On March 10, 1862, Defiance conversion was completed and she steamed from New Orleans to Fort Jackson on the lower Mississippi to operate in the Confederate defense of New Orleans. Defiance, with five other ships of Montgomery's fleet in that area was under the overall command of Capt. J. A. Stevenson, who operated under Capt. J. K. Mitchell, commanding Confederate naval forces on the lower Mississippi.
When Flag Officer D. G. Farragut, USN, ran his fleet past Forts Jackson and St. Philip on April 24, 1862, on his way to New Orleans, Defiance, under Capt. J. D. McCoy, was the only river defense vessel to escape destruction or capture. On April 26, Captain Stevenson turned her over directly to Captain Mitchell after her captain, officers, and crew left her. On April 28, Captain Mitchell, not having enough men for a crew, and realizing that capture was inevitable after the forts surrendered, burned her to keep her from falling into Union hands.[1]