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.

In one embodiment, a system for steering a marine vessel includes a first marine drive having a first engine control module and a second marine drive having a second engine control module, where the first and second marine drives are connected by a mechanical link. A first steer-by-wire steering actuator is configured to rotate the first and second marine drives to steer the marine vessel, and a first actuator control module controls the first steer-by-wire steering actuator. The system operates such that the first actuator control module activates the first steer-by-wire steering actuator if either the first marine drive or the second marine drive is running.

In one embodiment, a system for steering a marine vessel includes a first marine drive having a first engine control module and a second marine drive having a second engine control module, where the first and second marine drives are connected by a mechanical link. A first steer-by-wire steering actuator is configured to rotate the first and second marine drives to steer the marine vessel, and a first actuator control module controls the first steer-by-wire steering actuator. The system operates such that the first actuator control module activates the first steer-by-wire steering actuator if either the first marine drive or the second marine drive is running.

An embodiment of a system for controlling a marine vessel includes an electrical power steering unit coupled to a mechanical control system, the mechanical control system including a steering wheel connected by a shaft to a mechanical cable assembly, the mechanical cable assembly configured to be actuated by the steering wheel to control a steering mechanism of the marine vessel. The electrical power steering unit includes an electric motor configured to apply a torque to the mechanical cable assembly. The system also includes a processor configured to control the electrical power steering unit to provide at least one of steering assist and control of the marine vessel.

An embodiment of a system for controlling a marine vessel includes a torque and/or position sensor configured to measure at least one of a torque applied by a steering wheel of the marine vessel and a rotational position of the steering wheel, and a processing device configured to receive a measurement of the steering wheel and electronically control a steering mechanism at a stern region of the marine vessel. The processing device is configured to estimate an angle of the steering wheel, determine a corresponding angle to be applied to the steering mechanism, and transmit a steering command based on the corresponding angle to an actuation device at the stern region.

An embodiment of a system for controlling a marine vessel includes a torque and/or position sensor configured to measure at least one of a torque applied by a steering wheel of the marine vessel and a rotational position of the steering wheel, and a processing device configured to receive a measurement of the steering wheel and electronically control a steering mechanism at a stern region of the marine vessel. The processing device is configured to estimate an angle of the steering wheel, determine a corresponding angle to be applied to the steering mechanism, and transmit a steering command based on the corresponding angle to an actuation device at the stern region.

A traction control system is for a marine vessel. The traction control system comprises a first internal combustion engine that causes rotation of a first propulsor to thereby propel the marine vessel in the water. A second internal combustion engine causes rotation of a second propulsor to thereby propel the marine vessel in water. A sensor senses a change in operation of the first internal combustion engine that is indicative of a loss of traction between the first propulsor and the water. A control circuit is programmed to temporarily slow rotation of the first propulsor when the sensor senses the change in operation of the first internal combustion engine, thereby allowing the first propulsor to regain traction with the water. When the control circuit slows rotation, the control circuit is further programmed to temporarily slow rotation of the second internal combustion engine, thereby preventing unintended movement of the marine vessel.

A traction control system is for a marine vessel. The traction control system comprises a first internal combustion engine that causes rotation of a first propulsor to thereby propel the marine vessel in the water. A second internal combustion engine causes rotation of a second propulsor to thereby propel the marine vessel in water. A sensor senses a change in operation of the first internal combustion engine that is indicative of a loss of traction between the first propulsor and the water. A control circuit is programmed to temporarily slow rotation of the first propulsor when the sensor senses the change in operation of the first internal combustion engine, thereby allowing the first propulsor to regain traction with the water. When the control circuit slows rotation, the control circuit is further programmed to temporarily slow rotation of the second internal combustion engine, thereby preventing unintended movement of the marine vessel.

An outboard motor includes a cooling device which includes a supply passage supplying a cooling water taken into a lower unit to a cooling mechanism. A first shaft portion of the connecting mechanism has a cylindrical shape, is provided in an upper part of the lower unit, and has an axis coaxial with the axis of a drive shaft. A second shaft portion has a cylindrical shape, is provided in a lower part of an upper unit, and has an axis coaxial with the axis of the drive shaft. One shaft portion of the first and the second shaft portions is inserted into the other shaft portion to be pivotable relative to the other shaft portion. The drive shaft is inserted into the one shaft portion with a space. A part of the supply passage is formed of the space between the drive shaft and the one shaft portion.