The
island of Corregidor
is one of five
islands guarding the
entrance to Manila
Bay. Running from
north to south are
La Monja, Corregidor
(Fort Mills),
Caballo (Fort
Hughes), El Fraile
(Fort Drum) and
Carabao (Fort
Frank).
Corregidor, the largest of the islands, some
1,735 acres in total, lies two miles from the southern tip of Bataan peninsula
and seven miles from Cavite Province, dividing the mouth of Manila Bay into what
was called the North Channel and the South Channel.
Corregidor is shaped like a tadpole with the
head facing the South China Sea and the tail curling back into Manila Bay.
Topographically, the island is divided into five parts. The high, round head of
the island rising to 628 feet in elevation forms an area about a mile in
diameter which was nicknamed, "Topside" and was the site of all the heavy
batteries, the post headquarters, a nine-hole golf course, a huge enlisted
barracks, a parade ground, and most of the living quarters. Moving eastward
toward the tail of the island, the group slopes downward about 100 feet to a
plateau nicknamed "Middleside" where the hospital, post stockade, service
buildings, warehouses, more barracks, and quarters were located. On the north,
or Bataan side of "Middleside" was a ravine called Power Plant Ravine which
contained the island's electrical generation plant. From "Middleside" which is
the lowest part of the island occupying an area about 300 yards from beach to
beach and about 200 yards wide. Located here were more warehouses and various
post utilities as well as the small village of San Jose, where most of the
island's workers lived. Two docks, one each side of the island, permitted small
ships to unload supplies. Separating "Bottomside" from the eastern part of the
island is Malinta Hill, some 390 feet high, through which Malinta Tunnel was
dug. Passage around Malinta Hill was possible via two narrow roads, carved from
the slopes of the hill which were called the North and South Shore roads. The
remainder of Corregidor is the long, twisted tail of the island, about two and
one-half miles long, which were given no particular name.
The move of Station "C" to Corregidor
represented the conclusion of several years of plans, negotiations, and
construction. The original idea of moving the Radio Intelligence Station, as it
was then called, was apparently first conceived by CINCAF, Admiral Upham, and
the Asiatic Communications Intelligence Officer, Lieutenant J.N. Wenger, in
1933.
About 29 May 1934, a proposal was
informally presented to the Army which requested authorization to establish a
radio direction finder station on Caballo Island. On 15 June 1935 the Army
replied that no immediate action was necessary since it appeared the Navy
Direction Finder Station was functioning well at the Cavite site. In actual
fact, disapproval by the Army was due to the fact they were due to undertake a
plan to install a D/F on Caballo, and the Army did not want intermingling of
Army and Navy personnel..."as the Army contends that it is conducive to lowering
the morale of the Army troops owing to differences in pay." Negotiations
continued.
Several years later, the Secretary of War
informed the Secretary of the Navy that the Commanding General, Philippine
Department had been authorized to begin work on the construction of the tunnel
for the radio intercept station. By 31 August 1939, the following projects were
identified: Project AFIRM, the Radio Intelligence Tunnel; BAKER, the Direction
Finder Site, and CAST, the quarters of personnel of Station "C".
In early October 1939, Project AFIRM was given
the official title of "Navy Emergency Radio Station," and the cover story that
it was to "provide standby (communications capability) for Cavite and conduct
research (in) long distance reception with experimental equipment." A model DY
Direction Finder was to be installed, a Model DT-1 Direction Finder was to be
calibrated and placed in storage on Corregidor and a Model DP IFDF (Intermediate
Frequency) was scheduled to be installed and the Pan American Airways' variously
located D/F's were to be calibrated to assist the District Radio Security and
Inshore Tracking Organizations in time of emergency.
Finally, on 14 October (Z) Station "C" began to
move to Tunnel AFIRM. Station "B" Guam, was to establish watches to insure
maximum coverage until the new "C" was operational, which occurred on 17 October
1939. The station reported that noise level permitted coverage of frequencies
not copyable at Cavite. Coverage, staff, and equipment was increased when
Station "A" at Shanghai was closed on 10 December 1940, and coverage of the
Japanese Consular net was assumed.
References suggest two units had been
established at Station "C", a "general unit," assumed to be the intercept space,
and a "special unit," assumed to be a crypto unit, which included a Purple
Machine, to decipher Japanese Diplomatic traffic. The "special" unit also used
various IBM (International Business Machines) equipment including an
alphabetical tabulator, a card sorter, a punch, and a reproducing gang punch.
Attempts were made to have Ensign Ralph E. Cook, at Cavite Navy Yard, assigned
to the Station "C" complex, but this was not accomplished until after Cavite was
destroyed by bombing on 10 December. This IBM equipment was dismantled and
readied for shipment to Australia when the evacuation of Station "C" personnel
began, and IBM in Manila had instructions to destroy the equipment if Manila
fell; but the equipment was not destroyed. It was taken to Tokyo. (Even
though a Tokyo IBM person was removed from prison camp to work on the
installation, it was later reported the Japanese never used the equipment).
On 8 January 1942, COMSIXTEEN reported to OPNAV
that all radio intelligence publications had been destroyed except the RIP 5
typewriters and several communication ciphers. The Purple Machine was readied
for evacuation, copies of intercept material were not being filed. A message
from COMINCH, Pacific to CINCAF of 31 January 1942, read in part:
SINCE THE WITHDRAWAL OF
SINGAPORE CI UNIT TO COLOMBO, COMMUNICATIONS INTELLIGENCE ORGANIZATION UNDER
YOUR COMMAND IS OF SUCH IMPORTANCE TO SUCCESSFUL PROSECUTION OF WAR IN FAR EAST
THAT SPECIAL EFFORT SHOULD BE MADE TO PRESERVE CONTINUITY. SUGGEST CONSIDERATION
OF PARTIAL EVACUATION FORT MILLS UNIT TO ESTABLISH NEW CI UNIT AT . . . OR
AUSTRALIAN BASE. . .. .
