THE SUBMARINE OF TO-DAY AND TO-MORROW. 217 



the design of a seagoing boat. If you want high surface speed you must sacrifice submerged 

 speed, and, on the other side, if you want submerged speed the surface speed must be sacri- 

 ficed. You cannot have both of them at the same time in the same boat, due primarily to the 

 distribution of weights. 



The President : — Gentlemen, we have before us the paper entitled "The Submarine of 

 To-day and To-morrow," by Mr. L. Y. Spear, which has been presented by Mr. Ewertz. 



Mr. Philip B. Brill^ Member: — I would like to ask the gentleman if he can give me 

 a little information on two matters appearing in this paper. In Table I, page 202, type 

 "B," the surface displacement is given as 663 tons. The submerged displacement is 912 

 tons. That gives a reserve buoyancy of 249 tons, or 37.5 per cent of the surface displace- 

 ment. I would like to ask whether the paper as printed is correct, or whether there has been 

 some typographical error. The buoyancy appears to be 



Mr. Ewertz : — I am not in a position to answer that question, as I have not gone over 

 this paper with the author. I had the pleasure of reading it here, and that is as far as I have 

 gone with it. 



I suggest that the Secretary be instructed to ask the author of the paper that question in 

 behalf of Mr. Brill. 



Mr. Brill: — There is another question with reference to matter on page 206, which is of 

 the same nature, and I judge probably the gentleman would not be able to answer that if he 

 could not answer the other question. 



The President : — You might give it to the Secretary, and it can be transmitted to the 

 author at the same time. Indicate what the question is. 



Mr. Brill : — On page 206, Table VI, in the U. S. "K" class, the surface displacement is 

 given as 389 tons, and the submerged displacement is 519 tons, or a reserve buoyancy of 33 

 per cent. That is possible, depending on the condition of load, and I would like to ask what 

 is the condition of load in the surface displacement given, as to the fuel carried and the cor- 

 responding surface radius of action. 



Also, in regard to type "B" on page 202. the surface radius of action is stated as 3,000 

 knots. I would like to ask at what speed that radius of action was made. 



Mr. Elmer A. Sperry, Member: — This is a very important and timely paper, and I hope 

 it will be quite fully discussed. We need all the light on the subject that we can get. The 

 weak points in the submarine to-day are known to be the motive power, and the fact that the 

 submarine has no eye. It is barely possible that in the near future we will find a way to 

 throw a beam out ahead of the submarine so that it can see. Think of the situation of the 

 men who man these submarines, when they are about to emerge from the water, and think 

 of the three or four accidents, very serious ones, that have occurred in England especially, 

 when they have emerged up under a ship and suffered injury. The submarine is very sensitive, 

 the plates are only one-quarter or three-eighths of an inch thick, and any small injury is likely 

 to sink it immediately. 



