Diameter is the width of the circle that the prop would make when rotating. The diameter can vary by up to 1/2" with no discernable change in performance.
Caution: Before increasing the diameter of your prop, make sure there will be enough clearance between the blades and cavitation plate or anode on your engine.
Diameter is the first number listed on boat propeller dimensions.
We tell you everything you need to know about props from cupping to ventilation.
If you want to modify your boat's performance, consider the above before making your selection.
For safety and efficient performance, it is critical that your engine operates within the RPM range recommended by the manufacturer.