Considered the first "Ironclad" vessel built by the US Navy at the start of The American Civil War (1861-1865), the USS "Cairo" was originally a steam powered Paddle Wheel Riverboat. Commandeered in 1861, she was refitted with 2.5 to 3-inches of armor plate. Her paddle wheel propulsion was replaced with 5-boilers to power a steam engine. She was capable of only 4-knots. Using the Casemate design, "Cairo" displaced 500-tons and was 175-feet long. She stood 50-feet tall. Armed with dual 7-inch Dalhgren Cannon, she was immediately put against Confederate positions on the Mississippi River approach to the City of Vicksburg (1862). Before she could be of any further use however, she was struck by a Mine. Without loss of life, she sunk. "Cairo" was left on the River bottom until 1996, when she, was brought up and conserved. She is currently a "Museum" Ship.