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History of the Atlantic Cable & Undersea Communications
from the first submarine cable of 1850 to the worldwide fiber optic network

Cape Town Cable Station - 1890

The Electrician, July 4, 1890, p.223

THE CAPE TOWN CABLE STATION.
BY H.D. WILKINSON.

With the extension of the system of submarine cables and the ultimate duplication of existing lines it becomes a matter of necessity to have means for storing cable at convenient points on shore, where it may be kept in good condition, and drawn from as required by the repairing steamers. For this purpose tanks have been erected on shore at Gibraltar, Malta, and Suez, in which cable is stored for the maintenance of the network of cables in the Mediterranean, while there are also tanks at Perim, and storage hulks moored off Zanzibar and Mossamedes for the same purpose. And now that, with the exception of the Government land lines between Cape Town and Natal, the dark continent is completely encircled by submarine cables, it has been decided upon by the Eastern and South African Cable Company, whose lines extend between Aden and Delagoa Bay on the East, and between Cape Town and Loanda, on the West Coast, to erect tanks with ample storage capacity at the terminal station of Cape Town. The usual practice is to construct the tanks of riveted iron plates, similar to those on board cableships, and to erect them inside a covered shed of light angle-iron girders. An exception to this exists at Malta, where the tanks, or rather wells, are of concrete, opening flush with the ground.

Fig. 1. Cable tanks and hauling gear

The site for the tank-house at Cape Town has been selected on the promontory of land from which the new breakwater starts, immediately overlooking the docks. From this situation cable can be conveniently led over to a cableship in dock by simply crossing the dock road on overhead leads. The building, which is of corrugated iron, covers a space of nearly 6,000 square feet. In Fig. 1 we have a sectional view of the building, showing the position of the tanks. Derricks are erected as shown, on which to suspend the leading-in pulleys, and at the point of entering or leaving the shed the cable passes between two vertical rollers (Figs. 1 and 3). The sectional view shows the arrangement of pulleys and hauling gear. For the latter an engine and boiler are fixed as shown. The engine is an ordinary double-cylinder winch-engine, with 7in. cylinders and 15in. stroke, fitted with reversing gear. The motion is transmitted to the hauling pulley by a vertical shaft driven from the engine and connected by speed-reducing bevel gear. Altogether the speed is reduced in the ratio of 8:1.

Fig. 3. In-leads to tank house

The cable passes, as shown, over the V pulley, being kept down in the groove by the jockey-wheel J (Fig. 1), mounted on a lever with weight attached; while the speed and direction are controlled by the engine the necessary grip on the cable for hauling is controlled by the position of the weight. The rim of the jockey-wheel is turned slightly concave to take the cable; but an improvement in this is to construct the wheel in two halves, adjustable towards or from each other, so as to fit over and grip any type of cable, from type D to the heavier types.

The shed contains three tanks, the centre one being 30ft. diameter and 6ft. deep, while the two others are 40ft. diameter and 8ft. deep. These have a total capacity of over 500 miles of cable. The cable passes over anti-friction pulleys fixed to the highest point in the span of the roof, and a platform is constructed at a convenient distance below them on which two or three men can work at keeping the cable taut. An improvement suggested by Mr. George Beckwith, the Company’s engineer, under whose charge the erection of the plant has been carried out, is to place a second V pulley and jockey-wheel at the distant end of the shed to assist in the hauling and taking-up of the slack when cable is being led in to the further tank, the same being connected to the driving power by an overhead horizontal line of shafting. This arrangement would dispense with the hand labour of three men.

Each tank is provided with an inlet and outlet service, by which water can be admitted or drained off, the inlet pipes being connected to the Harbour Board pumping engine in the docks supplying the convict station. The tanks are bedded on to a foundation consisting of rough concrete, 1 ft. 6 in. deep, covered with a 1½in. layer of cement and sand. Before this layer has set, the tank is let down and grouted in all round, A layer of cement is also run into the interior of the tanks, this being 1½ in. deep round the circumference and sloped down to 1in. at the centre to assist in draining off. The leading pulleys over which the cable passes to the tanks are mounted on rollers R R, as shown (Fig. 2), reducing the friction to a minimum. A suitable testing-room is also fitted up in the tank-house, and provided permanently with instruments.

Fig. 2. Anti-friction cable lead

The last section in the chain of cables on the East Coast was laid as recently as last year. This connects the port of Mossamedes with Cape Town, the cable being 1,383 knots in length. At a point some 384 miles from Cape Town a short length of cable is connected on to this cable by a “T” joint, and taken into theĀ  intermediate station of Port Nolloth. This joint, instead of being completely armoured over as in an ordinary joint, is enclosed and sunk in a cast-iron box. The strain is then taken off the joint by turning back the wires of the armour through holes in the box, and making them fast to the main cables. At Cape Town the cable has been laid round the outer bend of Table Bay, well outside the limits of the anchorage, and its course indicated by a series of mark buoys. The Cable House stands close to the old jetty at the bottom of the main street (Adderley-street), and is connected to the office in the same street by about a quarter of a mile of type D laid underground. The office itself is situated in the Standard Bank Buildings, the finest and most prominent building in this thoroughfare, and consists of an instrument room, battery and testing room, store room, and receiving office on the ground floor, and superintendent’s office on the first floor. One remarks on entering that there is ample room for everything, not often the case in cable stations, and that the rooms are particularly lofty. One syphon recorder is, of course, only necessary, as messages for stations in the Colony and for the West Coast pass over the Government land lines, and arc handed over to their offices. A mirror instrument is, however, kept in reserve. The recorder is of the latest pattern, permanent magnets being employed. By reference to the signals on this cable herewith reproduced (Fig. 4), it will be seen that they are for this length of cable, and the vibrator method of driving the ink, very clearly defined. The line has a capacity of 549 microfarads, a resistance of 8,832 ohms, an insulation of 8,500 megohms per knot, and 20 microfarads are signalled through at each end.

Fig. 4. Signals on Cape Town Mossamedes cable. 1383 knots.

This account of the station, though so brief, could not well be considered complete without some mention being made of the staff quarters. These are well situated on rising ground in Caledon-street, and from the upper balcony command a fine view of Table Bay. The house, known as Buckingham Lodge. is surrounded by a tastefully laid-out garden, and approached through a thick avenue of trees. There are some twelve rooms, besides mess room and billiard room; a certain portion being reserved for the superintendent’s use. As this station, from its temperate and agreeable climate, is also used as a sanitorium for men who may be invalided from stations on the coast, the Company have spared no pains to make the quarters well appointed in every way. To the superintendent, Mr. Thomas Cassidy, is due most of the general arrangements for the comfort of the staff; and it is to his courtesy, and that of the staff working with him, that we are indebted for much of the information obtained.

Staff quarters, Cape Town, circa 1900
Image courtesy of Wayne Babb, from the
photograph album of Harry George Hilliar

Last revised: 15 November, 2015

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