Estimation of Wave Loads acted on Ships in Service based on AIS Data.

- Evaluation of Operational Effects on the Maximum Loads. -

Abstract

Improvement of the estimation accuracy of the wave load is necessary to realize a rational ship structure design. However, a rational method has not been established to determine the operation limit which influences the wave loads. In this study, in order to clarify the effects of the weather routing in North Atlantic, the sea state ship encountered is investigated by utilizing AIS data and wave data (Hindcast). In addition, the maximum wave load is estimated by using the Strip method for the container ships and the relationship between the vertical bending moment (VBM) and the maneuvering is confirmed. Based on Hindcast, in which the position of ships is not considered, the maximum value of the significant wave height in North Atlantic is about 16m. In contrast, the ship encountered wave height based on AIS is estimated about 13m. The wave load is reduced by about 15% due to the storm avoidance. A method is proposed to estimate the wave load with considering the actual ship speed and actual wave direction. It is confirmed that the maximum wave load estimated by the proposed method is smaller about 27% than the long-term prediction value which assumed a constant ship speed (75% of the service speed) and uniform distribution of wave direction.