On the Bottom Structure of Steel Ships

Abstract

This paper consists of two parts written under the following subjects.1. Standard of the Strength of Floor Girders.2. Spacing of Transverse Strength Bulkheads or of Compound Floor Girders.Now the writer begs to explain briefly the meaning of some terms used in this paper in order to avoid miscomprehension or confusion.Floor Girder: A girder consisting of a solid floor plate, main and reverse frames, and shell plate in the case of single bottoms, and a girder consisting of similar member stogether with tank top plate in the case of double bottoms.Longitudinal Bottom Girder:(a) Single Bottom.A girder consisting of keelson plate, keelson and keel angles, foundation and rider plates, and flat plate keel in the case of centre line bottom girder, and a girder consisting of similar members on the side of the centre line of ships in the case of side bottom girder.(b) Double Bottom.A girder consisting of centre girder plate, top and bottom angles, centre line tank top plate, and flat plate keel in the case of centre line bottom girder, and a girder consisting of similar members on the side of the centre line of ships in the case of side bottom girder.Compound Floor Girder-A compound girder consisting of two. or three of the floor girders fitted on consecutive frames and connected between the longitudinal bottom girders by an additional short keelson or side girder. The writer's idea of fitting girders of this kind is to specially reinforce the bottom of ships in lieu of a transverse strength bulkhead, and therefore these girders should be used in association with side frames and beams of the lowest deck specially reinforced, together with suitable number of rivets in gusset connection.