Page:The American Cyclopædia (1879) Volume IX.djvu/392

 378 IRON-CLAD SHIPS driven by four compact beam engines working entirely below the water line. Cylinders are 3 ft. 9 in., with 3 ft. 6 in. stroke, driven by 10 boilers and capable of developing 8,600 horse power. The leading principles of this ves- sel's construction are as follows: 1. When ready for action the ship is to be settled 2 ft. lower in the water, by letting water into compartments which can again be emptied rapidly by powerful steam pumps provided for that purpose; this is done in order to save the weight and cost of the additional ar- mor which would otherwise be necessary ; to al- low a flatter slope and secure greater resistance of the armor ; to employ the resistance of the water ; to give the vessel a greater speed by expelling the water from her compartments, and to enable her when thus lightened to enter harbors into which she could otherwise not go. 2. The use of inclined instead of vertical pla- ting, for the purpose of changing the direc- tion and throwing off instead of stopping the enemy's projectiles. The side plating consists of the best iron slabs 3J- in. thick, laid upon a triangular backing of locust timber extending outside the shell of the vessel from stem to stern, and to a depth of 4 ft. below the water line when the vessel is ready for action. From the outer edge of this side protection the shot- proof casemate or main armor proceeds, up- ward and inward, at an angle of one vertical to two horizontal, to a height of 28 ft. from the bottom of the ship, and 5J ft. from the fighting line, where it is covered by a flat shot- proof deck. The main armor extends only over the engine's boilers, blowing and pump- ing machinery, that is, 107 ft. forward and 74 ft. aft the centre. Its ends slope upward and inward at a similar angle, from the 21-foot deck, which is shot-proof, and which extends forward and aft the armor to the extreme bow and stern. The inclined armor, or casemate, is composed of 6J- in. of iron plates, backed by 14 in. of locust timber, in which are im- bedded six-inch wrought-iron girders 2 ft. apart. The whole is lined with half-inch plate iron. It is supported by the engine frames, by heavy braces and girders between the boilers, and by the frames and sides 6f the ship. The horizontal shot-proof decks are composed of 1 in. of iron plates, resting on six-inch wrought- iron girders, filled in with locust timber and backed with half-inch iron plate. The guns will be loaded by being pivoted to a hole in the deck protected by a shot-proof hood, be- low which is a steam cylinder of which the piston rod is the ramrod of the gun. All the machinery and men for working the guns are thus within the shot-proof armor. The guns are protected by a covering of wrought-iron armor in addition to their own immense thickness, and will be trained by steam power. The shot-proof deck fore and aft the central case- mate affords ample accommodation for men and officers. Above this deck, and flush with the 28-foot gun deck, which forms the top of the casemate, is a light deck, extending at the sides of the casemate, and forward and aft from stem to stern. The entire 28-foot or gun deck is thus level (excepting the usual camber), and unencumbered over the whole vessel. Only the part of it that forms the top of the case- mate is shot-proof. Above the 28-foot deck are flying bulwarks to be turned down in time of action. The height of the bulwarks from the water at the load line will be 13 ft. The 14- foot deck affords ample space for stores, and for the salt-water tanks designed for settling the vessel to the fighting line. Below the 14-foot deck, forward of the boilers, are the blowers and pumping engines and coal bunkers. Abaft the engines are coal bunkers also. Capacity for coal, 1,000 tons. The vessel will have two light masts for emergencies, but will not ordi- narily carry sails. Her projector claimed that her iron casemate, C| in. thick backed by 14 in. of hard timber, and standing at the acute angle of one base to two perpendicular, is a stronger protection than lias ever been ap- plied, and that at the same time it is compara- tively light, as its extent is reduced by con- fining it to the central part of the vessel, and by immersing the vessel to a deeper fighting draught. The parts of the vessel fore and aft the central casemate are also thoroughly protected by a horizontal deck, which is not only shot-proof but one foot below the fight- ing water line. The water protection, as far as it can be judiciously employed, is at once the most perfect and cheapest armor. 3. The side protection, extending from stem to stern, is intended to answer these four important pur- poses: 1, protection from projectiles; 2, from disaster by collision ; 3, increasing the immersed beam, and the consequent stability of the ship when fighting; 4, adding in a very great de- gree to the horizontal and vertical strength and stiffness of the vessel. 4. The immense power of the engines and the fine lines are in- tended to give a much higher speed than has been attained by any sea-going war or com- mercial steamer. The sharpness of her lines is unprecedented in any government practice, and in any except the latest and most success- ful commercial practice. 5. The ability of the vessel to turn rapidly round on her own centre, without making headway, by means of two screws, instead of occupying the time and ma- king the circuit required by all other war ves- sels, it is thought, will give her remarkable and important facilities for manoeuvring when in action. 6. The employment of barbette guns, or on the top of the casemate instead of within it, gives the free range of the entire horizon. Three guns can be fired at a time in line with the keel, forward or aft. 7. As there is no casemate over the guns, the enemy cannot pour shot and shell into port holes at close quar- ters ; for the same reason the guns will not be limited to the few degrees of range permitted by the ports, but can sweep the horizon. The cost and weight of the casemates over the guns