抄録
Authors devised a theoretical formula to explain the method of "Williamson turn" as described in "Naval Shiphandling" published by U.S. Navy. This formula based on simple approximations and steering indices T and K. We examined the reliability of the formula by the ship experiment of G.T. 150t-training ship to obtain satisfactory result. Then we may know theoretically the most suitable chance of reversing the helm in the "Williamson turn".
