Techniques are disclosed for systems and methods to provide accurate positioning for a hydraulic steering system without a need for a steering reference transducer. A hydraulic steering system may include a logic device in communication with an autopilot pump controller. Control and sensor signals provided by the pump controller are used to determine a linear or uncompensated steering actuator speed and an estimate of the hydraulic elasticity of the steering system, which can be modeled as an estimate of the air volume trapped within the steering system. The hydraulic elasticity/air volume estimate is used to determine a corrected or compensated steering actuator speed, and the corrected steering actuator speed is used to accurately control the steering system.

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.

According to an example aspect of the present invention, there is provided a steering system of an azimuthing propulsion system, the steering system comprising at least one hydraulic motor configured to operate an azimuthing system of a propulsion unit, the propulsion unit being arranged outside a vessel, a fluid cycle from the at least one hydraulic motor via a separate hydraulic overload protection unit and back to the motor, the overload protection unit comprises a pressure relief unit and a heat management unit, and wherein the pressure relief unit comprises a pressure relief valve, and the heat management unit comprises a heat storage, a heat exchanger, or a combination of both, and wherein the fluid cycle comprising the overload protection unit is configured to at least partially absorb heat generated during turning of the propulsion unit.

A steering apparatus comprises a rotatable steering shaft and a sensor which senses angular movement of the steering shaft. An electromagnetic actuator actuates a stop mechanism to releasable engage the steering shaft. There is a microcontroller which causes the electromagnetic actuator to actuate the stop mechanism to fully engage the steering shaft and prevent rotation of the steering shaft in a first rotational direction, which corresponds to movement towards the hardstop position, while allowing rotational play between the steering shaft and the stop mechanism in a second direction, which corresponds to rotational movement away from the hardstop position, when the sensor senses that the steering shaft has reached a hardstop position. A driver applies a reverse polarity pulse to the electromagnetic actuator when the stop mechanism is fully engaged and the steering shaft is rotated, as permitted by the rotational play, in the second rotational direction.

A steering apparatus comprises a rotatable steering shaft and a sensor which senses angular movement of the steering shaft. An electromagnetic actuator actuates a stop mechanism to releasable engage the steering shaft. There is a microcontroller which causes the electromagnetic actuator to actuate the stop mechanism to fully engage the steering shaft and prevent rotation of the steering shaft in a first rotational direction, which corresponds to movement towards the hardstop position, while allowing rotational play between the steering shaft and the stop mechanism in a second direction, which corresponds to rotational movement away from the hardstop position, when the sensor senses that the steering shaft has reached a hardstop position. A driver applies a reverse polarity pulse to the electromagnetic actuator when the stop mechanism is fully engaged and the steering shaft is rotated, as permitted by the rotational play, in the second rotational direction.

A boat includes a planing hull, a propeller, a main rudder, and a pair of flanking rudders. The planing hull has port and starboard sides, a transom, a hull bottom, and a centerline running down the middle of the boat, halfway between the port and starboard sides. The propeller is positioned forward of the transom and beneath the hull bottom. The main rudder is positioned aft of the propeller. The main rudder has a rotation axis about which the main rudder rotates. The flanking rudders are positioned forward of the propeller. One of the flanking rudders is positioned on the port side of the centerline, and the other flanking rudder is positioned on the starboard side of the centerline.

The invention provides a device which can reduce the drag and assist the steering of the ship, mainly to set up a 3-way pipe in the bow where is below the water level. The 3-way pipe leads to three openings at the stem, the port side and the starboard side respectively. At least one control valve (or deflector) can be provided in the 3-way piping system. The valve (or deflector) can be controlled from the bridge, with a diversion device. When the ship sails forward, water flows into the 3-way pipe from the forward pipe, distributed to both side pipes and then outflow, so that it can reduce the pressure drag to the stem, improve the ship's speed and save bunker. When the valve (or deflector) is set as neutral, the water will be distributed evenly to both side pipes, which will not affect the ship's heading. When the valve (or deflector) deflects more water to either side's pipe, the ship will turn to the opposite side.

An outboard propulsion system comprising a first portion for attachment to a boat, wherein the first portion is fixed about a substantially vertical axis, and a second portion connected to the first portion and configured to rotate about a steering axis, wherein the first portion comprises a sealed housing enclosing a member having a longitudinal axis relative to which it may move and the second portion comprises a gear configured to engage with the member such that movement of the member relative to its longitudinal axis generates rotational movement of the gear about the steering axis, and wherein the sealed housing comprises a sensor configured to determine the position of the member within the sealed housing.

An outboard propulsion system comprising a first portion for attachment to a boat, wherein the first portion is fixed about a substantially vertical axis, and a second portion connected to the first portion and configured to rotate about a steering axis, wherein the first portion comprises a sealed housing enclosing a member having a longitudinal axis relative to which it may move and the second portion comprises a gear configured to engage with the member such that movement of the member relative to its longitudinal axis generates rotational movement of the gear about the steering axis, and wherein the sealed housing comprises a sensor configured to determine the position of the member within the sealed housing.