The first battle between ironclad warships was a dud, but it changed naval warfare forever

• On March 9, 1862, Confederate Navy ship CSS Virginia and Union navy ship USS Monitor met in battle off the coast of Virginia.
• Their clash was inconclusive, but the battle was the first time metal warships had squared off, and it changed naval warfare forever.

As dawn broke over Hampton Roads, Virginia, on March 9, 1862, the Confederate Navy ironclad CSS Virginia left the Gosport Naval Yard and sailed toward the grounded Union frigate USS Minnesota.

The day before, on its maiden voyage, the Virginia achieved a shocking victory against the Union Navy's North Atlantic Blockading Squadron, sinking two ships and causing three more to run aground. Virginia's crew now planned to finish off the three ships and break the Union blockade of Norfolk.

But as Virginia approached, its crew noticed what looked like "an immense shingle floating on the water with a gigantic cheese box rising from its center."

It was the USS Monitor, a unique ironclad built hastily and specifically to deal with Virginia.

Once it was in range, Virginia fired at Monitor but missed, hitting Minnesota instead. Monitor, already charging forward, rotated its turret and returned fire. It was the first time in history that metal warships were facing off, and although it was an inconclusive battle, it changed naval warfare forever.

Making up for smaller numbers

Virginia wasn't always an ironclad. It was originally the 40-gun steam frigate USS Merrimack, commissioned in 1856. Merrimack was a sister ship of Minnesota and had sailed between the Caribbean and Europe before becoming flagship of the Pacific Squadron.

In 1860, Merrimack was brought to the Gosport Navy Yard (now the Norfolk Naval Shipyard), decommissioned, and slated for a refit, but that was prevented by the start of the Civil War and Virginia's secession in April 1861.

Now in enemy territory, the Union Navy hastily evacuated Gosport and attempted to destroy anything of value left behind, including Merrimack.

Despite those attempts, Merrimack's hull beneath the waterline and its steam engine remained intact. The Confederates, in desperate need of ships, raised Merrimack, renamed it Virginia, and rebuilt it as an ironclad.

The Union was blockading Southern ports and had started its own massive ship-building program, and the Confederates hoped to overcome the larger Union Navy with superior technology.

The first American ironclads

Ironclad warships were still a new concept. The first ones, built by France and Britain, had only been launched between 1859 and 1861. Those ships were designed to be ocean-going vessels, and none saw combat.

In contrast, Virginia was designed to operate along the coast. It was 275 feet long and protected by 24 inches of oak and pine covered by 4 inches of iron plates, all sloped at a 36-degree angle.

It was armed with 12 guns, all housed in its casemate: two 7-inch guns fore and aft able to fire from 3 ports, and three 9-inch guns and one 6.4-inch gun in four ports on each side.

Virginia's boiler furnaces allowed it to fire heated shot, and its bow was fitted with a ram. Completely steam powered, it had a top speed of 6 knots and a turning radius of a mile.

The Northern press covered Virginia's construction closely, and it acquired the nickname "The Rebel Monster." Worried that a metal Confederate vessel could pierce the blockade and wreak havoc on Northern coastal cities, the Union hurried to build its own ironclads.

USS Monitor was the most successful of the three designs selected. Built in about 100 days, the 172-foot ship's hull was completely submerged. Its rotating turret held two 11-inch guns. The hull was covered with 3 to 5 inch thick plates, while the turret was 8 inches thick. Its top speed was also 6 knots.

Virginia was commissioned on February 17, 1862. Monitor entered service eight days later and immediately sailed south to confront Virginia.

The first battle

On the morning of March 8, Virginia and several smaller wooden vessels set out to break the Union blockade. Reaching Hampton Roads, Virginia headed straight for the sloop-of-war USS Cumberland and opened fire.

Return fire from Cumberland and the frigate USS Congress couldn't penetrate Virginia's armor. As Virginia's guns lashed the Union ships, it rammed Cumberland at full speed, leaving part of its ram lodged there when it reversed.

As Cumberland sank, Virginia turned toward Congress, which had intentionally grounded itself to avoid Cumberland's fate. Virginia's guns pounded the Union frigate for over an hour, killing scores and forcing the ship to surrender.

Union ships and land batteries continued to fire on Virginia while it oversaw Congress' evacuation, prompting Virginia's crew to fire on the frigate until it caught fire and then turn to finish off the three other frigates, which had all unintentionally run aground while trying to intercept the ironclad.

But they were spared. The tide had begun to fall, and the growing darkness prevented accurate gunfire.

Virginia returned to port, intending to finish the job the next day. The ironclad had sunk two Union ships and killed over 240 sailors while only losing two crewmen.

The Monitor arrives

Monitor arrived in the evening of March 8 and sailed to the still-grounded Minnesota. "I will stand by you to the last if I can help you," Lt. John L. Worden, Monitor's commander, told Minnesota's captain.

The next day, as Virginia began its attack, Monitor engaged it. Neither could penetrate the other's armor.

Virginia only had high-explosive ammunition, which at the time was designed for wooden ships. Poor visibility and the constant rotation of Monitor's turret - the crew found it easier to keep the turret spinning rather than moving it back and forth - reduced the rate of fire of its guns, which were not powerful enough to penetrate Virginia's armor anyway.

The two ironclads fought for over four hours, until a lucky shot from Virginia temporarily blinded Worden. Monitor briefly disengaged before returning to fight, but Virginia had interpreted that as a retreat and withdrew.

Virginia hit Monitor 22 times during the battle. Monitor, other Union ships, and land batteries hit Virginia over 100 times.

Aftermath

It was a tactical victory for the Confederates but inconclusive overall, as the Union blockade remained.

The ships never faced one another again. Virginia was scuttled to prevent its capture when Norfolk fell in May 1862, and Monitor was lost in a storm on December 31, 1862.

But the battle had an immense impact on naval warfare.

It proved that metal ships - particularly ones with rotating turrets and powered entirely by steam - were the future. Thicker armor and more powerful guns had to be developed, rams were reintroduced, and "monitor" became the moniker for a new type of warship: a small coastal vessel with oversized guns.

The Union and Confederacy built over 70 ironclads before the end of the Civil War, while the world's major naval powers embarked on an ironclad building spree.

Russia quickly built 10 Uragan-class monitors based on designs from the US's Passaic-class ships, which succeeded Monitor. France and Britain both halted construction of all new wooden ships and built ocean-going and coastal ironclads.

In 1866, Italian and Austrian ironclads faced off at the Battle of Lissa. It was the first major sea battle between metal ships and proved they were now the kings of the seas.