The stem of the ship is protruded forwards below the water for about 8 ft., thus forming a huge ram which would itself render the _Glatton_ a truly formidable antagonist at close quarters even if her guns were not used. The engines are capable of being worked up to 3,000 horse-power, giving the ship a speed of 9½ knots per hour, and means are provided for turning the turret by steam power. The turret can be rotated by manual labour, requiring about three minutes for its complete revolution, but by steam power the operation can be effected in half a minute. The commander communicates his orders from the pilot-house on the hurricane deck to the engine-room, steering-house, and turret, by means of speaking-tubes and electric telegraphs. The _Glatton_ was not designed to be ocean-going, but is intended for coast defence. [Illustration: FIG. 77.—_H.M.S. Thunderer._ ] The British navy contains two powerful turret-ships constructed on the same general plan as the _Glatton_, but larger, and capable of steaming at a greater speed, and of carrying coal for a long voyage. These sister ships are named the _Devastation_, Fig. 69, and the _Thunderer_, Fig. 77. The _Thunderer_ has two turrets and a freeboard of 4 ft. 6 in. Space is provided for a store of 1,800 tons of coal, of which the _Glatton_ can carry only 500 tons. The vessel is fitted with twin screws, turned by two pairs of independent engines, capable of working up to 5,600 horse-power, and she can steam at the rate of 12 knots, or nearly 14 miles, an hour. With the large supply of coal she can carry, the _Thunderer_ could make a voyage of 3,000 miles without re-coaling. Though the freeboard of the heavily-plated hull is only 4 ft. 6 in., a lighter iron superstructure, indicated in the figure by the light shading, rises from the deck to the height of 7 ft., making the real freeboard nearly 12 ft. This gives the ship much greater stability, and prevents her from rolling heavily when at sea. The length is 285 ft. and the width 58 ft., and the draught 26 ft. The hull is double, the distance between the outer and inner skins of the bottom being 4 ft. 6 in. The framing is very strong and on the longitudinal principle, and the keel is formed of Bessemer steel. Each turret is 24 ft. 3 in. in internal diameter, and is built with five layers of teak and iron. Beginning at the inside, there is a lining of 2⅝ in. iron plates; then 6 in. of teak in iron frames, arranged horizontally; 6 in. of armour plates; 9 in. of teak, placed vertically; outside of all, 8 in. armour plates. Each turret carries two Fraser 35–ton guns, rifled muzzle-loaders. The turrets revolve by hand or by steam-power. There are no sails, and thus a clear range for the guns is afforded fore and aft. The bases of the turrets are protected by the armoured breastwork, of which a portion is seen in the figure in advance of the fore turret.