The second wave-maker of plunger type has been set up at a right angle to the first one in the No. 1 Ship Model Basin of the Ship Research Institute to generate short-crested waves from two directions, as a part of a co-ordinated programme of long term research based on the view that it is reasonable to expect a fairly complete description of various hydrodynamic forces acting on ships in waves in relation to ship motions to be achieved eventually, and that this will provide a tool capable of solving most structural design problems. Model tests in short-crested regular cross waves were carried out and analyzed with special emphasis on the roll and pitch motions of an ore-carrier at the full load condition. The ship responses in long-crested regular waves were simply superposed, and the results were compared with those measured in short-crested regular waves. The varidity of the linear superposition principle was examined to the prediction of ship motions at various headings to the waves.