Boat Prop Pitch

There are three types of pitch for a propeller. There is the flat pitch, the regressive pitch and the progressive pitch. The flat pitch will have the same pitch on the leading and trailing edge. The flat pitch is the fastest. The regressive pitch is higher on the leading side and lower on the trailing edge. The progressive pitch is the most common and is higher on the trailing edge and lower on the leading edge. For better hole shot performance especially on ski boats, the progressive pitch will be the most effective.

The manual of the engine is the best guide to the required pitch. The manual will help to determine the maximum WOT RPM range that the engine can effectively work with. To test the current propeller configurations, the boat must be run on WOT conditions with only the boater on board. The boat should have only the driver as passenger on board. A note should b e made of the maximum WOT RPM reading on the trachometer. This reading should be subtracted from the manufacturer's WOT RPM in the manual and from this figure, 200 should be subtracted to get the correct boat propeller pitch.

Another method of finding the pitch of the propeller is by examining the blades. The pitch may be etched on the propeller itself. Before fitting a propeller it is important to find the recommended pitch for the application from the manual given by the manufacturer. If there is no manual, the dealer will have the expertise to recommend the best propeller pitch for the application.

Figuring out the ideal pitch also depends on the type of boat and the way the boat is used. Boating websites have an online calculator which can give an accurate figure. The boater needs to fill a questionnaire including the type of boat, what the boat is used for and other technical details and a calculation is made by the tool to give an accurate recommendation of what the pitch should be. The performance of a boat may require a different pitch. A high pitch will give good high end performance for a speed boat while medium or low pitches give better hole shot performance and acceleration for ski boats and pother towing boats.

In some case the pitch may have to be reduced. When a three blade prop is replaced by a four blade prop, experts believe that a one inch reduction of pitch is required for optimum performance of the four blade prop. The result will be a 150-200 increase in the RPM of the prop at full throttle.

The pitch is one of the most important dimensions of a boat propeller and the correct pitch will increase the performance of the boat immensely.