Choosing Boat Props

By Author: Robert Thomson
Total Articles: 3764
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As the weather starts to heat up on of the most popular ways to enjoy a vacation is out on the water either boating or fishing. After a long winter you may find it is time to replace your boat props, so the question is what type of boat props is right for your needs. When it comes to choosing boat props you want to consider the pitch, material and number of blades.
While these three areas will help influence your decision you also need to choose boat props based on the size of your boat and the recommended operating range for your boat engine.

First you want to consider the pitch. It can be difficult to understand this obscure propeller parameter. Essentially if boat props have a flat blade angle then they will be easier to turn with a faster spin when compared to boat props with steeper angles. So how can you determine which level of pitch is right for your needs? First you need to look at the engine owner's manual to find the wide-open-throttle range for your specific engine. Once you have this WOT RPM range you can make your selection based on the following three criteria.

The first criteria is that for ...
... each inch of propeller pitch you will be reducing the WOT RPM by anywhere between 150 to 200. Second, if you take away an inch of propeller pitch then you will be increasing your WOT RPM by 150 to 200. Finally, if you have a four-blade propeller it will turn 50 to 100 RPM less than a three-blade prop, even when the pitch is the same.

Next you should consider the material that the boat props are made out of. Typically, boat props will be made out of composite, aluminum and stainless steel. The benefit of composite boat props is that they have good performance, are very durable and can be cheap. Most boat props are aluminum since they work for a variety of uses due to the many models and styles they are available in. For highest performance and best
durability you should choose stainless steel, however they are also the most expensive.

Finally you need to consider the number of blades on boat props. Typically recreational boats will have three bladed props. If greater horsepower, speed and load requirements are needed then a four or five
bladed prop can be considered. Four blade propellers have the added benefit of keeping the boat on plane at lower speeds, giving increased speed in the mid-range, giving you quicker acceleration, smoother running speeds and holding power better under rough boating conditions.