with the watercraft and extend lengthwise with respect to a centerline of the watercraft, and the recess and undercut are integral, and communicate, with each other.

Fin arrangement for a water sports device, having a base body (1) and a fin (3) which is detachably connected or connectable to the base body (1) via a spring element (2), whereby the base body (1) has a mounting surface (21) for resting against the sliding surface (5) of the main body (4) of the water sports device, and whereby the fin (3) has a recess (24) for receiving at least part of the base body (1). The fin arrangement may be arranged on the sliding surface (5) of the main body (4) of a water sports device.

Fin arrangement for a water sports device, having a base body (1) and a fin (3) which is detachably connected or connectable to the base body (1) via a spring element (2), whereby the base body (1) has a mounting surface (21) for resting against the sliding surface (5) of the main body (4) of the water sports device, and whereby the fin (3) has a recess (24) for receiving at least part of the base body (1). The fin arrangement may be arranged on the sliding surface (5) of the main body (4) of a water sports device.

A foam product includes a foam core, a soft skin covering the foam core, and a base structure on which the foam core is disposed. The foam core of expanded beads has an outer surface on which some outermost beads of the expanded beads are exposed and bulging outward with different heights to form a bubbly texture. The foam skin has an inner surface attached to the outer surface of the foam core, and has at its inner surface a plurality of concave cavities each matedly surrounding a respective one of the bulging, outermost beads on the outer surface of the foam core.

A foam product includes a foam core, a soft skin covering the foam core, and a base structure on which the foam core is disposed. The foam core of expanded beads has an outer surface on which some outermost beads of the expanded beads are exposed and bulging outward with different heights to form a bubbly texture. The foam skin has an inner surface attached to the outer surface of the foam core, and has at its inner surface a plurality of concave cavities each matedly surrounding a respective one of the bulging, outermost beads on the outer surface of the foam core.

Methods of tracing a lengthwise half of a board sports board and applying a substrate film cutout onto the board having the steps of centering a centerline of a tracing scale onto a center of the board, the tracing scale having an off-centerline on both sides of the centerline; aligning a centerline mark of the film with the off-centerline of the tracing scale; flipping the board over such that the board is on top of the film; tracing a trace outline of half of the board onto the film, such that the half of the trace outline is incrementally larger or smaller than the half of the board; removing a release liner from the trace outline to expose an adhesive in the film; wetting the adhesive with a solution of water and liquid soap; flattening the wetted film onto the board with a spreader; and wiping with a wiping cloth.

A surfboard with an electric drive (2), a battery for the electric drive (2), said battery being arranged in a battery housing (3), a first recess (4) for the battery housing (3), and a handle (5) on the battery housing (3), wherein the handle (5) is designed as a bracket handle which is mounted pivotably around a respective centre of rotation (21) at each of the handle ends on opposite sides (6) of the battery housing (3), and in each case a lug (9) protrudes from the base side of the recess below the centres of rotation (21) inside the first recess (4), and at each handle end of the bracket handle a second projection (33) is formed, which has a curved edge (34) and which rests on the lug, and a distance between a contact point of the curved edge (34) with the lug (9).

An improved wooden surfboard and method of construction comprised of pre-cut layers of wood longitudinally arranged of predetermined thicknesses (502-512) stacked and bonded together following the shape of the surfboard. The longitudinal layers include slots (208) to slide and embed multiple transverse ribs (210) in perpendicular direction for joining the longitudinal layers together. The bonded longitudinal layers form a pre-shaped plank with the geometrical features of the surfboard without the need of carving and shaping the surfboard's geometry. A smooth finish is achieved after a light sanding of the pre-shaped plank. In some embodiments the longitudinal layers have predetermined perforations (202) to create air chambers (204) reducing the weight of the surfboard. Other embodiments are as described and shown.

An improved wooden surfboard and method of construction comprised of pre-cut layers of wood longitudinally arranged of predetermined thicknesses (502-512) stacked and bonded together following the shape of the surfboard. The longitudinal layers include slots (208) to slide and embed multiple transverse ribs (210) in perpendicular direction for joining the longitudinal layers together. The bonded longitudinal layers form a pre-shaped plank with the geometrical features of the surfboard without the need of carving and shaping the surfboard's geometry. A smooth finish is achieved after a light sanding of the pre-shaped plank. In some embodiments the longitudinal layers have predetermined perforations (202) to create air chambers (204) reducing the weight of the surfboard. Other embodiments are as described and shown.