Calculate the theoretical propeller pitch required to achieve a target speed at a specific RPM.
Last updated: March 2026 | By ForgeCalc Engineering
Propeller pitch is the theoretical distance a propeller would move forward in one complete revolution if there were no slip. It is similar to the 'thread' on a screw. A 21-inch pitch prop would theoretically move forward 21 inches per turn.
Choosing the right pitch is critical for marine performance. Too much pitch can lug the engine, while too little pitch can cause the engine to over-rev and lose efficiency.
Most pleasure boats see 10% to 20% slip. High-performance racing hulls can see as low as 5%, while heavy workboats might see 25% or more.
Lower pitch propellers act like a lower gear in a car, providing better 'hole shot' and acceleration but lower top speed.
The engine will not be able to reach its recommended wide-open throttle (WOT) RPM range, leading to poor performance and potential engine damage.
Yes, diameter and pitch work together. Generally, as diameter increases, pitch must decrease to maintain the same load on the engine.
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