The U.S. Navy does not abandon it's right to any of it's property, anywhere, this is protected by law. All Confederate Naval equipment or equipment used in combat against the U.S. Navy, either captured, abandoned, destroyed or lost, -- by right of conquest, belongs to the U.S. Navy. Federal courts have protected these rights.
Strangely, the U.S. Navy, has not used these rights as aggressively in issues of salvage on foreign vessels sunk in combat by U.S. Naval forces in wars that clearly were won by the United States.