A vessel propulsion system includes a bow thruster located at a bow of a hull, an outboard motor located on the hull and provided separately from the bow thruster, and a navigation controller. The navigation controller controls at least one of the bow thruster and the outboard motor in accordance with a state of at least one other of the bow thruster and the outboard motor.

A steering assist unit for a tiller handle of an outboard motor includes a housing, a pump, and a hydraulic actuator. The housing is connected to the tiller handle. The pump is housed in the housing. The hydraulic actuator is driven by hydraulic fluid from the pump. The hydraulic actuator applies an assist steering force to the outboard motor.

Virtual anchor features for a navigation/autopilot system for use on a marine vessel are provided herein. An example apparatus associated with a marine vessel includes a processor and memory including computer program code, the memory and the computer program code configured to, with the processor, cause the apparatus to receive user input indicating at least a first geographic location and a desired offset distance; determine a current geographic location of at least one of the marine vessel or the apparatus; determine if the current geographic location is within a distance threshold of the desired offset distance from the first geographic location; and cause, in an instance in which the current geographic location is not within the distance threshold, one or more motors of the marine vessel to operate to cause the marine vessel to move to a new geographic location accordingly. A desired orbit pattern may also be employed.

A method for maintaining a marine vessel at a global position and/or heading includes receiving measurements related to vessel attitude and estimating water roughness conditions based on the measurements. A difference between the vessel's actual global position and the target global position and/or a difference between the vessel's actual heading and the target heading are determined. The method includes calculating a desired linear velocity based on the position difference and/or a desired rotational velocity based on the heading difference. The vessel's actual linear velocity and/or actual rotational velocity are filtered based on the roughness conditions. The method includes determining a difference between the desired linear velocity and the filtered actual linear velocity and/or a difference between the desired rotational velocity and the filtered actual rotational velocity. The method also includes calculating vessel movements that will minimize the linear velocity difference and/or rotational velocity difference and carrying out the calculated movements.

A method controlling a thruster of a marine vehicle is provided. The marine vehicle is at least partially submerged in a liquid and includes a body and a thruster including two propellers. Each propeller includes blades intended to tum about a rotation axis of said propeller. The method includes a step of low-speed maneuver controlling, during which the thruster is controlled in such a way that each propeller generates a flow directed toward the flow generated by the other propeller and reaching the flow generated by the other propeller.

A marine vessel has a hull with a bottom, a bow, a stern, and a propulsion arrangement including at least three propulsion units arranged at the stern of the marine vessel. The marine vessel has a base line and a centerline. The at least three propulsion units include a fixed centerline shaft propulsion unit with a shaft line and a propeller, and two turnable propulsion units with respective propellers and arranged at opposite sides of the fixed centerline shaft propulsion unit for steering of the marine vessel. For improving thrust efficiency, while maintaining optimal steering capability, the propeller of the fixed centerline shaft propulsion unit is arranged at a given distance aft of the stern of the marine vessel.

Retractable thruster system for moving a thruster (1) on a vessel between an extended position, in which the thruster (1) is extended below a hull's bottom, and at least one retracted position, in which the thruster is located above the hull's bottom, the system comprising a canister (2) to which a thruster is mountable, wherein the canister is configured to be movable in a trunk (3) in a vessel's hull structure between said extended position and said at least one retracted position, and in which a rack-and-pinion lifting system is arranged to move the canister (3) in said trunk (3) between said extended position and said at least one retracted position, the lifting system including at least one rack (6) being fixedly connected to the vessel, and a pinion drive (7) including at least one pinion (8) arranged to cooperate with said at least one rack (6), said pinion drive being connected to the canister (2).

A method of operating a thruster apparatus involves causing a first propeller to rotate in response to pressure of a first flow of pressurized hydraulic fluid, and causing a second propeller to rotate in response to pressure of a second flow of pressurized hydraulic fluid separate from the first flow of pressurized hydraulic fluid. Thruster apparatuses are also disclosed.

A method for maintaining a marine vessel at a global position and/or heading includes receiving measurements related to vessel attitude and estimating water roughness conditions based on the measurements. A difference between the vessel's actual global position and the target global position and/or a difference between the vessel's actual heading and the target heading are determined. The method includes calculating a desired linear velocity based on the position difference and/or a desired rotational velocity based on the heading difference. The vessel's actual linear velocity and/or actual rotational velocity are filtered based on the roughness conditions. The method includes determining a difference between the desired linear velocity and the filtered actual linear velocity and/or a difference between the desired rotational velocity and the filtered actual rotational velocity. The method also includes calculating vessel movements that will minimize the linear velocity difference and/or rotational velocity difference and carrying out the calculated movements.

A catamaran oil production apparatus is disclosed for producing oil in a marine environment. The apparatus includes first and second vessels that are spaced apart during use. A first frame spans between the vessels. A second frame spans between the vessels. The frames are spaced apart and connected to the vessels in a configuration that spaces the vessels apart. The first frame connects to the first vessel with a universal joint and to the second vessel with a hinged connection. The second frame connects to the second vessel with a universal joint and to the first vessel with a hinged or pinned connection. At least one of the frames supports an oil production platform. One or more risers or riser pipes extends from the seabed (e.g., at a wellhead) to the production platform (or platforms). In one embodiment, the production apparatus includes crew quarters.