The authors present the results of statistical predictions on the horizontal wave shearing force for a gigantic oil tanker of 310 meters length and similar ships of different lengths. In the first place, the response functions of horizontal wave shearing force are calculated by the aid of the modified strip theory. Then, the standard deviations of horizontal wave shearing force are evaluated based upon the linear superposition theory, by using the caluculated response functions and the formulated wave spectra for given sea conditions. Finally, the longterm predictions of horizontal wave shearing force are determined by the obtained standard deviations and the wave statistics of the North Atlantic Ocean. According to the systematic prediction analysis, the longitudinal distributions of horizontal wave shearing force, which are predicted with the exceeding probability of 10^-6, are investigated in relation to the ship speed, heading angle and ship length.