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 boat hull includes a bow section and a flat aft section to allow an air film to be introduced under the boat hull. At least one slot or round hole is arranged proximate a location where the bow section meets the flat aft section. The slot or round hole provides a low-pressure injection point for pumped or drawn-in air and/or exhaust gas, which lubricates an operative surface of the flat aft section.

An air supply apparatus for a ship is described. The air supply apparatus includes a fuel cell and an air lubrication device for resistance reduction of the ship. An exhaust gas outlet of the fuel cell is connected with the air lubrication device via an exhaust gas line for supplying exhaust gas to the air lubrication device. Further, a ship comprising an air supply apparatus according to any embodiments described herein as well as a method of supplying air to an air lubrication device of a ship are described.

A rudder assembly, including a steering engine; an axial hollow rudder stock; a rudder blade; a gas release unit; and a tiller. The steering engine is disposed in a vessel stern. The tiller is connected to the steering engine. The axial hollow rudder stock includes a through hole. The through hole is small and disposed along the axis of the axial hollow rudder stock. The gas release unit is disposed in the vessel stern, and includes a control cabinet. The control cabinet includes a reagent storage tank, a reagent conveying hose connected to the reagent storage tank, a compressed air bottle, a pressure hose connected to the compressed air bottle, and a console. The pressure hose and the reagent conveying hose pass through the through hole of the axial hollow rudder stock, and then communicate with the cavity of the rudder blade.

Disclosed is an air supply system for supplying air to an outside of a hull of a vessel, the vessel holding a combustion engine. The air supply system comprises one or more air discharge units (ADUs) for releasing compressed air to an outside of the hull below a waterline of the vessel. The air supply system comprises a plurality of turbocharger(s) for supplying a compressed air flow to the combustion engine of the vessel via a first flow path. The plurality of turbochargers each comprises a turbine configured to be driven by an exhaust gas flow of the combustion engine and a compressor connected to the turbine and comprising an inlet for receiving air and an outlet for providing the compressed air flow to the first flow path. The plurality of turbochargers comprises a first turbocharger and a second turbocharger arranged in series with the compressor of the second turbocharger being downstream of the compressor of the first turbocharger in the first flow path. The air supply system comprises a first sub-path and a second sub-path branching off the first flow path and supplying the sub-flow of air to the ADUs. The first sub-path branches off from the first flow path downstream of the first turbocharger and upstream of the second turbocharger and wherein the second sub-path branches off from the first flow path downstream of both the first turbocharger and the second turbocharger.

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.

Disclosed is an air supply system (100) for supplying air to an outside of a hull (201) of a vessel (200). The vessel comprises an engine. The air supply system comprises one or more turbocharger(s) (10) for supplying a compressed main air flow to the engine of the vessel via a respective first flow path (11A). The air supply system comprises an exhaust gas recirculation (EGR) system for recirculating exhaust gas into the compressed main airflow supplied to the engine via a second flow path (11B). The air supply system comprises a third flow path (11C) for supplying a sub-flow of compressed air to one or more Air Discharge Units (ADUs). The EGR system comprises a blower (31) arranged in the second flow path (11B) for supplying exhaust gas to the engine. The first flow path and the second flow path have a first connecting path (11AB) upstream of the blower (31) and a second connecting path (11BA) downstream of the blower. The third flow path is in fluid connection with the first flow path and the second flow path downstream of the blower, such that the sub-flow of compressed air can be extracted from the first flow path and/or the second flow path.

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.

An air supply apparatus for a ship is described. The air supply apparatus includes a fuel cell and an air lubrication device for resistance reduction of the ship. An exhaust gas outlet of the fuel cell is connected with the air lubrication device via an exhaust gas line for supplying exhaust gas to the air lubrication device. Further, a ship comprising an air supply apparatus according to any embodiments described herein as well as a method of supplying air to an air lubrication device of a ship are described.