The South had no navy.  Throughout the war it suffered under the blockade set up by Union ships.  But on 8 March 1862, Southern naval engineers unveiled a new ship that threatened the naval balance of power in the war—albeit for only a day.

One of the federal installations lost at the beginning of the war was a shipyard in Norfolk, Virginia.  One of the ships seized by the Confederates at Norfolk was a steam frigate named the Merrimac.  Before surrendering the shipyard, Union sailors had set fire to the ship.  But it was only partially burned; the hull remained essentially intact.  

Confederate engineers studied the damaged ship carefully.  Then they decided that rather than rebuild a conventional ship, they would build an ironclad.  They constructed a fortress-like gun house on top of the reinforced deck, sided it with two-foot pine walls, and covered them with two-inch iron plates.

The beast that chugged out of the shipyard on 8 March 1862 was neither fast nor pretty.  But it was unsinkable—armor piercing shells were an innovation waiting to happen.  In just one day, the ironclad—rechristened the CSS Virginia—sank two ships (the Congress and the Cumberland) and forced a third, the Minnesota, to run aground.  

Southerners celebrated their victories and excitedly spoke of the new naval conditions. Northerners lamented the emergence of an ironclad gap.  But the next morning, a Northern tug dragged a second, equally ugly and equally slow, but similarly plated iron ship into the Chesapeake.   

Union officials had known that the Confederates were building an ironclad, and consequently had launched their own Manhattan-like project.  The Northern ironclad employed a different design—it was essentially an iron-covered gun turret sitting on a long raft.  And when commissioned in February 1862 some of the mechanical features had yet to be worked out. Yet there was no time to fine-tune.  Once Northern intelligence reported that the South’s ironclad was ready, the North’s answer—the USS Monitor—set off for Virginia.

The battle between the two ironclads raged for more than five hours.  The heavy guns mounted on both ships, which had proven so deadly against wooden ships, could not penetrate the iron sheathing protecting the ironclads.  In the end, both chose to withdraw—and both chose to avoid a rematch.

The Merrimac (Virginia) sat at the mouth of the James River for another month, preventing Union ships from entering the river and moving against the Confederate capital in Richmond. But after Union troops retook the Norfolk shipyard in May, the ironclad became a sitting iron duck.  Without a home port and, because of her design, unable to travel into the more shallow waters upriver or the tumultuous waters of the sea, the Merrimac had nowhere to go. Therefore, on 11 May, she was scuttled.