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Many types of marine propulsion, according to the principle of different propeller, water jet propeller, special propeller.

Propeller

By the hub and a number of radial fixed to the hub of the composition of the propeller, commonly known as the car leaves. The propeller is mounted below the aft waterline and is powered by the mainframe (see the ship's power unit), pushing the water to the ship and pushing the ship forward with water. Propeller structure is simple, light weight, high efficiency, under the waterline and be protected.

Classification

Propeller is the main propulsion tool for modern ships, and now most ships are propelled by propellers. There are many types of propellers.

According to the number of blades, the propeller has 2, 3 or 4 blades, and even more. The larger the number of blades, the greater the absorbed power.

According to the different structure, the propeller is divided into fixed (pitch) distance and variable pitch propeller two categories.

Fixed pitch propeller, pitch is fixed its characteristics are simple structure, light weight, so the ship has been widely used.

Variable pitch propeller, pitch can be adjusted, through the propeller pitch mechanism, with hydraulic or electric drive to adjust the pitch. Initially used is a two-pitch propeller. High speed with high distance, low speed with low distance, and then gradually increase the number of the pitch.