Selecting the Proper Boat Propeller

The proper boat propeller provides many advantages. It directly affects the performance of your vessel as far as reaching maximum RPMs during different maneuvers and the shape and style determine how your boat moves through the water.

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Propeller Basics

There are two dimensions to a boat propeller - the diameter and the pitch. Diameter is the first number and it refers to the size of the outer circle made by the blades. Pitch is the distance, in one revolution, which the propeller moves the boat forward. This distance is considered theoretical because while operating in water it tends to slip. Therefore, a 14 x 19 propeller is one with a 14 inch diameter and 19 inches of pitch. Both of these dimensions are measured in inches.

How a boat propeller affects RPMs is that the pitch works in conjunction with the engine. At full throttle, the boat engine's RPMs should reach their maximum as defined by the manufacturer. If they do not, then consider replacing the propeller with one which has lower pitch. The converse is true as well; for engines which exceed RPMs at full throttle, you will want a propeller with higher pitch. Even at less than full throttle, the propeller helps the engine function best while cruising, planing, and trimmed up.

A general rule of thumb is that each inch of pitch results in approximately 200 RPMs. An increase of pitch means a decrease of 200 RPM in the engine, while a decrease in pitch of an inch will increase RPMs the same amount.

Types of Propellers

Boat propellers are made of either aluminum or stainless steel. Aluminum is usually the standard material on factory propellers. They are fairly good performers and are less expensive, but they are not as durable.

Stainless steel, however, is much stronger and more durable than aluminum but also more expensive. The blades are thinner, which means they can be formed into many more different shapes and sizes which can positively impact the performance of your boat. They are prone to rust.

Another option in boat propeller is the number of blades, three or four. The difference, in a nutshell, is speed and performance. A three-blade propeller is capable of the fastest speeds but doesn't perform so well during hard turns. A four-blade propeller produces better handling at lower speeds and in turns, but tends to propel a boat just a bit slower.

The type of boat propeller you choose will depend on what you want it to do for your vessel. Speed, performance, and durability are the factors which will help you decide. Make sure to look through internet sites offering boat propeller as well as other marine supplies to find the best discounts.