TEN THOUSAND DEADWEIGHT-TON TANKER. 325 



percentage of length, divided by entrance, parallel middle body, and run, I think it would 

 help out ; and also the general shape of the sections, whether V-shape, U-shape, or medium 

 shape. 



Mr. E. H. Rigg, Member of Council: — I have taken up too much of your time this 

 afternoon and will not take up any more than a few minutes now. I think we are to be 

 congratulated on having made available from time to time the standardization results of 

 typical merchant vessels at full load draught. As Mr. Everett says, they are generally not 

 readily obtained ; in this particular case, an oil tanker, the loading is easier, and it is grati- 

 fying that the builders and owners have seen fit to contribute the results of the model tank 

 tests compared with the actual runs. I would make one suggestion in connection with 

 the question of standardization, and that is, instead of making runs in pairs, which I think 

 was done 



Professor Everett: — They step up 



Mr. Rigg : — I have evidently not as yet read the paper carefully enough to catch that 

 point. What I was going to say was that the runs should be made in sets of three, as the 

 Navy does, rather than in pairs, in order to eliminate tidal variation. The stepping-up 

 method has a decided advantage in that R. P. M. have to be held with accuracy only during 

 single runs. Could you decide definitely as to whether a ship had actually made her contract 

 speed without a regular set of three or five high runs? 



We ran an oil tanker standardization recently on the Delaware breakwater course and 

 had some trouble with the wind. 



Our analysis of the results showed that a loss of about 0.3 knot at full power was caused 

 by the 20-mile breeze blowing down the course; however, I do not consider the data accu- 

 rate enough for recording in detail, though it is clear that for trustworthy results the trials 

 should be rtm over again on a day of less wind. 



Mr. Hugo P. Frear^ Member of Council: — I would like to ask where the vessel was 

 tried and the depth of water on the course, and whether or not any correction is necessary on 

 account of depth of water. 



Professor Everett: — There was about 120 feet mean depth of water. 



Mr. Frear : — Was that on the Annapolis course ? 



Professor Everett: — ^Yes, right off Annapolis. 



The Chairman: — Is there any further oral discussion? If not, I will ask the Secre- 

 tary to read a commimicated discussion by Chief Constructor D. W. Taylor. 



Rear Admiral D. W. Taylor, C. C, U. S. Navy, Vice-President (Communi- 

 cated) : — This paper, giving actual results of careful trials, is of the type which is always 

 welcome to our Transactions ; its value is permanent, for those of the profession interested 

 in such matters refer to such papers for years. 



I was particularly interested in the method adopted for running trials, as it follows to 

 some extent one of two methods proposed by me some years ago as desirable. The cor- 

 rections for wind effect constitute a new departure, and I think few of us have realized how 



