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Study on Ship Operational Effect for Defining Design Values on Ship Motion and Loads in North Atlantic


 Ships are being operated under consideration of the safety for lives and properties, economical reasons and so on, therefore the sea states in natural phenomena and those actually encountered by ships are thought to be different, and the latter includes some effects of human operational factors (so called “ship operational effect”). Quantitative evaluation of the ship operational effect is important to consider rational wave design loads for the evaluation of hull structure strength.
 The purpose of this study is to evaluate the ship operational effect in actually encountered sea states quantitatively for defining design values on ship motion and loads.
 In this study, the quantitative evaluation of ship operational effect is carried out considering the wave heights and wave periods in the North Atlantic. It was confirmed from the results that the quantitative ship operation effects vary depending on the hindcast wave source. Furthermore, the ship speeds tend to decrease in head, bow and beam seas when the encountered significant wave heights became higher. Moreover some patterns are observed on the typical encountered wave headings in the North Atlantic, which comes from the combination of the features of the North Atlantic routes and the wave propagation directions of the natural phenomena.