A marine propulsion system includes marine propulsion devices each including a propeller shaft, an engine, an electric motor, a power transmission to transmit mechanical power to the propeller shaft from at least one of the engine and the electric motor, an electric circuit connected to the electric motor, and a controller to control the engine. The controllers in the marine propulsion devices are communicable with each other when in a communicable state. When the controller in each of the marine propulsion devices is in the communicable state, but the controller of one of the marine propulsion devices is incommunicable with any other controller of the marine propulsion devices, the incommunicable controller limits an output of the engine controlled by the incommunicable controller.

A drive source switching system for a marine propulsion device includes a first drive source, a second drive source, a propeller shaft, a first driving member, a second driving member, a first driven member, and a second driven member that are movable in an axial direction of the propeller shaft, and a controller. The first driven member transmits a drive force generated by the first drive source to the propeller shaft when engaged with the first driving member. The second driven member transmits a drive force generated by the second drive source to the propeller shaft when engaged with the second driving member. When the controller moves the first driven member that is not engaged with the first driving member toward the first driving member, the controller moves the first driven member back when the first driven member fails to be engaged with the first driving member.

A system for operating a boat equipped with an electric drive includes a component controller. The component controller includes a component interface for connecting a system component of the electric drive, and a communication interface for connecting the component controller to a system bus of the drive control.

A navigation method for a ship which includes: a plurality of main generators that feed power to navigation equipment used in normal navigation and appliances for the living quarters provided within a ship body; and an emergency generator that feeds power to emergency equipment in case of fire or flood. The navigation method includes: an emergency power feeding step for feeding power to the emergency equipment using the emergency generator when at least one of the plurality of main generators is disabled due to fire or flood; and a return-to-port power feeding step for feeding power to return-to-port equipment, required for navigation for returning to port, using the main generators and the emergency generator after the fire or flood has subsided.

A ship propulsion system provides a first power transmission device that transmits power from an internal combustion engine to a propeller, a second power transmission device that transmits power from an electric motor to a propeller and that is mounted to the hull so as to be able to turn up and down independently from the first power transmission device, an actuator for causing the second power transmission device to turn up and down, and a control device. The control device is configured so as to be able to select a first drive mode in which the internal combustion engine is driven and the electric motor is not driven, and a second drive mode in which the internal combustion engine is not driven and the electric motor is driven. When the first drive mode is selected, the actuator is operated so that the second power transmission device turns up.

A hybrid type vessel propulsion apparatus includes an engine, an electric motor, a propeller shaft that rotates together with a propeller, a first transmission path, a second transmission path, and a third transmission path. The first transmission path transmits power of the engine to the propeller shaft. The second transmission path transmits power of the electric motor to the propeller shaft without transmitting the power through the first transmission path. The third transmission path transmits a portion of the power of the engine, which has been transmitted from the first transmission path to the propeller shaft, to the electric motor in order for the electric motor to generate electricity.

An outboard motor includes an engine, a drive shaft, and a shift shaft disposed forward of the drive shaft. The shift shaft includes a first shift shaft that extends in an upward-downward direction, a second shift shaft disposed below the first shift shaft and spaced apart from and rearward of the first shift shaft, the second shift shaft extending in the upward-downward direction, and a shift force transmission to transmit, to the second shift shaft, a shift force applied to the first shift shaft.

An outboard motor includes an engine, a drive shaft, and a shift shaft disposed forward of the drive shaft. The shift shaft includes a first shift shaft that extends in an upward-downward direction, a second shift shaft disposed below the first shift shaft and spaced apart from and rearward of the first shift shaft, the second shift shaft extending in the upward-downward direction, and a shift force transmission to transmit, to the second shift shaft, a shift force applied to the first shift shaft.

An outboard motor includes an engine, a propeller shaft that rotates together with a propeller and extends in a forward-rearward direction, and a lower case that houses the propeller shaft. The lower case includes a front case and a rear case separate from the front case and positioned rearward of the front case, and the front case and the rear case are assembled to each other.

An outboard motor includes an engine, an electric motor, a propeller that rotates due to a driving force from the engine and a driving force from the electric motor, and an anti-cavitation plate disposed above the propeller. At least a portion of the electric motor is disposed above the anti-cavitation plate and below a waterline of an outboard motor body.