View images of the USS Monitor and other iron-clad gunboats. The Monitor was part of a new class of naval warship, an iron-clad steamship, developed during the Civil War. The Monitor fought the Confederate Army’s CSS Virginia (Merrimack) in the first battle between two iron-clad boats. The battle was considered a draw between the North and South. While impressive in its initial battles, the Monitor was not fit for open sea and the poorly designed ship sank in 1862 off Cape Hatteras, North Carolina, with 16 men still aboard it.