USS Monadnock was one of four s built for the United States Navy during the American Civil War. Commissioned in late 1864, she participated in the First in December and Second Battles of Fort Fisher in January 1865. The ship was later assigned to the James River Flotilla on the approaches to the Confederate capitol of Richmond, Virginia and then sailed to Spanish Cuba to intercept the Confederate ironclad CSS Stonewall. Monadnock was then docked for a few months to prepare her for her transfer to California around the tip of South America. The monitor and her escorts departed in late 1865 and reached the Chilean port of Valparaíso in early 1866 where the Americans unsuccessfully attempted to prevent the Spanish from bombarding the undefended town during the Chincha Islands War. The ships reached California in June and Monadnock was decommissioned at the end of the month. The monitor was sold for scrap in 1874. The Navy Department evaded the Congressional refusal to order new ships by claiming that the Civil War-era ship was being repaired while building a new monitor of the same name. Description and construction The Miantonomoh class were designed by John Lenthall, Chief of the Bureau of Construction and Repair, although the ships varied somewhat in their details. Monadnock was long overall, had a beam of and had a draft of . The ship had a depth of hold of , a tonnage of 1,564 tons burthen and displaced . Her crew consisted of 150 officers and enlisted men. Monadnock was powered by a pair of two-cylinder horizontal vibrating-lever steam engines, each driving one four-bladed propeller about in diameter using steam generated by four Martin vertical water-tube boilers. The engines were rated at and gave the ship a top speed of . She was designed to carry of coal. Armament and armor Her main battery consisted of four smoothbore, muzzle-loading, Dahlgren guns mounted in two twin-gun turrets, one each fore and aft of the single funnel. Each gun weighed approximately . They could fire a shell up to a range of at an elevation of +7°. The sides of the hull of the Miantonomoh-class ships were protected by five layers of wrought-iron plates that tapered at their bottom edge down to total of , backed by of wood. The armor of the gun turret consisted of ten layers of one-inch plates and the pilot house had