Between late March 1862 and June 1863, the steam frigate Roanoke was cut down to her gun deck and rebuilt as a triple-turret armored warship. It was originally expected that this work would produce a seagoing ironclad ram in minimal time, but problems with armor supply and fabrication slowed her conversion considerably. Commissioned in late June 1863 and sent to Hampton Roads, Virginia, to rejoin the blockade, her voyage southward convincingly demonstrated that she was unsuitable for fighting on the opean ocean.

Roanoke was therefore employed in the defenses of Hampton Roads. While her deep draft restricted her to the main shipping channels, her six heavy guns provided a final barrier in case the Confederate ironclads on the James River should break out. Following the end of the war, she was sent to New York, where she was decommissioned in June 1865. Despite her flaws, Roanoke lasted for nearly two more decades. Though most of this time was spent laid up "in ordinary", she was commissioned for harbor service during 1874-75. USS Roanoke was finally stricken from the Navy list in August 1882 and sold for scrapping in September 1883.