Neosho - class monitor The " Neosho " - class monitors were a pair of ironclad river monitor s laid down in the summer of 1862 . After completion in mid - 1863 both ships spent time patrolling the Mississippi River against Confederate raids and ambushes as part of Rear Admiral David Porter ' s Mississippi Squadron . Both ships participated in the Red River Campaign in March – May 1864 , although " Osage " supported the capture of Fort DeRussy in March and participated in the Battle of Blair ' s Landing in April . " Osage " was grounded on a sandbar for six months after the end of the campaign while " Neosho " resumed her patrols on the Mississippi . The latter ship supported the Union Army ' s operations on the Cumberland River and provided fire support during the Battle of Nashville in December . " Osage " , after being refloated and repaired , was transferred to the West Gulf Blockading Squadron in early 1865 for the campaign against Mobile , Alabama . During the Battle of Spanish Fort in March 1865 she struck a mine and rapidly sank . The ship was later salvaged and sold in 1867 . " Neosho " was decommissioned after the war and remained in reserve until sold in 1873 . Design and description . The original plans for the " Neosho " - class ships , designed by James Eads , resembled the s with a draft of , but the successful performance of the during the Battle of Hampton Roads caused the navy to revise its requirement to include a gun turret . Eads responded with an impressive design that included a turret with of armor , a fully armored sternwheel and a draft of , but the navy wanted even less draft and rejected his design . Eads adopted a turtleback deck design that promised to only draw . The steam - powered turret was at the bow and they had a deckhouse between the funnel and the sternwheel , although another was later added between the turret and the funnel . The " Neosho " - class ships were long overall and had a beam of . When launched they proved to have a draft deeper than planned and they measured 523 tons burthen . The ships had four steam boilers powering one two - cylinder , western steamboat - type engine that drove the sternwheel . The " Neosho " - class ships had a maximum speed of in service and they carried of coal . The ships ' main armament consisted of two smoothbore Dahlgren gun s mounted in a single turret that had an arc of fire of 300° . Firing the guns tended to jam the turret 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 . Service . " 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 of the campaign in May she was assigned to patrol the Mississippi River . During that month she grounded on a sandbar near Helena , Arkansas and could not be refloated even when some of her armor was removed due to the rapidly falling water level . As the water receded " Osage " began to hog at the ends because only her middle was supported by the sand . This caused her longitudinal bulkheads to split and broke many rivets in her hull and on her deck . She was repaired in place before being refloated at the end of November . After being towed to Mound City for more permanent repairs , " Osage " was transferred to the West Gulf Blockading Squadron on 1 February 1865 for the attack on Mobile , Alabama . She participated in the Battle of Spanish Fort , defending Mobile from the east , but struck a mine in a previously swept channel and sank rapidly on 29 March . Two crewmen were killed and some others wounded . The ship was later refloated and sold at auction at New Orleans 22 November 1867 , along with three ex - Confederate ships , for $ 20 , 467 .