A propulsion system includes an electric motor assembly having an electric motor, a driveshaft, and a disconnect clutch. The disconnect clutch is structured to couple the driveshaft to an engine output shaft. The propulsion system further includes a fluid system having a cooling and lubrication fluid circuit fluidly connected to a first pump, and a clutch actuation fluid circuit fluidly connected to a second pump. The cooling and lubrication fluid circuit is fluidly connected to the clutch actuation fluid circuit via at least one of respective pump outgoing conduits from the first pump and the second pump or respective pump supply conduits to the first pump and the second pump. Related operating methodology is also disclosed.

A personal watercraft comprises a body; a driving power source mounted in the body; a water jet pump driven by the driving power source to eject a water jet in a rearward direction; a handle bar gripped by a rider; a rider operation member provided on the handle bar, the rider operation member being operated by the rider to be movable to an acceleration position for providing a forward movement command, a deceleration position for providing a rearward movement command, and a neutral position for providing an idling command, the neutral position being set to a position between the acceleration position and the deceleration position in a movement path of the rider operation member; and a control unit which controls the driving power source in response to the rider's operation for moving the rider operation member.

Disclosed is a method of discharging lubricant oil from a BOG reliquefaction system configured to reliquefy BOG by compressing the BOG by a compressor, cooling the compressed BOG through heat exchange with non-compressed BOG by a heat exchanger, and reducing a pressure of fluid cooled through heat exchange by a pressure reducer. In the lubricant oil discharge method, the compressor comprises at least one oil-lubrication type cylinder and it is determined that it is time to discharge condensed or solidified lubricant oil, if at least one of preset conditions is satisfied.

A propulsion system for a marine vessel includes a transom bracket being configured to be connected with a transom of the marine vessel, and a drive unit. The drive unit is rotatably connected with the transom bracket via a first pivot joint, wherein a harness is guided from the transom bracket via the first pivot joint to the drive unit.

Provided is a ship propelling apparatus including a rotation shaft on which a rear propeller is fixed; a front propeller rotatably supported on the rotation shaft in front of the rear propeller; and a counter-rotating device through which the rotation shaft passes, which includes a gear box including therein a plurality of gears configured to reverse rotation of the rotation shaft and transfer the reversed rotation to the front propeller, and which is installed in an installation space formed at the rear of a ship. The rotation shaft includes a measurement hole formed to pass through a center of the rotation shaft for centering of the counter-rotating device installed in the installation space; and an individual lubricant path separated from the measurement hole.

A marine motor assembly for a watercraft includes a housing, a motor, a housing gearset, a gearcase gearset and a propulsion device. The housing includes an upper housing portion and a gearcase connected to the upper housing portion. The gearcase includes a gearcase chamber, and a gearcase fluid port disposed on an exterior surface of the gearcase. The housing also includes a housing chamber spaced from the gearcase chamber, a housing fluid port that is disposed on an exterior surface of the housing and that is fluidly connected to the housing chamber, and a fluid conduit that fluidly connects the gearcase chamber to the housing chamber. The housing gearset is disposed in the housing chamber. The gearcase gearset is disposed in the gearcase chamber. A method for changing a lubricant in the marine motor assembly via the gearcase fluid port and the housing fluid port is also disclosed.

A watercraft (10) including a board (12), a mast (16) extending below the board, (12) the mast (16) carrying a foil (20) and a propeller (30) that is driven by a motor (32), the motor (32) being carried in a tube (18) connected to or extending from the mast (16), wherein a motor controller (34) is also positioned within the tube (18). In this manner, heat generated by the motor controller during use is dissipated into the water through which the watercraft is travelling. The watercraft (10) may also have a receptacle for holding lubricant, the receptacle being located above the motor, wherein the mast has a conduit that provides fluid communication between the receptacle and the lubricant lubricating the motor and/or driveshaft such that lubricant in the receptacle provides a hydrostatic head of pressure to prevent or minimise water ingress around a propeller seal or a driveshaft seal located adjacent a region where the driveshaft exits into the water.

A propulsion system includes at least one permanent magnet motor, the magnet motor including an outer housing structure. In the housing structure, a stator and a rotor are arranged in such a way that a gap is formed between the stator and rotor, the stator being fixedly connected to the housing structure, while the rotor is connected to a motor shaft extending through the housing structure. A plurality of coils/windings are arranged around an inner circumference of the stator, while a plurality of permanent magnets are arranged around an outer circumference of the rotor. Through a coupling, the motor shaft is connected to a propeller shaft including a propeller. A thrust bearing and a propeller pitch control system are integrated into the permanent magnet motor.

A fluid transportation apparatus includes a first suction pipe having a first intake opening and a second suction pipe having a second intake opening. The first and second suction pipes are attached to a vessel on opposite sides to move in rolling motion. The first intake opening is disposed in a fluid reservoir at a position lower than the second intake opening and a valve device moves toward a maximally opened position for a first proximal end of the first suction pipe and to move toward a maximally closed position for a second proximal end of the second suction pipe, as the first and second suction pipes move with the vessel in a first rolling direction of the rolling motion. The intake openings reverse roles and the proximal ends reverse roles, as the vessel moves in a second rolling direction of the rolling motion opposite from the first rolling direction.

Disclosed is an oil filtration and lubrication system for a sealing system of an azimuth thruster, oil filtration and lubrication system includes oil filter comprising layers of filter material, layers being arranged within oil filtration chamber, have predefined distance therebetween; and oil circulation arrangement, when system is in use, oil circulation arrangement enables passage of unfiltered oil between layers, at flow rate which is less than predefined flow rate, oil filter removes impurities from unfiltered oil, and then filtered oil is passed from oil filter to sealing system of azimuth thruster, by oil circulation arrangement, filtered oil lubricates azimuthing seal, propeller shaft seal, of azimuth thruster, and wherein oil filter is configured to remove impurities from oil, which impurities have a size down to 0.1 micrometre.