The selected boat propeller determines how well a boat shall perform. When choosing a boat propeller, there are some things you have to consider. You need to think of its size, number of blades, the material it is made out of, its RPM at the wide open throttle, and the use of the boat.
Of all these, you need to be most keen on the prop size. A wrong prop size means extensive damage to the boat and its engine system. As you calculate the size; you need to factor in the prop’s diameter and pitch. The higher the pitch, the more speed the boat shall manage, given it has a powerful engine. Its larger diameter means it will accelerate faster.
When it comes to blades, you shall find three to five ones. The higher blade count leads to better performance. The lesser the number of blades, the more top speed it can reach. This is why racing boats go for three bladed props. They will also stick to cupped blades. Cupping refers to the curve at the end of the blade, which essentially helps it turn sharper. The rake of the blade is also a consideration here. The rake is the angle the blade makes with the prop hub. It is there to keep slipping away.
The material used in making the prop matters. Aluminum props are readily available and cheap. They are strong and lightweight. They are however not good for use in salty water. Such stainless steel blades best handle waters. They are however more expensive. In case you hit an obstacle, you will damage the entire engine system, which is not the case with aluminum ones. There are also composite and plastic props, which serve their purpose well in case of an emergency.
Your boat also has a specific RPM at wide open throttle range rating it can work with. You only need to read about it in the manual to make the right selection.
You need to also factor in the use of the boat in your selection. There is no limit to the variety of props out there, each meant for a specific purpose. There are those meant for pontoons, bass boats, and skiing boats, those for fishing, racing, or relaxation. The kind of water the boat shall be traveling also matters. Some props are great for lakes, while others are ideal for rivers or slow-moving waters. There are those which are ideal for high seas. There are those for flat, heavy passenger boats. you thus have to select from those meant for the waters you frequent and boat type. It is also important that you buy an extra prop in case of an emergency.