The indecisive naval battle (or, rather, naval duel) fought out between the Monitor (for the North) and the Merrimac (for the South), in March 1862, virtually ended the era of wooden ships. The Merrimac was a captured US vessel which had been decked in armour and had caused some havoc before the Monitor - looking like "a can on a floating shingle"- was hastily built in New York and sent down to the Virginian coast to stop her. They slugged it out for some hours without hurting one another, but the Merrimac's brief reign of terror was over and soon after she was burnt by the retreating Confederates. The Monitor did not long survive her, foundering in a gale off Cape Hatteras, though most of her crew were saved. The story of the fight between these ungainly vessels has been told many times, but the historical and technical context is traced here in often fascinating ways .