VICKSBURG, Miss. (WJTV) – The USS Cairo as a City-class ironclad gunboat constructed for the Union Navy by James Buchanan Eads during the American Civil War. She was the lead ship of the City-class gunboats, sometimes also called the Cairo class, and was named for Cairo, Illinois. Cairo was the first ship sunk by a naval mine, on 12 December 1862 in the Yazoo River.
Service in the American Civil War Cairo was built in 1861 by James Eads and Co., Mound City, Illinois, under contract to the United States Department of War. She was commissioned as part of the Union Army’s Western Gunboat Flotilla, U.S. Navy Lieutenant James M. Prichett in command. Cairo served with the Army’s Western Gunboat Flotilla, commanded by Flag Officer Andrew Hull Foote, on the Mississippi and Ohio Rivers and their tributaries until transferred to the Navy 1 October 1862 with the other river gunboats.
Active in the occupation of Clarksville, Tennessee, 17 February 1862, and of Nashville, Tennessee, 25 February, Cairo stood down the river 12 April escorting bomb vessels to begin the lengthy operations against Fort Pillow. An engagement with Confederate gunboats at Plum Point Bend on 11 May marked a series of blockading and bombardment activities which culminated in the abandonment of the Fort by its defenders on 4 June.
Two days later, 6 June 1862, Cairo joined in the triumph of seven Union ships and a tug over eight Confederate gunboats off Memphis, Tennessee, an action in which five of the opposing gunboats were sunk or run ashore, two seriously damaged, and only one managed to escape.
That night Union forces occupied the city. Cairo returned to patrol on the Mississippi until 21 November when she joined the Yazoo Pass Expedition.
On 12 December 1862, while clearing mines from the river preparatory to the attack on Haines Bluff, Mississippi, Cairo struck a torpedo detonated by volunteers hidden behind the river bank and sank in 12 minutes; there were no casualties.
Armament like many of the Mississippi theatre ironclads, Cairo had her armament changed over the life of the vessel. To expedite the entrance of Cairo into service, she and the other City-class ships were fitted with whatever weapons were at hand, then had their weapons upgraded as new pieces became available.
Though the 8 in (200 mm) smoothbore Dahlgren guns were fairly modern, most of the other original armaments were antiquated, such as the 32-pounders, or modified, such as the 42-pounder “rifles” which were in fact, old smoothbores that had been rifled. These 42-pounder weapons were of particular concern to military commanders because they were structurally weaker and more prone to exploding than purpose-built rifled cannons.
Additionally, the close confines of riverine combat greatly increased the threat of boarding parties. The 12-pounder howitzer was equipped to address that concern and was not used in regular combat.