After mid-July 1941, the primary Soviet armoured formations were the tank regiment and the tank brigade. At the outset of the war in the East, each Soviet mechanized corps had five tank regiments: two in each of its two constituent tank divisions and one in the mechanized division. The tank regiments were intended to function as part of a combined-arms structure within a division and were tank-pure formations with no organic infantry or artillery; each tank regiment in the tank divisions was authorized three tank battalions with a total of sixty-two tanks. However, once the mechanized corps began to disintegrate under the hammer blows of the German Panzergruppen, the Stavka opted to rely upon independent tank brigades both for expediency of formation and simplicity of command and control. The tank brigades authorized in late August 1941 were based upon the remnants of the mechanized corps and were supposed to have three tank battalions with a total of ninety-one tanks and a motorized infantry battalion. However, as Soviet losses mounted and industry could not yet replace them, the size of the tank brigade continued to shrink. In September, the tank brigade was reduced to two tank battalions with sixty-seven tanks and in December to only forty-six tanks and the infantry battalion was omitted.
Prior to the war, most Soviet tank battalions were usually comprised of only one tank model, but the number of tanks could vary from thirty to fifty. The new T-34 and KV-1 tanks were being fielded by battalions, so there was little integration with existing models prior to the German invasion. The Soviet tank battalion was much smaller than its German counterpart and grew increasingly leaner throughout 1941. Typically, the Soviet tank battalion had a headquarters, an eighty-man maintenance company, a reconnaissance platoon with three BA-10 or BA-20 armoured cars, a twenty-one-man medical section, some fuel and ammunition elements and three tank companies. The Red Army kept tinkering with the size of tank platoons prior to the war, trying out 3-, 4- and 5-tank platoon configurations. Heavy tanks were normally kept in 5-tank platoons, but the light and medium tanks quickly abandoned the pre-war 4-tank platoon and relied upon a 3-tank platoon structure for most of the war.
Although the new KV-I, KV-II and T-34 tanks attract much attention in estimates of the Red Army’s relative combat power in June 1941, these tanks comprised barely 12 per cent of the available Soviet armoured forces at the outset of Barbarossa and were initially rendered nearly combat ineffective by a host of logistical and training defects. Many of these modern tanks had only arrived at their units a few weeks or months prior to Barbarossa and had been stored in warehouses, pending summer training in 1941. Very few crews had trained on either of these new tanks and they were so dissimilar to the earlier light tanks that even experienced tankers needed a transition course before they could effectively use these vehicles in combat. However, far more serious was the shortage of 76.2mm main-gun ammunition for the KV-I and T-34 and the almost complete absence of 152mm ammunition for the KV-II. The more fortunate T-34 tank battalions had a single basic load of ammunition – often with no armour-piercing rounds – while the less fortunate units had only been issued machine-gun ammunition. The fuel shortage was even worse, with most Soviet heavy and medium tanks having no more than one basic load of fuel, enough for a few days operation. Most of the fuel in forward depots was gasoline for the T-26 and BT-series light tanks, but diesel fuel for T-34s and KVs was still in short supply. Spare parts for the new tanks were virtually non-existent. Consequently, the only real advantage enjoyed by the T-34 and KV tanks at the outset of Barbarossa was the enormous effort required by the Germans to destroy them, but otherwise their innate firepower and mobility advantages were squandered by inadequate logistic readiness.
The main Soviet battle tanks employed in 1941 were the T-26 and the BT-7 light tanks, which comprised nearly 80 per cent of the available armour. The T-26 had been designed as an infantry support tank and reflected early-1930s thinking on tank design. About one-third of the operational T-26s in June 1941 were improved models built in 1939–40, but the rest were older models with negligible combat capability. Compared to the German Pz.III Ausf. G or H models, even the newer models of the T-26 were clearly inferior in mobility and protection. The T-26’s greatest weakness was its powerplant, derived from a GAZ truck engine and lacking in mechanical reliability. Between 30 and 40 per cent of the available T-26 light tanks were inoperative at the start of the campaign and most of the remainder suffered mechanical breakdowns after a few weeks of operations. The BT-series light tanks were more capable opponents, particularly the upgraded BT-7M model which first appeared in 1939. The BT-7M employed the same V-2 diesel tank engine as the T-34, giving it greatly superior mobility and reliability over the Pz.III. Unlike the T-26, the BT-7M had thicker, sloped armour, making it closer in protection to the Pz.III. Unfortunately, the KhPZ had ceased manufacturing the BT-7M just before Barbarossa began, in order to concentrate on T-34 production. Both the T-26 and BT-7 mounted the 45mm 20K cannon which – at least on paper – was comparable to the 5cm KwK 38 L/42 on the Pz.III.
Unfortunately, the 45mm gun was undermined by poor quality control in the manufacture of its BR-240 APBC rounds, with steel penetrators that shattered on impact and had difficulty penetrating the armour on the Pz.III and Pz.IV at ranges beyond a few hundred meters. The remaining Soviet armour, including the T-35 heavy tank, the T-28 medium tank, the older BT-2/5 series and the T-37/38/40 light tanks were too obsolescent and too few in number to matter much in the tank battles of 1941–42.
Doctrinally, the Soviet preference for armoured units throughout the war was to maintain three types of units: large formations for independent mobile operations, separate battalion, regiment or brigade-size formations for infantry support and separate RVGK (Reserve of Supreme High Command) units under direct Stavka control. After the dissolution of the mechanized corps in July 1941, the Red Army was left with only infantry support units until spring 1942. While the materiel-poor Red Army of late 1941 could not afford to set aside units for the RVGK until it was clear that Moscow would not fall, this became a priority in 1942 and would eventually provide the Stavka with an advantage that the OKH rarely enjoyed on the Eastern Front – an appreciable reserve of armour that could be shifted to critical fronts.
Soviet armoured tactics at the start of the war were very basic because the level of training was so low in most units. Tank platoons and companies were primarily taught to attack on line to simplify command and control, although wedge formations were also possible. Soviet tank platoons attacked in very dense formations, often with only five meters between vehicles. Soviet tank commanders usually lacked binoculars and were taught to operate ‘buttoned-up’ in combat – which drastically reduced their situational awareness versus German tankers. Since the Soviet Union had not developed an armoured personnel carrier analogous to the German Sd.Kfz.251 – a serious deficiency – Soviet tanks did not operate as closely with their attached motorized infantry as German panzer kampfgruppen did. Taken together, these bunched-up and nearly-blind Soviet tank-pure formations proved easy pickings for German panzer and panzerjäger units. Another tactical consideration was the tendency of the Red Army to substitute ‘scripted’ by-the-book methods for common sense; Soviet armoured tactics in 1941–42 were entirely proscriptive in nature. Indeed, the influence of Marxist dialectical materialism on Soviet military theory led to a slavish devotion to ‘scientific approaches’ to military problems. If an attack failed with heavy losses, Soviet political commissars blamed commanders for not following ‘the playbook,’ while refusing to admit that school-taught tactics needed to be modified to suit battlefield realities.