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.

A training device for balancing on boards is provided. The training device may be particularly suitable for the young, those with low body mass, or those lacking sufficient strength to enable them to stand on wakesurf boards and participate in the pastime of wakesurfing. A wakesurf board training device is disclosed that may include a pair of heel supports, each heel support having a main body configured to be secured to a wakesurf board, and the main body including a heel receptacle configured to receive a heel of a user of the wakesurf board, such that the heel receptacle provides lateral support to the heel of the user of the wakesurf board. A wakesurf board training device kit, and a wakesurf board system are also disclosed.

A training device for balancing on boards is provided. The training device may be particularly suitable for the young, those with low body mass, or those lacking sufficient strength to enable them to stand on wakesurf boards and participate in the pastime of wakesurfing. A wakesurf board training device is disclosed that may include a pair of heel supports, each heel support having a main body configured to be secured to a wakesurf board, and the main body including a heel receptacle configured to receive a heel of a user of the wakesurf board, such that the heel receptacle provides lateral support to the heel of the user of the wakesurf board. A wakesurf board training device kit, and a wakesurf board system are also disclosed.

The invention relates to a fiber reinforced structural component, which may be used in a surfboard for stand-up paddling, wave riding, wind surfing and the like, comprising a body made of plastic, wherein the body is delimited by a surface, to which a laminate layer made of a fiber mat and a matrix is undetachably connected. The surface has at least one circumferential groove-shaped recess, by means of which a predetermined partial area of the surface is delimited.

The invention relates to a fiber reinforced structural component, which may be used in a surfboard for stand-up paddling, wave riding, wind surfing and the like, comprising a body made of plastic, wherein the body is delimited by a surface, to which a laminate layer made of a fiber mat and a matrix is undetachably connected. The surface has at least one circumferential groove-shaped recess, by means of which a predetermined partial area of the surface is delimited.

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 surfboard having laterally opposed pairs of axial or lengthwise grooves with the pair forming opposed rails of greater stiffness and reduced mass. At least one of the grooves of each pair is at a board edge extremity and the other groove is nearby, preferably near or on the lower side of the surfboard. The grooves may be laid up with epoxy or fiberglass.

A surfboard having laterally opposed pairs of axial or lengthwise grooves with the pair forming opposed rails of greater stiffness and reduced mass. At least one of the grooves of each pair is at a board edge extremity and the other groove is nearby, preferably near or on the lower side of the surfboard. The grooves may be laid up with epoxy or fiberglass.

A manufacturing method contemplates performing vacuum-assisted resin infusion to enclose an elongated core within a cured composite laminate without employing a mold. Not relying upon an external mold enables the process to be efficiently performed for core shapes that are manufactured in low volumes. Typical resin infusion processes utilize flow media that induces bag bridging during vacuum draw in order to provide gaps facilitating resin flow. However, popular flow media also tends to impart directional aggregate forces during vacuum draw, which forces can deform the core since no mold is being used. To avoid unequal and non-dispersed directional forces from deforming the elongated core, a flow media is employed that is configured to disperse and/or reduce such forces. Some such flow media may be knitted so as to allow overlapping strands to slide over one another. Other flow media may ensure that strands are interleaved so that no one strand or group of strands is disposed outwardly of other strands along a substantial length of the strands, thus dispersing bag bridging forces in several directions and avoiding directional aggregate forces. However, such flow media may have inhibited resin flow relative to popular high-flow flow media, and thus new strategies have been developed to ensure appropriate wetting of fibrous reinforcement. An adjustable brace can also be employed to restrain the elongated core from deflecting during application of vacuum and/or resin infusion.

A personal riding board for aquatic sporting activities. The board includes multiple layers. At least two of the layers include a reinforcement member. The reinforcement members function together similar to a leaf spring to provide the board enhanced flexibility where needed while minimising the risk of breakage.