M18 Hellcat - Tank Destroyer Doctrine

Tank Destroyer Doctrine

American prewar armored doctrine was based on the assumption that enemy armoured attacks would be delivered at a time and place of the enemy's choosing against a US defense. Similarly, US armoured attacks would be delivered at a time and place of friendly forces choosing against an enemy defense. This the US envisioned using tanks in the attack solely in a support and exploitation role, usually in conjunction with infantry. Tank destroyers, such as the Hellcat, were to be used against tanks that had already penetrated the front most defense lines. To this end the Hellcat was not intended to engage in protracted combat, and had light armor and extremely high speeds to quickly respond to breakthroughs in the line by German armor. In reality, the opposite was true, as the attacks with the Sherman ran into defending German tanks far more often than intended. In Italy, TDs compensated for a shortage of 155mm artillery ammunition by using their 3 inch or 76mm guns in indirect fire role. Near the end of the war, there were so few German tanks that tank destroyers were increasingly used as self-propelled artillery in support of infantry for lack of any other targets.

The Hellcat was theoretically supposed to be used independently as a sort of mobile anti-tank gun, brought up from reserves to block an incoming armored thrust. In practice a TD battalion was assigned nearly permanently to a division and would move toward an enemy penetration from local assembly areas. The doctrine of the time had Shermans acting in support of infantry to break enemy defenses (Infantry leads, tanks follow or support by fire), and then exploiting the attack (Tanks lead, infantry follows) with infantry in support during exploitation.

Prewar expectation was that all anti-tank work was supposed to be done by tank-destroyer crews, because attacking tanks could concentrate against a small part of a defending line. Independent TDs groups were to counter concentrate, to stop enemy tanks from penetrating deeply. Speed was essential in order to bring the Hellcats from the rear to destroy incoming tanks. Obviously this would make it harder for an armored force to achieve a deep breakthrough, a main objective of armor, if the enemy had tanks. It would also be easier for an opposing armored force to achieve a local breakthrough against an Americans which would not have all of its anti-tank assets at the front during the beginning of any attack. This doctrine was not entirely used as it would create a small window of time of weakness in the armored battalion until tank destroyers moved to the front. TD battalions assigned to front line divisions often split up to companies attached to regiments, and platoons attached to infantry battalions. When so attached, defending TD units supplemented organic antitank weapons (bazookas and 57mm towed guns).