On the Statistical Prediction of Sea-margin

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This research project deals with the statistical prediction of sea-margin because of seasonal effect (wind and waves) in the case the sea-margin is represented by means of speed loss due to weather. The estimating method of speed loss is discussed on the basis of the quasi-probability theory from the viewpoint of propeller racing and deck wetness. The essential algorithm of the statistical prediction for propeller racing and deck wetness are reconstructed by using the probabilistic procedure of time lasting period during which random variable exceeds a value. The algorithms are set up to build the estimating method of speed loss.On the basis of the algorithms, a series of numerical calculations are executed for 150m class container ships with multi-screw propellers. The long-term statistical trend of ship responses (propeller racing, deck wetness etc.) in ocean waves are examined by using satellite information wave data. And a series of experiments are executed with a high-speed boat (Kyushu University fisheries research ship) at sea in order to survey an appraisal of the algorithms.It is certified that the ship responses (propeller racing, deck wetness, ship accelerations etc.) are predicted. However, it is slightly difficult to combine both estimating algorithm of speed loss and the algorithms (propeller racing, deck wetness) for the reason of complexity of those. Further investigations for reconstruction of the algorithms are necessary to estimate sea-margin.