The principle of operation of the propeller

Propeller blades push water in one direction, while the boat is moving in the opposite direction. Rotating and pushing back the water, the propeller blades also create a vacuum on the front surface of each blade. This vacuum is so strong that it begin to explode surface air bubbles. When improper screw or not optimal conditions of his work, these bubbles can peel paint, and even with the surface of the aluminum propeller blades. This phenomenon is called cavitation. This phenomenon occurs when there is a partial screw slippage, in this case, a water medium. Understand the time of occurrence of cavitation can be for a sharp increase in the rotation speed (rpm) of the engine. should reduce speed to eliminate this phenomenon, until the screw comes into contact with water
 
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