until modifications were made to the guns' recoil system. Each gun weighed approximately . They could fire a shell up to a range of at an elevation of 15°. The turret and the pilothouse were protected by of wrought iron while the hull had of armor. The deck's armor plates were thick. Ships Service history Neosho was commissioned at Cairo, Illinois on 13 May 1863, but was not completed until 1 July. She left Cairo on 14 July 1863 and reached Vicksburg on 6 August, just over a month after it had surrendered after a lengthy siege. Neosho and other warships patrolled the Mississippi and its tributaries to prevent Confederate raiders and flying batteries from ambushing Union supply ships. One example was on 8 December 1863 when "a Confederate shore battery attacked and disabled merchant steamer Henry Von Phul; Neosho and steamed up to defend the ship and silenced the battery." From 12 March to 22 May 1864, Neosho and Osage participated in the unsuccessful Red River Campaign under the command of Rear Admiral David Porter. During the retreat down the Red River, Neosho was trapped above the falls at Alexandria, Louisiana, along with most of the other ironclads of the Mississippi Squadron, when the river's water level unexpectedly began to fall. Two temporary dams, known as Bailey's Dam, had to be built in April–May to raise the water level high enough to allow the ironclads to proceed downstream. During the Franklin-Nashville Campaign in December 1864 Neosho, accompanied by the casemate ironclad , bombarded Confederate artillery batteries on the Cumberland River, near Bell's Mills, Tennessee, on 6 December. Despite being hit over 100 times, she was not seriously damaged. The monitor bombarded the Confederate right wing during the Battle of Nashville on 15–16 December. Neosho was decommissioned at Mound City, Illinois on 23 July 1865 and remained in ordinary. She was renamed Vixen 15 June 1869 and again renamed Osceola on 2 August 1869. The monitor was sold at Mound City to David Campbell 17 August 1873 for $13,600. During the Red River Campaign Osage was commanded by Lieutenant Commander Thomas O. Selfridge, Jr. She participated in the capture of Fort DeRussy on 14 March 1864, shortly after the beginning of the campaign. She successfully defended the navy transports attacked during the Battle of Blair's Landing on 12 April, driving off the Confederate forces with heavy losses. After the end