Did you know a properly tuned propeller can significantly boost a vessel’s performance?
Understanding how a propeller works—and how to measure pitch manually—is key for any marine engineer, technician, or boat owner.

What is a marine propeller?

A marine propeller is the core component of a vessel’s propulsion system. It converts rotational power from the engine into thrust, which moves the boat forward or backward through water. A propeller typically consists of several blades attached to a central hub, which spins along the drive shaft.

Main parts of a propeller:

• Hub: The central part that connects to the shaft.

• Blades: Curved surfaces that generate thrust as they rotate.

• Leading edge: The first point of contact with the water.

• Trailing edge: Where water exits after moving across the blade.

• Chord: An imaginary line between the leading and trailing edge.

• Pitch: The theoretical distance the prop would travel forward in one full revolution without slip.

What is propeller pitch?

Propeller pitch is one of the key parameters that determine how efficiently a vessel moves through the water. It refers to the theoretical distance a propeller would move forward in one full revolution, assuming no slip—similar to how a screw travels through wood. The higher the pitch, the more distance the prop covers per turn.

Why does pitch matter?

Choosing the right pitch means optimizing fuel efficiency, protecting the engine, and achieving target speeds. A pitch that is too high will overload the engine, while a pitch that is too low will cause the engine to over-rev without delivering proportional thrust. That’s why understanding pitch is critical—especially when working with customized or legacy propellers with no available design documentation.

How to measure pitch manually

While there are electronic tools for this, a manual method can provide surprisingly accurate results. Here’s how:

1. Select a blade section, typically at 70% of the propeller radius.

2. Measure the pitch angle of that section relative to a plane perpendicular to the shaft.

3. Apply the formula:
   Pitch=Height difference between the two located points (mm,ft or in) x 360º / Measured Angle (º)

This manual approach is ideal for inspections, maintenance, or when reverse-engineering a propeller for mold manufacturing.

If you’re looking for a custom-made propeller optimized for your vessel’s specific operating conditions, we can help. Our naval engineering team develops tailored solutions to maximize efficiency, performance, and durability.
Get in touch and let us help you improve your propulsion from the design stage.