FIG. 10b.—AUTOMATIC ANCHOR.
A 3,000-pound automatic anchor, similar to the 1,500-pound automatic anchor, is supplied for some localities.
The mooring sockets.—To connect the wire mooring rope to the shackles at the mine and the anchor, a closed socket is attached at each end. The eye of the socket has a clear opening, 1³/₁₀ inches, designed to receive the bolt of the shackle. The end of the rope is passed into the socket, spread out, and secured by pouring in a melted socket alloy.
A substitute method for connecting the wire mooring rope to the shackles is to bend the ends of the mooring rope by means of a small vise around a galvanized iron thimble and fasten the end by two bolted clips.
Wire mooring rope.—This is the highest grade of ¾-inch galvanized-steel wire rope, consisting of 6 compound strands, each made of 19 wires, the whole laid around a steel center. Its breaking strength when new is about 18 tons. Its weight per running foot, submerged, is about eight-tenths of a pound. It is used for mooring mines to mushroom anchors.
Marline-covered wire mooring rope.—For mooring mines to the automatic anchors and for raising rope marline-covered wire rope is used. This rope consists of five outer strands wound around a central hemp core. Each of the outer strands consists of a small twisted wire rope wound around with four strands of marline. One end of the rope is prepared for attachment to the mine by passing it over a thimble and fastening it to the standing part by means of two clips. A shackle joins the thimble and the bail of the mine. The other end of the rope is made secure to the reel of the anchor. The breaking strength of ½-inch marline-covered rope is 17,000 pounds, that of ⅝-inch marline-covered rope is 27,000 pounds. The weight per running foot of the ½-inch rope is 0.5 pound, that of the ⅝-inch rope is 0.8 pound. The weight of this rope submerged is about 60 per cent of its weight in air.
About 155 feet of the ½-inch and 85 feet of the ⅝-inch marline-covered rope can conveniently be wound on the 6-inch reel of the 1,500-pound automatic anchor.
Marline-covered wire distance weight rope.—For attaching distance weights to the automatic anchor ¼-inch marline-covered wire rope is used. This rope is identical in pattern with the marline-covered wire mooring rope.
The distribution box, 19-conductor.—This is a circular, cast-iron, disk-shaped box which receives the end of the multiple cable, in which taped joints are made between the separate conductors of this cable and the single-conductor mine cables, and from which these mine cables radiate. It is about 27 inches in diameter and weighs about 300 pounds. It consists of two parts, a bowl-shaped bottom 6 inches deep inside and a slightly curved lid. The latter has an iron ring in its center by which the box is raised and lowered.