US Marine Corps Pacific Theater of Operations 1944-45

97 Pages·2004·4.957 MB·English

by  Gordon Rottman

O
SPREY
Battle Orders
PUBLISHING
US Marine Corps Pacific
Theater of Operations
1944–45
Division
Troops
PIO
105MM
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3
Gordon L Rottman
• Consultant editor Dr Duncan Anderson
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Battle Orders • 8
US Marine Corps Pacific
Theater of Operations
1944–45
Gordon L Rottman
Consultant Editor Dr Duncan Anderson • Series editors Marcus Cowper and Nikolai Bogdanovic
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Contents
Introduction 4
Combat mission 6
Expanding the Marine Corps
Unit organization 10
Unit designation practices • 1944–45 divisional organization • Amphibious Corps units
Tactics 22
The multi-division assault • Fire support • Small-unit tactics
Tactical reserves • Logistics • Combat replacements
Weapons and equipment 30
Infantry weapons • Artillery • Tanks • Amphibian tractors
Command, control, communications, and intelligence 35
Command and control • Communications • Intelligence
Combat operations 39
Unit status • Guam • Peleliu • Iwo Jima • Okinawa
Reduction and occupation duty 91
Chronology 93
Bibliography 93
Abbreviations and linear measurements 94
Index 95
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Introduction
As a component of the Navy Department, the US Marine Corps (USMC) served
alongside the US Navy (USN) and US Coast Guard under the 18th Comman-
dant of the Marine Corps, LtGen Alexander A. Vandegrift (promoted to general
in March 1945). The Commandant oversaw Headquarters, Marine Corps
(HQMC) in Washington, DC, the Fleet Marine Force (FMF), and the Shore
Establishment. HQMC was purely an administrative headquarters with no
operational control over deployed combat units: it provided direction and
policy, and had responsibility for personnel procurement, education, training,
discipline, distribution, and discharge. The two broad organizations it oversaw,
FMF and the Shore Establishment, were only administrative categories of units
and organizations. Neither had a headquarters or commander.
From July 1944 HQMC consisted of the Commandant of the Marine Corps,
Assistant to the Commandant, Division of Plans and Policies (M-1 Personnel,
M-2 Intelligence, M-3 Operations, M-4 Supply, M-5 Training); Personnel,
“The difficult we do immediately. Quartermaster, and Paymaster departments; and Public Affairs, Administrative,
The impossible takes a little and Aviation divisions. Two key activities that the HQMC took care of were the
longer”—the unofficial Marine testing, evaluation, recommendation and standardization of operational
Corps motto.
equipment under the Marine Corps Equipment Board; and the training of
officers at the Marine Corps Schools. Both of these entities were located at
Marine Barracks, Quantico, Virginia.
The FMF contained the Corps’ operating elements: ground combat, aviation,
service, and most training units. On July 12, 1944 Fleet Marine Forces, Pacific
(FMFPac) was established under LtGen Holland M. Smith with headquarters at
Pearl Harbor, TH. FMFPac, a type command, controlled most FMF units in the
Pacific Ocean Area (POA) under the US Pacific Fleet.
The Shore Establishment included Marine Corps Schools, supply depots,
procurement stations, recruit training depots, and Marine barracks and
detachments guarding naval stations and depots. All Marine Stateside
installations, facilities, and camps fell under an organization called Posts and
Stations, again a category of activities with no dedicated headquarters.
By January 1945 the Marine Corps had grown to 35,598 officers, 5,384
officer candidates, and 366,353 enlisted Marines totaling 431,573 personnel (of
whom 17,837 were female). The peak Marine Corps strength was at the end of
August 1945—485,833 personnel. The FMF had grown to two amphibious
corps, six divisions, 26 non-divisional artillery battalions (artillery, antiaircraft,
defense), and numerous support and service units with a total of 224,855
Marines and sailors in its ground units. Marine Aviation had grown to five
aircraft wings, 32groups, and 135 squadrons with 118,030 personnel.
The Marines had suffered defeats on Guam, Wake, and the Philippines in
the war’s early days and fought through the Solomons on Guadalcanal, the
Russells, New Georgia, and Bougainville (discussed in Battle Orders 1: US Marine
Corps in the Pacific Theater of Operations 1941–43). They went on to fight on
New Britain, Tarawa, Roi-Namur, Eniwetok, Saipan, and Tinian (described in
Battle Orders 7: USMC in the Pacific Theater of Operations 1943–44). This book
The US Army conducted 26 major addresses the formation of the 5th and 6th Marine Divisions (MarDiv) along
amphibious landings in the Pacific
with the 1st Provisional Marine Brigade (Prov MarBde), from which the 6th was
Theater. The Marine Corps
organized, and the final and among the Corps’ most brutal battles on Guam,
conducted 15 landings, but
Peleliu, Iwo Jima, and Okinawa. All six of the Corps’ divisions were involved in
amongthese were some of the
toughest fighting experienced these engagements. Further planned titles in this series will examine Marine
4 against the Japanese. Corps Aviation, and Marine raider and parachute units separately.
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Japanese occupied territory
Marine Corps assaults
Army assaults
J A P A N S E A
0 50 100 150 mi
0 100 200 km
T
KOREA TRAI HONSHU
S
MA Tokyo
Fusan SHI
U
S
Tsushima T 30 AUG 45
SHIKOKU
Nagasaki
KYUSHU
OSUMI GUNTO N
A
NP
O S
NANSEI SHOTO HOT
Amami O Jima O
1 APR 45 Ie Shima
16 APR 45
Okinawa Jima OGASAWARA GUNTO
26–27 Kerama Retto
Kita Iwo Jima
MAR 45
KAZAN RETTO Iwo Jima
19 FEB 45 Marcus
Minami Iwo Jima
Parece Vela
Pagan
MARIANAS
P H I L I P P I N E S E A
15 JUN 44
24 JUL 44
Saipan
Tinian
29 JUL 44 Rota
Guam
ULITHI IS.
YAP 22 SEP 44
PALAU IS. TRUK IS.
15 SEP 44 NEUTRALIZED
N Peleliu 17 SEP 44 17–18 FEB 45
Angaur
C A R O L I N E I S L A N D S
The strategic situation in the Pacific Theater, late-1944–45. 5
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Combat mission
By mid-August 1944 the Marine Corps had completed the conquest of the
Marianas and would soon seize Peleliu. Marine artillery units were engaged in the
Philippines in support of the Army, but would be withdrawn before the end of the
year. The Marines were now poised for their final and most vicious battles: Iwo
Jima and Okinawa Gunto. Upon completion of those operations FMFPac prepared
for the invasion of the Japanese Home Islands. Instead its formations would
quickly reorient and deploy to Japan and North China as occupation forces.
While the Corps still conducted a wide variety of supplementary missions,
it was first and foremost an amphibious assault force. It could land, support,
and sustain a multiple-division amphibious force on a hostile island and sweep
it clean of resistance. It was more than just a specialized amphibious assault
force though. It possessed the organic logistical and aviation support necessary
to ensure success in a joint operational environment with other armed services.
The Marine Corps’ size and capabilities had multiplied almost 24-fold from
the day of the Pearl Harbor attack. Even though the war with Japan was
expected to grind on into late-1946, the Marine Corps would not organize any
additional formations or combat units. Only small, specialized service units
would be raised. The primary focus was to train additional replacements. Even
with the anticipated invasion of the Home Islands lurking on the horizon, the
Corps actually began to reduce in size.
At the end of the war (V-J Day—September 2, 1945), the Marine Corps
contained 484,631 personnel, a slight decrease from the previous month. At
the same time the Navy contained 3,383,196 personnel and the Army had over
8,300,000. In the Pacific Theater the Army counted over 1,400,000 troops in
the Sixth, Eighth, and Tenth Armies; I, IX, X, XI, XIV, and XXIV Corps; and 22
divisions backed by massive service forces. Eight numbered Army air forces
were serving in the Pacific.
The Marine Corps was not the predominant ground combat force in the
Pacific, as is sometimes stated, but its contribution far outweighed its size. The
Pacific Theater was subdivided into what were essentially two “sub-theaters,” the
Pacific Ocean Area (POA) under Admiral Chester W. Nimitz and the Southwest
The primary mission of the Marine
Pacific Area (SWPA) under General Douglas MacArthur. The POA stretched from
Corps was to “Maintain a mobile
California to the coast of China and the entire north to south expanse of the
force in immediate readiness as part
of the US Fleet for use in operations ocean. The SWPA encompassed the Philippines, most of the Netherlands East
involving shore objectives.” Indies, Australia, New Guinea, and the Northern Solomons. Two of the Army’s
field armies, all six corps, and most of the 22 divisions
fought in that area. Three of the Marine divisions
(1st–3d) fought in a corner of this area (Northern
Solomons and New Britain in 1942–43). Some Marine
artillery units served briefly in the Philippines under the
Army in 1944, alongside a Marine Aviation presence.
The focus of the Marine Corps was the vast South
and Central Pacific Areas, part of the POA command, a
Navy responsibility. All six of the Marine divisions and
a brigade fought there, where they conducted all but
two of the Corps’ 15 landings. Only the Army’s Tenth
Army, XIV and XXIV Corps, and the Americal, 7th,
25th, 27th, 77th, 81st, and 96th Infantry Divisions
(InfDiv) conducted operations in the POA, where they
6 executed six of the Army’s 26 major landings. Although
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these divisions fought ashore, in most cases they landed after D-Day and did
not receive credit for an amphibious assault. On six occasions the 7th, 27th,
77th, and 81st InfDivs served under Marine command between 1944 and 1945.
Expanding the Marine Corps
A new Marine brigade
The pre- and early-war provisional 1st–3d MarBdes had been disbanded by
November 1943. When the decision was made to form a new brigade the
numbering began anew, as was traditional. The 22d and 4th Marines were
assigned to the 1st Prov MarBde formed on April 19, 1944 at Tassafarougu,
Guadalcanal. Its staff had assembled on Hawaii the previous month under BGen
Lemuel C. Shepherd Jr. Assigned to IIIAC, the Brigade had a number of corps
troops units attached. It was the largest brigade formed by the Marines and was
sometimes referred to as a “two-regiment division.” It departed Guadalcanal in
June to stage at Eniwetok where the Army’s 305th RCT, 77th InfDiv was attached
for the July 1944 Guam operation. It began departing Guam at the end of August
and was fully assembled at Tassafarougu in early September and expanded into
the 6th MarDiv.
Two new Marine divisions
While the 1st–4th MarDivs were raised by drawing cadres from other regiments
and battalions or splitting units to create new regiments or battalions, this was
not the case with the 5th and 6th MarDivs.
THE5THMARDIV
The Marine Corps experienced some difficulty raising the 5th MarDiv as so
many replacements were replenishing units engaged in the Pacific and at the
same time filling the new 6th MarDiv. The “Spearhead Division” was activated
at Camp Pendleton, CA on January 21, 1944. Many officers were reassigned
from HQMC, Marine Corps Schools, the staffs of posts and stations, and
various administrative assignments. Marine barracks and detachments were
stripped of enlisted men qualified for overseas deployment. The deactivated
1st Marine Parachute Regiment’s four battalions were absorbed into the new
infantry regiments. Regardless of the difficulties in finding sufficient troops, 40
percent of the division had combat experience. The 5th Tank Battalion was the
first to receive M4A3 Shermans.
The 26th Marines had been activated at Camp Pendleton on January 10
with its 1st and 2d Battalions activated on the 19th and its 3d on February 15.
The 27th Marines was activated on the same date as the 26th. The 28th Marines
was activated on February 8 in lieu of assigning the existing separate
22d Marines then in the Pacific as had been proposed. The 13th Marines
[artillery] and its 1st, 3d, and 4th Battalions were activated on January 10, but
the 2d Battalion had been activated as a separate unit on October 16, 1943 at
Camp Lejeune, NC. The 16th Marines [engineer] had been activated at Camp
Lejeune on December 15, 1943, but was deactivated at Pendleton on May 25,
1944. The 26th Marines (Reinforced) departed for the Pacific in July to serve
as the 1st Prov MarBde’s floating reserve during the Guam operation. Not
needed ashore, it established itself in Hawaii at the end of the month. After
undertaking training from the Troop Training Unit, Amphibious Training
Command at San Diego, the Division echeloned into Hawaii between August
and October 1944.
THE6THMARDIV
The 6th MarDiv was built around the 1st Prov MarBde at Tassafarougu,
Guadalcanal, being activated on April 19, 1944. The Brigade’s 4th and 22d
Marines were assigned to the “Striking Sixth” along with the new 29th Marines
from the States. Their reinforcing companies (engineer, medical, motor transport, 7
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deactivated in October 1942 and 1943. Ships’ detachment Marines from
reestablished in January 1943. Marine the cruiser USS Philadelphiaaccompanied
Barracks, Navy Operating Base (NOB), Army units ashore for security missions
Rosneath, Scotland was established in during the invasion. InAugust 1944, 90
October 1942. The 1st Prov Marine Marines from the cruisers USS
Battalion arrived at Belfast, Ireland in Philadelphiaand Augustaaccepted the
May 1942 and was redesignated Marine surrender of an 850-man German naval
Barracks, NOB, Londonderry (the artillery battalion on islands outside of
insignia is shown here). Its advance Marseilles during the invasion of
detachment had arrived on January 26, Southern France. Marine officers served
1942, and were credited as the first US as observers with the British, and
troops to arrive in the European Theater Marines took part in Office of Strategic
after America’s entry into the war. A few Services covert operations in Europe.
Marines in Europe and the dozen Marines from this force Hundreds of ships’ detachment Marines
Mediterranean participated in the North African served aboard battleships and cruisers.
Marine Detachment, American Embassy, landings as raiders in November 1942. In total, seven Marines were killed,
London were the first Marines to arrive They then formed Marine Detachment, two were wounded, and eight were
in Europe, landing July 1941. It was briefly NOB, Oran until deactivated in March taken prisoner.
pioneer, service, tank) were redesignated as Companies A, B, and C respectively, of
the new supporting battalions. The division headquarters battalion was organized
from the 1st Prov MarBde’s HQ, MP, and signal companies while the
reconnaissance company was raised from the 4th, 22d, and 29th Marines’
reconnaissance platoons. The support battalions’ headquarters were activated on
Guadalcanal in September and October after the arrival of the 29th Marines. The
29th Marines was activated at Camp Lejeune on May 1, 1944, but its 1/29 had
been raised on Guadalcanal by the 2d MarDiv in April 1944 and fought with the
4th MarDiv on Saipan. This meant that seven of the new division’s infantry
battalions, two of its artillery battalions, and approximately two-thirds of its
supporting units had previously seen combat. The 15th Marines [artillery] was
activated on Guadalcanal on October 23 from the Pack Howitzer Battalions of the
4th, 22d, and 29th Marines with the 4th Battalion activated on November 14. The
The 5th MarDiv sleeve insignia, or Division undertook extensive training in preparation for the Okinawa assault.
“battle blaze,” was approved in March During that time all of its artillery battalions converted to 105mm howitzers. The
1944. The blue spearhead, from which 1st and 4th Battalions exchanged designations on July 1, 1945 after the battle.
the Division’s nickname was derived,
is symbolic of the Marine Corps
Fleet Marine Force, Pacific
amphibious assault mission. The “V”
signifies the Division’s number. The Established on July 12, 1944, FMFPac was a type command for all FMF ground
scarlet and gold colors are those of and air forces in the POA. Located at Camp Catlin, Oahu, TH, it was under the
the Marine Corps. command of LtGen Holland Smith. From September 17, 1944 it consisted of:
Headquarters and Service Battalion
Force Artillery
Force Antiaircraft Artillery
Force Amphibian Tractor Group
Force Reserve
Force Service Troops
FMF Supply Service
FMF Transient Center
IIIAC (1st, 6th MarDivs)
VAC (2d*, 3d, 4th, 5th MarDivs)
Aircraft, FMFPac
* 2d MarDiv reassigned to IIIAC Dec 44.
The 6th MarDiv insignia was
approved in October 1944.
On June 1, 1945 FMFPac was reorganized with Force Artillery, Force AAA, Force
Melanesia, Micronesia, and Orient
Amphibian Tractor Group, and Force Reserve disbanded and their units
were the areas in which the Division
fought, the Orient signifying the 4th reassigned to the new Force Troops, FMFPac. LtGen Roy S. Geiger, former IIIAC
8 Marines’ pre-war China service. commander, assumed command on July 5. In August FMFPac deployed a forward
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headquarters to Guam to control Marine units tagged for the November invasion
of Japan. In 1945 the 1st–6th MarDivs were assigned the following units:
1st MarDiv 2d MarDiv 3d MarDiv 4th MarDiv 5th MarDiv 6th MarDiv
Infantry Regiments 1st, 5th, 7th 2d, 6th, 8th 3d, 9th, 21st 23d, 24th, 25th 26th, 27th, 28th 4th, 22d, 29th
Artillery Regiment 11th 10th 12th 14th 13th 15th
Engineer Battalion 1st 2d 3d 4th 5th 6th
HQ Battalion 1st MarDiv 2d MarDiv 3d MarDiv 4th MarDiv 5th MarDiv 6th MarDiv
Medical Battalion 1st 2d 3d 4th 5th 6th
MT Battalion 1st 2d 3d 4th 5th 6th
Pioneer Battalion 1st 2d 3d 4th 5th 6th
Service Battalion 1st 2d 3d 4th 5th 6th
Tank Battalion 1st 2d 3d 4th 5th 6th
To control and support garrison units, Garrison Forces, 14th Naval District had
been activated on December 14, 1941 in Honolulu, TH. The 14th Naval District
was the administrative headquarters for naval forces in Hawaii and outlying
islands (Johnston, Midway, Palmyra, Wake, Samoa.) It controlled Marine barracks
and detachments and defense battalions securing those islands and not assigned
to the FMF as well as barracks and detachments in Australia and New Zealand.
Fleet Marine Force, Pacific, September 1944
FMFPac
H&S FAMAAF ReFsMerFve SSueFprMvpiFocret III V FAMircFrPaafct
x 16 Umnictotemd- DFeieplodt x 6 1 2 1 AWircinragft
units
MP x 2 DBeapsoet x 2 6 3 2 AWircinragft
Amph S & S SVC x 4 III AC 4 3 AWircinragft
Recon
III AC TCrooroppss 5 4 AWircinragft
FMF FMF FMF FMF
Arty Amtrac Service Transient VAC
Group Troops Center
Corps
Seacoast x 3 x 10 Base HQ x 3 VAC Troops
Misc.
x 3 units
9
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Unit organization
In the period under discussion, there were further changes in Marine unit
organization, but for the most part they were relatively minor compared to those
of earlier years. Unit organization was considered close to optimal, and the basic
structure of the 1945 Marine division remains in today’s divisions.
Unit designation practices
The raising of new divisions saw the activation of higher numbered infantry
regiments than had previously existed in the Corps, akin to Army regimental
numbers. Marine regimental designations did not include a branch or functional
designation, nor was the term “regiment” used. They were officially known
simply as, for example, 29th Marines. Marine infantry regiments were the
1st–9th and 21st–29th. The artillery regiments were the 10th–15th and the
engineer regiments, in the process of being deactivated, were the 16th–20th.
Those regimental numbers have never since been restored.
Battalions within infantry regiments were designated 1st–3d. The regimental
weapons company was designated, for example, Weapons Company, 4th
Marines. With the elimination of the battalion weapons companies in early
1944, rifle companies were designated: 1st Battalion—A–C, 2d—E–G, and 3d—I,
K, L (no company “J”). Companies D, H, and M had been the weapons
companies. It was envisioned that the rifle companies would be redesignated to
reflect this change, but that did not occur except in the 29th Marines, which was
organized after the change.
Artillery regiments consisted of four battalions with the 1st and 2d being armed
with 75mm pack howitzers and the 3d and 4th with 105mm howitzers until all
battalions were converted to 105mm in 1945. There were three batteries per
battalion: 1st Battalion—A–C, 2d—D–F, 3d—G–I, and 4th—K–M (no battery “J”).
Marine units were often designated with a Navy task-force designation for a
specific operation. Such designations were part of the Navy task organization
and communications plan. The Navy’s World War II task force concept
originated in April 1940 when LCdr Maurice E. Curtis proposed that Navy task
organization designations be standardized using prearranged numerical
designators rather than the unwieldy system of functional nomenclatures then
in use (such as Cruiser Scouting Force, Kyushu Bombardment Force, etc.). It was
impossible to predict which task organization nomenclatures would be
Regimental Combat Team, 1944–45
CT
H&S WPNS
MP S & S SVC Dets JASCO
10
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