288 ELECTRIC PROPULSION OF MERCHANT SHIPS. 



Realizing the situation, the U. S. Shipping Board adopted the wise policy of properly 

 training their engineers. Instruction classes were established at the East Pittsburgh plant 

 of the Westinghouse Electric & Manufacturing Company and at the Schenectady plant of 

 the General Electric Company, where the engineers are not only given a thorough insight 

 into the fundamentals of design, but they are afforded the opportunity of coming into direct 

 contact with every phase of the building and testing of units. 



One of the most striking effects of this course of instruction is the change that has 

 taken place in the mental attitude of the men. When they graduate from the course, which 

 extends for about three weeks at each plant, they go back to their ships with a degree, as it 

 were, and in the eyes of their fellow-engineers they are geared turbine experts. Needless 

 to say they do their utmost to live up to their reputation, and they are proud of their abihty 

 to keep out of serious trouble. 



There is no doubt, judging from the reports which have been received, that the 

 engineers who have gone out in command of machinery, after having passed through the 

 course, have proven themselves to be very much more capable and to have more pride in 

 keeping their engines going than was ever apparent in the untrained men, who knew com- 

 paratively little about turbines or gears; and this is only natural to expect. With this ex- 

 ample before us, it can readily be anticipated that a similar course of instruction on the 

 electric-drive equipment would bear corresponding results. 



In connection with geared-turbine units, Mr. Emmet has brought out one or two points 

 which I think would bear comment. In the first place, it seems rather unfortunate that the 

 comparison should have been made between the electric drive and the reciprocating engine, 

 whereas the main interest today is a comparison between the electric drive and the geared 

 turbine. It is probably correct to say that the reciprocating engine will weigh approximately 

 twice what a geared turbine will weigh of corresponding horse-power, so that on this point 

 the comparison is far from being correct. 



Then if we refer to Plate 116, which shows longitudinal sections of the two ships, one 

 with electric drive and the other with the reciprocating engine, we find that the condition 

 as represented is rather fictitious, because instead of having the engine in the center of the 

 ship it could be installed in the stem with just as short a shaft as used with the electric drive. 

 Therefore the space taken up by the shaft alley cannot rightfully be brought into the com- 

 parison. It is common practice in tankers to install the machinery in the extreme after por- 

 tion of the ship. 



The next point on which I would like to touch is with reference to the efficiency of 

 reduction gears. The figiires given in the paper show an efficiency of 95 per cent in one 

 case and 94.7 in the other. These are undoubtedly correct, but we do not know all of 

 the conditions under which the tests were made. For instance, the efficiency of the gears, 

 will depend considerably upon the viscosity of the lubricating oil used. If an oil with a high 

 viscosity is used and the bearing clearances are not increased correspondingly, the friction 

 losses will become quite large, and the indications are that this may have been the condition 

 existing on the tests in question. 



As a comparison with Mr. Emmet's tests I would like to quote some figures from a 

 test made on a 1,500 horse-power, single pinion, double-reduction unit to determine the 

 frictional losses. Two duplicate gear sets were used, coupled back to back, with a turbine 

 on one ginion and a brake on the other. The first test was run with oil at considerably over 

 500 seconds viscosity with a temperature of 97° F., and the losses amounted to 86.5 horse- 

 power per gear, which gave an efficiency of 94.!3 per cent. This corresponds very closely 



