Upon arrival to Hampton Roads, the Merrimack encountered two wooden Union warships; the Cumberland and the Congress. The Merrimack began the battle by firing on the Cumberland and then ramming the ship. The ram put a large seven foot hole in the hull causing the Cumberland to sink. The Merrimack then set out after the Congress. The captain of the Congress ran his ship into shallow water to avoid the ram of the Merrimack which had a much deeper hull and could not get to the ship. In response, the Merrimack heated its cannonballs before firing. The hot cannonballs started fires in the ship causing the ship to start on fire and forcing the Union Navy men to surrender. When two of the confederate ships approached, Union forces from the shore began firing on the ships. This angered Captain Buchannon. He went on deck and began firing on the shore at which time he was hit in the leg by a bullet and had to be taken below deck.
The Merrimack was turned over to Lieutenant Catesby Jones. Early in the day, three northern ships the Minnesota, Roanoke and the St. Lawrence arrived to help the Congress and Cumberland. The Merrimack turned to seek out these ships. The Minnesota is stuck in shallow waters and could not retreat with the other ships. The Merrimack decided to withdrawal until morning due to the lower tides.