After her commissioning, Carondelet was placed under the command of First Lieutenant Washington Gwathmey. As sailors were in short supply, the ship's crew was supplemented by 30 Confederate States Army soldiers from the garrison of Fort Pike. The 42-pounder guns had also come from Army stockpiles.[6] On April 3, two Union Navy ships – the steamers USS New London and USS John P. Jackson – and the troop transportUSS Henry Lewis left Biloxi, Mississippi, to move against Confederate positions at Pass Christian.[7] Along with the gunboats CSS Oregon and CSS Pamlico, Carondelet moved to combat the Union vessels on April 4.[2]Henry Lewis withdrew after a Confederate shot struck her deck, wounding three men, and two shots probably fired by Carondelet caused minor damage to John P. Jackson. However, after both Oregon and Carondelet were hit in their wheels and the steamer USS Hatteras arrived to reinforce the Union ships, the Confederate vessels withdrew to Lake Pontchartrain, guarding the Chef Menteur Pass and the Rigolets. The 1,200 troops aboard Henry Lewis were then unloaded onto shore, and the Union forces captured the Pass Christian area[8] and destroyed a local Confederate camp.[2]
On April 24, Union Navy ships passed the Confederate positions of Fort Jackson and Fort St. Philip and passed the weaker defenses at Chalmette the next day. New Orleans was now essentially indefensible.[9]Oregon was sunk as a blockship, but the location of the wreck later interfered with attempts by Carondelet, Bienville, Pamlico, and the transport CSS Arrow to escape. After ferrying Confederate troops out of the city to Covington across Lake Pontchartrain, Carondelet, Bienville, and Pamlico were scuttled by their crews on April 25. Their cannons were sent to Vicksburg, Mississippi, via the Confederate training facility Camp Moore.[10] Naval historian Neil P. Chatelain, Silverstone, and the Dictionary of American Naval Fighting Ships both state that Carondelet was sunk in Lake Pontchartrain, with Chatelain specifying the northern part of the lake.[2][9][3] Gaines states that she was sunk in either the Tchefuncte River or the Bogue Falaya River. The wreck later became covered with sand and was a hazard to navigation. According to Gaines, it was likely removed in 1871 by the United States Army Corps of Engineers.[5]
Chatelain, Neil P. (2018). "The Confederacy's Lake Pontchartrain Naval Squadron: A Cooperative Defense of the Coastal Approaches to New Orleans, 1861-1862". Louisiana History. 59 (2): 167–195. JSTOR26475479.
Chatelain, Neil P. (2020). Defending the Arteries of Rebellion: Confederate Naval Operations in the Mississippi River Valley, 1861–1865. El Dorado Hills, California: Savas Beatie. ISBN978-1-61121-510-6.