Bright also introduced a dynamometer apparatus for indicating and controlling the strain during paying out—a vast improvement on that embodied in the previous machines. The working of the entire machine was as follows:
“Between the two brake-drums and the stern of the vessel, the cable was led under the grooved wheel, O, of the dynamometer. This wheel had a weight attached to it, and could be moved up or down in an iron frame. If the strain upon the cable was small, the wheel would bend the cable downward, and its index would show a low degree of pressure; but whenever the strain increased, the cable, in straightening itself, would at once lift the dynamometer-wheel with the indicator attached to it, which showed the pressure in hundredweights and tons. The amount of strain with a given weight upon the wheel, G, was determined by experiments, and a hand-wheel in connection with the levers of the paying-out machine was placed immediately opposite the dynamometer; so that, directly the indicator showed strain increasing, the person in charge could at{79} once, by turning the hand-wheel, lift up the weights that tightened the friction-straps, and so let the cable run freely through the paying-out machine. Although, therefore, the strain could be reduced—or entirely withdrawn—in a moment, it could not be increased by the man at the wheel. The cable in coming from the tanks, passed under a lightly weighted ‘jockey,’[22] J, pulley. This arrangement, while leading the line on to the drums, at the same time checked it slightly. From here it was guided by a grooved pulley, or V-sheave,[23] L, along the tops of both drums, at B, then three times round them, and hence over another V-sheave, F, and on to the dynamometer. From this the cable was led over a second pulley, and so into the sea by the stern-sheaves.”[24]
This entire apparatus—simplified as regards the brake—has since been universally adopted for submarine-cable work,[25] with the exception that a single-flanged drum, fitted with a sort of plow, skid, or knife-edge—to guide or “fleet” the incoming turn of cable correctly on to the drum—is now used in place of the grooved sheave, or sheaves.
As soon as the new machinery was constructed, all the engineering staff gathered together for the purpose of thoroughly acquainting themselves with its working. Mr. F. C. Webb, having engagements elsewhere, had been replaced by{80} Mr. W. E. Everett, U.S.A., who had been chief marine engineer of the Niagara. Mr. Everett was to have charge of the machinery on the laying vessel, while Mr. Woodhouse controlled the cable operations.