HomeCalculatorsHeave RAO - Linear Approximation

Heave RAO - Linear Approximation

Linear heave response amplitude operator (RAO) at a given wave frequency using Froude-Krylov + damping - preliminary motion estimate for design sea state.

HeaveRAOSeakeeping
Frequency ratio ω/ω_n
0.778 -
Heave RAO
2.179m/m
Formula, assumptions, and limits

Single-degree-of-freedom approximation. Peaks at ω = ω_n. Full strip theory (Salvesen-Tuck-Faltinsen) accounts for coupling with pitch. For monohulls heave ω_n typically 0.7–1.0 rad/s.

Symbol legend

SymbolMeaningUnitSource
Wave angular frequencyrad/sspectrum
Natural heave frequencyrad/sship / water plane
Damping ratio - viscous + wave