To strengthen the New Orleans fleet, two sister ships were constructed on Bayou St. John: Carondelet and the steamer CSS Bienville.

As sailors were in short supply, the ship's crew was supplemented by 30 Confederate States Army soldiers from the garrison of Fort Pike.

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.

[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.