Attack by Submarine H.L. Huntley
The Confederate submarine CSS Huntley slipped through a Union blockade off Charleston harbor and attacked the USS Housatonic. The Huntley's torpedo was a 90-pound black powder charge placed onto the end of a long pole. Guards on board the Housatonic saw something approaching it underwater. They shot musket rounds at the submarine's iron hull but they bounced off the Hunley's sides.... When the Huntley hit the Housatonic with it's mine and pulled away, the resulting explosion sank the Housatonic in under five minutes. The Huntley sank as well. ... This was the first time in US Naval warfare that a submarine successfully sank another ship.