Ironclads were only a recent innovation, started with the 1859 French La Gloire. Afterwards, the design of ships and the nature of naval warfare changed dramatically.
Rebuilt under the supervision of Captain French Forrest, the new ship was named Virginia. She had four inch (102 mm)-thick iron deck with sloped sides, and casement and ten guns, one 7 inch rifle on the bow and the stern each and four on each beam, 3 of which are Dahlgren cannons. Further, Virginia’s designers had heard of plans by the North to build an ironclad. Figuring her guns would be unable to harm such a ship, they equipped her with a ram— at that time an anachronism in a warship. Merrimac's engines, now part of Virginia, had not been in good working order, and the salty Elizabeth River water and addition of tons of iron did not improve the situation.
The Battle of Hampton Roads began on March 8 1862 when Virginia sortied. Despite an all-out effort to complete her, the ship still had workmen on board when she sailed. Supported by Raleigh and Beaufort, and accompanied by Patrick Henry, Jamestown, and Teaser, Virginia took on the blockading fleet.
The first ship engaged, USS Cumberland, was sunk after being rammed. However, in sinking, Cumberland broke off Virginia's ram. Seeing what happened to Cumberland, the captain of USS Congress ordered his ship grounded in shallow water. Congress and Virginia traded fire for an hour, after which the badly-damaged Congress surrendered. While the surviving crewmen of Congress were being ferried off the ship, a Union battery on the north shore opened fire on Virginia. In retaliation, the captain of Virginia ordered Congress fired upon with red-hot shot, to set her ablaze.
Virginia did not emerge from the battle unscathed. Shot from Cumberland, Congress, and the shore-based Union troops had riddled her smokestack, reducing her already low speed. Two of her guns were out of order, and a number of armor plates had been loosened. Even so, her captain attacked USS Minnesota, which had run aground on a sandbank trying to escape Virginia. However, because of her deep draft, Virginia was unable to do significant damage. It being late in the day, Virginia left with the expectation of returning the next day and completing the destruction of the Union blockaders.
The next day, on March 9, 1862, the world's first battle between ironclads took place. The smaller, nimbler Monitor was able to outmaneuver Virginia, but neither ship proved able to do significant damage, despite numerous hits. Monitor was much closer to the water, and thus much harder to hit by the Virginia's guns, but vulnerable to ramming and boarding. Finally, Monitor retreated. This was because the captain of the Monitor was hit by gunpowder in his eyes while looking through the pilothouse's peepholes, which caused Monitor to haul off, but she soon returned, and the captain of Virginia, Catesby ap Roger Jones, thought it best to do the same to tend to any damages. It has been marked in history that the Virginia retreated, but the battle was a draw. The Union blockade remained.
During the next two months, Virginia made several sorties to Hampton Roads hoping to draw Monitor into battle. Monitor, however, was under orders not to engage. Neither ironclad was ever to fight again.
Finally on May 10, 1862, advancing Union troops occupied Norfolk. Virginia was unable to retreat further up the James River due to her deep draft, nor was she seaworthy enough to enter the ocean. Without a home port, Virginia was ordered blown up to keep her from being captured. This task fell to ap Roger Jones, the last man to leave CSS Virginia after all of her guns had been safely removed and carried to Drewy's Bluff to fight again. Early on the morning of May 11, 1862, off Craney Island, fire reached her magazine and she was destroyed by a great explosion.
When she was first commissioned into the United States Navy in 1856, her name was Merrimack, with the K. The name derived from the Merrimack River near where she was built. She was the second ship of the U.S. Navy to be named for the Merrimack River, which is formed by the junction of the Pemigewasset and Winnipesaukee Rivers at Franklin, New Hampshire. The Merrimack flows south across New Hampshire, and then eastward across northeastern Massachusetts before emptying in the Atlantic at Newburyport, Massachusetts.
The Confederacy bestowed the name Virginia on her when she was raised, restored, and outfitted as an ironclad warship, but the Union preferred to call the Confederate ironclad warship by either its earlier name, "Merrimack", or by the nickname, "The Monster".
Perhaps because the Union won the Civil War, the history of the United States generally records the Union version. In the aftermath of the battle, the names Virginia and Merrimack were used equally by both sides, as attested by the newspapers and correspondence of the day. Some Navy reports and pre-1900 historians misspelled the name as "Merrimac," which is actually an unrelated ship. Hence "the Battle of the Monitor and the Merrimac". Both spellings are still in use in the Hampton Roads area.
The name of the Monitor-Merrimac Memorial Bridge-Tunnel, built in Hampton Roads in the general vicinity of the famous engagement, with both Virginia and federal funds, also reflects the more recent version.
Should periodic modern efforts to recover more of the Confederate vessel from the depths of Hampton Roads prove successful, it is unclear what name will be applied to the remains.