SHP vs DHP - Transmission Efficiency
Shaft horse power (SHP) vs delivered horse power (DHP) accounting for bearing losses, gearbox / shaft-line transmission.
SHP (at pod)
9,800kW
DHP (propeller delivered)
9,702kW
Formula, assumptions, and limits
Direct-drive 2-stroke ships: η_trans = 1 (no gearbox). Medium-speed 4-stroke with reduction gear: η_trans = 0.97–0.99. Shaft bearing η_shaft = 0.98–0.99 depending on length & supports.
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| Brake horse power | kW | engine shaft | |
| Shaft horse power | kW | after gearbox | |
| Delivered horse power | kW | propeller hub |