Behavior of ships in shallow and restricted waters

Abstract

Ship motions in open waters and waves are always dynamic and most of the time are nonlinear. Even though behavior of ships in shallow and restricted waters does not sound as violent at first thought, it is equally important in terms of capsizing. There has been so many casualties reported that claimed so many lives. In this study, squat phenomenon is dealt with especially addressing its determination in the preliminary design stage. For this purpose, approximate formulae have been proposed to predict bow squat of ships and compared with the other methods and experimental data found in the literature to come up with a pragmatic method to guide naval architects and masters towards avoiding excessive squat in shallow water. It is known that forward speed plays an important role in squat, hence there exist a Froude number, called critical speed, for a particular ship at which squat characteristics start changing drastically. This fact is also taken into account in the regressional analysis. Some of the results are then compared with that of the similar studies and a real life incident. It has been found that the method compared fairly well with other methods and experiments.