Abstract
Recently classification societies developed the rules for mammoth tankers, but no definite theory is established for their structural arrangement. In order to find out the most effective structural arrangement an investigation has been made to analize the structural rules from the standpoint of saving the material. The conclusions are as follows : 1) The requirements of longitudinal strength are slightly different between the classification societies, and the Lloyd's rules are advantageous on weight saving as far as the mammoth tankers are concerned. 2) The depth of ship and the spacing of deck and bottom longitudinals are to be kept maximum as far as possible. 3) Two longitudinal bulkheads are to be arranged in cargo oil tanks unless otherwise required. 4) When the horizontal ring system is adopted, it is better to give each cargo oil tank an equal breadth. 5) To adopt long tank length is advantageous.
