Free running tests in regular and irregular waves were carried out to examine the relation between bow flare shape, ship motions and water impact pressure. Model of a post-panamax container carrier was used. Water impact pressures on the bow flare and ship motions were measured in head and bow seas. Based on the experimental results, the relation between water impact pressure and flare angle was discussed. It is found that relative angle between wave and the bow flare has much relation to the magnitude of water impact pressure.
Water impact pressure was estimated to examine these relations theoretically by means of non-linear strip method, which takes account of the instantaneous wetted surface of ship hull. It is found that present method gives good agreement with measured peak value of impact pressure. It is verified that measured impact pressure is consistent with the physical consideration. In addition, estimation method of probability density function of water impact pressure was developed. Having compared with measured probability, it was clarified that present method, which takes account of a bow flare angle, is useful for the prediction of water impact pressure.
It is important for a safety of container ship to examine impact pressure due to bow flare slamming. In particular, large container ships such as post-panamax container ship are increasing recently. As a consequence, further examination of wave loads for such a large container ship is required.
With regard to the flare slamming, many researches have been carried out. As a result, some prediction methods were proposed (Technical committee of West-Japan Society of Naval Architects, 1974; Takegawa, 1976). However, these prediction methods were constructed based on the experiments or damage data of container ship of those days. Therefore, further verification for recent container ships is required.
