During the launching of a ship, a large sagging moment nearly equal to the maximum one which will be experienced throughout her life is induced. Availing themselves of this chance, the authors have measured the stress distributions and the stress concentrations induced on the several parts of her hull such as transverse sections, hatch corners, expansion joints, under deck girders and so on. Genie, Christina, Nikko-maru, Yamazato-maru and Taiyu-maru were chosen as the experimental vessels. The electric wire resistance strain gauge equipments which were researched and manufactued by the authors have been used in all cases of the experiments. In this report the results of the measurement and brief considerations on them will be described.