Marine Propeller

Marine Propeller

The marine propeller consists of a propeller hub and a number of blades fixed radially on the hub. The propeller is mounted below the stern line and rotates under the power of the main engine, pushing the water behind the ship and using the water to push the reaction forward. The propeller is simple in structure, light in weight, high in efficiency, and protected below the waterline. 

Ordinary transport ships have 1-2 propellers. Ships with high propulsion power can increase the number of propellers. Large fast passenger ships have twin to four oars. The propeller generally has 3 -4 blades, the diameter depends on the horsepower and draft of the ship, to the bottom does not touch the bottom, the top does not exceed the full water line. Propeller speed should not be too high, ocean cargo ships for 100 rpm or so, small speed boats as high as 400-500 rpm, but the efficiency will be affected. The propeller material generally uses the manganese bronze or the corrosion-resistant alloy, also may use the stainless steel, the nickel aluminum bronze or the cast iron.