Results of model experiments on an ore carrier are presented to investigate hydrodynamic impact upon the hull surface in two-directional irregular waves. Short term analysis of peak values of impulsive pressures indicates that the expected peak value distributions of the pressures are well approximated by Rayleigh distributions. Distributions of impulsive pressure peaks over the stem and the hull side above water are examined. Effects of ship speed, course angle and mean wave period of irregular waves on impulsive pressures are also discussed.