802 Transactions of the American Institute. 



vessels from 200 to 3,000 tons. A clutch at one end of the spring 

 has a spare chain passed through it, and that chain is either made fast 

 to the bits or the windlass, clear of the chain cable which the ship is 

 riding by. In case more cable is required the spare piece of chain is 

 let go, Avhen the ship will ride by a cable ; the clutch is taken off in 

 a moment, and the cable veered away as much as required. So long 

 as ships ride in easy tides and in moderate weather the ordinary 

 strength of a cable as guaranteed by proof test is amply sufRcient ; 

 but when a ship is riding in a strong tideway and boiling eddies, or 

 in a heavy sea and hard gales, the case is entirely different. At one 

 moment she forges ahead toward her anchors ; at another she sheers 

 off at an angle of twenty-five degrees, or more, from the course of 

 the tide; again she falls astern, and is suddenly checked. It is at 

 this particular crisis that the anchor either starts from its holding bed 

 or is broken ; the chain snaps, the windlass is upset, or other serious 

 damage transpires. To mitigate this damaging shock in storms the 

 spring is applied. According to a well-known maxim, the strength 

 of a chain is the strength of its weakest link ; no more ; and one flaw 

 is fatal. But if at the moment of severest tension a few inches of 

 stretch can be given by means of a powerful spring the danger of 

 parting is thereby avoided. Many familiar examples might be given 

 to illustrate this well-known law of dynamics. One that will readily 

 occur to all seamen is the common use of fenders, particularly those 

 made of coir and cork combined ; how in a moment an otherwise 

 severe concussion is rendered harmless by throwing such a squeezable 

 cushion between the ship's side and the dockhead, or other rigid body 

 coming in contact. The explanation is obvious. In the one case the 

 shock is instantaneous, and, therefore, mischievous ; in the other the 

 momentum expends itself upon a yielding body, and no damage is 

 done. Precisely on the same principle it is that the use of a spring, 

 sufficiently powerful to act at the moment required, gives relief to a 

 chain by absorbing the surplus strain. Statistics would amply show 

 that where one ship is lost in mid-ocean, at least 100 are lost on various 

 shores. Certificates were read by Mr. Saunders touching the actual 

 use of these cable springs. The statements contained in one of these 

 is sufficiently convincing. H. M. lightship Comet, in Gaspar channel 

 had, previous to applying the spring, parted her cable on an average 

 five times a year. In November last she rode through a cyclone, 

 while two ships, a brig, and two ])owerful steamers, on better anchor- 

 age, within u few miles, each having two anchors down, all parted 



