A power supply system for a watercraft includes a first battery, a second battery, and a battery management device. The battery management device connects the first battery to a first engine to supply an electric power from the first battery to start the first engine. The battery management device connects the second battery to a second engine and a third engine to supply an electric power from the second battery to start the second engine and the third engine.

A power supply system for a watercraft includes a first battery, a second battery, and a battery management device. The battery management device connects the first battery to a first engine to supply an electric power from the first battery to start the first engine. The battery management device connects the second battery to a second engine and a third engine to supply an electric power from the second battery to start the second engine and the third engine.

A noise reduction system for a marine vessel having a plurality of marine propulsion devices including a first marine propulsion device and a second marine propulsion device, each of the plurality of marine propulsion devices including a drive source, each of the drive sources operating on a same principle as that of the other drive sources, and including a rotary member. The noise reduction system includes a controller configured to control rotation of the rotary member of the drive source in the second marine propulsion device, to thereby control a phase of a second noise caused thereby, such that a first noise caused by rotation of the rotary member of the drive source in the first marine propulsion device is canceled by the second noise.

A noise reduction system for a marine vessel having a plurality of marine propulsion devices including a first marine propulsion device and a second marine propulsion device, each of the plurality of marine propulsion devices including a drive source, each of the drive sources operating on a same principle as that of the other drive sources, and including a rotary member. The noise reduction system includes a controller configured to control rotation of the rotary member of the drive source in the second marine propulsion device, to thereby control a phase of a second noise caused thereby, such that a first noise caused by rotation of the rotary member of the drive source in the first marine propulsion device is canceled by the second noise.

This disclosure describes flanking rudders, including asymmetrically shaped flanking rudders and methods of manufacturing and using asymmetrically shaped flanking rudders. An exemplary asymmetrically shaped flanking rudder includes an exterior surface having a first shape and an exterior surface having second shape different from the first shape.

This disclosure describes flanking rudders, including asymmetrically shaped flanking rudders and methods of manufacturing and using asymmetrically shaped flanking rudders. An exemplary asymmetrically shaped flanking rudder includes an exterior surface having a first shape and an exterior surface having second shape different from the first shape.

A vessel operation system includes a propulsion apparatus to generate a forward thrust or a backward thrust by output of an engine, a throttle actuator to change a throttle opening degree of the engine, a first operator, a second operator, and a controller. When the propulsion apparatus generates a backward thrust, the controller sets a first target value within a range not more than a first upper limit value in accordance with an operation of the first operator and control the throttle actuator so that the throttle opening degree reaches the first target value. The controller sets a second target value within a range not more than a second upper limit value larger than the first upper limit value in accordance with an operation of the second operator and control the throttle actuator so that the throttle opening degree reaches the second target value.

A vessel operation system includes a propulsion apparatus to generate a forward thrust or a backward thrust by output of an engine, a throttle actuator to change a throttle opening degree of the engine, a first operator, a second operator, and a controller. When the propulsion apparatus generates a backward thrust, the controller sets a first target value within a range not more than a first upper limit value in accordance with an operation of the first operator and control the throttle actuator so that the throttle opening degree reaches the first target value. The controller sets a second target value within a range not more than a second upper limit value larger than the first upper limit value in accordance with an operation of the second operator and control the throttle actuator so that the throttle opening degree reaches the second target value.

A marine power supply system includes a battery unit including a first battery to supply power to a starter that starts an engine, and a second battery to supply power to an electric motor, and a power distributor connected to the first battery and the second battery. The power distributor outputs a demand power amount of power required by the first battery to the first battery, and outputs at least a portion of surplus power to the second battery when a total demand power amount required by the battery unit includes the surplus power.

A marine power supply system includes a battery unit including a first battery to supply power to a starter that starts an engine, and a second battery to supply power to an electric motor, and a power distributor connected to the first battery and the second battery. The power distributor outputs a demand power amount of power required by the first battery to the first battery, and outputs at least a portion of surplus power to the second battery when a total demand power amount required by the battery unit includes the surplus power.