A methane transportation system is provided. The system may include a methane source configured to dispense methane at a first location, and an underwater vehicle. The underwater vehicle may include a propulsion system configured to transport the underwater vehicle underwater from the first location to a second location and a vessel defining a storage chamber configured to receive water and the methane from the methane source. The storage chamber of the vessel may have a pressure exceeding one atmosphere and a temperature during transport from the first location to the second location sufficient to form methane clathrate in the storage chamber. The system may further include a methane receiver configured to receive the methane released from the storage chamber at the second location. Related methods are also provided.

A methane transportation system is provided. The system may include a methane source configured to dispense methane at a first location, and an underwater vehicle. The underwater vehicle may include a propulsion system configured to transport the underwater vehicle underwater from the first location to a second location and a vessel defining a storage chamber configured to receive water and the methane from the methane source. The storage chamber of the vessel may have a pressure exceeding one atmosphere and a temperature during transport from the first location to the second location sufficient to form methane clathrate in the storage chamber. The system may further include a methane receiver configured to receive the methane released from the storage chamber at the second location. Related methods are also provided.

An unmanned underwater vehicle propulsion system includes a turbine engine having a mechanical output, an electrical generator including a mechanical connection to the mechanical output, and an electrical input/output. At least one power bus connects the electrical input/output to one of a motor drive and a motor. A rechargeable energy storage system is connected to the at least one power bus and is configured to provide power to the power bus in at least a first mode and receive power from the power bus in a second mode. A controller is configured to control at least one of the electrical generator, the motor drive, the motor, and the rechargeable energy source.

An unmanned underwater vehicle propulsion system includes a turbine engine having a mechanical output, an electrical generator including a mechanical connection to the mechanical output, and an electrical input/output. At least one power bus connects the electrical input/output to one of a motor drive and a motor. A rechargeable energy storage system is connected to the at least one power bus and is configured to provide power to the power bus in at least a first mode and receive power from the power bus in a second mode. A controller is configured to control at least one of the electrical generator, the motor drive, the motor, and the rechargeable energy source.

A propulsion system for an unmanned underwater vehicle includes at least one fuel storage tank. A plurality of combustors is connected to the at least one fuel storage tank. Each of the combustors is connected to a turbine via a corresponding nozzle. An output shaft is connected to the turbine and configured to output rotational energy from the turbine.

A propulsion system for an unmanned underwater vehicle includes at least one fuel storage tank. A plurality of combustors is connected to the at least one fuel storage tank. Each of the combustors is connected to a turbine via a corresponding nozzle. An output shaft is connected to the turbine and configured to output rotational energy from the turbine.

A propulsion system for an unmanned underwater vehicle includes a turbine engine, a generator mechanically coupled to an output shaft of the turbine engine, an electrical motor mechanically decoupled from the turbine engine and electrically coupled to the generator via a power bus architecture, and a propulsor mechanically coupled to a rotational output of the electrical motor. The power bus architecture includes a pair of AC buses and a DC bus.

A propulsion system for an unmanned underwater vehicle includes a turbine engine, a generator mechanically coupled to an output shaft of the turbine engine, an electrical motor mechanically decoupled from the turbine engine and electrically coupled to the generator via a power bus architecture, and a propulsor mechanically coupled to a rotational output of the electrical motor. The power bus architecture includes a pair of AC buses and a DC bus.

An unmanned underwater vehicle propulsion system includes a turbine engine having a mechanical output, an electrical generator including a mechanical connection to the mechanical output, and an electrical input/output. At least one power bus connects the electrical input/output to one of a motor drive and a motor. A rechargeable energy storage system is connected to the at least one power bus and is configured to provide power to the power bus in at least a first mode and receive power from the power bus in a second mode. A controller is configured to control at least one of the electrical generator, the motor drive, the motor, and the rechargeable energy source.

An unmanned underwater vehicle propulsion system includes a turbine engine having a mechanical output, an electrical generator including a mechanical connection to the mechanical output, and an electrical input/output. At least one power bus connects the electrical input/output to one of a motor drive and a motor. A rechargeable energy storage system is connected to the at least one power bus and is configured to provide power to the power bus in at least a first mode and receive power from the power bus in a second mode. A controller is configured to control at least one of the electrical generator, the motor drive, the motor, and the rechargeable energy source.