Empirical and experimental roll damping estimates for an oil tanker in the context of the 2nd generation intact stability criteria

Abstract

This paper assesses the prediction approaches for the roll damping coefficients based on experimental decay tests, Ikeda's original method (Himeno, 1981) and the simplified approach (Kawahara et al., 2009) that has been proposed for the second generation intact stability criteria in IMO. The damping coefficients obtained from these procedures have been applied in a time domain nonlinear model for the simulation of ship motions in waves, developed to perform direct stability assessments. Furthermore, a set of model test results with a VLCC oil tanker in decay, regular and irregular wave tests have been used as benchmark to assess the accuracy of the damping estimates. A single degree of freedom numerical model has also been implemented to compare their results with those of the 6-dof direct assessment simulations.