While passing through the Irish sea, the Dunera was struck by a torpedo that failed to detonate; a second torpedo passed underneath the vessel, which was lifted out of its path by the rough seas. After the war it was discovered, partly from a German submarine captain's diary, that, on another occasion, the Dunera was saved from being destroyed because of the German-language items tossed overboard, "and picked up .. to inspect" by that captain's divers who concluded that the ship was carrying prisoners of war.