PROGRESS IN TURBINE SHIP PROPULSION. 



61 



of the pinion, thus demonstrating the adaptabiHty of the floating fi-ame to its in- 

 tended function. 



While this demonstration plainly opened the way for the application of the 

 steam turbine to the driving of all manner of ships without reference to speedy 

 obviously permitting fuel costs to be reduced in amounts of 15 per cent to 20 per 

 cent, the application to ships was slow, possibly because of the small number of ships 

 being built in this country and undue conservatism on the part of shipowners. The 

 reduction gear was, however, applied to a large number of land installations with 

 uniform success. It is argued by many that the performance of land machinery 

 can be no criterion of its suitability for marine work. This is particularly true in 

 the respect that alignment once secured on land will generally remain unimpaired 

 for an indefinite period, while, on the other hand, continual disturbances of align- 

 ment of necessity will obtain on ships. There is one respect, however, in connection 

 with these gears in which their application to land work is more exacting than in 

 marine work, owing to the much greater inertia of the slow-speed generator as com- 

 pared with the ship propeller. The gear operates between much more massive fly 

 wheels than in the case of the marine installation, demanding extreme accuracy of 

 gear cutting, so far as any errors of pitch which might result in any unequal an- 

 gular velocity are concerned. Any errors of this character, quite unobservable when 

 the gear is driving the relatively low inertia ship's propeller, will rack and pound 

 badly when driving heavy generators. 



In spite of the advantages ofl^ered by the geared turbine there were but few in- 

 stallations contemplated in this country until the complexion of the shipbuilding in- 

 dustry was completely changed by the war, although the collier Neptune was equipped 

 and contracts were placed for the destroyer tender Melville, as well as the cruising 

 gears for some battleships. Parsons had, in 1910, done some exploiting with the 

 fixed bearing gear in the S. S. Vespasian, transmitting 500 horse-power per pinion. 



So far as land gears are concerned. Table I shows those constructed by the 

 Westinghouse Company up to 191 5 and since: — 



Table I. 



