Evening Republican, Volume 19, Number 198, Rensselaer, Jasper County, 21 August 1915 — HOWA SUBMARINE CAVLE IS REPAIRED [ARTICLE+ILLUSTRATION]

HOWA SUBMARINE CAVLE IS REPAIRED

by OSCAR ODEE

in Me POPULAR MECHANICS

T a time when the public mJ expects its war news almost before the smoke of battle has cleared away, J the submarine cable and '*©'7 the methods used in keep-

ing it in repair are of interest Each submarina telegraph company has In service a fleet of cable ships, the units of which are stationed at different ports for quick access to the different sections of the cable. Let us take, for example, the cable stretching from San Francisco to Manila, a distance of 10,010 miles. This cable is divided into fotr sections —San Francisco to Honolulu, Honolulu to Midway island, Midway island to Guam., and Guam to Manila. The cable lies on the bed of the Pacific, which in places runs from three to five miles in depth, the latter depth being found off the island of Guam. Sufficient , slack must be paid out in laying a submarine cable to allow every part to rest on the bottom of the ocean, however irregular the bottom may be. A cable varies in thickness and type according to Its position and the nature of the ocean bottom in the locality where it is laid. The “shore end" of a cable, meaning a section laid close to land, is always thicker than a section out at sea. Ordinarily the diameter of a shore section runs about 2% Inches, while a section laid in deep water runs about % inch in diameter. About seven strands of copper, comprising a single conductor, form the core of the cable. Over this core are laid coatings of gutta percha, a layer of jute or oakum, and an envelope of composition rubber. Over this some strands of strengthening wires are wound on, and tarry rope and tape are wound about the whole. The average cost of a cable complete is about SI,OOO a mile. A surprisingly small amount of current is required for operating a submarine cable. One of the hardest worked of the Atlantic cables requires only 50 volts’ pressure at the sending end. and all that comes out at the receiving end is twenty-millionths ampere. Signals are transmitted simply by alternately charging and discharging the cable, which works much like a Leyden jar. One of the fastest of submarine cables transmits about 80 words a minute. Interruption In cable communication between two stations may come from one of several causes. There is the “fault” caused by the teredo, a submarine boring animal that penetrates the protective coatings in an effort to get at the core. Then the shore end of a cable, in spite of special protection, does not always -withstand the rolling and friction of the tides, and besides this, there is the risk that the cable may ’be fouled or lifted by a ship’s anchor. A cable may part completely, from one cause or another, forming what Is known as a "total break” Let us imagine that the cable from San Francisco to Manila is “down,” as it is technically expressed when the . cable is unworkable. in that section, 2,098 miles long, between San Francisco and Honolulu. We will assume that a series of tests based on the law of resistances has shown that the fault lies at a point 1,000 miles from San Francisco. Sometimes it is possible by testing to locate the position of the fault within onetenth mile, but the average is about five miles. Before the cable ship sails for the “ground,” as the location of the break, or fault, is called, the ship’s electricians will have made their own tests and advised both the San Francisco and Honolulu offices —the latter by an alternate route —to keep watch on their instruments in the office for the ship’s call. As soon as the cable ship reaches the “ground,” a signal, consisting of two red globes with a white diamond between, for day use, and replaced by similarly colored lamps at night, is hung in a vertical line in front of the foremast head. This signal indicates that the ship is engaged in cable-repair work, and is therefore not under control so far as getting out of the way of other craft is concerned. A marked buoy, moored to a mushroom anchor, is then dropped overboard at the point where the fault in the cable is supposed to be. The ship then proceeds to grapple for the cable. This is done by means of a grapnel, of which there are many kinds, all studded with prongs calculated to catch anything they encounter. To this grapnel is attached a steel hawser, the inboard end qf which Is connected to an instrument known as a dynamometer, or vertical scale,

and capable of registering a pull up to 15 tons. The ship then steams ahead at a speed of one or two knots an hour in a kind of a taking maneuver at right angles to the line of the cable. While the ship is engaged in grappling a member of the crew, ordinarily the fourth officer, sits on the grapnel rope near the bow and can usually tell by the strain when the cable has been hooked. The instant the 1 cable is hooke’d the ship is stopped and the grapnel rope is slowly wound in by the hauling machinery. Sometimes the cable will stand the heavy strain of being lifted until it reaches the surface, only to snap and sink to the bottom again before it can be secured. When this happens the ship steams to a new location and starts grappling anew.

When the cable is brought safely to the surface, it is first secured on either side of the grapnel by what is known as a chain "stopper,” this work being done by a man lowered over the bow in a boatswain's chair. The cable is then cut, each end is connected to the instrument in the testing room, and the stations at San Francisco and Honolulu are each called up. It is more than likely, of course, that the ship will not be able to speak to one of the stations, as the fault will probably lie at some point between the ship and the station. In case it is necessary for the ship to steam one way or the other to find the fault, as it usually is, it is necessary to leave one end of the cable behind and to secure it so that it can be raised again without grappling. One of the big seven-ton buoys shown in the illustration is made ready, a flag Is put on it, and it is lifted overboard by a derrick. One end of the cable is attached to the buoy by a long mooring chain and rope, and is allowed to sink to the bottom, the buoy itself being held in place by a mushroom anchor. At night time the buoy carries a light. The ship now starts picking up the cable toward the fault. This is a slow process, requiring careful navigation, as the ship must be kept going slowly ahead at such a speed as to relieve the 6trnin on the picking-up gear. The cable comes on board at the rate of one or two miles an hour and is coiled by the. men into one of the large round tanks that take the place of the hold in an ordinary ship. The cable is guided from the bow to the tank by a series of sheaves placed at intervals on the deck. While this operation is going on, the electricians continue testing and the cable may have to be cut several times before the actual fault is on board. With the fault found, the defective portion of the cable is cut out, and a good piece from the ship’s

tank is spliced in in its place. Then the cable is paid out as the ship returns to the buoy marking the location of the other end. With this recovered, the ship has both the San Francisco and Honolulu ends of the cable on board.- Tests are made to ascertain that no other faults have developed and that both sections are in good condition. A message reading “Communication restored —now making final splice” is sent to both of the stations. Following this message two hours are allowed before the stations attempt to communicate with each other. This is a very busy two hours on board the cable ship. The ends of the cable are secured over the sheaves at the bow and are connected by a splice from 36 to 40 feet long. With the splice completed two ropes, one at each side of the bow, are attached to the cable and It is lowered overboard and slacked out slowly until it reaches the surface of the water. A block of wood is placed on the deck under each of the ropes. At a given signal the ropes are cut at the same time with axes, the ends of the ropes fly overboard and the cable sinks to the bottom of the ocean. As the cable disappears from view, the engines are run full speed ahead and cable ship returns to port