PROGRESS IN TURBINE SHIP PROPULSION. 67 



faces. Several teeth were cracked. Subsequent examination of steel indicates defective material, most 

 probably due to faulty heat treatment, the fracture indicating the steel had been burned. This was con- 

 firmed by discovery that some teeth in port high-speed pinion were also cracked, although no failure oc- 

 curred in service. Both pinions were forged from the same billet and treated at the same time. These 

 pinions are similar as to material and design with twenty-five other pinions now in successful operation. 



NOTE E. 



S. S. Avondale. — An American oil tanker, built by the Chester Shipbuilding Company and being operated 

 by the Pan-American Oil Company for the United States Shipping Board. Just as ship was leaving Phila- 

 delphia for trial trip a heavy blade rub was heard in high-pressure turbine. Inspection indicated defective 

 workmanship. Some of the rotating blades were loose as a result of having been improperly put in. The 

 spindle was rebladed and ship proceeded satisfactorily from Philadelphia to New York. This turbine is a 

 counterpart of twelve others now in successful operation on various ships. 



NOTE F. 



S. S. West Ford. — This vessel left Seattle at 5 p. m. on July 14, 1918, on her maiden voyage to an 

 Atlantic port. Seven hours out from Seattle, oil commenced foaming out from the turbine, running over 

 the engine-room gratings. The chief engineer was called and, instead of investigating the reason for 

 augmentation of the oil, he was content to pump 200 gallons to a reserve tank. Later the same thing oc- 

 curred, oil again running out on the gratings, and later still at 2.14 a. m., the high-pressure turbine com- 

 menced vibrating so badly that it interfered with their lighting system. They shut down to remedy the mat- 

 ter of the lighting system, and on trying to start the turbine it required 125 pounds initial pressure to revolve 

 it. Serious vibration was again in evidence so the Chief decided to do what he termed "crank up on the 

 thrust." It was impracticable to anchor so they returned to Port Townsend at 40 revolutions per minute. 

 They then made an observation of the oil in the drain tank, and on removing the cap the oil squirted to the 

 roof of the shaft alley. It was later discovered an oil cooler tube had split, admitting large quantities of 

 salt water to the oil system. 



Instructions had been given that the level of the oil in the drain tank should be regularly observed, 

 and it is incomprehensible that it was not at once obvious that something was getting in the oil system 

 from some exterior source. Merely looking at the oil would have determined this was salt water. Then 

 all that would have been necessary was to shut off the water service to the cooler and separate the relatively 

 small quantity of salt water from the gravity tank, and there need have been no interruption whatsoever. 

 The result of such neglect was for the bearings, for want of lubrication, to let the rotor down, causing con- 

 siderable injury to the turbine. 



NOTE G. 



U. S. S. Arizona. — On a voyage from Cuba to the United States the teeth of one of the crusing gears 

 scored. Subsequent investigation showed that the oil pumps had stopped and the supply to the gears had 

 failed. The teeth were dressed up and no further trouble has been experienced. 



As in land installations, the overall economic performance is not dependent on 

 the prime mover alone. High performance is not to be secured without care being 

 bestowed on all the ancillary apparatus, attention to matters of heat balance with 

 the feed water heater, condensing apparatus capable of performing with a close 

 approach to the ideal, etc. 



Large size land turbines have been built which deliver to the shaft not less than 

 about 8o per cent of the theoretical energy available from the steam expanding 

 between the limits specified, so that further improvements in the turbine itself 

 will not materially raise this efficiency. Further improvement in economy must be 

 looked for from causes other than the prime mover itself. This is a subject of 

 the greatest importance in view of the rapidly increasing cost of fuel, and it justi- 

 fies considerably more capital expenditure for economizers and other such apparatus 

 which will reduce fuel cost. 



