Benefits of Repairing or Replacing a Damaged Propeller
Repairing or replacing a damaged propeller on your outboard or sterndrive comes with many benefits you might not have considered.
Of course repairing or replacing a damaged propeller maximizes your boat’s performance. You probably already knew that. What you might not know is a propeller is an extremely sensitive, precision-engineered component that can get ruined with simple imperfections such as nicks and abrasions.
About Propellers and Prop Repair
The fluid dynamics of a prop engaging with the water are mind-boggling, and must take into account fancy-sounding technical terms like “chord detachment,” “tip vortices” and numerous types of “cavitation,” to name a few. Even the smallest imperfection with the propeller reduces its effectiveness, and this loss of performance is greatly magnified as the speed of the prop increases.
Abrasions and nicks along the leading edges and across the faces of a prop’s blades cause cavitation damage. This reduces the propeller’s bite in the water and robs the boat of top speed and maneuverability. Bent propeller blades encounter water separation that also reduces prop-bite, and hinders the performance of the motor and the boat itself.
Minor damage to blades such as nicks can be filed flat, and abrasions can be smoothed away with fine-grit sandpaper. However, if the propeller’s blades are cracked, bent or deformed, the propeller should be replaced. These days propellers are relatively inexpensive, and buying a new one is often cheaper than having an old prop repaired.
Why Repair/Replace a Damaged Propeller
Other than the fact that you should repair or replace any boat parts that are damaged, consider the following reasons for fixing or swapping out a propeller.
Damaged propellers can:
- Increase fuel consumption
- Cause stress on the outboard or sterndrive
- Fail and leave you stranded
These three reasons alone should be enough to convince you that fixing a damaged propeller or replacing it altogether with a new one has its benefits.
When it comes to buying a new propeller, you have choices to make as far as both the material a prop is made of and the number of blades the new propeller has. Watch the 3-Blade vs 4-Blade and Aluminum vs Steel videos included above to help you choose the right propeller.