Abstract
The Projected light distribution method is applied to measure the unsteady wave pattern generated by ship oscillating with advance speed on calm water. The merit of this method is that the unsteady wave pattern can be evaluated two-dimensionally. In this method the unsteady wave patterns are projected onto a screen as to the brightness distribution which is proportional to the second derivative of the unsteady wave elevation. The projected brightness distributions on the screen are recorded by CCD video recorder digitally. Transverse cut method introduced by Naito is applied to evaluate Kochin function. The obtained Kochin functions are compared with the results from theoretical prediction and the results from the longitudinal cut method proposed by Ohkusu respectively. For Fn = 0.25 the results show good agreement in the smaller angle region of elementary waves.
