In August 1861, James B. Eads and Samuel Pook collaborated to develop a new Union warship which would serve on the Mississippi River and its tributaries. Seven ironclads were built at Carondelet, Mo., introducing a new weapon of war.
Prior to the Civil War, Eads had made a fortune in the river salvage business, building boats that were used to raise sunken vessels on the river bed. Due to his knowledge of boats and the treacherous Mississippi River, river men called Eads “Captain” even though he really had no rank.
Pook was a naval architect from Boston whose design would bring forth the new iron-covered river vessels.
With Pook’s design and Eads’ facilities near St. Louis, the two men began building seven city class ironclads. These ironclads would be named after the river cities of Cairo, Carondelet, Cincinnati, Louisville, Mound City, Pittsburg and St. Louis (later renamed the Baron De Kalb).
Eads had submitted a bid to build the ironclads with a cost of $89,600 per vessel, stating he could have all seven complete by October 1861.
Pook’s design called for a wooden vessel covered by iron above the water line. The boats would have a draft of only six feet, allowing them to operate in shallow water. The vessels carried thirteen guns which were fired from behind the safety of the sloping iron sides. A single paddle wheel, also protected by iron, powered the vessel.
Given their unusual shape, some sailors called the vessels Pook’s turtles although the name ironclads eventually caught on. Eads missed his October 1861 deadline and the cost of each vessel doubled upon completion. Still, all seven were completed by January 1862.
The ironclads proved invaluable for generals such as Ulysses S. Grant and William T. Sherman for operations against Confederate strong holds at Fort Henry, Fort Donelson, Island No. 10, Arkansas Post and the Gibraltar of the South, Vicksburg.
While protected above water, the ironclads wooden hulls were vulnerable below the water line. This made the ironclads susceptible to attacks by Confederate rams or mines. The wooden decks also made the ironclads vulnerable to any plunging fire.
This vulnerability was illustrated by the sinking of the USS Cairo when it hit a Confederate torpedo or electronically detonated mine in the Yazoo River during the Vicksburg campaign.
The ironclads were lauded by the likes of Grant and Sherman for helping to achieve early victories in the western theater.