ON THE PREDICTION OF IMPACT PRESSURE DUE TO BOTTOM SLAMMING ON A CONTAINER SHIP

The phenomenon of ship slamming has been known for a long time in ship design history and is one of the heaviest responses which a marine vehicle is subjected to in rough weather. In this paper the authors use a conformal mapping technique which maps an arbitrary section to a unit semi-circle using a three parameter and two parameter fit. The coefficients thus obtained by the transformation are put into the regression equation of Ochi to predict the slamming pressure at the bottom of a high speed container ship (SL-175). The mapped coefficients are obtained by using the following input data, i.e. half breadth, one tenth draught, sectional area and centroid of the ship section. These results are also compared with the experimental work carried out on a container ship model. Results of vertical acceleration, vertical relative motion, heave and pitch motion measurements in regular waves are also presented. The theoretical method developed about serves as an important tool at an early stage of ship design for predicting slamming pressure in regular waves.