Forced rolling trials on board a Portuguese navy frigate

The experimental results obtained during forced and transient rolling trials on board a frigate with active roll stabilizers are presented and discussed. Full-scale experimental data collected at different fin oscillating frequencies and ship advance speeds were recorded and processed in order to obtain transfer functions for the ship and the fin servos. Viscous roll damping coefficients and the ship's natural roll frequency were also calculated from free roll decay curves at different advance speeds. From these trials it was possible to identify open-loop operational parameters of the roll stabilization system, which can be used on a simulation and prediction model.