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BM-2 Amphitrite

The Civil War monitors of the MIANTONOMOH class, although regarded as the best of this type of warship by American naval officers deteriorated rapidly after the war. The wood armor backing and other timbers in the ships' hulls suffered from dry rot and within the first ten years after the war their combat value had become almost.

In 1874-75 Secretary of the Navy George Robeson decided to carry out extensive "repairs" the ships. The repairs were so extensive involving the construction of new iron hulls as to result in entirely new ships. However, since the funds for new construction had not been appropriated by the Congress, Robeson maintained the fiction that the ships were actually still the Civil War monitors and so the names never dropped from Navy List. A national scandal resulted when this and the fact that Robeson had been paying for the new ships with old came to light. But, Robeson's action marked the beginnings of the movement to reestablish the United States as a strong naval power.

The American monitors ordered in 1874 were five in number, the Amphitrite, the Miantonomoh, the Monadnock, the Terror, and the Puritan, elach provided with two turrets and in other respects presenting marked improvements over the single-turreted monitors of the Civil War. Of these, the four first named are sister ships, and a description of one will answer for all. The Puritan is a considerably larger vessel and more heavily armed than the others. The AMPHITRITEs were begun in private yards and completed in naval shipyards, construction having been suspended for a time and progress slow throughout. The delay in finishing these vessels proved to their advantage, in enabling them to be completed in the most approved manner and with the advantage of all recent improvements in guns and armor.


Amphitrite, an iron-hulled, twin-screw coastal defense monitor (turreted, armored warship) was officially a "repair" of Civil War-era monitor, but actually new construction that took two decades. Begun 1874, the incomplete hull was transferred to Norfolk Navy Yard in 1883 for completion. Launched 1895, she served in the Caribbean during the Spanish-American War, then served as a training ship. During 1st WW, guarded New York Harbor. Decommissioned 1919 and converted to floating hotel. She was scrapped 1952.

USS Tonawanda, a 3400-ton twin-turret monitor built at Philadelphia, Pennsylvania, was commissioned in October 1865. She was laid up at the Washington Navy Yard, D.C., between late 1865 and October 1866, then became a training ship at the U.S. Naval Academy, Annapolis, Maryland. In June 1869 she was renamed Amphitrite. The monitor's Naval Academy tour ended in 1872. She was broken up at the Wilmington, Delaware, in 1873-74 under the guise of being "rebuilt" into a modern monitor. The completely new monitor that replaced her was also named Amphitrite, but shared nothing but the name with the older ship. USS Amphitrite, a 3990-ton double-turret monitor, was constructed over two decades, from 1874 to 1895. Prior to the Spanish-American War, she was employed along the U.S. east coast, and served in the Caribbean during that conflict. After 1898, Amphitrite remained active as a training and station ship and guarded the approaches to New York Harbor during the First World War. The monitor was decommissioned in 1919 and sold the following year. Her new civilian owners converted her into a floating hotel, and she was not scrapped until 1952.


MONADNOCK was one of the only two monitors to cross the Pacific, doing so in 1898. USS Monadnock, first of a two-ship class of 3295-ton twin-turret monitors, was built at the Boston Navy Yard. Commissioned in October 1864, she was sent to Norfolk, Virginia, to begin her Civil War service. In 1874 her wooden hull was broken up as part of a program to "rebuild" Civil War era monitors into modern ones. In fact, she was replaced by a completely new ship, which was also named Monadnock.

The vessel was to all intents a double one, she having both an inner and an outer skin, the thickness of the latter being and inches thick, while inches is the dimensions of the former. Between these two skins there were 84 water-tight compartments, which added materially to her natural buoyancy, there being besides three athwart ship water-tight bulkheads, which are more particularly to keep her afloat should any unforeseen disaster occur. Her turrets, which were two in number, carried two guns in each, of 15-inch calibre. She was driven by two pair of compound engines of 500 horse-power each; she was provided with a twin-screw propeller of 11 feet in diameter ; all her machinery was below the water line ; her outside armor plates were 7 inches in thickness of solid iron, and extended for three feet below the water line ; her smokestack was armored for a certain distance ; it also had a telescopic working; she was rigged with one masts ; her draft was 14 feet ; she will had a freeboard, e., there was exposed above the water 30 inches of plating, and her displacement was calculated to be about 5,000 tons. When ready for sea the " Monadnock " was supplied with a steam launch, and the other necessary small boats, five in number, and her complement of officers and men was one hundred and fifty.

USS Monadnock, a 3990-ton monitor, was built over a 22-year period at Vallejo and Mare Island, California, finally commissioning in February 1896. During the next two years, she served with the Pacific Squadron in the U.S. west coast area. In June 1898, she departed San Francisco on a two-month voyage to the Philippines, where she was needed to provide heavy-gun support following Admiral Dewey's victory at Manila Bay. Monadnock remained in the Far East to the end of her career, serving in Philippine and Chinese waters. She decommissioned for the last time in March 1919 and was sold in August 1923. The MONADNOCK was similar in size, armor, and armament to the Amphitrite, but was superior in motive power and speed, her engines, of the triple expansion type, yielding 3000 horse-power and her speed being twelve knots.


USS Terror, a 3990-ton monitor, was built between 1874 and 1896 at the ship-yard of the Cramps at Philadelphia, Pennsylvania, and at the New York Navy Yard. Commissioned in April 1896, she spent her first two years operating off the U.S. east coast. During the Spanish-American War, Terror served actively in the West Indies area, participating in the bombardment of San Juan, Puerto Rico, on 12 May 1898. In 1901-05, the monitor was employed as a training ship at the U.S. Naval Academy. She was laid up from 1906 until 1915, when she was struck from the Navy List and utilized as a test hulk. She was sold for scrapping in 1921.

She differed from the two monitors described in having no barbettes, the turrets rising through and projecting above the main deck, as in the original Monitor. This boat is of the same dimensions and displacement as the Amphitrite and of the same horse-power, speed, and coal capacity. She differs, however, in armor and armament, her side armor being but seven inches in thickness. The turrets are plated with 11.5-inch armor. Her main armament consists of four 10-inch breech-loading rifles, two in each turret, the 4-Inch rapid-fire guns of the Amphitrite and Monadnock being omitted. Her secondary battery is nearly the same as that of the Amphitrite, consisting of two each of 6-pounder, 3-pounder, and 1-pounder rapid-fire guns, two Hotchkiss revolving cannon, and two Gatlings.


The keel of this boat was laid in the ship-yard of John Roach & Sons, at Chester, on the Delaware River, in 1874, but she was not finished until 1897, at League Island Navy-Yard. The hull of the Miantonomoh was begun in 1874 and launched 5 December 1876; completed, together with the engines, in 188O. From 188O to 1888 practically nothing was done on her. MIANTONOMOH was commissioned in an uncompleted condition 6 October 1882 and in commission briefly during 1882 and 1883, during which time she went from Philadelphia to Washington, and, later, to New York where the final phases of her reconstruction were completed. During this period she carried no main armament. In 1888 her turrets, which had been built in England, were received, and the work of completion was begun. Her four 10-in. guns were finished and installed during 1891, and she was placed in commission during the autumn of that year.

She is frequently referred to as having been rebuilt or repaired, but as being otherwise identical with the Mianianomoh which went to Europe shortly after tht war, This is a mistake. The only piece of the old Miantonomoh which is utilized on board the new is the ship's bell. The original Miantonomoh, moreover, had a wooden hull; the new one a hull of iron and steel.

The second Miantonomoh, an iron-hulled, twin-screw, double-turreted monitor. The Miantonomoh was a typical monitor. Her length is 250 feet; beam, 55.5 feet; draught, extreme, 14.75 feet; free-board, 30 inches; height of the axis of the guns above water; 6 feet; metacentric height, 14 feet (the Baltimore's is 1.5 feet); period of oscillation, 2.75 seconds.

The MIANTONOMOH, the fourth of the original double-turreted monitors, closely resembles the Terror in many particulars, being identical with her in dimensions, tonnage, and speed, but having a somewhat smaller motive-power, the indicated horse-power of her engines being 1426. Her armament consists of four 10-inch breech-loading rifles in the main battery, and in the secondary battery of two each of 6- pounder, 3-pounder, and 1-pounder rapid-fire guns.

In many respects she repeated the old monitor Miantonomoh, of the Civil War period. Her side armor was seven inches in thickness and extends through a width of six feet. The deck armor, of 1-3/4-inch steel, is divided into two plates, placed one above the other, the whole being planked over with four inches of pine flooring. The turrets, which are twenty-four feet in external diameter, and rise somewhat more than six feet above the deck, are plated with 11.5 inch compound armor (iron and steel), behind which are ten inches of wood backing, and internally two thicknesses of steel plate, each one-half inch thick.

The conning-tower surmounting the turret is nearly eight feet in diameter and two feet in height, and is armored with 9-inch steel. In describing the turret, a source of peril to the crew needs to be mentioned. The striking of the turret by a ball from a hostile ship is apt to cause the heads of the rivets to fly off and be hurled forcibly across the confined space. In order to prevent the firing crew from being bombarded with missiles of this kind, the turret is lined by an inner shield of 3/4 inch steel plate, which stands eight inches within the walls.

In the Miantonomoh hydraulic power is used, instead of the pneumatic system of the Terror. The processes of loading are similar to those already described, while the recoil of the gun is taken up by an hydraulic cylinder, in which the water escapes from behind the piston in limited quantity, so as to bring the gun to rest without serious shock. After firing, the turret is rotated by the conning officer, so as to present a solid front to the fire of a hostile ship while the guns are being reloaded. This operation performed, a touch brings them back to the firing position. The turret turns on steel rollers, twenty in number, linked together in a circle, while above them a double line of teeth encircles its base, in which the cogs of the wheels of the turning engine engage. A diaphragm of leather around the turret prevents the entrance of water.

Her deck is almost parallel at all times to the surface of the waves. The angle of inclination of an Atlantic storm-wave is - 18 degrees approximately, and its pe-riod about Io seconds. Now, in half the period of the wave, the extreme flat, shallow ship will roll through an arc equal to double the angle of inclination of the wave; that is; she will roll (approximately),through an arc of 36 degrees in 5 seconds, and that without any intermediate periods of rest. A simple calculation will show how long her guns will bear on an object 500 or 1,000 yards distant: The above figures, it must be remembered, are assuming the extreme, that is, the minimum of steadiness, because in the monitor type of ship stiffness is carried to an extreme, and consequently steadiness is reduced to a minimum. Steadiness may be increased in actual experience by the action of the water that breaks on board, or by other circumstances, but the principle remains the same.

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