What is Efoil/Surfboard propeller diameter and pitch

An Efoil/surfboard propeller has two basic dimensions: diameter and pitch. These dimensions are used to describe the propeller, usually in inches, and always stated as diameter x pitch. For example, a propeller described as 7.5 x 7 has a diameter of 7.5 inches and a pitch of 7 inches. These dimensions are often stamped or cast right on the propeller.

1. How to Calculate Propeller Diameter and Pitch?

Propeller diameter is simply the diameter of a circle scribed by the blade tips of the prop.

Propeller pitch is the distance the prop would move forward in one rotation if it were moving through a soft solid—think of a screw being turned into wood. The blades on a propeller are analogous to the threads on a screw. 

2. What happens if propeller pitch doesn't match motor?

If the propeller pitch is too low (lower in inches) the motor can run over the desired Max RPM which can lead to motor damage, or to the motor protecting itself with a rev limiter.

If the prop pitch is too high (higher in inches) the motor may run below the Max RPM range—called “lugging the motor”—which can also put undue stress on motor and gearcase components.

3. Because each customers efoil size, wing size, dust size, load, battery, etc are differnet, propeller size varies for different setup.

Usually for efoil 65162 fully waterproof motor at 12-14S, recommend 140-190mm for 100KV version; and 100-120mm for 195KV version.