A positional sensor detects a current position of a boat body and outputs position information indicating the current position. A controller receives the position information. The controller determines a target position of the boat body. The controller calculates the distance between the current position and the target position. The controller determines a target speed of the boat body to reach the target position in accordance with the distance. The controller calculates the force of an outside disturbance. The controller determines a target propulsion force of a propulsion device based on the force of the outside disturbance and the target speed. The controller generates an instruction signal to control the propulsion device to produce the target propulsion force.

An element for use in a watercraft is provided comprising a first rotatable support member mounted on the element such that the position of the first rotatable support member relative to the element can be varied by a user. A floating dock comprising at least one element is also provided.

Disclosed herein is an inflatable watercraft barrier in one example having an inflatable perimeter tube. Also disclosed is a diaphragm sealed to the perimeter tube to form the watercraft barrier between a watercraft and the water in which the watercraft barrier and watercraft float. In one example, a portion of the perimeter tube forms a gate portion which is at least partially selectively deflated so as to be denser than water, and therefore rotates about a gate pivot such that the watercraft may enter the watercraft barrier through the gate portion. Also disclosed is a water pump in fluid communication with the watercraft barrier so as to evacuate water from between the watercraft barrier and the watercraft.

A boat lift is attached to piles driven into the earth or to another object. The boat lift is held in horizontal position relative to piles or the object to which it is attached, but vertical movement of the boat lift relative to the object is permitted. The boat lift is connected to the piles by modular units or cube constructs that have a post extending there through. The post has a blade extending from it. The blades are attached at an angle, according to the application, to pile guides that engage piles. The pile guides vertically traverse the piles, permitting the boat lift to move vertically relative to the object, but fixing the horizontal position of the boat lift.

A roller ball assembly that provides a safe, efficient, unobtrusive and easy to install load conveyance system to facilitate the travel of a watercraft on or off of a floating vessel platform with no or minimal potential of causing damage to the watercraft's hull or to the float modules. The roller ball assembly is comprised of a sphere rotatable with respect to a floating vessel platform. A number of roller ball assemblies can be mounted into a floating vessel platform in the junction areas of float modules.

A loading ramp includes a contoured component with upwardly sloping surfaces and an opening for receiving the hull of a watercraft. The contoured component has a centrally located lower surface relative to the sides and front of the contoured unit. The loading ramp incorporates a way for the loading ramp to attach to a modular floating vessel platform.

A loading ramp includes a contoured component with upwardly sloping surfaces and an opening for receiving the hull of a watercraft. The contoured component has a centrally located lower surface relative to the sides and front of the contoured unit. The loading ramp incorporates a way for the loading ramp to attach to a modular floating vessel platform.

A floating dockable liquefied natural gas supply station, comprising: a main hull, a bottom base and a positioning system. The bottom base comprises a base plate or at least two base plates. The base plate is securely connected to a lower lateral side of the main hull by means of a splicing securing system. Therefore, the main hull and the bottom base of the floating dockable liquefied natural gas supply station can be assembled in a modular manner. It is possible to individually construct the main hull and bottom base of the floating dockable liquefied natural gas supply station, and to then use a modular method for connecting and assembling same on the ocean or on land, thus being able to flexibly form various types and dimensions of supply station, allowing for docking transport vessels accommodating various loading capacities of liquefied natural gas (LNG), and reducing the construction cost thereof.

A roller ball assembly that provides a safe, efficient, unobtrusive and easy to install load conveyance system to facilitate the travel of a watercraft on or off of a floating vessel platform with no or minimal potential of causing damage to the watercraft's hull or to the float modules. The roller ball assembly is comprised of a sphere rotatable with respect to a floating vessel platform. A number of roller ball assemblies can be mounted into a floating vessel platform in the junction areas of float modules.

A loading ramp includes a contoured component with upwardly sloping surfaces and an opening for receiving the hull of a watercraft. The contoured component has a centrally located lower surface relative to the sides and front of the contoured unit. The loading ramp incorporates a way for the loading ramp to attach to a modular floating vessel platform.