How Do I Choose a Propeller for an Engine & Boat Combination?
- 1). Examine the water types your boat will be used in to determine which type of material the propeller should be made of. The most common types of propeller material are aluminum and steel. Aluminum propellers tend to take the occasional contact with submerged objects without damage. They are cost-effective and relatively inexpensive to repair. Steel propellers are less forgiving when contacting fixed submerged objects, cost more initially and are expensive to repair. However, they are also longer-lasting and more efficient.
- 2). Select the propeller's diameter and pitch according to its expected uses. Diameter is usually a set number and is based on the motor. Pitch is variable, with a high-pitch propeller moving more water with each revolution than a low-pitch. High-pitch propellers generally give more fuel efficiency while cruising and a faster top speed--provided the engine is not overworked by choosing a pitch that is too high. Low-pitch propellers give the boat better responsiveness and quicker planing (the point where the boat skims across the water's surface). The downside is that propellers that are low-pitch make the engine work harder causing a loss of power and efficiency. The potential for engine damage exists if you go too low.
- 3). Install a propeller with the proper number of blades for your type of boating. Most engines come standard with three blades on the propeller. However, the number of blades you choose is dependent upon water conditions, load and desired speed. For instance, if you pull skiers you may wish to install a five-bladed propeller to help the boat achieve top speed and plane quickly. There are propellers, called duo-props, which have two counter-rotating blades mounted on a single shaft. These propellers help combat torque effects on the steering of large boats. Check with a reputable marine mechanic regarding the correct number of propeller blades for your needs. Doing so will ensure top performance of your boat's engine.