Purchasing a Boat Propeller, for Novices

 A proper boat propeller can significantly change the performance of a boat. The boat size, engine range, material, blades and propeller pitch will make an impact on the type of propeller chosen. Here are questions to ask when purchasing one:

What Kind of Boat Is It?

                This might be obvious, but different types of boats will require different propeller types.

How Do I Want to Improve the Performance of the Boat?

A boat propeller changes the performance of a boat by changing the pickup, the speed and the energy required. Some may maximize one aspect, while others may moderately affect all three performance types.

What Is Size of the Boat and Engine?

                The boat size and engine will affect the final choice of propeller.

What Material Should Be Used?

                Typically, boat propellers are usually made of aluminum, stainless steel or composite plastic.

Composite plastic propellers are durable, affordable and used for smaller engines.

Aluminum can be suited to most uses, and often sold with outboard and stem drive engines.

Stainless Steel blades are thinner than the composite plastic or aluminums, although heavier in weight than the other two types. It is more durable, less prone to bending and heavier in weight.

What Should the Pitch Be?

The pitch is important. Boat propellers with flat-angled blades allow for easier steering and responsiveness than blades with steeper angles. On the other hand, steeper angles can push out more water, but the engine will require more energy to spin the propeller, leading to slower pickup as well as lead the boat sideways during slower speeds. It could also overwhelm the engine if the pitch is too high.

The engine manual should have a recommendation for the pitch and a section entitled “wide open throttle range” (WOTRPM) that can give you the exact propeller blade pitch required, usually in DXP.

                Every inch increase in pitch will reduce the propeller’s WOTRPM by 150 – 200 RPM.

How Many Blades are Required?

Boats used for recreation have propellers with three blades. A high horse-powered engine may require four or five blades. This will allow for quicker acceleration, better power in rough waters and will keep the boat steady at low speeds.

Any Other Issues to Consider?

                Other factors may include the propeller blade rank angle, the cupping on the edges of the blades, surface piercing design or ventilation for exhaust gases.

                To request further information about boat propellers or ask a question, please do not hesitate to contact Eris Propellers for more details.

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