THE CABLE SHIP ON REPAIRS. 



251 



H.M. telegraph-ship the "Alert" (formerly the "Lady 

 Carmichael"). Steam Is delivered to two inclined cylinders 

 driving direct on to pin of crank-disc A. The first-motion shaft 

 (at the top in Fig. 147) carries the crank disc, four eccentric 

 sheaves (two for each valve, with links for reversing), and 

 a pinion of 14in. diameter, gearing into one of 22in. on the 

 intermediate shaft. A pinion of 12in. diameter on the 



Fig. 147. — End View of Cable Gear. 



intermediate shaft drives the drum spur-wheel of 6fc. 4in. 

 diameter, reducing the speed further in the proportion of 

 Q^ : 1, or a total reduction between engine and drum of 10:1. 

 At this speed the gear is capable of lifting ten tons at the 

 bows. The drum is keyed to the shaft and the large spur- 

 wheel driving it is made up in segments and bolted to the 

 internal flange of drum. With this arrangement no strain is 

 put upon the spokes of the drum or spur-wheel, as is the case 



