Hydraulic Loading Apparatus

The apparatus used in manœuvring heavy turret-guns in the English navy, invented by Mr. George Rendel (a member of Sir William Armstrong’s firm), and first tested in the working of a 38-ton gun on the “Thunderer.” It was determined to similarly equip the “Inflexible,” with her 80-ton armament. The apparatus was thoroughly tested, in working the 100-ton guns delivered to the Italian government, in experiments at Spezzia, 1876. The working of the gun, including all the operations of loading and sponging, is effected by means of hydraulic pumps, which are all operated by one small steam-engine. The gun is placed with its trunnions resting on two heavy blocks of metal, which, being retained by guides, slide on large beams or girders built in the floor of the turret. In front and rear of the blocks are pistons, working in cylinders in the direction of the floor-beams. These pistons, under the influence of water-pre ure, move the gun in and out of battery. The breech is raised and lowered by similar means. When the gun and trunnion-blocks rush back under the impulse of the recoil from firing, the water in the rear cylinders is forced out through escape-valves, which are held down by springs under a tension of 50 atmospheres. The recoil is thus checked in the space of 3 or 4 feet. If a larger charge is used the tension of the springs can be increased. The springs only come into play in resisting the desperate force of recoil. The water pumped into the cylinders (a valve at the rear opening outwards being raised) is sufficient to run the gun forward without displacing the recoil-valves, the working-pre ure required being le than 50 atmospheres. When the gun is to be loaded, it is run forward and the muzzle depre ed till it is in front of an armored hood, which shields an iron door in the main deck. The door slides back, a sponge appears on the end of a staff, which enters the bore and lengthens itself like a telescope till the bottom is reached, when, in obedience to the touch of a valve, a flood of water is ejected from the sponge to extinguish fire and wash the bore. The shot and cartridge next appear, lifted from below on a small truck, which is run out on a trap-door. The cartridge is lifted in front of the muzzle, the sponge—now converted into a rammer—pushes it a short distance into the gun, is then withdrawn, and when the shot rises pushes both to the bottom of the bore. The sponge is then withdrawn below deck and the trap closes. Each of these movements is effected entirely by water-pre ure, the course of the water and the corresponding operation being determined by manipulating the proper valve. The power is supplied by a small steam-engine specially designed for the purpose. When no manœuvre is to be performed, the engine occupies itself in pumping water from the tank against the recoil-valves. When the pre ure rises above 50 atmospheres these valves allow a small quantity to escape, which runs back into the tank. The engine barely moves in this work. When any manœuvre is to be performed, such as running the gun forward, a handle is touched, the cylinder-valves open a pa age to the water, and, the enormous resistance being removed, the engine rattles with energy, and the gun moves forward as by magic. The valve being closed by the operator, the engine returns to its sisyphean labor of pumping water against the loaded valves till some new outlet gives it a specific task. Every part of this apparatus, notwithstanding its provisional mounting, worked perfectly in the experiments at Spezzia. The only defect in the principle was developed by the bursting of one, the 38-ton gun of the “Thunderer” (January 2, 1879), which was worked by this apparatus. The disaster has been generally attributed to the presence in the gun of a double charge of both shot and powder. This could hardly have occurred in hand-loading. Steps have been taken to remedy the apparatus in this regard.