In the first report, the authors carried out the various experiments with 1. 3 m ship model on manoeuvrability and response to various disturbances, in the circulating water channel. With these results, optimal control method which minimized the criterion function of cost or damage, was designed and was examined to be realizable by experiments. But criterion function depend on the type of ships, so optimal control method with various criterion function must be examined. In this report, at first, the authors investigate how to change the optimal control with the changes of criterion-function-coefficients γ₁, γ₂ which were defined in the first report. Next, in the case that ship navigates on the settled route in uniform wind, how to make optimal control method realizable is examined.