52 STEEL SHIP CONSTRUCTION 



figures are used to show this average to date. As drawn up, these graphs are in- 

 tended for use by the general superintendent and the general foremen responsible 

 for the different activities. For the information of the men the same general idea 

 can be followed out with such changes as may seem desirable. It is suggested that, 

 for this purpose, daily performance be used in connection with blackboards at each 

 way and in the fabricating shops. 



In considering these records it will be noticed that the steel fabricated at the 

 end of twelve weeks is 12 tons short of the required average output, that steel 

 erected is 39 tons short and ship rivets 3,000 short. Investigation or study of the 

 data recorded shows at once that the steel erection is not keeping pace with the 

 fabricating, while the rivetting is being held back on account of erecting. This in- 

 formation in the hands of the general superintendent tells him, beyond any ques- 

 tion, where to concentrate his attention to correct troubles or remedy faults not un- 

 der control perhaps by the erecting foremen. Naturally this would be done before 

 twelve weeks had elapsed ; in fact, his attention would have been called to existing 

 conditions after the second or third week, and the results at the end of the twelfth 

 week would show the extent to which he had been able to correct the trouble. In 

 actual practice, of course, it is highly probable that the erecting and rivetting records 

 were below the standard set for well-known reasons, but the fact remains that the 

 yard has fallen down on the program because the erectors have been unable to keep 

 up with the fabrication, also that the daily average output of the fabricating shops 

 was not up to standard. 



As a final example of the necessity of giving consideration to all the elements 

 involved in shipbuilding, the curves shown in Plate 30 were developed as indicative 

 of what happens in actual practice. A five-way yard is taken with a man efficiency 

 of 35 equivalent deadweight tons per man per year. The problem is treated from 

 two points of view, namely : — 



1. Constructing cargo vessels of different deadweight tonnage on a fixed 100- 

 30 building program. 



2. Constructing cargo vessels of different tonnages at a fixed fabricating 

 capacity. 



It is evident that a fixed building program involves different fabricating capa- 

 cities and number of men per way for ships of different tonnage, while, with a fixed 

 fabricating capacity, the men per way remain the same but the building program 

 varies. That a proper comparison between these two conditions might be made, it 

 was assumed that the yard was organized and equipped to build 5,000 deadweight- 

 ton ships on a 100-30 building program. 



The conclusions to be drawn from a study of these curves show, beyond any 

 question of doubt, that construction costs are dependent to a very large extent on 

 tonnage, and, consequently, that each individual yard should confine itself to vessels 

 that come within its field. Just what the field of any yard might be is determined 

 from the most economical building program at a given man efficiency for ships of 

 different tonnage. For a 7,500 deadweight-ton cargo ship (see Plate 21) the most 



