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.
An ironclad is a steam-propelled warship protected by iron or steel armor plates, constructed from 1859 to the early 1890s. The ironclad was developed as a result of the vulnerability of wooden warships to explosive or incendiary shells. The first ironclad battleship, Gloire, was launched by the French Navy in November 1859 – narrowly pre-empting the British Royal Navy, though Britain built the first completely iron-hulled warships.
USS Onondaga was an ironclad monitor built for the Union Navy during the American Civil War. Commissioned in 1864, the ship spent her entire active career with the James River Flotilla covering the water approaches to the Confederate States capital of Richmond, Virginia, although her only notable engagement was the Battle of Trent's Reach. After the war, she was purchased by France where she served as a coastal defense ship in the French Navy.
A casemate is a fortified gun emplacement or armored structure from which guns are fired, in a fortification, warship, or armoured fighting vehicle.
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.
USS Neosho, the lead ship of her class, was an ironclad river monitor laid down for the Union Navy in the summer of 1862 during the American Civil War. After completion in mid-1863, the ship spent time patrolling the Mississippi River against Confederate raids and ambushes as part of Rear Admiral David Porter's Mississippi Squadron. She participated in the Red River Campaign in March–May 1864. Neosho resumed her patrols on the Mississippi after the end of the campaign. She supported the Union Army's operations on the Cumberland River and provided fire support during the Battle of Nashville in December 1864. Neosho was decommissioned after the war and remained in reserve until sold in 1873.
The casemate ironclad was a type of iron or iron-armored gunboat briefly used in the American Civil War by both the Confederate States Navy and the Union Navy. Unlike a monitor-type ironclad which carried its armament encased in a separate armored gun deck/turret, it exhibited a single casemate structure, or armored citadel, on the main deck housing the entire gun battery. As the guns were carried on the top of the ship yet still fired through fixed gunports, the casemate ironclad is seen as an intermediate stage between the traditional broadside frigate and modern warships.
The Preussen class of armored frigates was a class of three ships built for the German Imperial Navy in the early 1870s. The lead ship, Preussen, was laid down in 1871 and launched in 1873. Friedrich der Grosse also was laid down in 1871 and launched in 1874. Grosser Kurfürst, although the first to be laid down, in 1869, was the last to be completed, launched in 1875. The ships served in the fleet starting in 1876, when Preussen was commissioned.
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 Alagoas was the third ship of the Pará-class river monitors built for the Imperial Brazilian Navy during the Paraguayan War in the late 1860s. Alagoas participated in the Passage of Humaitá on 19 February 1868 and provided fire support for the army for the rest of the war. The ship was assigned to the Upper Uruguay flotilla after the war. Alagoas was transferred to Rio de Janeiro in the 1890s and participated in the Navy Revolt of 1893–94. The ship was scrapped in 1900.
The Brazilian monitor Piauí was the fourth ship of the Pará-class river monitors built for the Brazilian Navy during the Paraguayan War in the late 1860s. Piauí passed the fortifications at Humaitá in July 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. Piauí was scrapped in 1893.
The Brazilian monitor Ceará was the fifth ship of the Pará-class river monitors built for the Brazilian Navy during the Paraguayan War in the late 1860s. Ceará arrived in Paraguay in mid-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. Ceará was scrapped in 1884.
The John Ericsson-class monitors were a group of five iron-hulled monitors; four were built for the Royal Swedish Navy and one for the Royal Norwegian Navy in the mid to late 1860s. They were designed under the supervision of the Swedish-born inventor, John Ericsson, and built in Sweden. Generally, the monitors were kept in reserve for the majority of the year and were only commissioned for several during the year. The ships made one foreign visit to Russia in 1867 but remained in Swedish or Norwegian waters for the rest of their careers. Two of the monitors, Thordon and Mjølner, ran aground, but were salvaged and repaired. Most of the monitors were reconstructed between 1892 and 1905 with more modern guns, but one was scrapped instead as it was not thought cost-effective to rebuild such an old ship. The surviving ships were mobilized during World War I and sold for scrap afterwards.
HSwMS John Ericsson was the lead ship of the John Ericsson-class monitors built for the Royal Swedish Navy in the mid-1860s. She was designed under the supervision of the Swedish-born inventor, John Ericsson, and built in Sweden. John Ericsson made one foreign visit to Russia in 1867, but remained in Swedish or Norwegian waters for the rest of her career. The ship was reconstructed between 1892 and 1895, but generally remained in reserve. She was mobilized during World War I and sold in 1919 for conversion to a barge.
HNoMS Mjølner, named after the hammer of the god Thor, was the fourth of five ships of the John Ericsson-class monitors built for the Royal Swedish Navy and the Royal Norwegian Navy in the mid-1860s. Influenced by the use of ironclads during the American Civil War, the design was based on that of USS Monitor. They were designed under the supervision of the Swedish-born inventor John Ericsson—coincidentally designer of Monitor—and built in Sweden. Mjølner was delivered in 1868. She ran aground the following year, without serious damage, and reconstructed in 1897 with later breech-loading guns. Mjølner was sold for scrap in 1909.
