ShipCalculators.com

Open-Water Efficiency η_O

η_O = (J · KT) / (2π · KQ). Peak open-water efficiency of a typical merchant propeller 0.60–0.72.

Propulsion
Loading calculator…

Formula, assumptions, and limits

ηO=JKT2πKQ\eta_O = \frac{J \cdot K_T}{2\pi \cdot K_Q}
SymbolMeaningUnit
JJAdvance ratio
KTKTThrust coefficient
KQKQTorque coefficient
ηO\eta_OOpen-water efficiency

Source: Carlton - Marine Propellers and Propulsion

In short

\u03b7_O = (J \u00b7 KT) / (2\u03c0 \u00b7 KQ).

Learn the theory Marine propeller