Principles of naval engineering - Historic Naval Ships Association

PRINCIPLES OF NAVAL ENGINEERINGMACHINERYFOUNDATION^n~rn3147.18Figure 2-14.— Deep floor assembly formachinery foundations.Stern StructureThe aftermost section of the ship's structureis the stern post^ which is rigidly secured to thekeel, shellplating, and decks. On single-screwships, the stern post is constructed to accommodatethe propeller shaft and rudder stockbosses. Because of its intricate form, the sternpost is usually either a steel casting or a combinationof castings and forgings. Inmodern warshipshaving transom sterns, multiple screws,and twin rudders, the stern post as such is difficultto define, since it has been replaced by anequivalent structure of deep framing. This structure(fig. 2-17) consists of both longitudinal andtransverse framing that extends throughout thewidth of the bottom in the vicinity of the stern.In order to withstand the static and dynamic loadsimposed by the rudders, the stern structure isstrengthened in the vicinity of the rudder post bya structure known as the rudder post weldment.Figure 2-15.— Bulbous-bow configuration.147.1922