DATA ON HOG AND SAG OF MERCHANT VESSELS. 143 



inches inches 



Station No. i ^ Station No. 6 o 



Station No. 2 ^^ Station No. 7 % 



Station No. 3 % Station No. 8 i^ 



Station No. 4 % Station No. 9 xV 



Station No. 5 o Station No. 10 ^ 



The difference in the above measurements can be accounted for by the varia- 

 tions in fitting packing, cribbing and shoring under the ship. It would be fair to 

 assume that all the packing, cribbing and shores would not be wedged up or fitted 

 uniformly to exactly the same reactive pressure and the ship when under test 

 would naturally deflect the least where the reactive pressure was the greatest. This 

 is evidenced by reference to the check measurements above, taken January 14, 191 5, 

 showing no permanent settlement at stations No. 5 and No. 6 and 3^ -inch settle- 

 ment at station No. 7, which can be accounted for as noted in the foregoing re- 

 garding fitting of packing, etc. 



It was in way of stations 4, 5 and 6 that the extra cribbing was provided hav- 

 ing a ground bearing area of 104 square feet. 



Allowance must also be made in a test of this character for initial settlement 

 where a heavy load is applied. 



It would add considerable interest to the data given in Mr. Smith's paper and 

 this addition, if some of our Lake members could present data of their observations 

 on the usual Lake type in the discussion. 



In a discussion before the Institution of Naval Architects in London on March 

 24, 191 5, Mr. French stated that some of the Lake vessels were sagged as much 

 as 10 inches, which would appear to be excessive. 



DISCUSSION. 



The Chairman : — The paper on "Data on Hog and Sag of Merchant Vessels," by Mr. 

 T. M. Combrooks, Member, is now open for discussion. 



Professor H. A. Everett, Member: — I think with reference to papers of the character 

 of those by Mr. Combrooks and Mr. Gatewood, that the value of such work largely lies in 

 the possibility of tying in the theoretical calculations for deflections with the actually meas- 

 ured deflections under conditions where the load is known, and in that connection we recently 

 did some work, which, perhaps, will be of interest, on the large freight steamers Atlantic and 

 Pacific, built at Fore River. These vessels were not quite as large as the one Mr. Combrooks 

 speaks of, but I will give the dimensions later. In carrying out the work our primary object 



