300 SUBMABINK CABLE LAYING AND REPAIRING. 



When the plungers are on the downward stroke there is no 

 pressure below the diaphragm, and water is therefore free to 

 enter from the service, while on the upward stroke water can 

 enter above the diaphragm, thus keeping the chambers always 

 full. One lever opens the water service cocks, and one hand wheel 

 regulates all the moving grids in the diaphragm. The cylinders 

 are enlarged at the diaphragm so that the port area is nearly 

 equal to the full bore of the cylinders, thus allowing the plungers 

 to run without offering any resistance when first starting up. 



In addition to the hydraulic brake, the machine is provided 

 with a screw brake complete with water-service pipes, similar 

 to those on the double machine forward. This would be used 

 for holding a cable " dead," and it can also be used in con- 

 junction with the hydraulic brake if required. The paying- 

 out machine is provided with a double sheave " holding-back " 

 gear, having screw brakes. There is no engine to the machine, 

 but, in case it might be necessary to haul back at any time, a 

 worm gear is provided, arranged to drive from the winch by 

 ropes. The machine is very compact and occupies less space 

 than one of the older type. 



It is now known that a ship is much better under control in 

 strong tideways by paying out cable from the bows. With a 

 sea or tide running, say, at right angles to the proposed route, 

 the cable is paid out from the bows on the weather side and 

 the ship's head kept in a direction between those of the route 

 and tide, the exact angle depending on the velocity of the latter. 

 By this means cable falls clear of the ship, and with her head 

 to the weather and stern free she is easily steered. When 

 paying out from stern, the weight of cable hanging is almost 

 equal to anchoring the ship, with the result that she is easily 

 swung round in a beam tide. These remarks apply only to 

 shallow-water work in strong tides, such as prevail round our 

 coast. Moreover, the heavy armouring necessary to resist 

 wearing effect of tide-wash increases weight hanging to ship 

 and brake power required. In deep-sea work these considera- 

 tions do nob apply. Cables are light, brake power small, and 

 no tides to cross, and it is found that for lengths above ten 

 miles paying out from stern is preferable. 



On cable-ships special smartness is necessary in handling the 

 ship. On some ships, in addition to the ordinary hand wheel 



