Abstract
It is inevitable to maintain the safety of cargo for vessels during the navigation. This study reveals some operational difficulties of cargo management in rough weathers from some interviews. These casualties tend to happen in weather conditions due to atmospheric depressions. Two cases of cargo damage happened in each ferry are analyzed in detail, using offshore wave and AIS database. Numerical simulations of ship motions reveal that roll motions of "A Maru" have increased more than three times after she has altered her course. It would cause the chaotic cargo shift by repeating roll motions in high waves. It is shown that condition of vessels, waves, and cargo loading are inevitable to estimate the safety of cargo damage. Offshore waves and AIS database make possible to estimate the situation of marine casualty on some level. In future studies, the relation between ship motions and cargo damage must be grasped, including dynamic forces to prevent these casualties.