Choosing the right outboard propeller can be perplexing, but it doesn’t have to be. In propeller designation, diameter is the first number listed, followed by pitch. Diameter is measured across the outer circle of the blade tips, while pitch is the distance a prop theoretically moves forward in a single revolution. So, a 15x17x3 designation indicates a 15-inch diameter and 17-inch pitch with three blades.
“There is no perfect propeller that does it all,” says David Meeler, Yamaha Outboards propeller information manager. “There are too many variables in boat design, and performance. Each propeller is a compromise. You have to give up a little of one aspect, such as top speed, to get more of another, like acceleration.”