Disclosed are a frictional resistance reducing device that effectively reduces the frictional resistance of a ship, and a ship including same. The frictional resistance reducing device comprises: a first air discharge part formed on the leading undersurface of a ship and discharging air into water; a second air discharge part formed behind the first air discharge part and discharging air into water; and an air supplying source supplying air to the first air discharge part and the second air discharge part, wherein the first air discharge part and the second air discharge part are disposed in-line along the lengthwise direction of the ship, and at least a portion of a first air discharge period of the first air discharge part and at least a portion of a second air discharge period of the second air discharge part overlap each other.

Disclosed are a frictional resistance reducing device that effectively reduces the frictional resistance of a ship, and a ship including same. The frictional resistance reducing device comprises: a first air discharge part formed on the leading undersurface of a ship and discharging air into water; a second air discharge part formed behind the first air discharge part and discharging air into water; and an air supplying source supplying air to the first air discharge part and the second air discharge part, wherein the first air discharge part and the second air discharge part are disposed in-line along the lengthwise direction of the ship, and at least a portion of a first air discharge period of the first air discharge part and at least a portion of a second air discharge period of the second air discharge part overlap each other.

A jet-propelled water-entry composite buffer device for multi-channel gas recycling includes a head fairing, an underwater vehicle, a buffer, a cavitator and a side fairing. The side fairing is internally provided with a fairing body and a sealing choke plate, and a high-pressure gas cavity, a transition cavity and a sub-high-pressure gas cavity are formed by the fairing body and the sealing choke plate from front to back; a quota air pressure valve is disposed on the sealing choke plate; the fairing body is provided with pressure reducing holes; the high-pressure gas cavity, the transition cavity and the sub-high-pressure gas cavity form an gas cushion buffer. Gas acceleration holes communicated with the high-pressure gas cavity are further provided in the outer wall of the side fairing, so that a supercavity can be more favorably formed after the underwater vehicle enters water.

A jet-propelled water-entry composite buffer device for multi-channel gas recycling includes a head fairing, an underwater vehicle, a buffer, a cavitator and a side fairing. The side fairing is internally provided with a fairing body and a sealing choke plate, and a high-pressure gas cavity, a transition cavity and a sub-high-pressure gas cavity are formed by the fairing body and the sealing choke plate from front to back; a quota air pressure valve is disposed on the sealing choke plate; the fairing body is provided with pressure reducing holes; the high-pressure gas cavity, the transition cavity and the sub-high-pressure gas cavity form an gas cushion buffer. Gas acceleration holes communicated with the high-pressure gas cavity are further provided in the outer wall of the side fairing, so that a supercavity can be more favorably formed after the underwater vehicle enters water.

A device for reducing hydrodynamic drag of a vessel including a hull; a fuel cell, and a system of conveyance of a first amount of air discharged by the fuel cell to at least one system of injection included by the hull, the system of injection being configured to inject the first amount of air opposite a surface of the hull intended to be immersed.

A device for reducing hydrodynamic drag of a vessel including a hull; a fuel cell, and a system of conveyance of a first amount of air discharged by the fuel cell to at least one system of injection included by the hull, the system of injection being configured to inject the first amount of air opposite a surface of the hull intended to be immersed.

A cavitator system for suppressing a cavity buoyancy effect and a control method thereof are provided. The cavitator system for suppressing a cavity buoyancy effect includes a cavity generating unit disposed at a front portion of an underwater vehicle and generating super-cavity, a pneumatic hose transferring compressed air stored in a compressed air tank to the underwater vehicle, a ventilation module positioned at a tail portion of the underwater vehicle and including at least one hole ventilating compressed air transferred through the pneumatic hose vertically downwards, and a controller sensing rise of a cavity tail portion and a change in posture of the underwater vehicle when a super-cavity is generated and ventilating compressed air through the ventilation module such that a vertically downward lift is generated at the cavity tail portion.

A cavitator system for suppressing a cavity buoyancy effect and a control method thereof are provided. The cavitator system for suppressing a cavity buoyancy effect includes a cavity generating unit disposed at a front portion of an underwater vehicle and generating super-cavity, a pneumatic hose transferring compressed air stored in a compressed air tank to the underwater vehicle, a ventilation module positioned at a tail portion of the underwater vehicle and including at least one hole ventilating compressed air transferred through the pneumatic hose vertically downwards, and a controller sensing rise of a cavity tail portion and a change in posture of the underwater vehicle when a super-cavity is generated and ventilating compressed air through the ventilation module such that a vertically downward lift is generated at the cavity tail portion.

A drainage device may include a channel body mountable on the surface proximate to an outlet on the surface and extendable away from the surface. A drainage device may include a groove formed along at least a partial length of the channel body. A drainage device may include a lip protruding from a bottom edge of the channel body at an end of the channel body that is distal from the surface when the drainage device is mounted thereon, wherein when the drainage device is mounted on the surface proximate to the outlet, fluid from the outlet is directed by the drainage device away from the surface.

A marine surface vessel includes an air ventilated hull, and a deck, where the vessel includes at least one air conduit leading to at least one ventilation opening beneath a waterline of the vessel. The at least one air conduit is arranged to guide air to the at least one ventilation opening, where the deck is at least party surrounded by a gunwale, where the at least one air conduit is arranged to guide the air from at least one water drainage opening arranged to drain water from the deck.