♦ The Tank Destroyer Force 1941-45 ♦

The United States Army in World War II


US tank destroyers of World War II. Left to right, the M3 (75mm gun), the M10 (3in gun), the M18 (76mm gun) and the M36 (90mm gun). (US Army Center of Military History)

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The World War II US Army was unusual in establishing a separate branch embodying antitank units and personnel. The startling success of the German Army’s Panzerwaffe in Poland and France focused the Army leadership’s attention on the importance of antitank defense. To the new triangular infantry division, therefore, an infantry antitank (AT) battalion was added. Additionally, the division’s three infantry regiments each received a separate AT company, for a divisional total of 72 x 37mm antitank guns (ATG). The guns and personnel were drawn from the Field Artillery branch, which thereby lost control of antitank gunnery. But as things turned out only two divisions actually received this battalion, for as they were being set up the Army’s thinking on AT defense continued to evolve.

Lieutenant General Leslie McNair, the Chief of Staff, General Headquarters (GHQ), US Army, believed that it was wasteful for tanks to oppose tanks on defense when a much cheaper ATG could do the job. But even so it seemed obvious that a unit with more firepower and mobility than the infantry AT battalion would be required. Thus was born the concept of the tank destroyer (TD) battalion: a self-contained nondivisional antitank unit capable of conducting a mobile defense against attacking enemy armor.

On 27 November 1941 the War Department ordered the activation of 53 TD battalions under the direct control of GHQ. The two existing infantry AT battalions were transferred from their parent divisions and reorganized accordingly. Also ordered was the establishment of a Tank Destroyer Tactical and Firing Center at Fort Meade, Maryland. The Center was made responsible for TD doctrine, equipment and training. Soon thereafter the Tank Destroyer Force (TDF) became a separate Army branch.

Distinguishing Flag, 1st Tank Destroyer Group

Two fundamental questions confronted the new TDF: How were TD battalions to be organized and equipped, and how were they to be employed? The first question was quickly resolved thanks to the existence of the 93rd AT Battalion, an experimental nondivisional unit that had successfully participated in the 1941 Carolina maneuvers, a major field training exercise. Renumbered from 93rd to 893rd, it became the prototype TD battalion. Initially there were three authorized organizations, one towed (T) and two self-propelled (SP): the light TD battalion (T), the light TD battalion (SP) and the heavy TD battalion (SP). The light battalions had 36 x 37mm ATG, either towed by 0.25-ton trucks (the ubiquitous Jeep) or mounted on a 0.75-ton truck (M6 TD). It being recognized that the 37mm ATG was verging on obsolescence, these battalion types were considered interim organizations.

The desired unit was the heavy TD battalion (SP), whose primary equipment was the M3 halftrack mounting an M1917 75mm gun. The M1917 was the American version of the famous “French 75” of World War One vintage, which had proved effective in the AT role against German armor in 1940. The M3 was an interim design, eventually to be replaced by the fully tracked tank destroyer already in development, but it saw combat in the Philippines, North Africa and Sicily, and was also employed by the Marine Corps in the Pacific.

The heavy TD battalion embodied a battalion headquarters company, a reconnaissance company and three TD companies, each with three platoons. Two of the platoons had 4 x M3 TD each and one had 4 x M6 TD. The platoons also had an SP antiaircraft section with 2 x caliber .50 antiaircraft machine guns (AAMG). The M6 platoon was earmarked for upgrade to heavier equipment when it became available. The headquarters company consisted of a command section plus signal, transportation, maintenance and supply platoons. The reconnaissance company had three scout platoons and a pioneer (engineer) platoon. The first SP TD battalions to see action in North Africa were organized in this manner.

The M3 Tank Destroyer (75mm gun) saw action with the US Army in the Philippines, North Africa and Sicily (1941-43), and with the US Marine Corps in the Pacific (1943-45). (US Army Center of Military History)

Though the Army envisioned an ultimate force in excess of 200 TD battalions, only 106 were actually activated during the war and for various reasons—industrial priorities, shipping space—not all of them could be SP units. So a heavy TD battalion (T), organized similarly to the SP battalion but with the guns towed by halftracks, was also specified. The AT gun was the 3in M5, which combined the barrel of the 3in antiaircraft gun (AAG), already in service, with the suitably modified breech, recoil mechanism and carriage of the 105mm M2 howitzer. For both battalion types, overall manpower was cut from 900 to about 650 by eliminating the AAMG sections and streamlining the headquarters company.

Development of a fully tracked tank destroyer to replace the M3 had begun in 1940. Various designs were evaluated and rejected before the T35E1 model was approved for production as the M10 in June 1942. This tank destroyer was based on the chassis of the M4A2 medium tank, with an open-topped turret mounting the 3in M7 ATG—a modified M5—and a caliber .50 heavy machine gun (HMG). Though bearing a superficial resemblance to a tank, the M10 had much thinner armor and was expected to rely for protection on speed and agility. The M10 was destined to be the Army’s most numerous tank destroyer of the war, with around 6,500 manufactured. Late in the war it was supplemented by the M18 (76mm gun) and the M36 (90mm gun).

The M10 Tank Destroyer (3in gun) was based on the chassis of the M4A2 medium tank. Though it superficially resembled that tank, the M10 had thinner armor, higher speed and a more powerful main gun than the M4A2. (Tank Encyclopedia)

Doctrine governing the employment of tank destroyer forces was based on theoretical conceptions of armored warfare, studies of the 1939-41 campaigns in Europe, and experience acquired in the Army’s own field exercises. These led to the conclusion that a static antitank defense would be inadequate in the face of tanks attacking en mass. What was required was active defense in depth. This could of course be provided by one’s own tanks, but then they would be unavailable for offensive action. Instead, mobile tank destroyer forces would do the job, deploying rapidly to contain any enemy armored breakthrough by occupying key terrain behind the front line, launching counterattacks and aggressively opposing the enemy’s advance.

Such tactics required a higher headquarters to coordinate the actions of the TD battalions: the tank destroyer group, a brigade-level echelon capable of controlling up to four TD battalions. The TD group was purely a tactical headquarters, with no responsibility for logistical support of its subordinate battalions. This group organization, which was later extended to all Army branches except the Infantry, was intended to provide the flexibility necessary to carry out the TD mission.

The Tank Destroyer Force had its baptism of fire in North Africa—with mixed results. The problem was not due primarily to poor leadership and training—though instances of such deficiencies were noted—but to faulty doctrine. The concept of aggressive defense in depth proved problematical in opposition to the German Army’s tactics, which were based on the combined-arms Kampfgruppe (battle group). Rather than charging forward en masse, the panzers operated in close cooperation with infantry and artillery, always covered by a screen of mobile antitank guns. Thus the US tank destroyers, with their thin armor, were severely disadvantaged. In only one instance were they able to fight as they had trained. The 601st TD Battalion, an SP unit equipped with the M3 and reinforced by a company of the 899th TD Battalion with M10s, turned back an attack by some fifty tanks of the 10th Panzer Division at El Guettar (Tunisia). Employing fire and movement, the US tank destroyers accounted for some thirty panzers but the price was high: 20 of 28 M3s plus seven M10s were knocked out.

An M5 antitank gun being prepared for action. The weapon itself was effective, but towed guns proved vulnerable due to their relatively low mobility compared with self-propelled tank destroyers. (US Army Center of Military History)

More typically, the tank destroyers operated in close support of the infantry, usually being allotted by companies and platoons to infantry battalions and companies. Perforce, they developed methods of cover, concealment and combat that prewar doctrine had never anticipated. Instead of operating independently, tank destroyers reinforced the infantry’s antitank defenses. Instead of fighting on the move, they were sited in carefully chosen, well-camouflaged firing positions. In this role they proved useful but such attachments caused considerable logistical and command problems, such that senior commanders’ dissatisfaction with the whole tank destroyer concept grew steadily as the Tunisian campaign wore on. And in fact, there would never be an opportunity for the tank destroyers to operate in their originally conceived role. The large-scale armored clashes of the early years of the war and on the Eastern Front were not repeated in Sicily, Italy or Northwest Europe, where the Germans fought largely on the defensive. Thus by 1944 tank destroyer battalions found themselves attached more or less permanently to infantry and armored divisions. In most cases they remained administratively subordinate to their TD group HQ, but these no longer exercised tactical control. TD group HQs deemed surplus to requirements were either dissolved or used to form a third, reserve combat command HQ for armored divisions (CCR).

Fortunately, as the Tunisian campaign had shown there were other viable missions for the tank destroyers. The US infantry division’s organic antitank assets were minimal: 21 x 57mm ATG, three in the divisional headquarters company and eighteen in the regimental AT companies. The attachment of a TD battalion was, therefore, a welcome reinforcement. SP tank destroyers also served as assault guns in close support of the infantry. With their high-velocity main armament they were effective bunker busters, though their thin armor and open-topped turrets made them more vulnerable than tanks. They were also employed as regular artillery firing high-explosive ammunition, the necessary techniques having been developed during the Tunisian campaign.

Shoulder Sleeve Insignia of the Tank Destroyer Force 1941-46. (US Army Institute of Heraldry)

TD battalions were heavily engaged during the Battle of the Bulge (December 1944-January 1945)—with mixed results. Though the self-propelled tank destroyers performed well, the towed units fared poorly. Guns towed by wheeled prime movers proved insufficiently mobile to cope with the Germans’ armored battle groups: Once emplaced they had to fight it out where they stood, and all too often companies or whole battalions were overrun. The Army therefore decided to convert the remaining towed battalions to SP. A few TD battalions, mostly equipped with the M10, served in the Pacific. Since Japanese armored forces were minimal, the tank destroyers served as assault guns.

The end of the war heralded the end of the Tank Destroyer Force.  The late-war introduction of the M26 heavy tank, armed with a 90mm gun, scotched the argument that tank destroyers provided greater firepower that tanks. A postwar review concluded that the tank destroyers, though useful, had performed no mission that could not be performed by tanks. So the TD battalions were quickly inactivated (though some were to reappear later as tank battalions) and the Tank Destroyer Center was closed down in 1946. Such was the unceremonious demise of an Army branch that whatever its shortcomings had played a significant and gallant role on the battlefield, from North Africa to the Elbe River.

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