83 



ENGINEERING PROGRESS IN THE U. S. NAVY. 

 COAL CONSUMPTION TRIALS . 



Chester 



Birmingham . 



Salem 



Chester 



Birmingham. 



Salem 



Chester 



Birmingham . 

 Salem 



Knots. 



10.03* 

 9.86* 

 9.90* 



19.90! 



i9.83t 



20.25t 



25.o8t 

 24.oot 



24-32t 



Coal consump- 

 tion, tons, 24 

 hours. 



42.06 

 32.14 

 53-85 

 162 .90 

 153.45 

 202 . 03 

 429.40 

 375-72 

 415-15 



Make-up feed 



water, tons per 



day. 



10.97 

 10. 10 

 11.66 



17-51 

 26.10 

 16.80 

 27.00 

 120. oo§ 

 45-63 



*Test, 96 hours. fTest, 98 hours. |Test, 24 hours. §I,eak in receiver pipe. 



This list gives the water losses in the scout cruisers on three trials : — 



1 . At low speeds, slightly in favor of reciprocating engine. 



2. At one-half and full power the losses in reciprocating-engine very great 

 over that of the turbine-driven ships. 



I would refer you to "Jane's Fighting Ships," 191 2 edition, for an article on 

 "Progress of Warship Engineering," which compares two Italian battleships, 

 the San Giorgio with reciprocating engines, the San Marco with Parsons turbines. 



As regards the question of maneuvering, there are over 44 shaft turbine-driven 

 battleships and battleship cruisers now being handled successfully and easily. I 

 do not consider the backing tests made during the builder's trials any criterion. 

 In every case we have been very cautious about stopping the engines, and there is 

 no question but that this can be done in very much quicker time with absolute 

 safety to the machinery. The astern turbines are designed to develop 55 per cent 

 of full-ahead power with the same quantity of steam. 



In the case of the destroyers, on the builder's trials of the vessels finished this 

 year, the backing tests were carried out practically twice as quickly as they were 

 originally, and it was a matter of special comment on the way the boats stopped, 

 when put full speed astern, going 29I knots ahead. This will apply in a similar way 

 to battleships. 



CONCLUSION. 



As regards the choice between reciprocating engines and turbines for battle- 

 ships, I do not consider that the Navy Department has ruled in favor of recipro- 

 cating engines, for in the two battleships recently awarded one is being fitted with 

 reciprocating engines and the other with Curtis turbines. 



