The USS Cairo was one of a class of seven vessels all completed in January of 1862 for service on the Western rivers. They were known as "Pook's Turtles" after their designer, Samuel M. Pook, and the distinctive turtleshell look of their sloped armored casemates. Officially, they were designated the City Class and named after cities on the Western rivers, USS Cairo (pronounced "kare-o," or "kay-ro") after Cairo, Illinois at the confluence of the Mississippi and Ohio rivers. They were originally contracted by the Army to support its Western operations, but taken over by the Navy in October of 1862.

They were the first Union ironclads to see service and proved to be the workhorses of the Western naval forces. Pook's Turtles took part in nearly every operation in the Western theater: the captures of Forts Henry and Donelson, Island No. 10, Fort Pillow, and Fort Hindman; bombardments of Drumgould's Bluff, Vicksburg, St. Charles, Grand Gulf, and Ft. Beauregard; engagements with the Confederate naval forces at Lucas Bend, Plum Point and Memphis; battles with the CSS Arkansas on the Yazoo and Mississippi rivers; the Yazoo Pass (Ft. Pemberton), Steele's Bayou, and Red River operations; and general patrol duties on all the Western rivers.

In the course of the war, the City Class gunboats endured hard service. For example, Mound City sank in shallow water as a result of damage to her bow incurred in action against the Confederate River Defense Fleet at Plum Point on May 10, 1862. She was raised and repaired and later, in an engagement with Confederate batteries at St. Charles, Arkansas, was hit in the steam drum which exploded scalding 150 of her 175 man crew, 82 of whom died. Cincinnati bears the distinction of being one of only two Navy ships to have been sunk twice, once by ramming at Plum Point and later by Confederate batteries at Vicksburg. She was raised and put back into commission both times. Carondelet was badly damaged in action against the CSS Arkansas on the Yazoo River, and Pittsburgh was pummeled by 58 hits from Confederate batteries in the bombardment of Grand Gulf.

Still, with two exceptions, these ships fought throughout the war. The two exceptions are the Cairo and the Baron de Kalb (originally St. Louis but renamed when the Navy took over the vessels because there was already a commissioned ship by that name). Both were sunk by "infernal machines" (torpedoes, or, underwater mines) on the Yazoo river in Mississippi. The Cairo on December 12, 1862, and the Baron de Kalb on July 13, 1863. The Cairo was raised 102 years later (see below), the de Kalb is still below the muddy waters of the Yazoo.

The City class vessels followed the general shape shown in Pook's original plans:

The ships as built had only four gunports broadside and two aft, the number of boilers was increased to five, and there was an octagonal armored pilothouse forward (above and slightly abaft the forward battery).

While often referred to as "ironclads," the City Class were only partially armored. 2 1/2" iron plating protected the forward casemate and a a 60-foot section amidship that extended 5' below the "knuckle" (where the hull and casemate met) and 12' above it. The pilothouse was protected by 1 1/4" of iron. This partial armoring was adequate in general, though disastrous in some cases. The Mound City's woes at St. Charles came about when her casemate was penetrated by a shot through the unarmored forequarter. (It's notable that Cairo bore erzatz armor of 3 1/2" railroad iron in this very area.) All vessels were vulnerable to plunging shot from guns on higher elevations and often took hits through their large open gunports.

The general specifications for the City class ironclads are:

175' overall length; 51' 2" beam; 5' 7" draft forward, 5' 8" draft aft.
512 tons
5 high pressure boilers; noncondensing engine with two 22" dia. cylinders & 6' stroke driving a center-mounted 22' dia. paddle wheel via 110" pitman rods on either side; stacks 28' to 33' high, 44" in diameter; max speed roughly 9 mph (5 1/2 knts).
2 1/2" wrought iron plate on forward casemate backed by 24" oak. 2 1/2" wrought iron plate with 12" wood backing amidships extending from the third gunport to just abaft the engine space.
175 to 250 officers & men
Varied considerably from ship to ship and through various periods. In general, all seven vessels mounted 13 heavy guns: 3 forward, 2 astern, and 4 on each broadside. The types of guns ranged from 8" (64-pounder) smoothbores, to 42-pounder smoothbores or rifles, 32-pounder smoothbores, and 30-pounder Parrott rifles. The heaviest armament was forward since this is the aspect at which the vessels were expected to fight.

Cairo, at the time of her sinking, mounted two 42 pdr. rifles and one 8" (64 pdr.) smoothbore forward; three 32 pdr. and one 8" (64 pdr.) smoothbores in the port broadside; two 32 pdr., one 42 pdr. and one 8" (64 pdr.) smoothbores in the starboard broadside; and one 32 pdr. smoothbore and one 30 pdr. Parrott rifle aft.
The Cairo
In December, 1862 the Cairo under the command of Comdr.. Thomas O. Selfridge, along with the Pittsburgh, the ram Queen of the West, and the tinclads Marmora and Signal was sent up the Yazoo river to reconnoiter and clear the river of torpedoes. At 11:55 that morning, Cairo was moving to engage Confederate batteries firing from Drumgould's Bluff when two torpedoes exploded beneath her. These were fired by a galvanic battery operated by Confederate troops hidden on shore behind a levee that ran along the riverbank. She sank in about 12 minutes without loss of life. In order to hide her from the Confederates who might try to salvage her guns, her stacks and masts, which were protruding from the river's surface, were pulled down. The other ships of the flotilla continued their mission. Cairo's crew returned to Cairo, Illinois on board the Marmora, while their ship remained hidden beneath the waters of the Yazoo river.

Cairo sat undisturbed under the Yazoo for the nearly a century. In 1956 Edwin C. Bearss, park historian for the Vicksburg National Military Park undertook to locate the Cairo. By 1960 "Operation Cairo, Inc." a nonprofit organization under Bearss' direction, had determined that they found the Cairo and began to raise her. Starting with the armored pilothouse the ship was raised bit by bit over the course of several years. By 1965 the pieces, mostly a jumble of iron and timber, was deposited at a shipyard in Pascagoula, Mississippi for reconstruction. Due to shortage of funds, restoration wasn't completed for over a decade. Much of the ship was salvageable, while much was not. The ship was rebuilt in a special display berth at the Vicksburg NMP. To fill out the shape of the vessel, the structure was "ghosted" with newer timbers where the original ones were too decayed. Adjacent to Cairo is the museum that houses the numerous artifacts recovered from her.

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Last update April 16, 2008