A marine propulsion system for a marine vessel includes a marine propulsion device, a plurality of power storage devices, and a charge distribution circuit. The marine propulsion device includes an engine and an alternator driven by the engine to generate a charge current. The plurality of power storage devices includes at least a first power storage device and a second power storage device, wherein each power storage device is configured to receive current from the alternator. The charge distribution circuit is positioned between the alternator and the plurality of power storage devices and includes an isolator configured to isolate the first power storage device from the second power storage device, a charge sensor configured to sense a charge level of the first power storage device, and a relay configured to connect and disconnect the second power storage device to/from the alternator based on the sensed charge level.

An electrical power system for a watercraft including a first electrical power plant configured to operate in a variable frequency mode to output variable frequency power to a first electrical network and a fixed frequency mode to output fixed frequency power to a second electrical network. There is a first electrical load including a first high temperature superconductor (HTS) motor connected to the first electrical network and a second electrical load connected to a second electrical network. A controller selectively connects the first electrical power plant to the first electrical network and operates the first electrical power plant in a variable frequency mode to output variable frequency power to power the first HTS motor and selectively connects the first electrical power plant to the second electrical network and operates the first electrical power plant in a fixed frequency mode to output fixed frequency power to power the second electrical load.

An MV DC electrical energy distribution system includes two or more MV DC buses, coupled together in normal operation by a solid state switch. Each MV DC bus is adapted to be electrically coupled to one or more consumers. Each MV DC bus is coupled to one or more MV DC energy storage devices. The MV DC energy storage devices each have a plurality of LV energy storage stacks connected together in series. Each MV DC energy storage device uses a power control unit to distribute the power between different MV DC energy storage strings or to control the power of each MV-energy storage devices individually.

Wakeboats that include an aquatic invasive species control apparatus are provided. These wakeboats can include: a wakeboat with a hull; at least one throughhull fitting in the hull of the wakeboat; an irradiation chamber in fluid communication with the at least one throughhull fitting, the irradiation chamber having a radiation source; and at least one water destination aboard the wakeboat. Methods for irradiating invasive aquatic species aboard a wakeboat are also provided. The methods can include: receiving water from outside the wakeboat hull; and irradiating water aboard the wakeboat prior to discharging the water.

A vessel power supply system for a vessel including a propulsion device that includes an engine and a generator driven by the engine to generate electricity, includes a first battery that supplies power to the propulsion device, a second battery that supplies power to accessories of the vessel, a first open circuit voltage sensor that detects an open circuit voltage of the first battery, a second open circuit voltage sensor that detects an open circuit voltage of the second battery, and a switch that is turned on/off to open and close a current path between the first battery and the second battery.

A vessel power supply system for a vessel including a propulsion device that includes an engine and a generator driven by the engine to generate electricity, includes a first battery that supplies power to the propulsion device, a second battery that supplies power to accessories of the vessel, a first open circuit voltage sensor that detects an open circuit voltage of the first battery, a second open circuit voltage sensor that detects an open circuit voltage of the second battery, and a switch that is turned on/off to open and close a current path between the first battery and the second battery.

A drive arrangement for a cycloidal marine propulsion unit including at least two electrical blade motors each associated to a respective blade for pivoting thereof, each blade motor being operationally coupled to a respective blade drive for actuating the corresponding blade motor. The at least two blade drives each include a respective blade drive power converter operationally coupled to a first common intermediate DC-link, wherein the at least two blade drives being configured to feed power from the first common intermediate DC-link to their respective blade motors, and to feed regenerative power from their respective blade motors to the first common intermediate DC-link. The disclosure also concerns a marine propulsion unit having such a drive arrangement, and a method of operating such a drive arrangement.

A marine AC generator system includes a marine generator driven by an internal combustion engine and configured to generate an AC current and a rectifier configured to rectify the AC current to provide a DC current. At least one battery is configured to receive and be charged by the DC current. A battery powered inverter is configured to be powered by the at least one battery and to generate a variable current output frequency such that an AC electrical power is provided to a load when the marine generator is not running.

A marine propulsion system includes an engine effectuating rotation of an output shaft, a battery, an alternator having a rotor driven into rotation by the output shaft and that is configured to generate a charge output to the battery, a battery state of charge sensor configured to measure a battery charge value of the battery, and a control system. This control system is configured to receive a demand value and/or a temperature, receive the battery charge value from the battery state of charge sensor; and control the alternator to adjust the charge output based on at least one of the battery charge value and the demand value and/or temperature.

An electrical power system for a watercraft including a first electrical power plant configured to operate in a variable frequency mode to output variable frequency power to a first electrical network and a fixed frequency mode to output fixed frequency power to a second electrical network. There is a first electrical load including a first high temperature superconductor (HTS) motor connected to the first electrical network and a second electrical load connected to a second electrical network. A controller selectively connects the first electrical power plant to the first electrical network and operates the first electrical power plant in a variable frequency mode to output variable frequency power to power the first HTS motor and selectively connects the first electrical power plant to the second electrical network and operates the first electrical power plant in a fixed frequency mode to output fixed frequency power to power the second electrical load.