Long-Term Prediction of Ship Responses Considering Operation to Avoid Sea Conditions of Higher Wave Height

• Published in: Journal of the Japan Society of Naval Architects and Ocean Engineers Vol. 21; pp. 1 - 9
• Main Authors: Miyake, Seijiro, Minoura, Munehiko
• Format: Journal Article
• Language: English; Japanese
• Published: Tokyo The Japan Society of Naval Architects and Ocean Engineers 2015; Japan Science and Technology Agency
• Subjects: Deceleration; Hazards; Ice; Marine; Probability theory; Ship handling; Ship speed; Ships; Significant wave height; Significant waves; Tables; Wave data; Wave height; Wave period; Wave scattering
• ISSN: 1880-3717; 1881-1760
• DOI: 10.2534/jjasnaoe.21.1

Distribution characteristics of wave occurrence probability influence long-term prediction results that have estimated by using short-term ship responses and a wave scattering table. Because the observation volume of data and methods of analyzing wave data in each scattering table of significant wave height and mean wave period are different, long-term prediction results depend on the scattering table to apply. Especially, the difference of the frequency count of higher wave height in the scattering table strongly affects the results. When a ship encounters a severe wave condition, the ship speed decreases (nominal speed loss). When the wave condition becomes more severe, the captain judges the deceleration and the change of the course to avoid the danger of the damage of the ship. A long-term prediction method that has modeled the nominal speed loss and the ship handling is necessary to obtain a realistic prediction value. In this paper, the characteristics of a higher wave height for variety of scattering tables are investigated. Additionally, this paper proposes a long-term prediction method that models a situation when a ship is operated in such a way so as to avoid higher waves. Finally, this paper investigates the influence on a long-term prediction when the occurrence probability of a higher wave height is changed.