How to choose the right outboard propeller？

Each model of the outboard engine has a variety of propellers for use. The matching of the ship, the engine and the propeller has an important influence on the boat driving, the ride comfort, the sailing speed, the fuel economy and the the engine life. In order to get the boat to its best condition, the selection of a suitable propeller based on the line type, displacement, main engine power and use of the boat is one of the primary issues that must be solved in boat design and boat driving.

Propeller material: Outboard motor boat propellers are usually made of plastic, aluminum and stainless steel. Plastic propellers have poor strength and are easily broken or damaged by impact. They are prone to bending deformation and difficult to repair when subjected to heavy loads. They are only available for outboard motors with a power of less than 2 kW. Because of their corrosion resistance and low price, they are usually used on small recreational boats.

Standard aluminum propellers are most commonly used. These propellers have different sizes, including pitch, diameter, and caster angle. Aluminum propellers have good strength and corrosion resistance. They are easy to maintain and affordable, so aluminum propellers are widely used on outboard boats of all powers.

Among the materials used to make the propeller, stainless steel has the highest strength and the longest service life. Compared with aluminum propellers, steel propellers have good strength and they are not easily broken and deformed. The steel propeller can maintain stable performance of the engine, but due to its heavy weight, the impact load is too large when the engine accelerates. In addition, steel propellers are expensive. In summary, steel propellers are mainly used in outboards of more than 80KW and in the sea.

Since the structure of the outboard defines the choice of propeller diameter, the propeller size is primarily to determine the pitch of the propeller. The propeller specifications obtained from the matching table do not take into account the different hull line types, the smoothness of the bottom of the ship, the installation of the engine and the position of the center of gravity of the ship. They are generally only used for reference and preliminary estimation. The easiest way is to get it by real ship test.