A naval ram is a weapon fitted to varied types of ships, dating back to antiquity. The weapon comprised an underwater prolongation of the bow of the ship to form an armoured beak, usually between 2 and 4 meters (6–12 ft) in length. This would be driven into the hull of an enemy ship to puncture, sink or disable it.

The River Defense Fleet was a set of fourteen vessels in Confederate service, intended to assist in the defense of New Orleans in the early days of the American Civil War. All were merchant ships or towboats that were seized by order of the War Department in Richmond and converted into warships by arming each with one or two guns, protecting their engines by an interior bulkhead, and strengthening their bows so they could be used as rams. Although they were nominally a part of the Confederate States Army, all of their officers and most of their crews were civilians. A portion of the fleet was retained in the south part of the Mississippi River and a portion was sent north to defend against Union movement from the north.