Abstract
The water-lines of cargo ship forms, regarding as the straight lines at bow, midship and stern parts and the free stream-lines connecting these, are determined by the Schwarz-Christoffel method of conformal transformation for the both cases of the limited and unlimited widths of water. Comparing the distributions of pressure and velocity of water along these water-lines, the effect of the side-walls of an experiment tank upon the resistance of a model towed in it is discussed two-dimensionally, with some experiment results.