Pearl Harbor

According to David Kahn (The Codebreakers: The Story of Secret Writing, London: Weidenfield & Nicolson, 1967, pp. 10, 388, 503–04):

Commander Laurence F. Safford . . . founded the Navy’s communication-intelligence organization. . . . One of his principal accomplishments before the outbreak of war was the establishment of the Mid-Pacific Strategic Direction-finder Net and of a similar net for the Atlantic, where it was to play a role of immense importance in the Battle of the Atlantic against the U-boats. . . . He [Safford] built up the communications intelligence organization into what later became OP-20-G and, by adding improvements of his own to Edward Hebern’s rotor mechanisms, gradually developed cipher machines suitable for the Navy’s requirements of speed, reliability, and security. . . . [H]e is the father of the Navy’s present cryptologic organization. . . . Thanks to Commander Laurance F. Safford head of OP-20-G and father of the Navy’s communications-intelligence organization, the United States had, upon its entrance into the war, an Atlantic arc of high-frequency direction-finders to exploit the U-boat garrulity.