258 



SUBMAEIKE CABLE LAYING AND KEPAIEING. 



aboard. When lowered, the wheels are disengaged and the 

 speed of the sheave is regulated by a brake to a little under 

 the drum speed, so as to feed cable taut on the drum as it leaves 

 tank when paying out. 



Two speeds can be obtained on each set of gear by sliding 

 the pair of wheels on shaft 1 into gear with either one or other 

 wheel on shaft 2. The ratio of gears on each set is different, 

 so that four speeds in all are available. 



The engines are double-cylinder verticals placed abreast and 

 driving the port and starboard sets through bevel gear. The 

 starting valves, reversing gear and brake wheels are all 

 operated from the bridge platform. 



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Fig. 152. — Gear for Driving Hauling Pulley. 



Messrs. Johnson & Phillips, who have fitted picking-up and 

 paying-out gear to a large number of cable-ships, have made 

 several improvements in design, the most important of which 

 are the following. The brake rings are cast with the drums or 

 bolted up to them by internal flanges, so equalising the pulling 

 and holding-back forces at the periphery when paying out. The 

 shaft carrying the two drums is fixed and forms a stiffening tie 

 to the frame. The drums and brake rings are provided with 

 suitable bushings and lubricators and revolve loose on the shaft. 

 By this arrangement the strains are not transmitted through 

 the shaft or the spokes of drum or brake ring, as is the case 

 when these are fast on a revolving shaft and some distance apart. 



