Shaft Torsional - 1st Critical Speed

First torsional critical speed of the propulsion shaft - must stay outside the engine's continuous-running band.

Torsional vibrationCritical speedShaft

Loading calculator…

This calculator requires JavaScript to compute its result. The formula, symbols, and regulatory sources are shown in the Formula section below.

Formula, assumptions, and limits

\omega_n = \sqrt{K/I}

Symbol	Meaning	Unit
$I$	Propeller + shaft polar inertia	kg·m²
$K$	Shaft torsional stiffness	N·m/rad

Source: IACS UR M68 / Lloyd's TVC Guide

First torsional critical speed of the propulsion shaft - must stay outside the engine's continuous-running band.