52 A SUBSTITUTE FOR THE ADMIRALTY FORMULA. 



(4) At a given speed ratio the value of C increases as the size of the ship in- 

 creases, as shown in Table 11, Plate 45, and Plate 34. 



MATHEMATICALLY DEDUCED ASSUMPTION OF WHICH THE FORMULA IS BASED. 



y^ c;j i.H.p.xvz . 



By simple solution of the formula for values of its various terms it appears 

 that for ships of 



( 1 ) Same length and displacement, power varies as F'. 



(2) Same length and speed, power varies as D. 



(3) Same speed and displacement, power varies as — 7=-. 



VL 



conclusion. 



In all the tables except Table 9, Plate 43, the indicated horse-power for tur- 

 bine-driven ships is taken equal to the estimated horse-power divided by .92. 



Most of the data given here was taken from various articles in the Journal 

 of the American Society of Naval Engineers and from the transactions of this 

 Society. 



In presenting this formula before the Society, the writer does not claim that 

 it is an accurate means for estimating the speed of ships, but merely one that can be 

 used with more accuracy for preliminary calculations in place of the Admiralty 

 formula. It is also easy to handle and requires less judgment and experience in 

 its application. 



DISCUSSION. 



The Chairman : — This paper presented by Mr. Stevens on "A Substitute for the Ad- 

 miralty Formula" is now open for discussion. 



Naval Constructor D. W. Taylor, U. S. N., Vice-President: — This is the twenty- 

 first general meeting of our Society, so I presume the Society may be regarded as having 

 attained its majority, and I should like to note in connection with this paper what seems to be 

 an appropriate circumstance. I believe this is the first instance in which we have had a paper 

 presented to us by the son of a member from whom in the past we have had numerous valu- 

 able papers, and from whom, I hope, we will also have many more in the future. 



Mr. Stevens, I think, has made a distinct improvement on the Admiralty formula. I 

 also think it needs improvement. The trouble with the original Admiralty formula is that it 

 deals with a question in which there are a number of variables involved, speed, power, dis- 



