Civil War Ironclads: Casemate Type Ships

This entry is part 7 of 10 in the series The Civil War at Sea
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Civil War Ironclads: Casemate Type Ships

The American Civil War was the first conflict in which ironclads were widely used. The Age of Iron and Steam was gradually superseding the Age of Wood and Sail.

Korean Turtle ShipShips clad with some form of protective shielding had been used for some time. The Vikings had used shields to protect their oarsmen by hanging them along the sides of the their long ships. The Korean had invented an oar-powered “turtle” ship in the 16th century.

Other shipbuilders began to experiment with steel-hulled ships but strictly speaking these were not considered ironclads. The French built ironclads during the 1850s to attack Russian forts during the Crimean War. By the beginning of the Civil War the concept of ironclad warships was well-known and well researched by a number of European sea powers.

As the Civil War combatants developed their designs of ironclads, two general types began to emerge. The Confederate ironclads were casemate type ships. This class of ship carried guns on an wooden, armored casemate structure that was built on top of the armored hull. In the case of the Virginia the casemate wooden structure was two feet thick with a 35 degree angle. The angle gave the vessel an improved resistance to penetrating shot.

The casemate type carried anywhere from 2 to 15 guns positioned in the traditional broadside style of wooden warships plus gunports fore and aft. The casemate structure was heavily armored which required a deep draft to maintain stability. Because the guns had to fire through fixed gunports,CSS Palmetto State aiming them required a much larger gun crew of up to 20 men.

The Union Navy did build and utilize casemate type ironclad warships but mostly for use on the Mississippi River. The Confederate Navy utilized them against the Union blockade, protecting ports and river access for blockade runners. The CSS Virginia was the prototype vessel for casemate ironclad warships.

The CSS Virginia was the first steam powered ironclad warship built by the Confederate States Navy. The Virginia was built on the hull of the USS Merrimack which Union sailors had failed to scuttle in Norfolk harbor in April 1861. The Confederates cut away the burned superstructure, used the power plant and built a casemate structure on top of the Merrimack’s hull.

The Virginia had a twin-bladed screw propeller with powered by two steam engines and four boilers. The total displacement of the Virginia was about 4,100 tons. The casemate ironclad was 275 feet long with a beam of 51 feet 2 inches and draft of 21 feet. Her speed was between 5-6 knots per hour. The Virginia carried a crew of  320 officers and men. She had a total of 12 guns: 2-7 inch Brooke rifles, 2-6.4 inch Brooke rifles, 6-9 inch Dahlgren smoothbores and 2-12-pounder howitzers. The ironclad actually had 14 gunports to accommodate the repositioning of guns.

Battle of Hampton RoadsThe Virginia had various thicknesses of armor: the belt armor was between 1-3 inches thick, the deck armor was 1 inch thick and the casemate armor was 4 inches thick. The ship was equipped with an iron ram, a rather anachronistic device for a 19th century warship. The ironclad had a rather large turning radius of about one mile which took 45 minutes to accomplish. This was a definite drawback when fighting the much nimbler USS Monitor.

After the Battle of Hampton Roads on March 8-9, 1862 the Confederate States Navy immediately began to implement the lessons learned. Over the course of the next three years the Confederate States Navy commissioned 22 ironclads with one additional one built in France. Several others were built but were never completed. One monitor-type was started but the war ended before its completion.

The CSS Virginia was one of six ships that the Confederates converted into ironclads from different types of vessels. All would have significant design flaws due to their underlying foundation vessels. In late 1862 the Confederates built five new ironclads from the keel up. Four were used for coastal defense while the fifth was a design failure and was eventually used as a floating battery. The other four had divergent designs. All of them were for use on or around the Mississippi River. Only two of the four saw combat; the other two were destroyed to prevent their capture.

In early 1862 the Confederate Navy Department came up with two new designs. The Richmond class had six ships plus several others that wereC.S.S. Manassas never completed. The design called for a length that varied from 150 to 174 feet and a draft of 12 to 14 feet, considerably less than the Virginia. The most vulnerable part of the Virginia was the “knuckle” where the casemate met the hull. In the Richmond class this vulnerable area was protected by a 2″ plate of armor that went all around the hull and 6″ below the waterline.

The later “modified” Richmond class or Charleston class was a 180′ long vessel with heavier armament and thicker armor. The Virginia II had three and in some places four layers of 4″ armor. Only two of these vessels were completed: the Charleston and the Virginia II.

The Tennessee class followed but only one, the Tennessee II was commissioned. It was 189′ long with a 14-16 ‘ draft.

A second type of casemate ironclad was built for use in rivers rather than coastal waters. Often called the “diamond hull” type they were characterized by a smaller casemate and a shallower draft of 8’ to navigate rivers. Neither of the two vessels built in Selma, Alabama ever saw active service. Several other vessels were never completed.

Two Albemarle class ironclads were built in North Carolina but one ran aground on her maiden voyage while the CSS Albemarle had a brief but distinguished career before being destroyed by a torpedo. Both of these vessels were 139′ feet long and carried 4 guns. They were succeeded by the CSS Albemarle170′ long CSS Fredericksburg.

The Confederates built a rear paddle wheel vessel with the paddle wheel being protected by the casemate and a side wheeler. Both of these vessels were built because of the availability of paddle wheels.

The Confederates were never able to build enough ironclads to catch up with the Union’s incredible industrial advantage. They built ships along rivers, on riverbanks, wherever they could do so safely. They often had problems with armor, armaments and power plants. The Union Navy was everpresent and maintained a tighter control on the coasts and rivers as the war progressed.

 

 

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One thought on “Civil War Ironclads: Casemate Type Ships

  1. Typo: Paragraph 10- After the Battle of Hampton Roads on March 8-9, 1862 the Confederate States Navy immediately began to implement the lessons learned. Over the course of the next three years the Confederate States Navy commissioned 22 ironclads with one additional one built in France. Several others were built but never completed or just never completed. One monitor-type was started but the war ended before its completion.

    This is the sentence, it has redundant wording: Several others were built but never completed or just never completed.

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