Mark 48 Torpedo Scores First U.S. Submarine Kill Since WWII, Sinking Iranian Frigate

In March 2026, a U.S. Navy fast-attack submarine sank the Iranian Moudge-class frigate IRIS Dena in the Indian Ocean with a single Mark 48 ADCAP torpedo, marking the first American submarine torpedo kill since World War II. The strike occurred roughly 20 nautical miles south of Sri Lanka as the Dena returned from an international naval review in India. At least 80 of the 180 crew were killed. The article argues the Mark 48, in service since 1972, remains a decisive weapon due to its under-keel detonation capability and lack of reliable defenses. It cites CSIS wargames on a Taiwan scenario where undersea dominance is critical, but notes the high cost and limited magazine capacity as drawbacks.