ENGINEERING PROGRESS IN THE U. S. NAVY. 97 



son is arrived at by basing water consumption of machinery on the effective horse- 

 power results obtained with the models of vessels pulled in the experimental tank. 

 This method is correct when we have similar types of machinery working under 

 the same conditions as to steam pressures and temperatures, vacuum, and feed 

 temperatures, but when these conditions are different we must reduce to British 

 thermal units required to evaporate this water from similar conditions of feed 

 temperatures, where it is possible to obtain such similar condition, exactly as it is 

 done when we compare the efficiencies of boilers of different types by a comparison 

 of rates of evaporation under similar conditions of fuel consumption, reducing the 

 results to "from and at 212 degrees Fahrenheit." He carries this mistake into his 

 comparison of the water consumptions for the auxiliaries, and makes no allowance 

 whatever for the greater amount of heat required to evaporate a pound of water 

 under the Delaware conditions over what was required under the Utah conditions, 

 thus exaggerating the apparent difference between the two vessels, and attempting 

 to cast discredit on the Delaware's performance by such exaggeration. I thoroughly 

 agree with Mr. Anderson in his statement that the only way to arrive at a true 

 comparison between the Delaware and the Parson turbine-driven ship is to send 

 them out together for runs at cruising speeds, but modify it by stating that they 

 should be under similar conditions as to displacement and length of time out of 

 dock, and that the runs attempted should be for not less than 5,000 knots. 



He speaks of curve D as being hypothetical. In this I do not agree with him. 

 If it were not possible for the Delaware to carry the same feed temperatures as the 

 Utah we might regard the case as being hypothetical, but where these feed tempera- 

 tures can be obtained, and the condition of curve D be made actually to exist, it 

 is perfectly fair to reduce the consumption of British thermal units to this curve. 



Referring to the measurements of water consumption on the Delaware and to 

 the guarantees for this vessel which were required of the contractors, I would state 

 that the only guarantee was the speed guarantee. There was absolutely no guar- 

 antee on fuel consumption, nor on water consumption. The water consumptions 

 were measured as accurately as it is possible to do such work on board ship. The 

 reserve feed used was discharged into the measuring tanks and was weighed with 

 the other water so that the weights of water given do include the reserve feed used. 



Mr. Anderson's statement that the "loss water, or make up feed water, has 

 never been checked on a battleship trial; in a reciprocating engine it amounts to 

 a very large quantity at the higher speeds," is in the case of the Delaware absolutely 

 incorrect. Furthermore, there being no penalty on water consumptions in the case 

 of the Delaware, and as both the contractors and the Bureau were extremely de- 

 sirous of obtaining as accurate data of water consumptions as possible, for use in 

 future design work, there was no attempt whatever made by the contractors to 

 jockey the results, and the water measurements were checked by both representa- 

 tives of the contractors and by representatives of the Bureau of Steam Engineering. 



Mr. Anderson intimates that the engine-room weights given for the Utah are 

 not correct. In reply to this I would state that the weights which I quoted cover 



