The United States Marine Battalion, 1942 to early 1943
The Battalion organisation the USMC went to war with had been largely agreed upon in early 1941. It was a very light unit as regards transport, with only eleven Jeeps, but had an impressive collection of thirty light and heavy machine guns.
The 'D' Series Marine Battalion, circa 1942 to 1943
Headquarters Company (11 Officers, 100 men)
Battalion Headquarters Section (7 Officers, 8 men)
US Navy Medical Detachment (2 Officers, 20 men)
Intelligence Section (1 Officer, 12 men)
Supply Section (6 men)
Communication Platoon (1 Officer, 40 men)
Company Headquarters (14 men)
Weapons Company (9 Officers, 264 men)
Company Headquarters (3 Officers, 26 men)
Antiaircraft and Antitank Platoon (1 Officer, 23 men)
Mortar Platoon (2 Officers, 74 men)
Three Machine Gun Platoons, each (1 Officer, 47 men)
Three Rifle Companies (6 Officers, 177 men) each comprised of;
Company HQ (2 Officers, 27 men)
Weapons Platoon comprised of;
Platoon HQ (1 Officer, 3 men)
Mortar Section (11 men)
Machine Gun Section (13 men)
Three Rifle Platoons, each comprised of;
Platoon HQ (1 Officer, 6 men)
Automatic Rifle Squad (8 men)
Three Rifle Squads, each comprised of 9 men
Total Strength of 933 all ranks (38 Officers and 895 men)
Points of note
The original Battalion was fairly orthodox, and shared some similarities with the 1940 model US Army equivalent. Throughout the war Marine Infantry Battalions included a US Navy Medical Detachment, who from 1943 onwards were allowed to carry Carbines for self defence.
The elements of the Battalion
Headquarters Section - this consisted of the Battalion Commander (Lieutenant-colonel), Executive Officer (Major), Plans and Training officer (Captain), and four Lieutenants. Of these latter, one acted as Adjutant and Headquarters Company commander, the second as Supply officer and the final two Liaison officers.
Intelligence Section - commanded by a Lieutenant, this provided clerks, draftsmen and observers and also one scout per Rifle Company. The Section was responsible for gathering and collating information and making this readily available for the Battalion Commander.
Supply Section - handled the distribution and allocation of supplies throughout the unit.
Communication Platoon - maintained radio, wire and telephone communication between the Battalion and higher and parallel formations.
Company Headquarters - provided mess facilities and specialist personnel such as a barber and cobbler, and a few men for 'other duties'.
Weapons Company Headquarters - as well as commanding the various fire support elements, Company HQ included the largest concentration of transport within the Battalion, namely four Jeeps.
Antiaircraft and Antitank Platoon - the 20-mm Oerlikon was a Swiss designed weapon, built under licence in numerous nations and used by the US Navy as a shipboard antiaircraft weapon, designated the Automatic Gun Mark IV. In the early war years, 20-mm calibre weapons were still considered effective in the antitank role with suitable armour piercing ammunition. The Platoon was authorised two such weapons, in theory to give it a dual capability against enemy aircraft and armour.
In fact this deployment does not appear to have taken place. Two types of substitute weapon were shown on the tables, either the .50-cal heavy machine gun, or the towed 37-mm antitank gun. Later developments would suggest the .50-cal was the actual replacement as two such 'spare' equipments appeared in the following 'E' Series Weapons Company. Each weapon was assigned a ten man Squad with just two handcarts for transport.
Mortar Platoon - the original Mortar Platoon was a particularly large unit. While it only served four 81-mm weapons it contained over seventy personnel, thirty-two of who acted as ammunition and supply numbers. The Platoon was allocated two Jeeps and fourteen handcarts for transport.
Machine Gun Platoon - each Machine Gun Platoon had four M1917A1 heavy machine guns, with nine men and two handcarts provided per Squad. Not a little confusingly, each Weapons Company also had a pool of another twelve M1917s noted as 'additional, for defense' on the table. In theory this would allow the Weapons Company to double its firepower, while reducing the strength of each gun crew by roughly half. The idea of support units being able to choose between two types of weapon would recur in later Marine Infantry organisations (causing me some head scratching along the way I might add...).
The Rifle Company - it is within the structure of the Rifle Company that the difference between Army and Marine become most apparent. The Marine Rifle Squad underwent a constant series of amendments as the war progressed, each resulting in more manpower and more firepower.
The original Rifle Squad was nine men strong, with a Corporal commanding an automatic rifleman, a rifle grenadier and six riflemen. The Corporal was allocated a .45-cal submachine gun, the automatic rifleman a BAR, and the rifle grenadier an M1903 Springfield rifle with M1 grenade launcher. The balance of six men, one of who acted as assistant Squad Leader, were intended to carry the M1 Garand . An unusual problem faced the Marines when it came to the matter of the rifle. The US Army received priority for the issue of the M1 Garand semi-automatic weapon. Until production increased, the Marines had to make do with the M1903 Springfield, a reliable but old bolt action weapon. It took until about 1943 for sufficient numbers of the M1 to reach the troops. Until then, they had to rely on the same weapon their predecessors had used in France in 1918.
Another area the Marines found themselves in competition for sufficient stocks of weaponry was the submachine gun. The Thompson submachine gun was required in massive numbers by the rapidly expanding Army and the Marines found themselves searching for an alternative source of supply. The weapon chosen was the M50 Reising, developed a few years before the outbreak of war. The M50 fired the same .45-cal round as the Thompson but was significantly lighter and proved very accurate in semi-automatic mode. Unfortunately however, the advantages ended there. The complicated internal mechanism of the M50 created a number of traps for dirt, dust and sand, all of which were in abundance on the first major Marine objective of Guadalcanal. The performance of the M50 was so abysmal that it was quickly abandoned by those issued it, who rearmed themselves with whatever else they could obtain on the battlefield. Perhaps most significantly, the submachine gun disappeared from future Marine Infantry Tables of Organization issued during the war.
The three Rifle Squads in a Platoon were supported by a fourth, Automatic Rifle Squad. The Squad Leader was again a Corporal armed with a submachine gun, there were two automatic riflemen, each with a BAR, and five riflemen, each with a Springfield. Presumably this allowed for an assistant leader and two assistant automatic riflemen men per BAR.
The Platoon was commanded by a Lieutenant, with a Platoon Sergeant, a Platoon Guide Sergeant, three messengers and one Supply Private (listed as responsible for ammunition, water and rations). The Officer and senior Sergeant were to carry carbines, with a pistol or submachine gun as substitute weapon, all others rifles. Platoon HQ also had a sixth, unallocated BAR, designated as a reserve weapon. This was perhaps a holdover from the numerous experiments in Squad organisation carried out by the Marines during the 1930s and 1940s, a process that was by no means over.
The Weapons Platoon had two Sections, the Mortar with two 60-mm weapons, six men per team under a Sergeant, the Light Machine Gun with two M1919A4 weapons, five men per team again under a Sergeant.
Company HQ was commanded by a Captain, with a 1st Lieutenant as Executive Officer. There were three antitank launchers, the Bazooka, allowing one per Rifle Platoon, and a single Jeep for Company transport.
This was the organisation used by the USMC during their first major offensive of the war, at Guadalcanal in August 1942. It was reviewed and altered in light of experience, a process that would continue throughout the Pacific campaign.
The United States Marine Corps
The United States Marine Infantry Battalion