566 



CABLE 



Perfection of practice is found when the link and the stay yield together ; in the 

 largest chain cables ever produced, such were the due proportions and symmetry of 

 form affording equality of resistance, that the cross-piece split or broke at the time tho 

 link fractured and opened. 



To measure these chains, or be near them when under such tension, is not without 

 danger. The cable, on being struck, rings out with strange shrill sound, a link may 

 suddenly snap, the chain lashes about, and the fragments fly to a great distance, pene- 

 trating the factory roof at times, and, at the moment of fracture, the link becomes 

 very hot. 



The cables are usually told-off into lengths. The Government length is 12 J 

 fathoms ; for the merchant service the length is 15 fathoms ; as explained, these 

 lengths are united by shackles. In the merchant service cable', larger links are 

 placed at each extremity for the anchor shackle to pass through, but in the Royal 

 Navy cables, each length is alike provided with large links ; thus, then, at any time, 

 any end of any length may be placed to the anchor stock. See figs. 321, 322. 



321 



To obviate evils from the twisting of the chain cable, swivels are inserted : in the 

 Government cables, a swivel is inserted in the middle of every other length ; for tho 

 merchant service there does not appear to be any precise rule. Sometimes one, two, 

 or more swivels may be in 100 fathoms ; and in cheap chains, bought and judged by 

 weight and figures, no swivel whatever exists in the cable. 



'The effect of such twisting, or torsion, is to form a link, and give powerful lateral 

 pressure upon the link ; the stud or cross-piece is forced out, and the link itself may 

 yield at the moment that any flaw from imperfection of welding occurs. 



The mooring swivel is that by which a ship can ride with two anchors down at 

 the same time and two bridles on board the ship. The mooring swivel, being equal 

 in strength to the two cables, is over the bow, and enables the ship to swivel round 

 her anchors without fouling hawse ; in any direction the ship can swing round this 

 swivel or point, leaving her anchors undisturbed, whereas by two cables out, without 

 this, she would require great care to prevent them from fouling, and even being lost. 

 This is an essential advantage of chain over hemp. 



The splicing shackle is to unite or splice a hempen cable to be used on board ship, 

 attached to the chain cable, which lies on the ground or bottom, so that the vessel 

 rides lightly at her anchor, while the iron chain cable preserves the hempen cable 

 from being destroyed by the rocky bottom, and the ship has the light hemp cable 

 rendered buoyant by the water, which lifts portions of the chain cable by the motions 

 of the vessel; and thus, the ship is relieved from weight and the anchor from 

 jerks. 



The splicing shackle, on the Hon. George Elliott's plan, is shown above (fig, 322). 

 The rope is served round an iron thimble A, on the shackle B, with end links, and en- 

 larged links without stay-pins c, D, leading to the anchor, while the hempen cable A 

 goes to the ship. 



In the Royal Navy, 4 cables are employed to moor the ship, two being end to end. 



When the ships lay long on certain shores, the pin or fastening often gets loose by 

 constant tappings and vibrations of the chain cable on the rocky or shingly bottom. 

 Men-of-war at some stations suffered severely in this way, and the commander at 

 Malta had reason to represent it as a very serious matter. Mr. Lenox's plan for 

 securing the bolts and pins is now made a point of contract to be adopted in all 

 fastenings for the Eoyal Navy. 



Simple as it wonld seem to devise a plan, yet it was years before all the difficulties 

 could be surmounted. This arrangement may be understood by reference to the 



