But the climax, the call that taxed the wire rope makers most heavily and kept the arc lights burning in the mills was for the 84,000,000 and odd feet of rope and half million fittings which were required by the Naval Establishment for the North Sea Mine Barrage, which put a prompt and distinguished shackle on the German submarines. The fitting of this rope was a task of moment, calling as it did for delivery of the rope in lengths and made up ready for attachment on the ingenious plan which the mine involved. It was all done with time to spare.
The Adriatic Barrage, an even more ambitious project since it dealt with a depth of 3,000 instead of 900 feet, was all ready to be laid when the Armistice was signed. This took over 12,000,000 feet of rope.
When the fighting stopped, there was a perfectly good mine barrage in the North Sea that had to be taken up and put out of commission. This called for 616,000 feet more of rope, with fittings to make it of use. Every mine was cancelled without a mishap, and there are now more than eighty million feet of “A No. 1” wire rope reposing at the bottom of the North Sea. But it did its work, capturing no less than seventeen German submarines in the first week.
AND MORE THAN WIRE ROPE WAS ASKED FOR
The Roebling plant, for the time, was given over to the manufacture of war necessities, hence its problems of material were made easy by the Director of Steel Supply. But the Roebling output for war purposes did not end with wire rope. In May, 1918, the company was employing close to ten thousand men, and in addition to rope making they were busy with the manufacture of immense quantities of steel strand, strand for outpost cables, copper strand, telephone wire, copper wire and miscellaneous wires of all descriptions, which were needed in the service at home and abroad.
A material part of the war work was the manufacture of wire especially for the field telegraph and telephone systems of the Signal Corps in Europe, where the American Army communications were the admiration of Europeans. This material possessed certain peculiar characteristics, and while speed in its production was an essential yet it was necessary that every strand be perfect, for the fate of armies rested upon it.
The manufacture of this wire involved a great deal of detail and intimate knowledge of all sorts of materials, for while copper is used for electrical transmission there is an exterior protection of other metals and materials, each of which has its peculiar manufacturing difficulties.
THE COMPOSITE STEEL AND COPPER STRAND
For example, the “Composite Steel and Copper Strand” wire used by the Army was made up as follows: There was a center wire of tinned copper with ten outside wires of tinned steel. This wire had a maximum weight of 75 pounds a mile with a maximum breaking weight of 300 pounds. Other types of wire were silk wrapped, covered with a rubber compound or with a covering of cotton braid treated with a waterproofing compound.
TO MEET THE SIGNAL CORPS’ REQUIREMENTS