Both Hypo and Negat began an urgent campaign to recruit personnel with all the various skills necessary to support their radio intelligence collection, direction finding, analysis, decryption and reporting. With Admiral Nimitzís support, Hypo obtained former band personnel from the California and Oklaholma for IBM machine operations as well as radiomen and other technical personnel rushed to Pearl Harbor after the attack or without a ship assignment. Out of Hypoís personnel, a new organization, Combat Intelligence Center (CIC) began to emerge to work directly with the Fleet Intelligence Officer. Negat grew tremendously with reserve personnel and large numbers of Waves. Substantial percentages of school graduates, particularly radiomen, yeomen and maintenance personnel were allocated to OP-20-G requirements for U.S. and overseas billets. In addition to recruiting Japanese linguists, a Japanese language school was established at the University of California at Berkley. It later moved to Boulder, Colorado and provided OP-20-G with many additional language officers.
From 5 February to 8 April 1942, Cast personnel were evacuated from Corregidor to Australia in three submarine trips. Their new station, which eventually was called Fleet Radio Unit, Melbourne (FRUMEL), was set up in Melbourne so as to take over Castís cryptologic duties when the last group departed Corregidor.
Nimitzís support and approval, Hypo commenced a program of providing major
fleet commanders with a small on board Radio Intelligence Unit (RIU) for
cryptologic support. This started out with a junior language officer,
a Chief Radioman and two or three radiomen. The program began with
the early carrier raids on the outlying islands of Marcus and Wake, targets
in the Marshals and Gilberts, and, of course, the Halsey/Doolittle raid
on Japan. The success of these RIUís varied with the confidence or
lack thereof the fleet commander had in such units. Most fleet commanders
soon saw the tremendous advantage of having such units aboard particularly
for their early warning capability. As time went on, more and more
fleet commanders insisted on having such units and more personnel for each
By the end of the war, expanded RIUís were provided to all carrier task forces, battleship force commands and some smaller commands.
became available, Hypo commenced copying all the Japanese weather broadcasts
and soon their weather code was broken. U.S. weather observations
were augmented by these Japanese weather reports and the resulting forecasts
were sent out to all U.S. forces by the CinCPac weather unit.