The present is peculiarly a scientific age, rife with great enterprises which have originated within the memory of most people. It is not a great many years ago when the completion of the first ocean telegraph was celebrated with great pomp and enthusiasm. Transoceanic telegraphy is distinctively a modern institution ; as such it is necessarily controlled by modern methods. One of the great companies, the Commercial Cable Company, owns and operates three complete submarine lines between Europe and the United States. To keep these cables in order this enterpris ing company has a fine steamer, the Mackay-Bennett, which was built especially for the purpose by John Elder & Company, at Govan on-theClyde, at a cost of $320,000. She is 260 feet long, 40 feet beam, and 22 feet deep, and is propelled by twin screws driven by independent compound engines, each having a high pressure cylinder 15 inches in diameter and a low pressure cylinder 25 inches in diameter, the stroke heing 3 feet. The combined horse power of the engines is 1,500. The gross tonnage of the vessel is 1,700 and the coal capacity is 750 tons. Her speed is 12 knots per hour. The Mackay-Bennett is provided with three cable-holding tanks with a total capacity of 385 nautical miles; tank 1 holding 60 miles; 2, 195 miles; and 3. 130 miles. The central cores around which the cable is coiled are utilized as fresh water tanks. The steamer is fitted up with all the modern machinery for grappling, picking up and paying out cable. It is lighted throughout by electricity and is furnished with electric search lights, so that work can be carried on during the night. The steering is done by steam, and the necessary steadiness is secured by hilge keels. The vessel is provided with a bow rudder, so that it can steam astern. The maneuvering qualities are excellent: A staunch steam launch is provided, which is much used in work near the shore. On the deck are placed two powerful engines for heaving in and paying out the cable. At the bow and stern are placed immense sheaves, as shown in our engravings, over which the cables pass when delivered or received. The engines tor handling the cable are geared to drums 6 feet in diameter, 2 feet in width, each being mounted on a shaft 11 inches in diamc'ter. The cable, which is wound severai times around this drum, passes over quadrants or guides at the hatches. If it is being taken up, it is coiled around the core in the tank below, as shown in the large engraving. In this case it requires a powerfnl engine to bring it up from the depths of the ocean, but where the cable is paid out, it simply passes over the drum, which is then detached from the engines, and the paying out is controlled by a brake operated by the man on the platform. The cabie in its passage to the bow or stern of the steamer goes under the sheave of the dynamometer, which iudicates the amount of tension on the cable. -'fhe strain on the cahle usually ranges from two to three tons. On the upper deck at the bow and stern are electrical signals, by means of which the engineer in charge of the ship's engine and also the engineer in charge of the cable handling engines may be notified to stop, start, or go ahead or astern, fast or slow, as circum stances may require. Attached to the shaft of the drum is an indicator which sllows the number of miles of cable paid out or taken in. On the deck of the steamer are guides which lead to the different tanks. The cable may be drawn from either of the three tanks by either of the cable handling engines. Upon the deck are carried huoys, which are launched and to which the cable is secured when it is desired to detach the cable from the steamer, and leave it to be subse- quently picked up and extended. The cable tanks are watertight, and the cable is kept in water, and while the laying of a cable is going on, electrical tests afe progressing continuously, so that any defect may be detected and remedied before the cable reaches its final resting place upon the ocean bot- tOlD. The electrical testing room has a very complete electrical equipment, and the electrician is always in attendance to discover and locate any faults. To one not familiar with the characteristics of ths electric current, it seems a difficult matter to locate a fault in an ocean cable hundreds of miles at sea, but a competent electrician can generally locate the fault within a few miles. The insulation of the conductor must he maintained in a very perfect condition; otherwise the cable is rendered useless. A puncture in the insulation of the diameter of a hair is sufficient to interfere with the proper working of the cable, and to necessitate the journey of the repair steamer to the point where such an , apparently insignificant thing exists. On reaching the vicinity of the fault the grapnels are thrown out and the cable lifted to the steamer, when it is taken on board and dissected and repaired, the defective section being removed and replaced by a perfect piece of cable. The manner in which the cable is spliced is illustrated in Fig. 2. After the defective portion is cut out, the ends of the cable adjoining the splice are unwound, and the copper conductor at the center is laid bare. The ends of the copper conductor are scarfed and lapped, as shown ; then the joint is secured by soft solder, after which a spiral wrapping of fine copper wire is laid over the joint, as shown at 3 in Fig. 3, four or five fine wires being laid on parallel with each other, forming a spiral wrapping of considerable pitch. Upon the first layer of fine wires another layer is placed which is wound in the opposite direction, thereby causing the wires to cross each other. These wires are soldered smoothly, the interstices being completely filled with the solder, and while the conductor still retains the heat acquired in soldering theguttapercha covering is worked over the joint, as shown at 4 in Fig. 3, the splice having been previously coated with a cement to insure the perfect adhesion of the gutta percha to the metaL The appearance of the cable core after the completion of this step in the process is shown at 5 in Fig. 3. A wrapping of gutta percha is now placed on the joint, as shown at 6 in Fig. 4, this part of the work being done with the greatest of care to avoid the slight6st possible air space communicating with the conductor. The gutta percha covered conductor is served Wl '.h marline (7, Fig. 4), and this is wrapped with fine t vine, as shown at 8 in Fig. 4, aud last of all the wire armor is replaced. The total length of the splice is from 40 to 80 feet. The operation of splicing the armor is practically the same as that of splicing any wire cable. The splice thus made is stronger than the cable and its electrical conductivity is also greater than that of the other parts of the cable. The Mackay - Bennett can lay cable at the rate of 6 to 8 miles per hour. It is obvions that in laying cable it is neces sary to know something of the character of the ocean bottom. It is especially desir able to avoid shal low places. The steamer is prm'ided with the James "sentry and sounding machine," which 410 gives notice on board of the approach to shoal watere. A device called a li kite," shown in Pig. 6, is trailed behind the steamer, as shown in Pig. 5, being attached to the end of a piano wire wound upon the drulll of the sounding machine. The kite is attached to the wire in such a manner that it dives under the stern of the boat to the minimum depth. Should the steamer enter shallow water, the lever at the lower eno of the kite strikes the bottom and releases the front end of the kite so that it trails behind the steamer at or near the surface and offers less resistance at the machine. The diminished pull causes a bell to ring on the sounding machine and another on the bridge. The sounding machine is adjustable for different depths. On the deck at suitable places are placed elec1ric signaling machines, made by Eliott Brothers, of London, for communicating with the engineer of the paying-out machines and with the ship's engineer. The Mackay-Bennett came on from Halifax in September last to lay cable for r6porting the yacht race. The shore end of the cable was droppeo at Coney Island at a point east of the Oriental Hotel. From this point it was laid out to the lightship, and an extra mile was run ont in great coils to enable the ship to change her position if necessary. By the use of this cable, reports of the movements of the yachts were instantly transmitted to New York City, so that the progress of the race was better known to ohservers of the bulletins than to most of the actual spectators. Through the courtesy of Captain E. G. Srhenk, Chief Officer W. F. Linton. Engineer J. W. Burn, and Electrician C. Priest, we were enabled to thoroughly inspect everything on board the steamer.
This article was originally published with the title "The Cable Repair Steamer Mackay-Bennett"