ShipCalculators.com

Propeller Torque Coefficient KQ

Non-dimensional torque KQ = Q / (ρ·n²·D⁵). Open-water charts typically tabulate 10·KQ to keep KQ and KT on the same chart scale.

Propulsion
Loading calculator…

Formula, assumptions, and limits

KQ=Qρn2D5K_Q = \frac{Q}{\rho \cdot n^2 \cdot D^5}
SymbolMeaningUnit
QQShaft torqueN·m (input as kN·m)
ρρSea-water densitykg/m³
nnShaft rev/srev/s
DDPropeller diameterm
KQKQTorque coefficient

Source: Carlton - Marine Propellers and Propulsion

In short

Non-dimensional torque KQ = Q / (\u03c1\u00b7n\u00b2\u00b7D\u2075).

Learn the theory Marine propeller