Studies on a Mathematical Model for Manoeuvering Motions of Ships Moving Slowly in Shallow Waterways.

本文试图建立浅水中船舶慢行操纵运动的数学模型。本研究包括以下四个部分。(1)为研究船舶低速运动时的水动力特性，进行了详细的系留模型试验。本文从实用的角度出发，在准稳态假设下，对试验结果进行了仔细的分析，导出了一个新的船体力的数学表达式。(2)通过系留模型试验研究了浅水对船体受力的影响。报告了对主要衍生物的影响。（3）对拖轮的性能进行了研究，并对拖轮的顶推能力极限进行了估算。（4）讨论了水动力导数的确定方法，并报道了水动力导数的一种记忆效应。从实用角度出发，推荐了准稳态数学模型。（5）研究了港内船舶的操纵运动，提出了基本操纵的概念，以掌握港内船舶的运动。

In the present report, an attempt is done to establish a mathematical model for manoeuvering motions of ships moving slowly in shallow waterways. The stuties contain the four parts mentioned below.(1) To investigate hydrodynamic properties of ships moving slowly, detailed captive model tests were carried out. Examining carafully the results of the tests, a new mathematical expression for hull forces is derived on the assumption of quasi-steady state from the practical viewpoint.(2) Shallow water effects on hull forces were investigated by captive model tests. The effects on main derivatives are reported.(3)Performances of tugs were studied and the limits of the pushing abili ties were estimated.(4)The procedure to determine hydrodynamic derivatives is discussed and A kind of memory effect on the measured hydrodynamic forces is reported. The quasi-steady mathematical model is recommended from the practical view-point.(5)Manoeuvering motions in harbours are investigated and the concept of elemental manoeuvers is proposed to grasp the ship motions in harbours.