At the squatting or critical speed, the bow begins to rise and the stern to settle abruptly, and the increase of ship resistance happens at the same time. Mr, Wigley and other researchers calculated the wave resistance by the Michell-Havelock theory; those conclusions agreed with the experimental results very well even at speeds beyond squatting. Hitherto the effect of trim on the ship resistance has been slight, and Mr, Taylor expresses in his work that the rapid change of trim is a symptom rather than a cause of resistance. From the same point of view the “shallow-water effects” had been analysed by the Michell-Havelock theory, and it has seemed as if this theory solved the cause of increasing resistance. But in the case of the “restricted-water effects” this theory yielded results that differed widely from the experimental results. On one hand Mr, Kreitner dealt with this subject by the one-dimensional theory and explained the wave that is in advance of the ship. This Kreitner's theory could not also explain the increase of ship resistance. The author developed a new theory for the restricted-water and explained the cause of the increase of trim. Then he verified that greater part of the increase of resistance is the resistance by R _??_ρ gV δ/ L , where V =volume of displacement, δ=increase of trim, L =length of a ship. Moreover the author pointed out that the resistance based on the trim or based on the unsym-metrical local disturbance is a possible phenomenon in shallow-water and even in deep-water.