Sailboat Propeller Calculator helps you find the optimal prop size and pitch for your sailboat engine. Improve cruising speed, fuel efficiency, and control.
Propeller Results
| Metric | Value |
|---|---|
| Propeller Diameter | |
| Propeller Pitch | |
| Propeller Slip |
| Condition | Typical Slip (%) |
|---|---|
| Cruising Speed | 5–10 |
| Low Speed | 10–20 |
| Heavy Load | 15–25 |
How to Use
- Horsepower: Check your engine manual for rated power (e.g., 30 HP).
- RPM: Use maximum engine RPM from the manufacturer (e.g., 3000 RPM).
- Gear Ratio: Find in engine specs (e.g., 2:1 means 2 crankshaft revolutions per prop revolution).
- Desired Speed: Enter cruising speed in knots (imperial) or kph (metric).
- Waterline Length: Measure hull length at waterline in feet (imperial) or meters (metric).
Understanding Results
- Propeller Diameter: Size of the propeller circle (inches or cm). Larger diameters suit heavier displacement hulls.
- Propeller Pitch: Theoretical distance the prop moves per revolution (inches or cm). Higher pitch increases speed but requires more power.
- Propeller Slip: Percentage of lost efficiency (5–20% typical for sailboats). Lower slip indicates better performance.
- Fit Tips: Ensure prop fits shaft and clears hull. Consult a marine professional for final selection.
Common Issues
- High Slip (>20%): Prop may be too small or pitch too high; try a larger diameter or lower pitch.
- Low RPM at WOT: Prop pitch too high; try a lower pitch.
- Over-Revving: Prop pitch too low; try a higher pitch.
Note: Results are estimates based on standard formulas for displacement hulls. Consult a marine professional for final propeller selection. Visit VicProp for more info.
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