In the first report, the authors et al. have made an experimental study on the viscous effect on thrust deduction using two bodies of revolution. In the second report, theoretical attack to the problem has been attempted by solving the Navier-Stokes equation by the finite difference method with the assumption of eddy viscosity and the calculated results have been compared with the experiments. In the present paper, the calculation is made for high Reynolds Number corresponding to actual ships. The scale effect on thrust deduction is studied based on the numerical results and analytical consideration.