Study on Prediction Method for Ship Manoeuvring Motion in Shallow Water

大型油轮一旦发生海难，往往会造成严重的石油污染和环境破坏。国际海事组织（IMO）通过了船舶操纵性临时标准，从海上安全的角度消除了操纵性不足的船舶。鉴于浅水区海难的发生，由于船舶的操纵性能取决于水深，因此有必要开发不仅在深水而且在浅水区的操纵性能预测方法。准确地估计作用在船舶上的水动力对于预测船舶的操纵性能是非常重要的。提出了基于细长体理论的深水船体水动力预测方法。采用预测方法可以考虑对水动力有较大影响的船体形状。结果表明，用预测方法预测的水动力与实验结果吻合较好。此外，航向稳定性作为重要的操纵性能之一，可以用由预测方法估计的水动力导数来评估。我们还研究了预测方法在浅水区的推广。该预测方法在初始设计阶段具有足够的精度，可供实际应用。

Once marine disaster of large oil tanker breaks out, it often causes serious oil pollution and destruction of the environment. International Maritime Organization (IMO) adopted interim standards of ship manoeuvrability to eliminate ships which have insufficient manoeuvrability from viewpoint of marine safety. In view of outbreak of the marine disaster in shallow water, it will be necessary to develop prediction method for manoeuvring performance not only in deep water but also in shallow water because manoeuvring performance depends on water depthe. For predicting ship manoeuvring performance, it will be very important to estimate the hydrodynamic forces acting on a ship with high accuracy.We developed prediction method of hydrodynamic forces acting on ship hull in deep water based on slender body theory. We can take account of hull form which has much influence on the hydrodynamic forces by using the prediction method. It was shown that hydrodynamic forces predicted by using the prediction method shows good agreement with experimental results. Furthermore course stability which is one of the important manoeuvring performance can be evaluated with hydrodynamic derivatives which is derived from the hydrodynamic forces estimated by the prediction method. We also investigated expansion of the prediction method in shallow water. The prediction method has enough accuracy for practical use at initial design stage.