Battle of the Head of Passes. She had been converted from a commercial vessel in New Orleans for river and coastal fighting. In February 1862, the larger joined the Confederate Navy, having been rebuilt at Norfolk. Constructed on the hull of , Virginia originally was a conventional warship made of wood, but she was converted into an iron-covered casemate ironclad gunship, when she entered the Confederate Navy. By this time, the Union had completed seven ironclad gunboats of the , and was about to complete , an innovative design proposed by the Swedish inventor John Ericsson. The Union was also building a large armored frigate, , and the smaller . The first battle between ironclads happened on 9 March 1862, as the armored Monitor was deployed to protect the Union's wooden fleet from the ironclad ram Virginia and other Confederate warships. In this engagement, the second day of the Battle of Hampton Roads, the two ironclads while shells bounced off their armor. The battle attracted attention worldwide, making it clear that the wooden warship was now out of date, with the ironclads destroying them easily. The Civil War saw more ironclads built by both sides, and they played an increasing role in the naval war alongside the unarmored warships, commerce raiders and blockade runners. The Union built a large fleet of fifty monitors modeled on their namesake. The Confederacy built ships designed as smaller versions of Virginia, many of which saw action, but their attempts to buy ironclads overseas were frustrated as European nations confiscated ships being built for the Confederacy – especially in Russia, the only country to openly support the Union through the war. Only CSS Stonewall was completed, and she arrived in Cuban waters just in time for the end of the war. Through the remainder of the war, ironclads saw action in the Union's attacks on Confederate ports. Seven Union monitors, including , as well as two other ironclads, the armored frigate New Ironsides and a light-draft , participated in the failed attack on Charleston; one was sunk. Two small ironclads, and participated in the defence of the harbor. For the later attack at Mobile Bay, the Union assembled four monitors as well as 11 wooden ships, facing the , the Confederacy's most powerful ironclad, and three gunboats. On the western front, the Union built a formidable force of river ironclads, beginning with several converted riverboats