This section is for outboard and stern drives. Propeller changes made for these boats will not react the same on Cruisers & Sport Fishing Yachts. Bay Propeller has several Computer Programs available that help us suggest the best suited propeller for your particular Cruiser or Sport Fishing Yacht.

The propeller size for your boat and engine combination is based on the wide open throttle (wot) operating range for your particular engine. This information is in your owners manual and will be expressed in terms of a certain horsepower at a certain rpm. The goal in propeller selection is to determine what propeller size will maximize performance for your boat while allowing your engine to operate in the recommended rpm range.

Using your existing propeller, determine the maximum r.p.m. you are able to obtain. If during this test you begin to exceed the maximum rated r.p.m. of the engine, reduce the throttle setting to a position where the maximum r.p.m. is not exceeded. If you can exceed the recommended r.p.m. of your motor, you need to increase the pitch of your propeller. A 2" increase in pitch will reduce your r.p.m.'s by approximately 300-400. If you can not reach your rated r.p.m.'s, you need to decrease the pitch. A 2" decrease in pitch will raise your r.p.m.'s 300-400. Once your wide open throttle r.p.m.'s falls within the recommend range of your engine manufacturer, you have a propeller that is suited correctly for your boat, but you may not be satisfied with respect to water-skiing performance or trolling speed. It is best in circumstances like this to have two propellers. A propeller with 2" less pitch would give you better acceleration for pulling water skiers, but you must watch that you do not exceed wide open throttle r.p.m.'s specified by your engine manufacturer. As a rule, a propeller that tops out at the lower end of your r.p.m. scale is best for cruising and a propeller that tops out at the high end of your r.p.m. scale is best for water skiing.

You don't drive an automobile without a spare tire, don't drive a boat without a spare propeller.