You should settle for the right boat prop when you need your boat to work properly. You will thus need to look at the prop size, number of blades, material used to make it, its rpm at wide open throttle, and the functions of the boat.
A lot shall depend on the prop size. By choosing the wrong size, you shall inflict damage on the boat and the engine. The same goes for the ventilation and cavitation. The prop’s diameter and pitch determine the size. This is normally found on its hub. The first digit you see it the diameter followed by the pitch. Should the boat be powerful enough, the higher pitch would boost its speeds considerably. A larger diameter would then mean the boat gets to accelerate much higher.
A prop can come with three to five blades. The more the number of blades, the better its performance. Racing boats rely on three bladed props for their top-end speed. Cupped blades improve on such performance. Cupping refers to the curve at the end of the blade. This is what will keep ventilation at bay and help make the boat turn sharply. The rake of the blade is also an important consideration. The angle of the blade with the propeller hub influences what performance is achieved
The material for making the prop of the boat shall also matter. Aluminum is the most common and most affordable option. It is the lighter choice that shall also keep the boat safe when you hit obstacles. It is unfortunately not resistant to rust and salt water. You would need stainless steel for that, but be prepared to pay its higher price. It is more durable and can withstand the effects of salt water. You can, however, be sure it will destroy the engine if you hit an obstacle. You shall need to have a composite and plastic prop for emergency cases.
Every engine shall also have its unique settings when it comes to rpm at wide open throttle. This should guide you as you make your choices.
You need to also think of the job the boat was designed to do. There are props designed for different types of boats, such as pontoons, bass boats, as well as those meant for skiing, fishing, racing or leisure. You need to also think of the water on which you shall use the boat. You will find several designed for the lakes, rivers, and other slow waters. The rest are for the high seas. You will find some for flat, heavy boats commonly used for transporting passengers and goods. Other are designed for high performance, such as in racing.
When you are aware of all these factors, it becomes easier for you to choose the right boat prop.