EXPERIMENTAL METHODS FOR DETERMINATION OF THE EFFECT OF SHALLOW WATER ON CONTROLLABILITY OF SHIPS

Shallow water effects on the controllability of ships have been extensively investigated over the past 30 years. This paper reports on experimental investigations in the specially constructed circulation tank of the University of Rostock. The test facilities and measuring equipment developed for the performance of model tests in the tank are described. These include a section of flooring built up of trapeze-shaped elements, the height of which can be adjusted to vary the depth of water in the tank. First results on the effects of water depth on the coefficients of transverse force and yawing moment, as well as on propulsion force and trim are presented and discussed. The magnitude of these factors in shallow water was found to vary considerably from ship motions in deep water. Additionally, investigations have been made of draught and trim angle variations and on motion characteristics under transverse thrust.