PRESENT DAY STATUS OF THE ART 69 



I am glad that Mr. Rigg in No. 14 of his summary backs up my efforts to have adequate 

 (progressive) trials made the rule; it is sad to think of so many opportunities of acquiring data 

 being lost by the absence of such trials. 



The President: — Are there any further remarks? Does Mr. Rigg desire to say any- 

 thing further? 



Mr. Rigg : — Mr. Chairman and gentlemen, I should like to thank Professor Sadler for 

 his remarks, and in closing I would like to ask you to be kind enough, if you recall any ref- 

 erences to the subject, that you will let me have them, that they may be incorporated in the 

 final printing of the Transactions. 



Mr. Gatewood has been kind enough to send some references to the classical Froude 

 experiments, which have been added to the bibliography. These British Association papers 

 give the pioneer work of the elder Froude, from which our modern experimental tank work 

 all dates. 



I wish to thank Sir Archibald Denny for his written discussion; he very clearly states 

 the situation as regards uniformity of experimental tank methods. The proposed adoption of 

 a standard method for publishing information and results is a valuable suggestion. The diffi- 

 culties there to be encountered are considerably less than in the more ambitious and possibly 

 less desirable scheme of uniformity throughout. 



Regarding the temperature effect. Sir Archibald's suggestion that the same vessel be 

 tried under identical conditions, first in the extreme of winter and then in the middle of sum- 

 mer, on an American course, is a very good one, because we have very materially greater ex- 

 tremes of heat and cold than occur in Great Britain. I should like to refer here to Mr. G. S. 

 Baker's 1915 Northeast Coast paper on the effect of temperature on resistance both with and 

 without modifications necessary due to the particular speed at which a vessel travels. 



The President : — The next paper will be No. 7, entitled "Some Comparisons Relat- 

 ing to Electric Propulsion of a Battleship," by Mr. W. L. R. Emmet, Member of Council. 



Mr. Emmet: — Mr. President and gentlemen, this paper does not contain very much 

 text, and it is not necessary to read it. I have sought in this paper to make some comparisons 

 between the cost of electric propulsion, exemplified by the battleship California, for which 

 we are designing the machinery, and other methods of propulsion. Of course this compari- 

 son cannot be an absolutely just one, because I have no very good data concerning the other 

 methods with which I am comparing — I have taken the records of tests of battleships which 

 are some years old, turbine-driven ships and engine-driven ships, and have made certain com- 

 parisons with what the California would do if our guarantees were met. 



I have also presented in this paper three plates (Plates 37-39), which show a 

 comparison between a geared turbine-driven ship, as shown in the paper published some time 

 ago by Sir Charles Parsons, a direct-connected Parsons turbine equipment as applied to 

 the battleship Utah, and the layout for the California, which we submitted to the gov- 

 ernment in connection with our proposals. I made certain comparisons concerning the inter- 

 changeability, compactness and number of turbines in the three different arrangements, and 

 these are just comparisons for these particular cases; but there are many forms of design, 

 of course, which might be compared. 



