Propeller Finder
🚤 How to Choose the Right Propeller Size
Understanding propeller sizing is key to getting the best performance from your engine. Follow this guide to find your perfect match.
🎬 Watch: Propeller Selection Guide
This short video by Mercury Marine explains how to read propeller specs and choose the right size for your boat and engine.
🔢 How to Read a Propeller Size
Propeller sizes are written as: Diameter × Pitch
For example: 13 × 19 means 13" Diameter and 19" Pitch
📏 What is Diameter?
The diameter is the distance across the full circle made by the propeller blades as they spin — measured in inches.
- A larger diameter moves more water → better for heavy/slow boats
- A smaller diameter spins faster → better for lighter/faster boats
- Always match diameter to your engine's recommended range
💡 Example: A 13 x 19 propeller has a 13-inch diameter
🔄 What is Pitch?
The pitch is the theoretical distance (in inches) a propeller would move forward in one full revolution — like a screw going into wood.
- Higher pitch = more speed at top end, but needs more power
- Lower pitch = better acceleration and pulling power
- Changing pitch by 2" changes RPM by ~400 RPM
💡 Example: A 13 x 19 propeller has a 19-inch pitch
✅ Quick Propeller Selection Tips
| Situation | Recommendation |
|---|---|
| Engine over-revving (RPM too high) | Increase pitch by 2" |
| Engine under-revving (RPM too low) | Decrease pitch by 2" |
| Heavy load / slow boat | Use larger diameter, lower pitch |
| Speed / performance focus | Use smaller diameter, higher pitch |
Still not sure? Use our Propeller Finder tool above or contact our team for expert advice.