A REVIEW OF THE PREDICTION OF SQUAT IN SHALLOW-WATER

Recent evidence has shown that the effect of a ship moving in shallow water and the resultant squat are not well understood. This paper revi ews the general problem of a ship in shallow water and illustrates the corresponding resistance, trim and sinkage at both sub-critical and a lso at super-critical speeds. The paper then reviews the various metho ds of predicting the squat of a ship in shallow water in the sub-criti cal range, which is applicable to most skips. It is suggested that the simple rule-of-thumb methods are, at best, unreliable and the paper g ives examples of empirical methods which have been tested against vari ous sets of data and seem to give more representative answers. A summa ry of the notation used is given at the end of the paper.