It is an important job for ship designer to determine adequate scantling of primary supporting members. For this purpose, it is essential to investigate the structural behaviour of each member of ship structure in advance. The transverse strength of cargo tank has been fully investigated so far. However, few reports on the longitudinal strength of members which are, for instance, deck center girder, bottom center girder, etc. are not issued. Then, the author has analysed the bending moment and shearing force of longitudinal ring, which consists of deck center girder, bottom center girder and centerline vertical web on transverse bulkhead, regarded as grillage structure. And, by making use of the results of grillage calculation, the stress distribution around the bracket toe of centerline vertical web has been estimated by finite element method and good agreement has been obtained in comparison with experiment. In consequence, it will be possible to evaluate the strength of each supporting member in detail based on these results.
