Appendix F. Geographical considerations and Navy and Army
installations ................................................... 489
Geographical considerations ................................... 489
Navy and Army installations ................................... 490
Navy ........................................................ 490
Army ........................................................ 491
Illustrations ................................................. 499
(Illustrations will be uploaded at a later date.)
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GEOGRAPHICAL CONSIDERATIONS AND NAVY AND ARMY INSTALLATIONS
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GEOGRAPHICAL CONSIDERATIONS AND NAVY AND ARMY INSTALLATIONS
The Territory of Hawaii consists of a chain of eight principal islands.
 The island of Oahu is to be regarded as of most importance by reason
of the excellent enclosed fleet anchorage at Pearl Harbor and the
commercial port of Honolulu. Pearl Harbor is located on the southern or
lee side of Oahu, in a strategically and commercially important position
in the North Pacific Ocean, 3,430 nautical miles southeast of Tokyo,
approximately 2,000 nautical miles west to southwest of San Francisco,
and 4,767 nautical miles east of Manila. 
The islands have a mild subtropical climate with moderate seasonal
changes of temperature. They lie in the path of the steady northeasterly
trade winds; therefore, the northern portions of Oahu and the
immediately adjacent waters are characterized by fresh winds from a
northerly direction. The force of the trades is broken by the
configuration of the land so that so the south of Oahu the seas are
Much of the moisture of the trade winds is deposited on the high peaks
to the north, forming mist and clouds. Because of this, the visibility
to the south of the islands is better than to the north. The northern
fringe of the trade belt lies roughly about 300 miles to the north of
Oahu, a belt which is characterized by low ceilings, poor visibility,
squalls and rain.
The sea area around the Hawaiian Islands was, on December 7, 1941,
divided into certain restricted fleet training areas where units and
aircraft of the Pacific Fleet might carry out exercises and target
practice. Two defensive sea areas were mapped off Pearl Harbor and
Kaneohe, these areas having been designated by the President of the
United States. Entry of all merchant ships, both United States and
foreign, and of all foreign men-of-war was prohibited unless specific
permission for such entry had been granted by the Secretary of the Navy.
When the Japanese attacked Pearl Harbor at 7:55 on the morning of
December 7, 1941, it was 1:25 in the afternoon of the same day in
Washington, D. C., and 3:25 a. m., December 8, in Tokyo. In order to
obtain the corresponding time in Washington and Hawaii, it is necessary
to subtract 14 hours and 19 1/2 hours, respectively, from Tokyo time.
The time of sunrise on the morning of December 7,
 They are the islands of: Oahu, Hawaii, Maui, Kahoolawe, Lanai,
Molokai, and Kauai, Niihau. See attachment No. 1.
 A nautical mile is roughly 1 1/6 land miles. For a table of
distances with respect to Pearl Harbor, see committee exhibit No. 6,
 For maps of the Hawaiian Islands and descriptions of the defensive
sea areas, see committee exhibit No. 6
490 PEARL HARBOR ATTACK
1941, was 6:26 a. m., and morning twilight was at 5:06 a. m., both
Hawaiian time. 
NAVY AND ARMY INSTALLATIONS 
Pearl Harbor was the base of the United States Pacific Fleet at the time
Japan struck on December 7, 1941, having been such since May of 1940.
The island of Oahu was the headquarters of the Fourteenth Naval District
which included the Hawaiian Islands, Midway, Wake, Johnston, Palmyra,
and Canton Islands. Except for Pearl Harbor itself, other installations
were characterized as "minor" naval installations and were naturally
integrated in the over-all defense of the islands, of which Pearl Harbor
was the focal point.
On the island of Molokai there was the Homestead Field Naval Air Base,
which consisted of a runway, a warming-up platform and supporting
On the island of Maui there was the Puunene Naval Air Base, which
consisted of runways, a warming-up platform, and a CAA Territorial
landing field. Also on Maui was the Maalaea naval emergency landing
field, which consisted of two runways and other supporting
On the island of Hawaii, the largest island in the Hawaiian chain, was
located the naval radio station at Hilo.
On the most important island of the group, Oahu, there was a naval air
station at Ewa, which consisted of a mooring mast, a landing mat, and
At the naval air station Kaneohe, on the opposite side of the island,
was a landing mat and warming-up platform and supporting installations
and also a seaplane base.
At Kahuku Point, up at the north end of the island, there was an
emergency landing field.
At Lualualei was located a naval radio station-a transmitting station.
At Wahiawa, in the interior, was located a naval radio receiving
At Heeia, a naval radio transmitting station was located and at Wailupe
a naval radio receiving station.
Referring to Pearl Harbor itself, it is to be noted that the only
entrance is from the south by way of a channel which was blasted through
the fringing coral reef that had formerly blocked entrance to the
harbor. This channel extending to the harbor entrance proper was 375
yards wide and 3,500 yards long with a minimum depth of 45 feet. The
entrance proper to Pearl Harbor is between Keahi Point and Holokahiki
Point. From here the channel leads to the various lochs and Passages
which form the harbor. The major channels or the main channels and water
in the vicinity of the major ships' berths had a depth of 40 feet. From
the sea buoys to the large dry-dock a portion of the channel had a
minimum depth of 45 feet to provide for the entrance and docking of
damaged vessels. The entrance to the harbor was closed by two protective
nets where the channel through
 See committee exhibit No. 6 item 4 for a table showing comparative
times and dates for Greenwich, England; Washington D. C.; San Francisco;
Hawaii; Tokyo; and Manila on December 6, 7, and 8, 1941.
 See committee record pp. 50 et seq.; also committee exhibits Nos. 5
PEARL HARBOR ATTACK 491
the coral reefs was about 400 yards wide and the depth from 41 to 50
feet. The nets themselves consisted of a combined anti-torpedo net and
anti-boat boom to seaward and an inner anti-torpedo net without the boat
The Pearl Harbor fleet base included every type of naval activity. Many
of the installations operable at that time were new, having been built
subsequent to August 1939. Major installations in operation were, at the
Navy Yard, Pearl Harbor: one battleship dock, built in 1928; one
battleship dock, under construction; one floating dry-dock, 18,000 tons;
one large repair basin, supporting industrial establishments for repairs
to anything afloat; one fuel depot with two tank farms above ground; 
one submarine base with all services for war conditions; one section
base, inshore patrol and harbor entrance control post; and, the
administrative office of the Fourteenth Naval District which was inside
the navy yard.
At the Naval Air Station-Ford Island, which is the large island at the
center of the harbor-there was a large flying field, warming-up
platform, sea plane parking areas, and supporting installations.
On December 6, 1941, the Hawaiian Department included approximately
43,000 troops under the over-all command of Lt. Gen. Walter C. Short.
The principal elements of the department were two Infantry divisions and
supporting ground troops composing the beach and land defense forces;
the Coast Artillery command, consisting of the seacoast and antiaircraft
defense forces; and the Hawaiian Air Force.
In the Kauai district were located the Third Battalion, Two Hundred
Ninety-ninth Infantry (less Companies K and L) and attached troops;
Company C, Two Hundred Ninety-ninth Infantry; First Platoon, Signal
Company Aircraft Warning; Air Corps detachment.
In the Maui district were the First Battalion, Two Hundred Ninety-ninth
Infantry, less Company C and attached troops; Company K, Two Hundred
Ninety-ninth Infantry (Molokai); Fourth Platoon Signal Company, Aircraft
Warning; Air Corps detachment.
In the Hawaii district were the Second Battalion, Two Hundred Ninety-
ninth Infantry and attached troops; camp detachment, Kilauea Military
Camp; Fifth Platoon Signal Company, Aircraft Warning; Air Corps
On the principal island, Oahu, were located:
The Twenty-fourth Infantry Division (less Two Hundred and Ninety-ninth
Infantry Regiment); Twenty-fifth Infantry Division; Hawaiian Coast
Artillery Command; Hawaiian Air Force; Thirty-fourth Engineers; Eight
Hundred and Fourth Engineer Battalion (Aviation); Eleventh Tank Company;
Company A, First Separate Chemical Battalion; Hawaiian Pack Train. The
Twenty-fourth Infantry Division was responsible for the ground defense
of the northern half of Oahu, and the Twenty-fifth Division for that of
the southern sector. Most of the components of these divisions were
located at Schofield Barracks.
 A tank farm is a collection of fuel oil storage tanks.
492 PEARL HARBOR ATTACK
The Hawaiian Coast Artillery Command, under Maj. Gen. Henry T. Burgin,
consisted of the following harbor defense units:
Fifteenth Coast Artillery Regiment (Harbor Defense).
Sixteenth Coast Artillery Regiment (Harbor Defense).
Forty-first Coast Artillery Regiment (Railway).
Fifty-fifth Coast Artillery Regiment (155 mm., tractor-drawn) and
Sixty-fourth Coast Artillery Regiment, semi-mobile.
Ninety-seventh Coast Artillery Regiment, semi-mobile.
Ninety-eighth Coast Artillery Regiment, semi-mobile.
Two Hundred and Fifty-first Coast Artillery Regiment, mobile. Other
large-caliber guns available for defense but manned by field artillery
were two 240-mm. howitzers and thirty-two 155-mm. howitzers. The
seacoast guns were installed principally in permanent fortifications.
The fixed antiaircraft guns were emplaced generally to defend the
seacoast artillery, and the mobile antiaircraft units were normally
stationed at Fort Shafter, Schofield Barracks, and Camp Malakole.
The principal units of Maj. Gen. Frederick L. Martin's Hawaiian Air
Force were the Fifth and Eleventh Bombardment Groups, the Fifteenth and
Eighteenth Pursuit Groups, the Eighty-sixth Observation Squadron, and
the Air Corps services. The Air Force was generally disposed on four
fields-Hickam, Wheeler, Haleiwa, and Bellows.
For reference purposes in orienting the locations of various Army and
Navy installations (as of December 7, 1941), the following illustrations
are attached hereto:
1. Map of the Hawaiian Islands showing the disposition of Army forces.
2. Map of the island of Oahu showing Army installations, including
3. Map of the Hawaiian Islands showing United States naval installations
in the Hawaiian area.
Page maintained by Larry W. Jewell, firstname.lastname@example.org. Created: 12/5/96 Updated: 12/5/96