Ship's cable

“ It consists of an exchange of currents sent alternately every ten minutes by each ship. These not only serve to give an accurate test of the continuity and insulation of the conducting-wire from end to end, but also to give certain signals which it is desirable to send for information purposes. For instance, every ten miles{121} of cable paid out is signalized from ship to ship, as also the approach to land or momentary stoppage for splicing, shifting to a fresh coil, etc. The current in its passage is made to pass through an electromagnetometer, [34] an instrument invented by Mr. Whitehouse. ”

“ There are some cables, however, manufactured of four strands; which are chiefly the production of Italy and Provence.
All ships ought to be furnished with at least three good cables; the sheet cable, and the two bowers; best and small.
All cables ought to be one hundred and twenty fathoms in length; for which purpose the threads or yarns must be one hundred and eighty fathoms; inasmuch as they are diminished one third in length by twisting. Besides this length, it is necessary to splice at least two cables together, in order to double the length when a ship is obliged to anchor in deep water. ”

“ Up to 4 P. M. on that day the egress of the cable had been regulated by the power necessary to keep the machinery in motion at a slightly higher rate than that of the ship; but as the water deepened it was necessary to place some further restraint upon the cable by applying pressure to the friction-drums in connection with the paying-out sheaves. By midnight 85 miles had been safely laid, the depth of the water being then a little more than 200 fathoms.
At eight o’clock on the morning of the 9th we had exhausted the deck coil in the after part of the ship, having paid out 120 miles. ”

“ No strain could be placed upon the cable, of course, and though the dynamometer occasionally registered 1,700 lbs., as the ship lifted, it was oftener below 1,000 lbs., and was frequently nothing, the cable running out as fast as its own weight and the speed of the ship could draw it. But even with all these forces acting unresistingly upon it, the cable never paid itself out at a greater speed than eight knots at the time the ship was going at the rate of six knots and a half. ”

“ According to recent statistics, the North Atlantic Ocean is now crossed by no less than 17 cables, the number of cables all over the world being 2937, with a total length of 291,137 nautical miles.
Before describing the actual working of a submarine cable, a few words on cable-laying may be of interest. Before the cable-ship starts, another vessel is sent over the proposed course to make soundings. Galvanized steel pianoforte wire is used for sounding, and it is wound in lengths of 3 or 4 nautical miles on gun-metal drums. ”

“ On September 8th, when only thirteen miles from the Bay of Heart’s Content, just after receiving a summary of the news in The Times of that morning, the tests showed a fault in the cable. The mischief was soon found to be on board the ship, and caused by the end of a broken wire, which, bending at right angles under the weight of the men employed in the tanks, had been forced into the core. ”

“ What is called the shore-end of the cable—i.e., that part nearest the shore, which is thicker than the rest—was first laid by a smaller steamer. It extended from Valentia to a point twenty-eight miles at sea. Here it was buoyed, until the great ship arrived. On a wet day in July, 1866, it was joined with the main cable on board the "Great Eastern," and on the same day that vessel started on her voyage to Newfoundland.
It may seem a simple matter to distribute or "pay out" the cable, but in practice it is exceedingly difficult. ”

“ The regulation of the United States Navy for chain cables, is one inch and a half for a sloop of war, and one and a quarter for brigs and schooners. In the merchant service, a ship of 400 tons would probably have a best bower cable of one and five sixths, and a working bower of one and a quarter inches. A ship of 700 tons would have a best bower of one and five eighths, and a working bower of one and a half inches. Chain cables have a shackle at every fifteen fathoms, and one swivel at the first shackle. ”

“ This was, of course, before the days of cutting and holding grapnels as we now have them, which render it{199} possible for a single ship to effect repairs—even where it is out of the question to recover the cable in one bight.
Fig. 40.—S.S. Great Eastern Completing the Second Atlantic Cable.
Setting to Work: Repeated Failures.—When the Great Eastern arrived on the grappling ground, the Albany (with Mr. Temple in engineering charge) had already hooked and buoyed the cable, but the buoy-chain having been carried away, they not only lost the cable, but 2,000 fathoms of wire rope besides. ”

“ We have fallen into consideration of the length of cables, and by it we resist the malice of the greatest winds that can blow, witness our small Milbrook men of Cornwall, that ride it out at anchor, half seas over between England and Ireland, all the winter quarter.... For true it is, that the length of the cable is the life of the ship in all extremities. We carry our ordnance better than we were wont, because our nether overloops are raised commonly from the water, to wit, between the lower part of the port and the sea. ”

“ Should any interruption of signals from the ship occur by reason of an accident on board, shore will continue to free the Cable at the usual time, and to put to earth direct at the usual time, and in the intervals to put into circuit with the Cable a galvanometer, and watch the same for signals, and continue doing so until communication with the ship is restored, or information is received by other means from the ship. ”

“ The commotion in the testing-room spread instantly to every part of the ship; the whole staff of electricians was at once roused, and soon afterwards the engines of the Great Eastern were slowed and stopped, while, with bated breath and anxious looks, men whispered to each other that there was “a fault in the cable.” ”

“ By what has been said on this subject, we may see how very necessary it is to furnish a ship with sufficiency of cables, or what is called ground-tackle; and what an inconsiderate policy it is in merchants to expose their vessels to such evident dangers from the want of them. For we may venture to assert, without violation of truth, that many good ships have been lost only on account of a deficiency in this important article.
A cable ought neither to be twisted too much or too little ”

“ Then too it is necessary that the ship should answer swiftly and surely to his will; that she should vary her speed, stop, or turn round, as promptly as he desires. The telegraph-ship is the helot of her cargo, and should be completely subservient to the work of laying the cable. A well-found steam-ship answers all requirements. Up till a few years ago no specially built telegraph-ship existed. The majority of cables have been laid from ordinary iron screw-steamers, fitted with tanks to contain the cable and paying-out gear. ”

“ When the first attempt to lay the Atlantic cable had failed,—partly because the number of ships which carried it was insufficient—engineers thought of the "Great Eastern." She alone could store on board the 2100 miles of metallic wire weighing 4500 tons. She alone, thanks to her perfect indifference to the sea, could unroll and immerse this immense cable. But special arrangements were necessary for storing away the cable in the ship's hold. Two out of six boilers were removed, and one chimney out of three belonging to the screw engine ”

“ In other respects a perfectly simple-minded man.
It was in his palmy days that he invited me to run down to Sheerness with him, and go over the ‘Great Eastern’ before she left with the Atlantic cable. This was in 1865. The largest ship in the world, and the first Atlantic cable, were both objects of the greatest interest. The builder did not know the captain—Anderson—nor did the captain know the builder. But clearly, each would be glad to meet the other. ”

“ At forty-five minutes past four, Greenwich time, the cable engineer in charge took one weight off each brake of the paying-out machinery. At forty minutes past seven all weights taken off, the assumed depth being three hundred fathoms. The indicated strain on the dynamometer gradually decreasing. Speed of ship five knots. We are going to try and pick up the cable of 1865 in two thousand five hundred fathoms (and we mean to succeed too) ; therefore should the cable we are now paying out part, it can be understood how easy it would be to raise it from a depth of three hundred fathoms. ”

“ The depth and nature of the bottom, the strength and direction of currents, the temperature at the bottom, should all be ascertained beforehand by a special ship appointed to survey the proposed track of the cable. The best route for the cable is then laid down on the charts, as a guide to the navigator and engineers engaged in the laying. ”

“ The electricians, however, made much of the importance of being in continuous communication with shore during laying operations; and this view appealed to the Board—partly, no doubt, on account of the novelty of being able from headquarters to speak to a ship as she proceeded across the Atlantic. It had, therefore, been arranged for the laying of the cable to be started by the Niagara from the Irish coast, the Agamemnon laying the remaining half from mid-ocean. ”

“ Just as they were winding for the first heavy pull on the cables the right main cable on the under side of the access tube snapped clean in two. The whole system of cables is put out of business. Cap says——"
At this juncture Captain Austin leaped forward and took up the telephone. ”

“ The frame or unit of the ship's structure is suspended on a running block on the cable, which is then made taut, partly by the working of the winch and partly by the large derrick post being inclined backwards. The running block with its load travels down the taut cable by gravity, under the guidance of the squad of fitters. The gradient of the cableway is only sufficient to enable the load to move slowly to its position in the shipbuilding berth. ”

“ The cable was taken into the electrical room by Mr. Whitehouse, and attached to a galvanometer, and the first message was received through the entire length now lying on the bed of the sea.
Too much praise can not be bestowed upon both the officers and men of the Agamemnon for the hearty way in which they have assisted in the arduous and difficult service they have been engaged in; and the admirable manner in which the ship was navigated by Mr. Moriarty materially reduced the difficulty of the company’s operations. ”

“ They ought never in common cases however to be exposed to a greater stress. A cable destined for ships of a certain tonnage, should not be employed in those of greater burden. Thus treated it may be always trusted to do its duty, and will last longer than the ship to which it belongs. A considerable part of this decided superiority which iron cables have over hemp ones, is undoubtedly due to the admirable form contrived by Brunton. ”

“ The testing-room is where the subtle current which flows along the conductor is generated, and where the mysterious apparatus by which electricity is weighed and measured—as a marketable commodity—is fitted up. The system of testing and of transmitting and receiving signals through the cable from ship to ship during the process of paying out must now be briefly referred to. ”

“ Joy over the recent restoration to health of the ailing cable, the comfortable stability of the ship in rough weather, and the satisfactory progress then being made, all contributed to raise the spirits of every one connected with the great work, so that, while some were amusing themselves at the piano, others were scattered about in little groups, discussing the profounder mysteries of electric science, or prophesying the speedy completion of the enterprise, while a few were speculating on the probability of sport in Newfoundland, or planning out journeys through the United States. ”

“ It must be understood, however, that although the testing of the cable went on continuously during the whole voyage, the sending of messages was not frequent, as that interfered with the general work. Accordingly, communication with the shore was limited to a daily statement from the ship of her position at noon, and to the acknowledgment of the same by the electrician at Bombay.
One of the greatest dangers in paying-out consists in changing from tank to tank when one is emptied, and a full one has to be commenced. This was always an occasion of great interest and anxiety. ”

“ Captain Anderson had an idea that we grappled it for a moment soon after noon, when the ship’s head came 3 points to the N., and the strain increased for a moment to 60 cwt. The buoy was now 21⁄2 to 3 miles E.—ship’s head being W.N.W. All that could be done was to take up grapnel, and make another cast for the Cable. The wind increased from eastward. At 4·15 p.m. ship’s head was set N. by E. by screw, in order to enable the grapnel line to be taken in, and the capstan was set to haul up the grapnel. The wire rope came over the bows unstranded, and in very bad condition. ”

“ It is sad to think of the way this poor old ship was metaphorically passed from hand to hand. Even at this period three separate companies had already been formed one after another to work her. As promoter and chairman of one of these, Mr. (afterward Sir Daniel) Gooch took an active part in arranging for her charter on this undertaking, and it was in this way that he became a prominent party in the enterprise.
All the cable machinery was fitted to the Great Eastern, on behalf of the Telegraph Construction Company, by Mr. Henry Clifford to the designs of Mr. Canning and himself. ”