Can Different Propellers Make a Difference in Boat Speed?

The right propeller makes a big difference in your boat's performance.

Bigger isn't necessarily better. A propeller that is too big for your boat will strain your engine, while one that is too small will waste energy by over-revving the engine.

Several variables determine the right propeller for a boat, including the hull type, your engine's horsepower and the boat's weight.

Choosing a Propeller

Do your math homework and calculate the right size propeller. Your reward will be more power and speed, while reducing vibration and engine strain, and providing better acceleration and fuel economy.

Calculating the Right Propeller Size

You can get a rough calculation by using the horsepower of your engine and the boat's weight. One horsepower will push 30 pounds through the water at 30 mph. For an accurate result, it's worth the expense to hire a professional to do the hydrodynamic calculations.

Measuring a Propeller

Count the number of blades on a propeller and use a tape measure to determine its diameter, that is the distance from the tip of one blade to the other or across the circle created when the Prop spins. Propeller pitch is the theoretical forward movement of a propeller during one revolution of the propeller.

References

• "Yachting Magazine; Spin to Win: Turn the Right Propellers at the Correct Rate and Your Yacht Will Thank You With Efficient Speed"; Dudley Dawson; October 2009
• "Popular Science magazine; Find the Best Prop for Your Boat on Paper First"; Jim Martenhoff; Jun 1969