An electric actuator comprises a housing and an output shaft reciprocatingly received by the housing. There is a screw assembly disposed within the housing and coupled to the output shaft. The screw assembly includes a plurality of annular rollers and a central screw received by the annular rollers. The annular rollers are rotatable about the central screw. There is a motor which includes a stator and a rotor. The rotor has an inner bore which engages the annular rollers. Rotation of the rotor causes the central screw to translate axially relative to the rotor and the output shaft to reciprocate relative to the housing.

An electric actuator comprises a housing and an output shaft reciprocatingly received by the housing. There is a screw assembly disposed within the housing and coupled to the output shaft. The screw assembly includes a plurality of annular rollers and a central screw received by the annular rollers. The annular rollers are rotatable about the central screw. There is a motor which includes a stator and a rotor. The rotor has an inner bore which engages the annular rollers. Rotation of the rotor causes the central screw to translate axially relative to the rotor and the output shaft to reciprocate relative to the housing.

A maneuvering system for a ship provided with, in the stern, a port-side propulsion system, and a starboard-side propulsion system. For controlling the system, a forward or backward force of the ship 1 is obtained by the difference between the forward and backward propulsion forces of the propulsion systems and a first turning moment in a turning direction of the ship generated by the propulsion forces is offset by a second turning moment in the turning direction of the ship generated by steering a port-side rudder, whereby the ship moves in a transversal manner toward its starboard side while rotation of the ship is avoided. A high degree of maneuverability is thereby achieved with a relatively simple maneuvering operation.

A rudder assembly, including a steering engine; an axial hollow rudder stock; a rudder blade; a gas release unit; and a tiller. The steering engine is disposed in a vessel stern. The tiller is connected to the steering engine. The axial hollow rudder stock includes a through hole. The through hole is small and disposed along the axis of the axial hollow rudder stock. The gas release unit is disposed in the vessel stern, and includes a control cabinet. The control cabinet includes a reagent storage tank, a reagent conveying hose connected to the reagent storage tank, a compressed air bottle, a pressure hose connected to the compressed air bottle, and a console. The pressure hose and the reagent conveying hose pass through the through hole of the axial hollow rudder stock, and then communicate with the cavity of the rudder blade.

A rudder assembly, including a steering engine; an axial hollow rudder stock; a rudder blade; a gas release unit; and a tiller. The steering engine is disposed in a vessel stern. The tiller is connected to the steering engine. The axial hollow rudder stock includes a through hole. The through hole is small and disposed along the axis of the axial hollow rudder stock. The gas release unit is disposed in the vessel stern, and includes a control cabinet. The control cabinet includes a reagent storage tank, a reagent conveying hose connected to the reagent storage tank, a compressed air bottle, a pressure hose connected to the compressed air bottle, and a console. The pressure hose and the reagent conveying hose pass through the through hole of the axial hollow rudder stock, and then communicate with the cavity of the rudder blade.

A steering system for a marine vessel comprises a helm, a control head, and a joystick. The helm and control head may respectively provide user inputted steering commands and user inputted shift and throttle commands on a first CAN network. The joystick and the control head may respectively provide user inputted steering commands and user inputted shift and throttle commands on a second CAN network. The helm may provide user inputted steering commands on the first CAN network. The control head may provide user inputted shift and throttle commands on the second CAN network. The joystick may provide user inputted steering commands and user inputted shift and throttle commands on either the first CAN network or the second CAN network.

A steering system for a marine vessel comprises a helm, a control head, and a joystick. The helm and control head may respectively provide user inputted steering commands and user inputted shift and throttle commands on a first CAN network. The joystick and the control head may respectively provide user inputted steering commands and user inputted shift and throttle commands on a second CAN network. The helm may provide user inputted steering commands on the first CAN network. The control head may provide user inputted shift and throttle commands on the second CAN network. The joystick may provide user inputted steering commands and user inputted shift and throttle commands on either the first CAN network or the second CAN network.

A steering for a marine propulsion unit adjusts at least one of a required steering speed and a required steering torque such that the required steering speed and the required steering torque fall within an output region when the required steering speed and the required steering torque are outside the output region, sets a target steering angle according to the adjusted required steering speed and required steering torque, and sets the target steering angle according to a rotation angle of a steering wheel when the required steering speed and the required steering torque are within the output region.

An electric actuator comprises a housing and an output shaft reciprocatingly received by the housing. There is a screw assembly disposed within the housing and coupled to the output shaft. The screw assembly includes a plurality of annular rollers and a central screw received by the annular rollers. The annular rollers are rotatable about the central screw. There is a motor which includes a stator and a rotor. The rotor has an inner bore which engages the annular rollers. Rotation of the rotor causes the central screw to translate axially relative to the rotor and the output shaft to reciprocate relative to the housing.

An electric actuator comprises a housing and an output shaft reciprocatingly received by the housing. There is a screw assembly disposed within the housing and coupled to the output shaft. The screw assembly includes a plurality of annular rollers and a central screw received by the annular rollers. The annular rollers are rotatable about the central screw. There is a motor which includes a stator and a rotor. The rotor has an inner bore which engages the annular rollers. Rotation of the rotor causes the central screw to translate axially relative to the rotor and the output shaft to reciprocate relative to the housing.