Estimation method of the capsizing probability in irregular beam seas using non-Gaussian probability density function

This paper aims to describe a probabilistic assessment technique for ship roll behavior in beam sea conditions. Here, following the work of Kimura and its previous application by the author, probability density function (pdf) of roll response is calculated by combining the moment method with equivalent linearization technique. Results produced using this method are shown to be in good agreement with Monte Carlo simulation results. Moreover, this procedure is extended to the estimation of the capsizing probability. The final results concerning capsizing probability for the linear damping coefficient case are well correlated to the Monte Carlo simulation results. The advantage of this method is that it does not require a significant amount of computation and it enables the direct assessment of capsizing probability for ships with strongly nonlinear restoring terms.