Dunderberg, which is a Swedish word meaning "thunder(ing) mountain", was an ocean-going casemate ironclad of 14 guns built for the Union Navy. She resembled an enlarged, two-masted version of the Confederate casemate ironclad CSS Virginia. She was originally designed to have both gun turrets and a casemate but the turrets were deleted while the ship was still being built. Construction began in 1862, but progress was slow and she was not launched until after the end of the American Civil War in 1865.
USS Agamenticus was one of four Miantonomoh-class monitors built for the United States Navy during the American Civil War. Commissioned as the war was ending in May 1865, the ironclad saw no combat and was decommissioned in September and placed in reserve. The ship was reactivated in 1870, having been renamed Terror the previous year, and was assigned to the North Atlantic Fleet where she served in the Caribbean Sea. The monitor was decommissioned again in 1872 and was sold for scrap two years later. 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.
HMVS Cerberus is a breastwork monitor that served in the Victoria Naval Forces, the Commonwealth Naval Forces (CNF), and the Royal Australian Navy (RAN) between 1871 and 1924.
The Iron Duke class was a group of four dreadnought battleships built for the British Royal Navy before the First World War. The class comprised four ships: Iron Duke, Marlborough, Benbow, and Emperor of India. Launched from October 1912 to November 1913, this was the third class of Royal Navy super-dreadnoughts. The ships were essentially repeats of the King George V-class battleships; they retained the same ten 13.5 inch (34.3 cm) guns in five twin gun turrets on the centreline. However, the Iron Dukes had improved armour and a more powerful secondary armament of 6-inch weapons instead of the 4-inch mounted on the earlier ships.
HMS Hood was a modified Royal Sovereign-class pre-dreadnought battleship built for the Royal Navy in the early 1890s. She differed from the other ships of the class in that she had cylindrical gun turrets instead of barbettes and a lower freeboard. She served most of her active career in the Mediterranean Sea, where her low freeboard was less of a disadvantage. The ship was placed in reserve in 1907 and later became the receiving ship at Queenstown, Ireland. Hood was used in the development of anti-torpedo bulges in 1913 and was scuttled in late 1914 to act as a blockship across the southern entrance of Portland Harbour after the start of World War I.
HMS Vanguard was a British fast battleship built during the Second World War and commissioned after the war ended. She was the largest and fastest of the Royal Navy's battleships, and the only ship of her class. Vanguard was the last battleship to be built in history.
The first USS Miantonomoh was the lead ship of her class of four ironclad monitors built for the United States Navy during the American Civil War. Completed after the war ended in May 1865, the ship made one cruise off the East Coast before she began a voyage across the North Atlantic in May 1866 to conduct a lengthy showing the flag mission in Europe. Miantonomoh was decommissioned upon her return in 1867, but was reactivated two years later and assigned to the North Atlantic Squadron before decommissioning again in 1870. The monitor was sold for scrap three years later as part of a scheme where 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.
HMS Terror was an Erebus-class monitor built for the Royal Navy during the First World War in Belfast. Completed in 1916, she was assigned to the Dover Patrol where her primary duties involved bombarding German targets on the coast of occupied Belgium, particularly at the ports of Zeebrugge and Ostend. In October 1917 Terror was hit by three torpedoes, taking severe damage to the bow, and had to be towed into Portsmouth for repair. In April 1918 she participated in the Zeebrugge raid and provided gunnery support for the Fifth Battle of Ypres in September of the same year.
USS Saugus was a single-turreted Canonicus-class monitor built for the Union Navy during the American Civil War. The vessel was assigned to the James River Flotilla of the North Atlantic Blockading Squadron upon completion in April 1864. The ship spent most of her time stationed up the James River where she could support operations against Richmond and defend against a sortie by the Confederate ironclads of the James River Squadron. She engaged Confederate artillery batteries during the year and later participated in both attacks on Fort Fisher, defending the approaches to Wilmington, North Carolina, in December 1864 – January 1865. Saugus returned to the James River after the capture of Fort Fisher and remained there until Richmond, Virginia, was occupied in early April.
HNoMS Skorpionen was the lead ship of her class of three monitors built for the Royal Norwegian Navy in the 1860. She was scrapped in 1908, well after her muzzle-loading guns were outdated.
USS Oneota was a single-turreted Canonicus-class monitor built for the Union Navy during the American Civil War. Completed shortly after the end of the war, Oneota was laid up until sold to her builders in 1868, and then resold to the Peruvian Navy. Renamed BAP Manco Cápac, the ship participated in the defense of Arica during the War of the Pacific. When the town was taken by Chilean troops in 1880, she was scuttled to prevent her capture. Her wreck was rediscovered in 1960 and it has been heavily looted.
USS Ajax, originally named USS Manayunk after a town in Pennsylvania, was a single-turreted Canonicus-class monitor built for the Union Navy during the American Civil War. Completed after the end of the war, Ajax was laid up until 1871, although she received her new name in 1869. The ship was briefly activated in 1871, before a much longer commission began in 1874–1875. She was assigned to the North Atlantic Squadron during this time. Ajax was again placed in reserve in 1891. The ship was on militia duty when the Spanish–American War began and she was recommissioned in 1898, to defend Baltimore, Maryland, although she was decommissioned later in the year before the necessary refit could be completed. Ajax was sold for scrap in 1899.
The two Scorpion-class ironclads, HMS Scorpion and HMS Wivern, were ironclad warships ordered by the Confederate States Navy in 1862 and seized in 1863 by the British to prevent their delivery. This would have violated the Foreign Enlistment Act, which forbade British subjects to build or arm any ships for governments at war with governments friendly to Great Britain. The Scorpion class were masted turret ships, each with two gun turrets that were designed to mount a pair of heavy muzzle-loading guns. They were purchased for service in the Royal Navy in 1864 and served briefly with the Channel Fleet before they became guard ships at Bermuda and Hong Kong. Scorpion was sold in 1903 and sank under tow to be scrapped, while Wivern was sold for scrap in 1922.
HMS Neptune was an ironclad turret ship originally designed and built in Britain for Brazil, but acquired for the Royal Navy in 1878. Modifications to suit the Royal Navy took three years to complete and the ship did not begin her first commission until 1883 with the Channel Fleet. She was transferred to the Mediterranean Fleet in 1885, but refitted in Portsmouth in 1886–87. Neptune then became the coastguard ship for the 1st Class Reserve at Holyhead until 1893 when she was placed in reserve in Portsmouth. While she was being towed to the breakers in 1903, Neptune unintentionally rammed HMS Victory, then serving as a training hulk for the Naval Signal School, collided with HMS Hero, and narrowly missed several other ships. She was scrapped in Germany in 1904.
HMS Humber was a Humber-class monitor of the Royal Navy. Originally built by Vickers for Brazil as Javary, she was purchased by the Royal Navy in 1914 on the outbreak of the First World War along with her sister ships Severn and Mersey.
Monitor National Marine Sanctuary is the site of the wreck of the USS Monitor, one of the most famous shipwrecks in U.S. history. It was designated as the country's first national marine sanctuary on January 30, 1975, and is one of only two of the sixteen national marine sanctuaries created to protect a cultural resource rather than a natural resource. The sanctuary comprises a column of water 1 nautical mile (1.9 km) in diameter extending from the ocean’s surface to the seabed around the wreck of the Civil War ironclad, which lies 16 nautical miles (30 km) south-southeast of Cape Hatteras, North Carolina. Average water depth in the sanctuary is 230 feet (70 m). Since its sinking in 1862, the Monitor has become an artificial reef attracting numerous fish species, including amberjack, black sea-bass, oyster toadfish and great barracuda.
Chesma was the second ship of the Ekaterina II-class battleships built for the Imperial Russian Navy in the 1880s. When the ship was completed she proved to be very overweight which meant that much of her waterline armor belt was submerged. Russian companies could not produce the most advanced armour and machinery desired by the Naval General Staff, so they were imported from the United Kingdom and Belgium. Chesma spent her career as part of the Black Sea Fleet.
The Neosho-class monitors were a pair of ironclad river monitors laid down in mid-1862 for the United States Navy during the American Civil War. After completion in mid-1863, both ships spent time patrolling the Mississippi River against Confederate raids and ambushes as part of Rear Admiral David Porter's Mississippi Squadron. Both ships participated in the Red River Campaign in March–May 1864, although Osage supported the capture of Fort DeRussy in March and participated in the Battle of Blair's Landing in April. Osage was grounded on a sandbar for six months after the end of the campaign while Neosho resumed her patrols on the Mississippi. The latter ship supported the Union Army's operations on the Cumberland River and provided fire support during the Battle of Nashville in December.
The Brazilian monitor Pará was the lead ship of the Pará-class river monitors built for the Brazilian Navy during the Paraguayan War in the late 1860s. Pará participated in the Passagem de Humaitá in February 1868 and provided fire support for the army for the rest of the war. The ship was assigned to the Mato Grosso Flotilla after the war. Pará was disarmed and discarded in 1884.
Norway 
