ENGINEERING PROGRESvS IN THE U. S. NAVY. 91 



that they do not go into the same space, as a matter of practical fact. It is of course 

 true that we can and sometimes have put reciprocating engines in the larger 

 space designed for turbines. 



But, coming back to the subject of the increased horse-power that may be up 

 your sleeve with the turbine-driven ship, my own opinion is, if it is there, as it 

 appears to be, the proper thing to do would be to squeeze down the machinery that 

 you use on the ship, so as to give you the horse-power that is necessary to give the 

 speed you want, and make the ship smaller, or else put the difference to the credit 

 of radius by increasing the fuel, or else add to the protection. 



Mr. Anderson: — The engine-room floor spaces for the five classes of ships 

 are as follows: Delaware, 2,222 square feet; Utah, 3,060 square feet; Wyoming, 

 3,150 square feet; Texas, 3,210 square feet; Oklahoma, 3,480 square feet. 



You will see from this list that the engine-room spaces have steadily grown, 

 and that the Delaware has not been repeated. 



Mr. Luther D. Lovekin, Member: — There has been a great deal of talk 

 about turbines and reciprocating engines and we have learned of their relative 

 merits through the discussion by the various members of this society. Captain 

 Dyson's remarks leave little to add to the great value of the reciprocating engine 

 as applied to a battleship, as they are facts and not mere figures. 



About two years ago I made a very comprehensive study of the excellent 

 work presented by the late Dr. Thurston on the promise and potency of high pres- 

 sure steam. Dr. Thurston predicted the use of steam of 500 pounds pressure and I 

 wanted to see how such a pressure could be best utilized under existing conditions. 

 I found it impossible to design a turbine for large powers that would handle this 

 pressure with any degree of efficiency, in fact, where we use 300 pounds pressure 

 the efficiency of the first stages is very poor. The reason for this is obvious, for 

 as we all know, the turbine is an ideal "volume unit," but regardless of efficiency, 

 we come to a point where casings of large turbines for the high-pressure units have 

 a limit on account of the material necessary to use, viz., cast-iron. It, therefore, 

 seems as though we would come to a standstill unless we again revert to the old 

 reciprocating engine, which is the best accepted "pressure unit" that we know of 

 to-day. 



With the reciprocating engine we would have no difficulty in designing cylin- 

 ders for 500 pounds steam pressure and exhausting the steam from these cylinders 

 at 250 to 300 pounds pressure into properly designed turbines, and a water rate of 

 9 pounds, or even less, would be within reason. 



We all know that if we are to save coal with the steam-engine it must come 

 from the high-pressure end of the heat scale, and I should not hesitate for a moment 

 to design an outfit of reciprocating engines and turbines combined, using 400 pounds 

 steam pressure at the reciprocating engine and exhausting at 200 pounds into 

 turbines, where the expansion would be completed. In order to obtain the greatest 



