Converts engine brake power to power delivered at the propeller shaft.
Formula
$$ P_D = P_B \cdot \eta_S \cdot \eta_G $$Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $P_B$ | Brake power (engine output) | kW | NOx Technical File |
| $P_D$ | Delivered power (at propeller shaft) | kW | result |
| $\eta_S$ | Shaft-line efficiency - direct-coupled two-stroke ≈ 0.99; long shaft lines ≈ 0.98 | - | shaft-line design |
| $\eta_G$ | Gearbox efficiency - 1.0 if direct-drive, 0.97–0.99 otherwise | - | gear-maker data |
SFOC is invariably quoted on brake power, so $P_B$ is the natural bridge between fuel-based and hydrodynamic calculations.
Sources
- ITTC - Propulsion Committee Standard Procedure 7.5-02-03-01.2.
- MAN Energy Solutions - Basic Principles of Ship Propulsion.