One of those to pass the Vicksburg and Warrenton, Mississippi batteries in April 1863, "Carondelet" took part on 29 April in the five-and-a-half-hour engagement with the batteries at Grand Gulf. She remained on duty off Vicksburg, bombarding the city in its long siege from May to July. Without her and her sisters and other naval forces, the great operations on the rivers would not have been possible and the Federal victory might not have been won.