National Geographic : 1947 Jul
U.S.Navy, Official Up in Smoke Goes an American Tanker, Victim of a Baffling Attack in Closely Guarded Ulithi Lagoon Here the Navy massed an armada. Suddenly it began losing ships to torpedoes fired from-no one knew where. Premature death of aJapanese pilot on asuicide errand disclosed the secret. His stealthy torpedo-submarine ran on compressed air. To detectors the engine noisessounded likefish(pages 138, 146).