Could a full T-class submarine torpedo spread sink a cruising Yamato-class battleship?
Short answerPotentially: a ten-torpedo bow salvo producing three or four hits would put even Yamato in serious danger, especially before the ship reached battle stations.
NotesYamato or Bismarck would be among the few targets worth expending all ten forward torpedoes at once. The outcome is not guaranteed, but multiple underwater hits could overwhelm the margin provided by the battleship's size and protection.