A collar assembly for a watercraft includes an elongate tubular casing with a lengthwise sealable opening. A foam core is removably positioned in the tubular casing, and includes a body portion and a plurality of circumferentially spaced foam springs that extend outwardly to engage the tubular casing, to bias the foam core towards a center position in the tubular casing. In some embodiments a body portion of the foam core has a circular cross section, and the foam springs are co-formed with the body portion. In some embodiments the foam core comprises a plurality of longitudinal sections that are enclosed in a membrane having an inflation valve that extends through the tubular casing.

An eco-friendly buoy includes a foam including a cylindrical accommodation space in the interior of the foam, and coupling grooves at predetermined intervals at an outer surface circumference of the foam in order to fasten the foam to fixing members through wire; and a protective layer formed on an entire outer surface of the foam and protecting the foam from damage by waves or wind. The eco-friendly buoy is manufactured from eco-friendly expanded polypropylene and expanded styrene and has a protective layer on an outer surface thereof, thereby being protected from damage by waves or wind. In addition, the eco-friendly buoy may be used for a long time, thus reducing maintenance costs.

A method of manufacturing a boat hull comprising: forming a foam mold of a predetermined shape and size from one or more pieces of foam; cutting, into the foam, at least one C-channel running in a longitudinal or a lateral direction within the foam; and coating the foam with at least one layer of reinforcing fiber and resin.

A wind turbine platform configured to float in a body of water and support a wind turbine thereon includes a buoyant hull platform. A wind turbine tower is centrally mounted on the hull platform and a wind turbine is mounted to the wind turbine tower. An anchor is connected to the hull platform and to the seabed, and a weight-adjustable mass is suspended from the hull platform.

The present invention utilizes the resilient force (i.e. the force to deform when pressure is added and to return to the original shape when the pressure is removed) of an elastic member or bias member. A large pressure if added in advance to the elastic member or bias member disposed in a preserver body to set the preserver body in a thin and flat state. In an emergency, the resilient force of the elastic member or bias member causes water or air to be sucked into the preserver body. The volume of the preserver body is expanded by the air sucked in due to the resilient force of the elastic member or bias member or by gas generated by a chemical reaction between the sucked-in water and a foaming agent. The increased volume causes the preserver body to float, thereby enabling a wearer to breathe.

The presently disclosed subject matter relates to a flotation device suited to teach beginner swimming techniques or provide enjoyment in an aquatic environment while providing flotation to at least a portion of the swimmer's body. The flotation device for aiding a swimmer in a body of water may comprise a body formed from an extruded foam and comprising a top surface, a bottom surface, a first side rail, a second side rail, a leading lateral surface, and a trailing lateral surface, and wherein the extruded foam is a flexible cellular foam. The presently disclosed subject matter also relates to methods of making the flotation device.

An improved swim noodle system is described. The system has a first interlocking swim noodle including a first central core defining a first longitudinal axis coaxial with the first central core and a first periphery disposed about the first central core. The first elongated swim noodle further comprises alternating nodes and alcoves disposed about an entirety of the first periphery. The first nodes diverge outwardly from the first central core and extend longitudinally generally parallel to the first longitudinal axis. The first alcoves converge outwardly from the first central core and extend longitudinally generally parallel to the first longitudinal axis. The first nodes and the first alcoves are arranged to mate by resistance fit with the second elongated swim noodle.

A method of manufacturing a submersible vessel, the method comprising: forming a foam mold of a predetermined shape and size from at least a first piece of foam having a first density and at least a second piece of foam having a second density; cutting at least one channel into the foam running in a longitudinal direction or a lateral direction within the foam; and coating the foam with at least one layer of reinforcing fiber and resin.