DATABASE SYSTEM APPROACH FOR PREDICTING SHIP MANEUVERING PERFORMANCE

已经发生了如此多的致命事故，可能会造成严重的海洋污染，国际海事组织正在讨论操纵性标准。因此，在设计初期对船舶操纵性能进行预测就显得尤为重要。建立了船舶细节、水动力和操纵性能的数据库，并开发了三个数据库之间的关系估计程序。操纵性能数据库包含了约760艘船舶的海试结果，这是有史以来最详细的一次。为了研究船舶主要细节与操纵性能之间的关系，对这两个数据库进行了统计分析，并成功地找到了转向能力的经验公式。然而，很难找到主要细节与方向稳定性之间的明确关系，还努力寻找主要细节与水动力之间的关系。似乎有可能估计这两个数据库之间的大致关系。然而，为了以足够的精度估计操纵性能，必须考虑船型，特别是船尾的形状。船型的概念是有效的，并指出应研究将数据库方法与水动力估计的理论方法相结合。为了评估人类控制下船舶的方向失稳允许极限，人们广泛开展了模拟器研究，并结合上述极限和由数据库分析估计的可能水平，提出了该能力的标准。该提案成为日本政府向国际海事组织提出的标准方案。

There have been so many fatal accidents which may cause serious marine pollutions and the maneuverability standards is now under discussion at the IMO. Then it becomes important to predict maneuvering performance of ships at the initial design stage. In the present research a database system is investigated for such predictions.The databases of ships' particulars, hydrodynamic forces and maneuvering performance were built up and the procedures to estimate the relations among three databases have been developed. The database of maneuvering performance contains the sea trial results of about 760 ships and this is the most detailed one ever built.To investigate the relation between ships' principal particulars and maneuvering performance, both database were analyzed statistically and the empirical formulae were successfully found for turning abilities. However, it is difficult to find the clear relation between the principal particulars and the directional stabilities.An effort was also paid for finding the relations between the principal particulars and the hydrodynamic forces. It seems possible to estimate the rough relations between both databases. To estimate the maneuvering performance with enough accuracy, however, hull forms, especially of sterns must be taken into consideration. The concept of type ship is shown effective and it is pointed out that the combination of the database approach and theoretical procedures of hydrodynamic force estimations should be investigated.To evaluate the allowable limit of directional instability of ships under human control, simulator studies were widely carried out and the standard of this ability was finally proposed, taking account of the above limit and the possible level estimated from the database analysis. The proposal becomes the standard plan proposed by Japanese government for the IMO.