This paper has been written with a view to examining whether or not it is possible to fix a general standard of the transverse strength of the hull-structure of steel ships. Here not only the transverse members such as floor, side frame. beam and pillar, but the longitudinal members such as shell plate, deck plate and inner bottom plate, which form a transverse belt, are also taken into account.The author's investigations are based on the “Principle of Continuity”.In Section 1, the outline of the “Principle of Continuity” is described briefly. As is well known, this principle developed by Prof. Hovgaard is equal in effect to the “Principle of Least Work” developed by Castigliano and suggested by Dr. Bruhn as a method of solutions of the transverse strength of steel ships. General equations of solution and the formulae for internal stress are given in the same Section.In Section 2, the strengths of standard frame rings are dealt with. The standard frame rings are one frame space in length and are assumed to represent cross sections under various conditions, of a steel ship of particular principal dimensions and draft.The ship is assumed to vary in type, i. e., to be of flush deck type having one or two decks in certain cases, and of one deck type with one tier erection. The number of rows of pillar is assumed to be one or two, and three in two special cases. The results of calculations are shown in tables.In Section 3, the transverse strength of steel ships is considered. The conclusions reached are : 1. The transverse strength of the hull should be considered in association with the stiffening effect of the transverse bulkheads as well as the co-operative action of the longitudinal members which serves to maintain the effect.2. It is not possible at present to fix a general standard of the transverse strength of the hull structure.3. The transverse deflection at the points of support of the transverse members can practically be disregarded when ships having sufficient longitudinal strength are subdivided by suitable number of efficient transverse bulkheads. When the value of the modulus of resistance of the cross section of the hull is not less than that calculated in accordance with the requirement of the Ship Load Line Regulation, the longitudinal strength of the ship is considered sufficient.4. The present method of determining the scantling of transverse members separately on the bases of lateral or axial load or both combined, is considered to be practically most preferable, if not perfectly correct.