Vindicator, originally acquired by the Federal Government in 1863 at New Albany, Ind., for use by the Army during the Civil War, was transferred to the Navy in 1864; and commissioned on 24 May, Lt. Comdr. Thomas O. Selfridge in command.
Shortly after her transfer from the Army, Vindicator was reworked at Mound City, Ill., for use as a ram in the Mississippi Squadron. She was assigned Command to the 5th District of the squadron on 4 July and deployed off Natchez, Miss., later that month. While off Natchez, Vindicator and her squadron performed patrol and reconnaissance duties, and the mere presence and vigilance of the formidable Union gunboats there were credited with preventing a planned Confederate crossing of the river on 22 August.
Vindicator was transferred to the 6th District of the Mississippi River for duty in early November. During an expedition up the Yazoo River, Vindicator and the stern-wheeler Prairie Bird transported and covered Union cavalry forces in an attack on Confederate communications in western Mississippi on the 27th. The Federals destroyed the railroad bridge over the Big Black River and tore up tracks for a distance of 30 miles around. Major General Napoleon J. T. Dana praised the performance of the two gunboats, saying: "The assistance of the vessels of the Sixth Division Mississippi Squadron rendered the expedition a complete success."
Vindicator remained in the 6th District for the duration of the war and conducted a spirited, though unsuccessful, pursuit of the ram CSS William H. Webb off the mouth of the Red River in Mississippi on 23 and 24 April 1865. During the chase, Acting Master D. P. Slattery of Vindicator stoked his boilers to near bursting point, commenting that "Such was the spirit animating every officer, man, and boy that all seemed to vie with each other in the rapid and intelligent execution of each order."
Vindicator was withdrawn from service soon thereafter and laid up at Mound City, Ill., where she was partially dismantled in July. She was sold at public auction at Mound City to W. L. Hambleton on 29 November; redocumented New Orleans on 27 February 1866; and dropped from documentation in 1869.
