The Confederacy led in the experimentation with submarines. The most successful was the HL Hunley. This submarine sunk a Union warship however the sinking ship damaged the submarine that also sank.
The Confederate submarine H L Hunley sank a Federal warship, Housatonic
H. L. Hunley
Hunley.
May 7th, 1915
It sank an enemy warship
A U-boat
The USS Indianapolis sank after being hit by torpedoes launched from a Japanese mini-submarine.
They really developed the Iron Clads, the forerunners of the modern ships with armored sides. Submarines were also experimented with, the Confederates having a submarine that successfully attacked a Union ship, but then sank with all hands.
Only one US submarine sank in World War One.
He was Commander Mochitsura Hashimoto.
HMS Conqueror ("Conks") remains to date the only nuclear-powered attack submarine credited with a wartime sinking. She sank the Argentine Light Cruiser General Belgrano (a converted American CL) during the Falklands War in 1982, using standard (not homing) torpedoes.She was decommissioned in 1990.
In the U.S. submarine force, USS Flasher (SS-249) sank the most tonnage according to official records, 21 ships totaling 100,231 tons.