Final answer:
The USS Constitution earned the nickname 'Old Ironsides' during the War of 1812 due to its strong construction and ability to withstand cannonfire. This iconic ship showcased American naval prowess and boosted morale during the conflict.
Step-by-step explanation:
The ship that earned the nickname 'Old Ironsides' during the War of 1812 was the USS Constitution. The USS Constitution was an American-designed and constructed frigate made from American oak. It gained its nickname when a shot fired from the HMS Guerriere bounced off its side, hence proving its sturdy construction. This victory boosted American morale and celebrated the ship's ability to out-sail the British navy.