MARINE UNITS
The Marine Corps grew rapidly with America’s involvement in World War II. From two under-strength divisions, two small aircraft groups and a smattering of support units in December 1941, it swelled to an army-level command of two corps, six divisions, five aircraft wings, scores of support units and a large Stateside supporting establishment by VJ-Day.
Unit designation practices
The numbering of Marine units was quite straight-forward. The six divisions were numbered in sequence of activation. Marine regiments were designated in blocks by functional type: 1st–9th and 21st–29th were infantry, 10th–15th artillery, and 16th–20th engineer. Regimental titles did not include a functional designation; the initiated would know, for example, that the 10th Marines was artillery. For convenience, in this book artillery and engineer regiments will be identified as such in parentheses; it is emphasised that this is not part of their designation. Since 1930 it was not required for ‘regiment’ to be included in a unit’s designation, e.g. 4th Marines. The 1st Parachute Regiment, 1st and 2nd Raider Regiments, 7th and 8th Service Regiments were not numbered in the above series, and their functional designations, as well as ‘Regiment’, were included in their titles.
With the exception of regiments, which were assigned to divisions almost at random, all other units within a division carried the division’s designation, e.g. 1st Signal Battalion. FMF units were numbered in sequence by functional category. Caution must be taken not to assume that every unit designated, e.g. ‘1st’, was assigned to the 1st MarDiv. Amphibious corps troops units carried the designation of their parent corps, e.g. III or V Corps Signal Battalion; I Corps units were designated ‘1st Corps . . .’.
Battalions were designated 1st–3rd in infantry and engineer regiments. Artillery regiments had four or five battalions. Companies were designated in alphabetic sequence through the regiment, e.g. Companies A, B, C, D were assigned to 1st Battalion and so on up through Company M, with four companies per battalion; Companies D, H and M were weapons. When weapons companies were dissolved in 1944, the rifle companies were not re-lettered (the sole exception was the 29th Marines, formed at the time of the reorganisation). Five-battalion artillery regiments possessed up to Battery S, with three lettered firing batteries per battalion. Traditionally, there was no company or battery ‘J’. Regimental weapons companies were designated simply, e.g. Weapons Company, 3rd Marines.
Provisional Marine brigades were numbered in sequence of activation. Early in the war, there were three such brigades on active duty. Once these brigades had been disbanded, the next new provisional brigade to be formed would be designated ‘1st’ and the series would start again.
Fleet Marine Force
The FMF traces its origins from 1913, when the Marine Advanced Base Force was formed. It consisted of a two-regiment brigade intended to seize and/or defend overseas naval bases in support of expeditionary operations. It was redesignated the East Coast Expeditionary Force in 1922, and a similar force was soon established on the West Coast. These two forces were redesignated the East and West Coast Fleet Marine Forces in 1933. The 1st and 2nd Marine Brigades, later expanded to divisions, were components of these forces. Two corps-size amphbibious forces were activated in June and March 1941. Both corps endured a bewildering series of designations before they received their final titles of Amphibious Corps, Atlantic Fleet and Pacific Fleet in March and April 1942, respectively. These were not tactical formations, but provided joint amphibious training to Marine and Army divisions.
Bougainville, 1944. The sign reads, ‘SNiPER iNN-COVER CHARGE 1 JAP’. A sandbagged fighting position doubles as living quarters with the addition of a camouflage shelter half.
When V Amphibious Corps was formed in September 1943 and deployed to the central Pacific to join 1 Marine Amphibious Corps, it was decided that a higher level controlling headquarters was needed. Administrative and service units of both corps were reassigned to V Amphibious Corps Administrative Command on 10 April 1944. On 11 June this organisation was reformed as Administrative Command, Fleet Marine Force, Pacific. On 24 August Provisional Headquarters, Fleet Marine Force, Pacific was established. Both the Provisional Headquarters and the Administrative Command were consolidated on 17 September 1944 to form Fleet Marine Force, Pacific (FMFPac) under the command of Lt.Gen. Holland M. ‘Howlin’ Mad’ Smith. FMFPac and its predecessors were headquartered at Pearl Harbor, where it remained. FMFPac had operational command of the I (later, III) and V Amphibious Corps; the six divisions; 1st 2nd, 3rd and 4th Marine Aircraft Wings, and attached Army divisions and Allied units.
Amphibious corps
Like the evolution of the FMF, the development of amphibious corps was complex. In 1941–42 the Amphibious Corps, Atlantic Fleet and the PhibCorps, Pacific Fleet were organised to provide amphibious training. I Marine Amphibious Corps (IMAC) was established on 1 October 1942 and deployed to the south Pacific in the same month under the command of Maj.Gen. Alexander ‘Sunny Jim’ Vandegrift. It controlled Marine operations on Guadalcanal in 1942 and oversaw the reduction of the remainder of the Solomon Islands until early 1944. In September 1943 Maj.Gen. Charles Barrett assumed command, but died three weeks later. Vandegrift briefly reassumed command, and Maj.Gen. Roy S. Geiger took over in November. IMAC moved to the Bismarck Archipelago in March 1944 to seize islands in that area. The 1st, 2nd and 3rd (briefly) MarDivs habitually served under IMAC. On 15 April 1944 IMAC’s support units were transferred to the V Amphibious Corps Administrative Command, and the tactical units were redesignated III Amphibious Corps.
A 10th Marines, 2nd MarDiv, 75 mm pack howitzer crew undergoes training, Hawke Bay, New Zealand, in preparation for the Tarawa assault. Note the gun pointer’s reversed helmet to allow him unhindered use of the sight.
Tarawa bound Marines of the 2nd MarDiv descend a debarkation net into their landing craft. They wear camouflage utility uniforms, M26 life belts, gas mask cases, and M1 carbines indicating a support unit. Gloves were often worn when descending nets to prevent injuries. Only the vertical ropes were gripped to prevent a Marine above from stepping on one’s hands.
III Amphibious Corps (IIIAC) was given the mission of seizing Guam in July and August 1944, and it went on to take Peleliu in September and October. The Army’s 77th Infantry Division was attached to IIIAC for these operations. IIIAC then moved to Guadalcanal to prepare for the Okinawa assault subordinate to Tenth Army. The operation began in April 1945 and lasted until July, after which it moved to the Marians. The 1st, 3rd and 6th MarDivs (and 1st Marine Brigade prior to 6th MarDiv’s formation) habitually served under IIIAC. The corps was deployed to North China in September 1945 to disarm Japanese forces. It was redesignated Marine Forces, China on 10 June 1946, and was greatly down-sized.
Amphibious Corps, Pacific Fleet (PhibCorpsPacFlt), formed in April 1942, played an important role controlling Marine and Army tactical units not assigned to the operational IMAC. Under the command of Maj.Gen. Holland Smith, it was based at Pearl Harbor. Its assets were later redesignated V Amphibious Corps.
V Amphibious Corps (VAC) was formed on 25 August 1943 at Pearl Harbor from PhibCorpsPacFlt. It originally included VAC Administrative Command, but this was redesignated Administrative Command, FMFPac on 10 April 1944 (which in turn was redesignated FMFPac in June). Formed as the amphibious landing force for Fifth Fleet to support central Pacific operations, VAC was commanded by Maj.Gen. Holland Smith. Its first mission was to seize the Gilbert Islands in preparation for future efforts in the Marshalls. This included the controversial assault on Tarawa and the attached Army’s 27th Infantry Division’s seizure of Makin; both operations took place in November 1943. In January and February 1944 the VAC, along with the attached 7th and 27th Infantry Divisions, seized Roi-Namur, Kwajalin and Eniwetok in the Marshalls. Its next task was to secure the Marianas. This it did from June to August 1944, which included seizing Saipan, Tinian, and Guam in concert with the Army’s XXIV Corps. Maj.Gen. Harry Schmidt took command of VAC in July. VAC’s next mission took place in February 1945, when it assaulted Iwo Jima. The island was secured a month later, but VAC’s losses were such that it was months before its three divisions were again ready for combat. VAC landed in Japan at Yokosuka and Kyushu in September 1945, where it remained as an occupation force until January 1946; it was deactivated the following month. The 2nd, 4th and 5th MarDivs were habitually assigned to VAC, while the 3rd was briefly attached.
Various service units were assigned to amphibious corps troops. For the most part these consisted of: corps headquarters and service battalion; corps signal battalion; corps motor transport battalion; corps medical battalion; corps artillery (not in IMAC); and corps evacuation hospital. IMAC also possessed the 1st Corps Naval Construction and 1st Corps Tank Battalions.
Navy corpsmen splint a Marine’s shattered leg at a beach aid station, Tawara, prior to his evacuation by returning landing craft. The painted white discs used to identify corpsmen can be seen on their helmets.
Marine divisions
The formation of the first permanent Marine brigade was on September 1935, when the 1st Marine Brigade was raised at Quantico, Virginia. It was built around the 5th Marines and the 1st Battalion, 10th Marines (artillery). This was followed by the 2nd Marine Brigade, formed on 1 July 1936 at San Diego, California. It deployed to China from 1937–38. Initially it included only the 6th Marines, but the 8th Marines was raised and assigned to the Brigade in April 1940 and the 2nd Battalion, 10th Marines (artillery) was added in December. These two brigades provided the core for the 1st and 2nd MarDivs when they were activated in February 1941. The two new divisions were at less than 60 per cent strength and possessed only minimal combat support and service units by the time of Pearl Harbor.
The 1st Marine Division (‘The Old Breed’) was activated at Guantánamo Bay, Cuba, on 1.February 1941 from the 1st Marine Brigade. It soon relocated to New River, North Carolina (renamed Camp Lejeune in 1944), and trained for overseas deployment. It consisted of the 1st, 5th, 7th, 11th (artillery) and 17th (engineer) Marines. The division formed the 3rd Marine Brigade in March 1942 and deployed it to Samoa as a defence force. The division deployed to New Zealand in May. It landed on Guadalcanal on 7 August 1942 (7th Marines did not arrive from Samoa until 18 September), and fought until late December, when it was withdrawn to Australia for a year-long rest and refit. It landed on Western New Britain on 26 December 1943 under Sixth Army. There followed a number of amphibious operations on other Bismarck Archipelago islands and along the New Britain coast. These operations were completed in April 1944 and the division was then moved to Pavuvu in the Russells for rest. On 15 September 1944 the division, under IIIAC, assaulted Peleliu in the Palaus Islands, the western-most group in the Carolines, and encountered the war’s first deadly cave defences. It was relieved on 16 October, and moved back to Pavuvu, then on 1 April 1945 assaulted Okinawa, where it fought until 21 June. It was deployed to North China on 30 September 1945 as an occupation force and to disarm Japanese forces in Hopeh Province, then was moved to Camp Pendleton in June 1947. (It has remained there to this day, and has participated in every major post-World War II US conflict.)
A 10th Marines 75 mm pack howitzer crew fires point blank at a Japanese strong point, Tarawa, 1943. They wear a mixture of sage green and camouflage utilities.
The 2nd Marine Division was activated on 1 February 1941 from the 2nd Marine Brigade at San Diego, California, where it trained for overseas deployment. It provided assets for the 1st Marine Brigade, sent to reinforce Iceland’s defences, and for the 3rd Marine Brigade to defend Samoa. Elements were deployed to the Pacific in mid-1942 and attached to the 1st MarDiv. They included the 2nd Marines; 3rd Battalion, 10th Marines (artillery); and 2nd Special Weapons Battalion. They landed on islands near Guadalcanal on 7 August to support operations on the larger island. The 8th Marines and 1st Battalion, 10th Marines further reinforced the 1st MarDiv in early November. On 4 January 1943 Advance Echelon, Headquarters, 2nd MarDiv arrived with the 6th Marines and 2nd Battalion, 10th Marines, and assumed command of the divisional elements that had arrived earlier. The Advance Echelon continued operations until 8 February, but most divisional supporting units did not participate. During the conclusion of the Guadalcanal campaign, a provisional joint force was formed by the Army’s XIV Corps on 25 January 1943 from elements of the 2nd MarDiv and the Army’s Americal Division. The 2nd MarDiv’s Advanced Echelon Headquarters acted as the Composite Army-Marine Division’s Headquarters; other elements of both divisions were exhausted from prolonged combat. The CAM Division was dissolved on 9 February and its units returned to their respective divisions’ control. The 2nd MarDiv reassembled in New Zealand in early 1943 for rest and retraining. It assaulted Betio Island (Tarawa) on 20 November 1943 and suffered appalling losses. It was then moved to Hawaii for recovery and rebuilding. The division assaulted Saipan on 15 June 1944 and then neighbouring Tinian on 26 July. It conducted mop-up operations on Saipan and Tinian through to the end of 1944. On 1 April 1945 the Division assaulted Okinawa and returned to Saipan on 15 June. It landed at Sasebo on Kyushu (the southern-most island of Japan) on 16 September 1945 for occupation duty, and remained there until July 1946 when it moved to Camp Lejeune, North Carolina (where it has remained ever since).
Numar, 1944, Marines await pause in their push across the island in under two days. This BAR man holds an M1918A1 BAR (magazine detached) with the flash hider removed to reduce its length.
The 3rd Marine Division was activated on 16 September 1942 with the Advance Echelon (9th Marines) at Camp Elliott, California, and Rear Echelon (19th (engineer), 21st and 23rd Marines) at New River, North Carolina. The 12th Marines (artillery) was not activated until February 1943. In early 1943 the division moved to New Zealand, where the newly formed 3rd Marines joined it in June, in place of the 23rd Marines, which had remained in the US. The division moved to Guadalcanal for additional training and then took part in the remainder of the Solomon Islands campaign under IMAC, by assaulting Bougainville on 1 November 1943. The division returned to Guadalcanal on 16 January 1944. It was to have assaulted New Ireland in April 1944, but the operation was cancelled. In June 1944 the division moved to the Marianas and assaulted Guam on 21 July under IIIAC. The operation was completed on 10 August, but the division remained there until February 1945. It landed on Iwo Jima on 24 February as VAC reinforcements; the division’s 3rd Marines remained afloat as the VAC reserve. The division fought on Two until the operation’s end on 16 March 1945. In April it was returned to Guam to prepare for the invasion of Japan, but was deactivated on 18 December 1945. (It was reactivated in 1952, and has remained active.)
The 4th Marine Division was activated on 16 August 1943 at Camp Pendleton, California, from units in training: 14th (artillery), 20th (engineer), 23rd, 24th and 25th Marines. It departed for the Pacific in January 1944 and on 1 February assaulted the twin islands of Roi-Namur (part of the Kwajalein-Majuro Occupation in the Marshalls) under VAC. The division relocated to Hawaii for rest and then assaulted Saipan on 15 June 1944 under VAC’s Northern Troops and Landing Forces. On 24 July the division assaulted Tinian and fought until 1 August. It was soon moved to Hawaii for rest. On 19 February 1945 it assaulted Iwo Jima, and fought there until 16 March, again returning to Hawaii to prepare for the invasion of Japan. Instead, it moved to Camp Pendleton, California, and was deactivated on 28 November 1945. (It was reactivated as a reserve division in 1962, and has remained as such ever since.)
The 5th Marine Division (‘The Spearhead’) was activated on 21 January 1944 at Camp Pendleton with the 26th, 27th and 28th Marines. The deactivated parachute battalions provided the cadre for the 28th Marines. It also included the 13th (artillery) and 16th (engineer – deactivated prior to overseas deployment) Marines. The division moved in phases to Hawaii later in the year and was completely assembled by October. It assaulted Iwo Jima, its only combat operation, on 19 February 1945 as part of VAC, and fought there until the end on 27 March. It moved to Hawaii for rest and then landed at Nagasaki, on Kyushu Island, Japan, on 22 September 1945 for occupation duty. It was withdrawn on 15 December, moved to Camp Pendleton, and deactivated in January 1946. (It was reactivated at Camp Pendleton in 1966 to replace the 1st MarDiv that had deployed to Vietnam, and was deactivated in 1970 upon the 1st MarDiv’s return.)
Members of the 4th MarDiv Headquarters drag a Japanese prisoner from a Numar pillbox. White stencilled unit markings can be seen on two of the men’s backs.
The 1st Provisional Marine Brigade was formed from separate units in mid-1944 for the Guam operation (see below). The 6th Marine Division was activated on 7 September 1944 on Guadalcanal, using the 1st Provisional Marine Brigade as a core (4th and 22nd Marines). Other personnel were provided by anti-aircraft and deactivated defence battalions, along with units from the US – 15th (artillery) and 29th Marines. The division was assembled on Guam and assigned to IIIAC. It assaulted Okinawa, its only combat operation, on 1 April 1945, and fought there until 21 June. It returned to Guam, and the 4th Marines accompanied the Fleet Landing Force for the occupation of Japan, being the first Marine unit to land. The division was deployed to North China as an occupation force, arriving on 11 October. It operated in Shantung Province until deactivated in Tsingtao, China, on 31 March 1946. Its remaining units were formed into the 3rd Marine Brigade. (The division has not since been reactivated.)
Provisional Marine brigades
The five provisional Marine brigades formed just prior to, during and immediately after the war were tied directly to specific divisions. Their assets were provided by their parent division, and they were returned to them upon the brigades’ deactivation. There is one exception: the 1st Marine Brigade formed for the Guam campaign was comprised of separate units and became the core of a new division.
The 1st Marine Brigade (Provisional) was formed on 16 June 1941 at Charleston, South Carolina, with units drawn from the 2nd MarDiv. Given the task of reinforcing British defences on Iceland, to allow the garrison to be reduced for more judicious use elsewhere, the brigade departed on 22 June and arrived in Iceland on 7 July (notably, prior to America’s entry into the war). It established defensive positions along the coast, mainly north of Reykjavik. On 22 September the brigade was placed under the command of the US Army’s Iceland Base Command. It was relieved by Army units and returned to the US between February and March 1942. It was disbanded on 25 March in New York City, and its units rejoined the 2nd MarDiv in California.
The 2nd Marine Brigade was formed by 2nd MarDiv on 14 December 1941 at Camp Elliott, California. It arrived with the 8th Marines in American Samoa on 19 January 1942. The first elements of Marine Aircraft Group 13 arrived in April, and the brigade was later joined by the 7th and 8th Defense Battalions. The 3rd Marines replaced the 8th on 14 September 1942. It was dissolved in January 1943, and its assets returned to 2nd MarDiv control.
An M5A1 light tank, ‘Hothead’, of the 4th Tank Battalion supports the advance of 4th MarDiv troops on Numar. White bands have been hand painted over its forest green base colour.
The 3rd Marine Brigade was formed by 1st MarDiv on 21 March 1942 at New River, North Carolina, and deployed to British Samoa on 19 January 1942. The Brigade’s 7th Marines redeployed to Guadalcanal, arriving on 16 September, and rejoined the 1st MarDiv. The 3rd Brigade remained on Western Samoa’s Upolu and Savai’i Islands until late 1943, under the Samoa Defense Force, along with the separate 22nd Marines (Reinforced); 147th Infantry Regiment (Army)2nd, 5th, 7th and 8th Defense Battalions, and 4th Marine Base Defense Aircraft Wing, garrisoning Samoa area islands.
A new 1st Provisional Marine Brigade was formed on Guadalcanal from the separate 4th and 22nd Marines (Reinforced) in mid-1944. The only Marine brigade of the era to see combat, it landed on Guam on 21 July 1944 and fought there until 15 August. It was moved back to Guadalcanal and provided the core of the new 6th MarDiv in September. The Brigade’s 22nd Marines was formed as a separate regiment in 1942, garrisoned Samoa through 1943, and participated in the Kwajalein and Eniwetok occupations in early 1944 as the brigade-size Tactical Group 1, VAC. The 4th Marines was formed from the disbanded raider battalions in 1944, and participated in the Enirau landing in March 1944.
A new 3rd Marine Brigade was formed, around the 4th Marines, on 1 April 1946 in Tsingtao, China, when the 6th MarDiv was deactivated. (A 3rd Marine Brigade had served in Shanghai from 1927 to 1929 and the new brigade carried its number.) The Brigade was deactivated on 10 June 1946 and provided the core of Marine Forces, Tsingtao, itself disbanded in September 1947.
Fleet Marine Force, Pacific units
A variety of mostly battalion-size combat support and service units were assigned to FMFPac. These in turn were assigned to amphibious corps and divisions to support specific operations. They could then revert to FMFPac control or be reassigned to other corps or divisions. Multiple-battalion provisional artillery, anti-aircraft artillery and LVT (amphibian tractor) groups were formed to support major landing operations. Army units often augmented these.
Beachheads quickly became crowded and cluttered after the initial landing with a continuous flow of reinforcements, service troops, and supplies competing for space. A Landing Vehicle, Tracked (Armored) Mk1 (LVT(A)1) ‘amtank’ is forced to wait at the water’s edge. In the background a 114 ft. Landing Craft, Tank Mk V (LCT(5)) dwarfs an LCVP.
The 22-man Observer Group was formed in January 1942 as an experimental unit from 5th Marines personnel. Originally part of a joint force preparing for the invasion of North Africa, it was transferred to the PhibCorpsPacFlt in September. The Observer Group was expanded to form the Amphibious Reconnaissance Company, PhibCorpsPacFlt on 7 January 1943 at Camp Pendleton, with 98 troops. It was redesignated Amphibious Reconnaissance Company, VAC on 25 August, and relocated to Hawaii in October. It was expanded to the 303-man, two-company Amphibious Reconnaissance Battalion, VAC on 14 April 1944, and was again redesignated Amphibious Reconnaissance Battalion, FMFPac on 26 August on Hawaii. This unit operated mostly in support of VAC. It was deactivated on 24 September 1945. IMAC provided personnel to the combined Special Services Unit No. 1 in April 1943. It was also comprised of Army personnel, Australian soldiers and New Britain and New Guinea natives. It served under Sixth Army until disbanded at the war’s end.
Navy corpsmen treat 4th MarDiv troops on Roi-Numar prior to evacuation. Plasma bottles are suspended from a makeshift support, a rope tied between two bamboo poles.
The concept of Marine parachute battalions emerged in May 1940, and training of the first parachutists began in October at Lakehurst, New Jersey, under Navy tutelage. The first unit formed was 1st Platoon, Company A, 2nd Parachute Battalion at San Diego in February 1941. This unit provided the core of the first full unit–the 1st Parachute Battalion formed at Quantico on 15 August 1941. It was to fight on Guadalcanal alongside the raiders. Company B, 2nd Parachute Battalion was activated on 23 July 1941 and the full battalion on 1 October. The 3rd Battalion was activated on 16 September 1942 at San Diego. It was originally planned that the battalions would be organic to divisions as reconnaissance and raiding forces, but this never fully germinated. They were actually assigned, but operated under higher command control most of the time. The 1st Parachute Regiment was activated at Tontouta, New Caledonia, on 1 April 1943 to control all three battalions in the Bougainville and New Georgia operations. The two parachute schools, located at San Diego and New River, were activated in February and May 1942 respectively; they also trained personnel for the air delivery sections organic to corps headquarters and service battalions. The 4th Parachute Battalion was formed from the cadre and students of the New River Parachute School, on 1 July 1943, but was never deployed overseas. The parachute units made no combat jumps, although jumps were planned on Kolombangra and Kavieng. On 30 December 1943 all units were ordered to deactivate. The 1st Parachute Regiment was deactivated on 29 February 1944 at San Diego, and used as a cadre for the 28th Marines.
The idea of raider battalions developed in early 1941, when Marine officers visited the British Commandos. The Marine Corps soon split into two schools of thought. Many opposed the organisation of specialised raider units, maintaining that all Marine units were capable of raider operations by nature of their training. (The Marines still maintain this policy, and continue to resist the formation of ‘an elite within an elite’.) Nevertheless, the 1st and 2nd Separate Battalions were formed as raider units by the 1st and 2nd MarDivs on 6 January and 4 February 1942 respectively. They were redesignated the 1st (Quantico) and 2nd (San Diego) Raider Battalions on 16 and 19 February, respectively. The 3rd Raider Battalion was formed on Samoa from 3rd Marine Brigade volunteers on 20 September 1942. It was followed by the 4th Raider Battalion at Linda Vista, California, on 23 October. In August it was directed that provisional raider battalions be formed in the 2nd, 7th and 8th Marines. This order was countermanded, but not before a 2nd Provisional Raider Battalion had been raised on Espíritu Santo, only to be disbanded when the ‘real’ 2nd Battalion arrived.
The 1st Raider Regiment was activated on 15 March 1943 to control the 1st and 4th Battalions during the New Georgia operation. The 2nd Raider Regiment (Provisional) was formed on 12 September to control the 2nd and 3rd Battalions during the Bougainville operation. The Raider Training Battalion provided replacements from Camp Pendleton from February 1943 to January 1944. In December 1943 it was directed that the raiders be reorganised as conventional infantry and the planned 5th and 6th Raider Battalions were deleted from the Force Operating Plan. The 4th Marines were reformed almost entirely from raiders at Tassafarougu, Guadalcanal, on 1 February 1944. It had been planned to reactivate the 4th Marines, lost at Corregidor in 1942, using particularly distinguished units.
Defence battalions were first organised in 1939 to defend advanced naval bases, namely island bases in the Pacific and Caribbean. By early 1944 the 1st–18th and 51st and 52nd Defense Battalions had been formed. As the US assumed the offensive, the battalions were employed to protect beachheads from enemy air attack and from amphibious landings in the rear areas. The artillery soon began firing support for ground forces. The changing nature of the war and Japan’s inability to mount serious counter-offensives led to most of the defence battalions being converted to anti-aircraft artillery by mid-1944, and their artillery group’s assets provided the core for FMF artillery battalions. Only the 6th on Midway and the coloured 51st and 52nd Defense Battalions remained.
A 2nd MarDiv 75 mm M3 anti-tank gun halftrack fires on an enemy strong point on Saipan, 1944. The crew’s gear is slung on the outside hull. Common Marine vehicle base colours were forest green shade 23 and the darker OD shade 9.
The 1st–18th Anti-aircraft Artillery Battalions (no 6th) were formed between April and September 1944, by converting defence battalions. The battalions were assigned to FMF artillery and placed in support of corps, in general support of divisions, or employed to defend forward naval operating bases on various Pacific islands. Only the 2nd, 5th, 7th 8th, 12th and 16th were committed to major combat operations. All but the 1st were deactivated after the war.
The 1st–6th 155 mm Howitzer Artillery Battalions and 7th–12th 155 mm Gun Artillery Battalions were formed during 1944. They were assigned to corps artillery and placed in general support of divisions. Only the 10th and 12th did not see combat. All were deactivated after the war.
The 1st–11th Amphibian Tractor Battalions proved to be among the most valuable of units employed in the Pacific. All but the 7th and 8th were committed to combat. The 1st–5th Battalions had originally been assigned to the 1st–5th MarDivs, but were transferred to FMF troops in May 1944. The 1st–3rd Armored Amphibian Tractor Battalions provided amphibious fire support during the final approach to the beach, and all saw combat. The Marines also employed similarly equipped Army amphibian tractor and amphibian tank battalions.
The 1st and 2nd Aviation Engineer Battalions were formed in 1943 as FMF troops. Lightly equipped, they were intended to be air-lifted onto islands to repair captured airfields. They were provided with heavier equipment and redesignated separate engineer battalions (to differentiate them from the 1st and 2nd (divisional) Engineer Battalions) on 1 June 1944. They remained FMF troops to serve with IIIAC and VAC respectively. Both were deactivated in 1946.
A wide variety of additional separate units were assigned to FMFPac. These were normally reassigned to amphibious corps and Marine divisions as operations required. They included: replacement battalions and drafts (over 100 were formed); provisional Marine companies and detachments (FMF base security units); 1st–3rd Military Police Battalions; 1st–6th Joint Assault Signal Companies; 1st–6th Amphibian Truck Companies; 1st and 2nd Bomb Disposal Companies; 1st–5th Separate Medical Companies; 1st and 2nd Separate Topographical Companies; 1st–5th Provisional Rocket Detachments; 1st–7th War Dog Platoons; 1st–6th Separate Wire Platoons, 1st–5th Separate Radio Intelligence Platoons; and 1st and 2nd Laundry Companies (reorganised into 1st–8th Separate Laundry Platoons in 1944).
Service Command, Fleet Marine Force, Pacific
Logistical support of the FMFPac and its far-flung units was of critical importance. The difficulties of providing across-the-beach logistics on a hostile shore were formidable, to say the least. This key command was formed as the Administrative Command, FMFPac on 11 June 1944 from the VAC Administrative Command. It was redesignated Supply Service, FMFPac in August 1944 and then Service Command, FMFPac on 1 June 1945.
A 2nd MarDiv company command post in Garapan, Saipan. The company commander, second from left, speaks on an EE-8 field telephone while the man to the right uses an SCR-536 ‘handitalki’.
The units assigned to the Service Command, and scattered across the Pacific at island bases or in general support of combat operations, included: 1st–4th Service and Supply Battalions; 10th–12th and 18th Service Battalions (Provisional), 1st–3rd, 5th, 7th, 8th and 16th Field Depots; 4th and 6th Base Depots; and 1st and 2nd Field Service Commands.
The 7th and 8th Field Depots were redesignated Service Regiments on 1 June 1945 and reorganised to include headquarters and service, motor transport, and supply and maintenance battalions. (The field and base depots were generally organised with one each of headquarters, general supply, engineer, motor transport, ordnance, signal, and military police companies.) A varying number of the Marine Corps’ 51 depot and 12 ammunition companies could be attached for additional support; the depots’ strength could range from fewer than 300 to almost 2,000 troops. The first of these were formed in early 1943 to provide logistical support to the divisions.
The service and supply battalions provided support to units in the Hawaii area. In early 1945 the 1st Field Service Command was formed in the Marianas to assist with logistical planning and invasion preparations for the 2nd and 3rd MarDivs. The 2nd Field Service Command was formed on Guadalcanal to assist the 1st and 6th MarDivs.
Its nickname was derived from its General Motors model designation: ‘D’ year model (1942), ‘U’ amphibian, ‘K’ – all-wheel drive, and ‘W’ duel rear avles.
CAM Division’s Marine components were 6th Marines, and 1st, 2nd and 3rd Battalions, 10th Marines (artillery). Army components were 147th (2nd Battalion) and 182nd (3rd Battalion) Infantry Regiments, and the Americal Division Artillery with 221st (155 mm), 245th, 246th and 247th (105 mm) Field Artillery Battalions. The Americal Division was formed on New Caledonia from a mix of separate Army units and its designation derived from the contraction of ‘AMERIcans on New CALedonia’.
These units were often referred to as ‘Paramarines’, a term the Marines frown upon as it implies they were ‘half-marines’.
See Osprey Elite 55, Marine Recon 1940–1990.
The 1st was habitually assigned to IIIAC and the 2nd to VAC.
Made organic to divisions in 1945.
