Keller - Cavitation Criterion
Minimum blade-area ratio A_E/A_0 to avoid cavitation per Keller formula - the screening calculation for propeller sizing given thrust and shaft depth.
Minimum A_E/A_0
0.561 -
Formula, assumptions, and limits
Z = number of blades (assume 4); K = 0.2 for single-screw merchant ships, 0.1 for fast twin-screw. If calculated > 1.0, propeller must be larger diameter or additional blades.
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| Thrust | N | powering calc | |
| Propeller diameter | m | prop geometry | |
| Atmospheric + hydrostatic − vapour pressure | Pa | hydrostatics | |
| Keller constant | - | Keller (1966) |