ABSTRACT
Ship operability study is a computational procedure to estimate the percentage of time during which the ship may not comply with her purpose or mission. Operability study consists of a seakeeping analysis and limiting criteria that are both subjected to uncertainties. The aim of the present study is to incorporate uncertainties in ship operability analysis and to express operability diagrams in probabilistic terms. For the seakeeping analysis, semi-analytical closed-form expressions are used, while probabilistic models of uncertainties in transfer functions were determined in a previous study. Seakeeping limiting criteria for pitch and vertical bow acceleration are used, where probabilistic models of the uncertainties are determined using values from the literature supported by an enquiry, which was performed among experienced seafarers. Monte Carlo simulation is used to calculate probabilities of exceedance of seakeeping criteria and results are presented in the form of a scatter diagram. A probabilistic operability index is proposed as the contribution of the present study.
