A marine vessel hull, and marine vessels comprising at least one such hue, comprising a non-entrapment hull having at least one longitudinally vented transverse step, each longitudinally vented transverse step comprising a transverse step, and one or.sup.- more longitudinal steps extending forward therefrom. Each longitudinal step portion has a cross-sectional profile defining a cutout into the hull relative to a line defined by a deadrise angle of the hull. The cutout defines a vertical rise starting from the line defined by the deadrise angle and a run tilted outwardly upward at a non-horizontal angle less than the deadrise angle and that extends to an intersection with the line defined by the deadrise angle.

A marine vessel hull, and marine vessels comprising at least one such hue, comprising a non-entrapment hull having at least one longitudinally vented transverse step, each longitudinally vented transverse step comprising a transverse step, and one or.sup.- more longitudinal steps extending forward therefrom. Each longitudinal step portion has a cross-sectional profile defining a cutout into the hull relative to a line defined by a deadrise angle of the hull. The cutout defines a vertical rise starting from the line defined by the deadrise angle and a run tilted outwardly upward at a non-horizontal angle less than the deadrise angle and that extends to an intersection with the line defined by the deadrise angle.

A ship hull microbubble system is adapted to reduce drag on a ship hull traveling through water. The ship hull microbubble system includes a ballast pump, mechanically coupled to a ballast main pipe which is further connected to a forward peak tank with a forward peak tank valve. A venturi injector is joined to the ballast main pipe with a riser pipe. A discharge pipe is joined to the venturi injector and further piercing the ship hull. An air water mixture is formed when water pulled into the ballast pump receives air from the venturi injector. Discharging the air water mixture through the discharge pipe creates a plurality of microbubbles against the ship hull that reduces the drag on the ship hull when travelling through water.

A ship hull microbubble system is adapted to reduce drag on a ship hull traveling through water. The ship hull microbubble system includes a ballast pump, mechanically coupled to a ballast main pipe which is further connected to a forward peak tank with a forward peak tank valve. A venturi injector is joined to the ballast main pipe with a riser pipe. A discharge pipe is joined to the venturi injector and further piercing the ship hull. An air water mixture is formed when water pulled into the ballast pump receives air from the venturi injector. Discharging the air water mixture through the discharge pipe creates a plurality of microbubbles against the ship hull that reduces the drag on the ship hull when travelling through water.

A system for reducing drag on a marine vessel (2) comprising a plurality of outlets (4) provided in the hull of the vessel (2) for delivering a layer of air bubbles between at least a portion of the hull and the water: at least one venturi tube (6) adapted to supply air and water to one or more of said plurality of air outlets (4): at least one seawater inlet (8) located in the bow region of the vessel (2) adapted to supply seawater to the at least one venturi tube (6) as the vessel (2) moves through the water: at least one seawater pump (10) adapted to supply seawater to the at least one venturi tube (6): at least one ambient air inlet port (16) adapted to supply ambient air to the at least one venturi tube (6) such that ambient air is entrained into sea water flowing through the at least one venturi tube (6): a compressor (18) supplying compressed air to the at least one venturi tube (6): a controller adapted to regulate the flow rate of sea water supplied from the at least one seawater pump and to regulate the supply of compressed air from the compressor to optimise the delivery of air bubbles through the plurality of outlets in the hull and thereby optimise drag reduction of the vessel.

A system for reducing drag on a marine vessel (2) comprising a plurality of outlets (4) provided in the hull of the vessel (2) for delivering a layer of air bubbles between at least a portion of the hull and the water: at least one venturi tube (6) adapted to supply air and water to one or more of said plurality of air outlets (4): at least one seawater inlet (8) located in the bow region of the vessel (2) adapted to supply seawater to the at least one venturi tube (6) as the vessel (2) moves through the water: at least one seawater pump (10) adapted to supply seawater to the at least one venturi tube (6): at least one ambient air inlet port (16) adapted to supply ambient air to the at least one venturi tube (6) such that ambient air is entrained into sea water flowing through the at least one venturi tube (6): a compressor (18) supplying compressed air to the at least one venturi tube (6): a controller adapted to regulate the flow rate of sea water supplied from the at least one seawater pump and to regulate the supply of compressed air from the compressor to optimise the delivery of air bubbles through the plurality of outlets in the hull and thereby optimise drag reduction of the vessel.

An air supply system applicable to an air layer drag reduction ship includes an air tank and a cooling assembly. The air tank is provided with an air outlet pipeline and multiple air inlet pipelines. The air outlet pipeline and the air inlet pipelines are each provided with a first monitoring assembly and a first remote control valve. The cooling assembly is disposed inside the air tank and includes a liquid inlet pipe and a liquid outlet pipe, where the liquid outlet pipe is provided with a second monitoring assembly, the liquid inlet pipe is provided with a second remote control valve, and the second monitoring assembly and the first monitoring assembly are communicatively connected to the second remote control valve. The air supply system is capable of supplying stable and low-temperature air.

An air supply system applicable to an air layer drag reduction ship includes an air tank and a cooling assembly. The air tank is provided with an air outlet pipeline and multiple air inlet pipelines. The air outlet pipeline and the air inlet pipelines are each provided with a first monitoring assembly and a first remote control valve. The cooling assembly is disposed inside the air tank and includes a liquid inlet pipe and a liquid outlet pipe, where the liquid outlet pipe is provided with a second monitoring assembly, the liquid inlet pipe is provided with a second remote control valve, and the second monitoring assembly and the first monitoring assembly are communicatively connected to the second remote control valve. The air supply system is capable of supplying stable and low-temperature air.

A combined disc-type cavitation structure for underwater navigation of an underwater vehicle has an underwater vehicle and a fairing. A plurality of cavitators having sequentially increased outer diameters are sequentially arranged in the fairing. A cavitator receiving groove matched with the cavitator located on the front side is arranged in the center of the front surface of the cavitator located on the rear side in every two adjacent cavitators. The plurality of cavitators can be integrated into a whole by means of the cavitator receiving groove. The cavitator located at the front-most end is a first cavitator, and the remaining cavitators are second cavitators. The first cavitator is connected to the underwater vehicle by means of a buffer. Each second cavitator is respectively connected to the underwater vehicle by means of a driving device configured to axially move the corresponding second cavitator.

A combined disc-type cavitation structure for underwater navigation of an underwater vehicle has an underwater vehicle and a fairing. A plurality of cavitators having sequentially increased outer diameters are sequentially arranged in the fairing. A cavitator receiving groove matched with the cavitator located on the front side is arranged in the center of the front surface of the cavitator located on the rear side in every two adjacent cavitators. The plurality of cavitators can be integrated into a whole by means of the cavitator receiving groove. The cavitator located at the front-most end is a first cavitator, and the remaining cavitators are second cavitators. The first cavitator is connected to the underwater vehicle by means of a buffer. Each second cavitator is respectively connected to the underwater vehicle by means of a driving device configured to axially move the corresponding second cavitator.