What effect do slip and cavitation have on a vessel's speed?

What effect do slip and cavitation have on a vessel's speed?

• A. Increased efficiency and speed
• B. No effect on performance
• C. A loss of power and reduced speed
• D. Improved maneuverability

Answer: (C)

Slip and cavitation both reduce the propeller’s ability to translate engine power into forward thrust, so the vessel ends up moving slower for the same power input. Slip is the difference between the waterspeed the propeller would produce in an ideal, lossless case and the actual speed of the ship. When slip is present, the propeller pushes water but not as efficiently as it could, so thrust is lower and speed falls unless more power is added. Cavitation happens when local pressure on the blade drops below the water’s vapor pressure, forming vapor bubbles. These bubbles collapse and create turbulence and blade damage, wasting energy and reducing thrust. With less effective thrust, ship speed drops under the same power setting. So both effects lead to a loss of effective propulsion, meaning the ship runs slower unless more power is supplied.

Slip and cavitation both reduce the propeller’s ability to translate engine power into forward thrust, so the vessel ends up moving slower for the same power input.

Slip is the difference between the waterspeed the propeller would produce in an ideal, lossless case and the actual speed of the ship. When slip is present, the propeller pushes water but not as efficiently as it could, so thrust is lower and speed falls unless more power is added.

Cavitation happens when local pressure on the blade drops below the water’s vapor pressure, forming vapor bubbles. These bubbles collapse and create turbulence and blade damage, wasting energy and reducing thrust. With less effective thrust, ship speed drops under the same power setting.

So both effects lead to a loss of effective propulsion, meaning the ship runs slower unless more power is supplied.