Probability approach on slamming: A tool for an optimum design for container ship B. Hamoudi Hydrodynamics Laboratory (NAOE), Acre Road, ABSTRACT It is meaningful to consider the probability approach as useful tool for predicting the ship behaviour due to slamming phenomenon. This paper explains the probability approach for the occurrence of slamming event. It revises a review on the calculation of pressure due to bottom slamming. The two parameter spectrum recommended by the 12th I.T.T.C. is given and used as a tool to predict the variance of the vertical relative motion and velocity which are derived from heave, pitch and wave elevation for the S175 container ship using the developed computer program on the base of the New Strip Theory (NST). These two variances are used in the basis for the prediction of the probability of occurrence of slamming event. Furthermore, the number of slamming impacts are calculated as function of ship operation time. The ship designer is interested on the extreme pressure which may cause a significant damage on the bottom of the hull structure; this extreme pressure is calculated for a given probability of occurrence, number of impacts and ship navigationtime. INTRODUCTION Slamming is a phenomenon associated with extreme motions of a vessel encountering a large amplitude of an incident wave. The moving vessel experiences an impact due to slamming when the forefoot hits the water surface during a severe pitching motion. Transactions on the Built Environment vol 2, © 1993 WIT Press, www.witpress.com, ISSN 1743-3509