
During the war, sailing vessels were completely supplanted by ships propelled by steam for combat purposes. To accomplish its wartime missions, the Union Navy had to undergo a profound technical and institutional transformation. The most radical change was the creation of the Bureau of Steam Engineering. Some of the older bureaus were rearranged or had their names altered. The system of naval bureaus was revised in the summer of 1862. Support the Army by providing gunfire support, rapid transport, and communications on the interior rivers. Carry the war to places in the seceded states inaccessible to the Union Army but could be reached by water. Meet in combat the war vessels of the CSN. Maintain the blockade of Confederate ports by restraining all blockade runners declared by President Lincoln on April 19, 1861, and continued until the end of the Rebellion.

The primary missions of the Union Navy were:ġ. The term is sometimes used carelessly to include vessels of war used on the rivers of the interior while they were under the control of the United States Army, also called the Union Army. The Union Navy was the United States Navy (USN) during the American Civil War, when it fought the Confederate States Navy (CSN).
