Ship's copper alloy impeller

Ship's copper alloy impeller
Due to good seawater corrosion resistance, many copper alloys, such as aluminum bronze, manganese bronze, aluminum brass, gunmetal (tin-zinc bronze), white steel, and nickel-copper alloy (Monel) have become standard materials for shipbuilding. Generally, copper and copper alloy account for 2 to 3% of the dead weight of the impeller of warships and merchant ships.
The propellers of warships and most large commercial ships are made of aluminum bronze or brass. Each propeller of the big ship weighs 20-25 tons. The propellers of the Queen Elizabeth and Queen Mary aircraft carriers each weigh 35 tons. "Admiral" gunmetal is commonly used for the heavy tail shaft of large ships, and the same material is used for the tapered bolts of the rudder and propeller. Steel and copper alloys are also used extensively in engine and boiler rooms. A nuclear-powered commercial ship in the world uses a 30-ton cupronickel condenser. Aluminum brass tubes are used as large heating coils for oil tanks. There are 12 such oil storage tanks on 100,000-ton ships, and the corresponding heating system is quite large. The electrical equipment on the ship is also very complex. Engines, motors, communication systems, etc. almost entirely rely on copper and copper alloys to work. The cabins of large and small ships are often decorated with steel and copper alloy castings. Even wooden boats require steel alloy (usually silicon bronze) screws and nails to fix the wooden structure. This type of screw can be mass-produced by rolling.