We presented already the report [1] **about the prediction of maximum acceleration due to ship oscillation using the model test results and some theory of statistics. Then, to confirm the above results by measurements on actual ship, we have carried out the acceleration measuring experiments on sister high speed cargo liner M.S. Montana-Maru and M. S. Oregon-Maru at New-York route. The period of experiments were long and covered almost fall and winter season of a year. In this paper, we describe mainly about the data obtained by these measurements on actual ships and their analysis. The data obtained by these measurements on actual ship were analized and following results were obtained. (1) Cumulative distributions of overall data are as shown in Fig. 9, 10, 11, 12 and predicted population distribution of vertical and transverse acceleration amplitude are expressed by equation (1). (2) Predicted maximum value of vertical and transverse acceleration due to ship oscillation can be obtained from above predicted population distribution as shown in Table 4 for tested ship. (3) Maximum accelerations shown in Table 4 are definitely related to the maximum accelerations obtained in [1] and therefore we can predict the maximum acceleration of ship differed from the tested ship by the method described in reference [1] with suitable modification. (4) Longitudinal accelerations of tested ship were less than 0.1 g in single amplitude throughout all period of experiments.