船舶建造時における船体変形の研究 (第6報 完結)

抄録

This final report concerns the problem of deformation on the propulsion shafting.
First, from the results observed in actual vessels on berth, it will be shown that the amount of eccentricity of stern tube bossing when plotted against progress of work differs a little with the size of vessel. And the data on this eccentricity on one vessel may be applicable to its sister ship with a considerable accuracy.
Secondly, the relation between the amount of vessel's deformation such as stern rising and the vessel's scantlings, the berth foundation rigidity, and construction seasons will be discussed.
Regarding this problem, some experimental model tests and theoretical investigation were carried out. The conclusions are as follows;
(1) The amount of stern rising due to main deck butt welding is decreased as the vessel's breadth, depth, and plating thicknesses are increased among which the influence of depth is most predominant.
(2) The amount of vertical bending deformation is decreased as the supports and/or berth foundation on which the vessel is being built become more rigid.
(3) The amount of vertical bending deformation is increased to a far greater degree when the vessel is water born than on building berth.
It follows from the aboves that the small, fine, thin vessel, if she is afloat, tends to deform easily by main deck welding, while the large vessel hardly deforms.
(4) The climatic conitions hardly affect the amount of stern rising because the temperature difference between main deck and bottom is very small during summer and winter.
Finally, from the actual vessel's service records, it will be shown that ore carriers and oil tankers tend to deform sagging when they are loaded. It is presumed, however, that even this heavy sagging condition will have only little affect on the deformation of propulsion shafting if the vessel is built with engine aft and the loading is mainly on the tanks or holds in way of vessel's parallel part.