First torsional critical speed of the propulsion shaft - must stay outside the engine’s continuous-running band.
Formula
$$ \omega_n = \sqrt{K/I} $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $I$ | Propeller + shaft polar inertia | kg·m² | rotor dynamics |
| $K$ | Shaft torsional stiffness | N·m/rad | material + geometry |
Sources
- IACS UR M68 / Lloyd’s TVC Guide.