The paper on the stress measurements of the transverse members of three actual tankers were already reported by the author, and after them, similar experiments were carried out on the two tankers under the auspices of the 38th. Research Committee of the Shipbuilding Research Association of Japan. In this paper, were described an approximate calculation method on the transverse strength of tanker by use of Slope-deflection method and the examples of the calculations to be compared with some data of the experiments.