An azimuth thruster system includes a pod configured to rotate relative the hull of the ship about an azimuthal axis of the pod, a propeller shaft extending from the pod and being configured to rotate relative to the pod about a central axis of the propeller shaft, an outer shaft disposed at least partially in the pod and configured to be driven by a first primary prime mover, an inner shaft disposed at least partially within the outer shaft and configured to be driven by a second primary prime mover, and a pod gear unit disposed within the pod and coupled to the outer shaft, the inner shaft, and the propeller shaft. The outer and inner shafts are configured to rotate at least one of the pod and the propeller shaft based on directions and magnitudes of the torques generated by the first and second primary prime movers.

An electric propulsion system is described that includes at least one branch for distributing electrical power, provided by a power source, to one or more loads. The at least one branch is partitioned into one or more zones and comprises a plurality of branch isolation devices that are configured to isolate the at least one branch from the power source in response to a fault current at the at least one branch. In addition, the at least one branch comprises a respective pair of zone isolation devices for each respective zone from the one or more zones. The respective pair of zone isolation devices for each respective zone is configured to isolate the respective zone from the at least one branch, during a test of the at least one branch for identifying which of the one or more zones is a source of the fault current.

An electric propulsion system is described that includes at least one branch for distributing electrical power, provided by a power source, to one or more loads. The at least one branch is partitioned into one or more zones and comprises a plurality of branch isolation devices that are configured to isolate the at least one branch from the power source in response to a fault current at the at least one branch. In addition, the at least one branch comprises a respective pair of zone isolation devices for each respective zone from the one or more zones. The respective pair of zone isolation devices for each respective zone is configured to isolate the respective zone from the at least one branch, during a test of the at least one branch for identifying which of the one or more zones is a source of the fault current.

A system for providing marine propulsion is provided including an input shaft driven by a prime mover, a pinion gear coupled to the input shaft, a plurality of planet gears coupled to the pinion gear, a planet carrier having the plurality of planet gears rotationally mounted thereto, and a ring gear surrounding the planet gears and coupled thereto. The planet carrier and ring gear are coupled to internal and external output shafts that are coaxially aligned, which are coupled to aft and forward propulsor elements. The ring gear and planet carrier rotate in opposite directions to provide contra-rotating forward and aft propulsor elements. The ring gear and planet gear are each coupled to rotation altering devices that, when at least one is activated, the rotation of both the planet carrier and ring gear will be altered, thereby altering the rotation of the propulsor elements.

A marine vessel includes a hull, an operator station having an operator interface configured to receive a mode input and a lever position input, a left propulsion system, a right propulsion system, and a control module. Each of the propulsion systems includes an engine, a transmission, a troll valve configured to adjust clutch slip, a shaft, a shaft speed sensor configured to detect the speed of rotation of the shaft, and a propeller. The control module is configured to receive the mode input and the lever position input from the operator interface, receive signals from the left shaft sensor indicating a left shaft speed, receive signals from the right shaft sensor indicating a right shaft speed, determine if the vessel is operating in a trolling state, and determine if a sync mode is active, based on the mode input. If the sync mode is active and the vessel is in a trolling state, the speed of the left shaft and the right shaft are synchronized.

A marine vessel includes a hull, an operator station having an operator interface configured to receive a mode input and a lever position input, a left propulsion system, a right propulsion system, and a control module. Each of the propulsion systems includes an engine, a transmission, a troll valve configured to adjust clutch slip, a shaft, a shaft speed sensor configured to detect the speed of rotation of the shaft, and a propeller. The control module is configured to receive the mode input and the lever position input from the operator interface, receive signals from the left shaft sensor indicating a left shaft speed, receive signals from the right shaft sensor indicating a right shaft speed, determine if the vessel is operating in a trolling state, and determine if a sync mode is active, based on the mode input. If the sync mode is active and the vessel is in a trolling state, the speed of the left shaft and the right shaft are synchronized.

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.

The control method of a ship is used for the ship. The ship is equipped with a plurality of power sources including a first power source and a second power source, and has a plurality of propulsion modes in which a power source used for propulsion of a hull is different between the plurality of power sources. The control method of the ship includes adjusting an output value related to a propulsive force of a hull to a value corresponding to an operation amount of an operation acceptor and changing a correspondence relation between the operation amount and the output value in accordance with a propulsion mode.

The control method of a ship is used for the ship. The ship is equipped with a plurality of power sources including a first power source and a second power source, and has a plurality of propulsion modes in which a power source used for propulsion of a hull is different between the plurality of power sources. The control method of the ship includes adjusting an output value related to a propulsive force of a hull to a value corresponding to an operation amount of an operation acceptor and changing a correspondence relation between the operation amount and the output value in accordance with a propulsion mode.