The first battle between armoured warships, known as ironclads; an inconclusive naval engagement in the American Civil War between the Confederate Merrimack and the Union battleship Monitor 8 March 1862 off the southeast coast of Virginia. The Merrimack has recently been renamed the Virginia. Neither vessel made any impression on the other after several hours of exchanging fire and eventually both withdrew.
Although the Merrimack made a few minor forays after that, it never encountered the Monitor again and did relatively little damage. The Union army then captured Norfolk and the Confederates set Merrimack on fire before abandoning the town. Monitor was sunk in a storm while sailing back to New York 31 December 1862.
Building the ships When the Confederates occupied Norfolk, Virginia, they found a damaged steam frigate, the Merrimack. The hull was sound and the engines repairable, so they cut away the upper works and built a new superstructure of pine timber 50 cm/20 in thick covered by equally thick plates of iron. Loopholes were left to allow four 18-cm/7-in and six 23-cm/9-in guns to be fired from this protected battery. The resulting craft was named the Virginia. Hearing of this threat, the Union government commissioned John Ericsson, a Swedish-born engineer, to devise an armoured vessel. His solution was the Monitor, an armoured raft carrying a revolving turret with two 28-cm/11-in guns.
Battle The Merrimack went into action 8 March 1862 in Hampton Roads, off Norfolk, against a Union fleet blockading the port. Union ships opened fire but the shots bounced off the Merrimack, which proceeded to ram the USS Cumberland and then bombarded the USS Congress into submission. Later that day, after the Merrimack had returned to its berth, the USS Monitor appeared, and on the following day both ships came out to give battle. Each captain watched their shots bounce off the other vessel, and although they circled and bombarded for some hours, no decision was reached. Monitor ran out of ammunition, and Merrimack withdrew to make some minor repairs.