Disclosed are a method and a device for reducing the wave-making resistance and friction force during ship navigation. The device includes a gas-liquid mixing device and a control device that are connected. The gas-liquid mixing device is provided with a water inlet, a gas inlet, a water outlet, and a gas-liquid mixing cavity arranged between the water inlet and the water outlet. Water and gas enter the gas-liquid mixing cavity via the water inlet and the gas inlet respectively, the control device controls gas intake at the gas inlet, and in this process, the water inlet is controlled to intermittently suspend water intake or intermittently implement low-speed water intake or implement continuous low-speed water intake, so that more gas enters the gas-liquid mixing cavity.

A boat hull includes a serrated keel which is utilized to dissipate local energy and increase efficiency by reducing drag. In one embodiment, the boat hull preferably includes serrations which are teardrop shaped with a ratio of 3 to 1 in that the length of the teardrop cutout is 3 times the depth.

An arrangement for reducing resistance to the advance of a vessel its navigation includes:

at least one rotating body of revolution attached to the vessel by support and draft control means associated with its longitudinal rotation axis which is arranged perpendicular to the direction of advance of said vessel, and associated with driving means, the at least one rotating body of revolution located in front of the bow or behind the stern of said vessel. The rotation of rotating body of revolution is synchronized with the vessel’s forward speed. The rotating body of revolution closest to the hull of the vessel is separated from the hull by a clearance of approximately 5% or less of its maximum diameter. The support and draft control means are forks associated with pistons and maintain the rotating body of revolution submerged in the order of 30% of its maximum diameter during navigation.

A system includes an outboard motor, an actuator, a pitch angle sensor, a trim angle sensor, and a controller to obtain at least either of a pitch angle of a watercraft and an angular velocity of the pitch angle, and to obtain a trim angle of the outboard motor. The controller is configured or programmed to selectively set either a trim-up direction or a trim-down direction as a trim direction based on the trim angle of the outboard motor and at least either of the pitch angle of the watercraft and the angular velocity of the pitch angle. The controller is configured or programmed to control the actuator to cause the outboard motor to perform a trim motion in the trim direction.

A system includes an outboard motor including a lift actuator, a pitch angle sensor, a lift position sensor, and a controller configured or programmed to obtain at least either of a pitch angle of a watercraft and an angular velocity of the pitch angle. The controller is configured or programmed to obtain a lift position of the outboard motor, and controller selectively set either a lift-up direction or a lift-down direction as a lift direction based on the lift position of the outboard motor and at least either of the pitch angle of the watercraft and the angular velocity of the pitch angle. The controller is configured or programmed to control the lift actuator to cause the outboard motor to perform a lift motion in the lift direction.

A system includes an outboard motor, a lift actuator, a sensor, and a controller. The sensor detects motion information indicating an up-and-down directional motion of a bow of a watercraft. The controller is configured or programmed to selectively set either a lift-up direction or a lift-down direction as a lift direction in accordance with the up-and-down directional motion of the bow based on the motion information. The controller is configured or programmed to control the lift actuator to cause the outboard motor to perform the lift motion in the lift direction, and set a duration of the lift motion to be different between when the outboard motor is caused to perform the lift motion in the lift-up direction and when the outboard motor is caused to perform the lift motion in the lift-down direction.

A system includes an outboard motor, an actuator, a sensor, and a controller. The sensor detects motion information indicating an up-and-down directional motion of a bow of a watercraft. The controller is configured or programmed to selectively set either a trim-up direction or a trim-down direction as a trim direction in accordance with the up-and-down directional motion of the bow based on the motion information. The controller is configured or programmed to control the actuator to cause the outboard motor to perform a trim motion in the trim direction, and to set a duration of the trim motion to be different between when the outboard motor is caused to perform the trim motion in the trim-up direction and when the outboard motor is caused to perform the trim motion in the trim-down direction.

The present invention provides a nose cone system that comprises an inflatable body, a plurality of retainer ribs, a retainer trough positioned below the inflatable body, a plurality of winches attached along the outer surface of the retainer trough, and a plurality of winch straps with which to pull in the inflatable body as it is deflated while holding it in place, in coordination with the winch.

The present invention relates to a fluid resistance reduction apparatus for a ship, and more particularly, to an apparatus for reducing fluid resistance of a ship, the apparatus capable of significantly reducing wave-making resistance as well as frictional resistance caused by seawater during navigation of a ship, thus improving the speed, allowing stable navigation, and saving fuel, wherein the fluid resistance reduction apparatus is disposed below the draft line of the hull and allows the ship to proceed while seawater is introduced through the bow due to rotation of a propeller disposed on the hull and is discharged through the back of the stern, thereby significantly reducing frictional resistance and wave-making resistance of seawater.

An air supply apparatus for a ship is described. The air supply apparatus includes a first turbocharger having a first compressor and a first turbine being drivable by exhaust gas provided from one or more engines. The first compressor is coupled to the first turbine via a transmission configured for changing a speed of the first compressor. Additionally, the air supply apparatus includes an air lubrication device for resistance reduction of the ship. The first compressor is connected with the air lubrication device for supplying air to the air lubrication device.