The American Iron-Clad VesselsThe Illustrated London News, vol. 40, no. 1139, p. 376.
April 12, 1862
The Merrimac was formerly the United States' frigate of that name, which was scuttled and sunk at the Norfolk Navy-yard at the commencement of the rebellion by the officers of the Union Government to prevent her falling into the hands of the Confederates. She was built at Charleston, in 1855, and was pierced for forty guns. After the Confederates took possession of the yard, she was raised and converted into a man-of-war for their own use. Her hull was cut down to within three feet of her water-mark, and a bombproof house built on her gun-deck. She was also iron-plated, and her bow and stem steel-clad, with a projecting angle of iron for the purpose of piercing vessels. She has no masts, and there is nothing to be seen over her gun-deck, with the exception of her pilot-house and smokestack. Her bombproof is three inches thick, and is made of wrought iron. Her armament consists of four 11-inch navy guns on each side, and two guns at the bow and stern. The Merrimac has been renamed the Virginia.
The turret or citadel of the Ericsson floating-battery Monitor, which constitutes its only means of offence, consists of a rolled plate-iron skeleton, 1in. thick, to which are riveted two thicknesses, of 1in. each, of rolled iron plates. Outside of this again are six plates of rolled iron, all firmly bolted together with nuts inside, so that if a plate is started it can be at once tightened again. The lower part of the gun-carriages consist of solid wrought-iron beams. These are planed perfectly true, and are placed parallel in the turret, both of the guns pointing in the same direction. The ports through the side of the turret are only large enough to permit the muzzle of the gun to be thrust through. Inside of them are wrought-iron pendulums, which close them against the enemy as soon as the gun recoils. A shellproof flat roof, of perforated plate iron, placed on forged beams, inserted six inches down the cylinder, covers the top. The sliding hatch in this cover is perforated to give light, and for musketry fire in case the battery is boarded., A spur-wheel, 6½in. in diameter, moved by a double cylinder-engine...turns the turret, guns and all, a rod connected with the running gear of the engine enabling the runner to control the aim. The height of the turret is 9ft., and its diameter 21ft. 9in.