A high temperature superconductor (HTS) rotating machine having a longitudinal axis and having a first rotational inertia. There is a cylindrical stator assembly disposed about the longitudinal axis and a cylindrical rotor assembly disposed within the stator assembly. The rotor assembly is configured to rotate within the stator assembly about the longitudinal axis. The rotor assembly includes at least one HTS winding assembly which, in operation, generates a magnetic flux linking the stator assembly. There is a cylindrical electromagnetic shield disposed about the at least one HTS winding assembly having a second rotational inertia. There is a cryogenic cooling system for cooling the at least one superconducting winding assembly of the rotor assembly. The second rotational inertia is at least eighty percent (80%) of the first rotational inertia.

A vessel energy management system for controlling power supply to and from a propulsion system of a vessel, the energy management system has a motor/generator unit adapted to receive power from a prime mover of the vessel; a frequency converter; an energy storage unit and a controller. The energy storage unit includes one or more capacitors, super capacitors or ultra capacitors. The controller of the energy management system determines an instantaneous power requirement of the propulsion system and average power generated by the prime mover; and a comparator compares the instantaneous required power and average power. If the instantaneous required power exceeds the average power, the motor/generator unit receives energy from the energy storage unit; and, if the instantaneous required power is less than the average power, the motor/generator unit supplies power from the prime mover to the energy storage unit.

This invention provides a water craft hull having an air chamber, wherein the sidewalls of the air chamber extend lower than the fore wall and the aft wall of the air chamber, and wherein the hull comprises at least one air injector configured to deliver pressurized air to the air chamber. Optionally, a hull of the invention has a high aspect ratio air chamber defined by a stable fore wall, a stable aft wall, and stable sidewalls, is a non-planing hull, has a wave-piercing bow, and has elongated keel fins (e.g. inner keel fins and/or outer keel fins). Optionally, the air chamber is configured for recirculating air flow.

A sliding surface located to one side in the axial direction relative to the axially central position of a rotary shaft is supported by the slide surface of a supply shaft in a slidable manner in the axial direction, the slide surface being the surface on which sliding occurs. The portion located to the other side in the axial direction side relative to the axially central position of the rotary shaft is fixed to an output shaft. The sliding surface is positioned on the surface of a hard coating, and the hard coating is positioned so as to cover a part of a substrate made of a GFRP. The slide surface is positioned on the surface of a hard coating, and the hard coating is positioned so as to cover a part of a substrate made of a GFRP.

An electric drive shaft is disclosed including at least one speed-variable generator for generating a voltage with a variable amplitude and a variable frequency, and at least one speed-variable drive motor supplied with the voltage. The drive shaft enables repercussions on the voltage during sudden load changes, and therefore the complexity of the regulation for stabilizing the voltage, to be reduced due to the generator including a supraconductor winding, especially a high-temperature supraconductor winding.

A ship drive system includes a first and one second drive shaft for driving a respective propulsion unit, wherein each of the electric drive shafts includes at least one speed-variable generator driven by an internal combustion engine for generating a motor voltage having a variable amplitude and variable frequency, and at least one speed-variable drive motor that is supplied with the voltage and coupled to the propulsion unit. The first and second drive shafts can be switched from a first operating state, in which they are electrically disconnected from each other, to a second operating state, in which they are electrically coupled to each other such energy can be transmitted from the at least one generator of the one drive shaft to the at least one drive motor of the other drive shaft. To this end, the at least one generator includes a superconductor winding.