Sec. 66.11 



STEPS IN PRELIMINARY DESIGN 



475 



The corresponding displacement volume at the 

 nominal figure of 35 ft^ per ton of salt water is 

 577,150 ft'. 



It is again pointed out that the percentages, 

 unit weights, fuel rates, and other values and 

 relationships in these weight estimates may not 

 agree with those used by some reader-designers 

 nor may they continue to be reasonable figures 

 in the light of technical developments in the next 

 few decades. They are intended only as numbers 

 in an example and they in no way affect the 

 procedures in the hydrodynamic design of the 

 vessel carried through here. 



66.11 Second Approximation to Principal Di- 

 mensions and Proportions. The second estimate 

 brings the weight displacement down by 810 t 

 from the 17,300 t of the first estimate. On this 

 basis alone the ship can be made smaller; for one 

 thing, the beam can be reduced from the order 

 of 75 ft to a more reasonable figure. It is to be 

 remembered, however, that the volumes to be 

 accommodated within the hull and deck erections 

 remain substantially the same, and that in the 

 first estimate of volume the hull appeared to be 

 none too large. 



Further, since it is customary to reckon the 



TABLE 66.e — Tentative Hydbodynamic Features of Sbvebal Vessels op Different Lengths 

 For the fourth and fifth approximations, 90 t has been deducted from the hull weights for the shell plating, to give 

 the molded displacement. 



