 Complete the following phrase:  With the onset of the American Civil War in April 1861, Colhoun returned to U.S. Navy service, becoming an acting lieutet on 24 September 1861. From 1861 to 1862 he was commanding officer first of the steam tugboat , then of the steamer , both operating as part of the Union blockade of the Confederate States of America in the North Atlantic Blockading Squadron. In command of Hunchback, he saw combat at the 