Slip is defined as what?

Slip is defined as what?

• A. The rotation axis of the propeller
• B. The propeller's efficiency
• C. The speed of twist of blades
• D. The difference between the distance a propeller should move in one revolution through a solid medium and the actual distance it moves through the water

Answer: (D)

Slip is the difference between the distance a propeller would move in one revolution through a solid medium (its pitch) and the actual distance it moves in water. In other words, slip = pitch − actual advance per revolution in water. This occurs because water isn’t a solid; some of the propeller’s energy goes into accelerating and swirling the water, so the boat moves forward less than the pitch would suggest. Example: if the pitch is 12 inches and the propeller actually advances 9 inches per revolution, the slip is 3 inches (25% of the pitch). Higher slip generally means lower efficiency.

Slip is the difference between the distance a propeller would move in one revolution through a solid medium (its pitch) and the actual distance it moves in water. In other words, slip = pitch − actual advance per revolution in water. This occurs because water isn’t a solid; some of the propeller’s energy goes into accelerating and swirling the water, so the boat moves forward less than the pitch would suggest.

Example: if the pitch is 12 inches and the propeller actually advances 9 inches per revolution, the slip is 3 inches (25% of the pitch). Higher slip generally means lower efficiency.