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 molded boat with a seat drain. The boat includes a molded hull having been molded using a first material to cause the boat to have a front portion and a rear portion. The boat is molded with a bench, having been molded together with the hull using the first material. The bench includes a drain hole formed through, an otherwise solid face of the bench allowing water to flow from the front portion of the boat to the rear portion of the boat, wherein the drain hole formed through the bench is formed by using a tube molded into, and under the bench, the tube comprising a material having a higher melting point than the first material.

A hull for a personal watercraft includes a compression-molded hull body. A main portion of the hull body includes a thermoplastic material embedded with non-directional chopped glass fibers. The main portion extends along an entirety of the length and of the width of the hull body. Port and starboard portions of the hull body include the thermoplastic material embedded with directional glass fibers. The directional glass fibers include longitudinally-oriented glass fibers. A majority of the longitudinally-oriented glass fibers have a length at least ten times greater than a mean length of the chopped glass fibers. The port and starboard portions extend vertically from proximate an upper edge of the hull towards a keel, and longitudinally along at least 50% of the length of the hull body.

In one example, a watercraft includes a hull in the form of a unitary, single-piece structure that is substantially hollow, and made of plastic. A grip is provided that is integral with the hull and includes a recess that is formed in a skin of the hull and is integral with the hull, and the grip also includes an undercut that is formed in the skin of the hull proximate an edge of the recess. The undercut is integral with the hull and communicates with the recess.

There is provided an assembleable boat made of fiber-reinforced plastic (FRP) including a bottom wall assembly; a left side wall assembly; a right side wall assembly; and a front wall assembly. the bottom wall assembly, the back wall assembly, the left side wall assembly, the right wall assembly, and the front wall assembly are mechanically connected to form the assembleable boat; and each of the bottom wall assembly, the left side wall assembly, the right wall assembly, and the front wall assembly is made of FRP.

Apparatus and associated methods relate to using an additive (material deposition) process to incrementally form a closed-cell lattice structure formed as a unitary body in the shape of a marine hull cavity, the unit cells of the closed-cell lattice structure are substantially hollow. In an illustrative example, a method may include (a) forming a closed-cell lattice structure through additive manufacture, the hull cavity material may be bonded to an upper manufactured liner and a lower manufactured liner through lamination or mechanical connection. Unit cells of the closed-cell lattice structure may include hollow voids filled with gases. Providing the additive manufactured closed-cell lattice structure with a unitary body and hollow voids to trap gases may further advantageously promote the buoyancy and reduce the degeneration of a marine hull.

Personal watercraft and personal watercraft fabrication using a thermoforming process are described. The personal watercraft manufacturing process includes a set of molds, thermoforming equipment, and thermal formable materials. The process greatly reduces manufacturing costs, decreases manufacturing time, increases part consistency and tolerances, offers better performance characteristics and durability and results in less environmentally harmful deposits and waste.

Personal watercraft and personal watercraft fabrication using a thermoforming process are described. The personal watercraft manufacturing process includes a set of molds, thermoforming equipment, and thermal formable materials. The process greatly reduces manufacturing costs, decreases manufacturing time, increases part consistency and tolerances, offers better performance characteristics and durability and results in less environmentally harmful deposits and waste.

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.