Scale model experiments of forced roll in a regular beam sea have been conducted on a fishing vessel. A methodology for the estimation of the parameters of the mathematical modelling of roll motion, based on the least squares fitting of the numerical solution to the experimental data has been developed and implemented in a computer code. The analysis of the experimental data allowed to obtain information on the different linear/nonlinear damping contributions and on the effective wave slope coefficient. The conclusions highlight the validity of different damping models in simulating forced roll in waves. At the same time, the conclusions enforce the known problem of the dependence of the estimated parameters on the excitation frequency.
