What is Cavitation?

Aluminum Cavitation Burn
Aluminum Cavitation Burn

What is Cavitation?

Cavitation is bubbles caused by excessive propeller speed or loading. The water vaporizes or boils due to the extreme reduction of pressure on the back of the propeller blade. Many propellers partially cavitate during normal operation, but excessive cavitation can result in physical damage to the propeller’s blade surface due to the collapse of microscopic bubbles on the blade.

Cavitation can cause:

  • pitting on the surface of propeller blades
  • vibrations when running – just like having an unbalanced or pitch-damaged prop
  • reduced bite
  • reduced overall efficiency

What can be done to prevent cavitation or fix the damage caused by cavitation?

There may be numerous causes of cavitation such as:
  • incorrect matching of propeller style to the boat application
  • incorrect pitch
  • too little clearance between the prop and the hull or skeg
  • physical damage to the propeller or lower unit or bottom of vessel
If you are experiencing cavitation, please seek professional advice and repair. We can repair your lower unit, as well as your propeller. You may need to be running a different propeller in style, diameter or pitch, and we can help there too! Notes:
  • Cavitation is not generally a problem on low-speed vessels with low RPMs.
  • Cavitation is often confused with ventilation, which we will address in another post.

Examples of Cavitation Burns and Handiwork on Bronze Propeller Repair