Open-Water Efficiency η_O
η_O = (J · KT) / (2π · KQ). Peak open-water efficiency of a typical merchant propeller 0.60–0.72.
Open-water efficiency η_O
0.546 -
Formula, assumptions, and limits
Peak η_O occurs at a J value (usually 0.7–0.9) that lies to the right of the design point. Selecting design J at peak η_O gives the 'full' propeller; running left of peak is 'heavy', right is 'light'.
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| Advance ratio | - | input | |
| Thrust coefficient | - | input | |
| Torque coefficient | - | input | |
| Open-water efficiency | - | result |