The Development of Mobile Forces, Sept 39-June 41
Introduction
To Soviet military planners, armour was the key to modern warfare. Unfortunately, this view was not shared amongst all senior officers, and, equally, there were significant debates about how best to make use of the mobile forces available,
As late as January 1941, Kulik was arguing for the scrapping of the armoured forces and their replacement by 18,000 strong cavalry divisions. Others such as Zhukov saw the full benefits of armoured forces but still believed they would operate most effectively if dispersed amongst the regular formations.
However, there was agreement on several key areas. First the T-26s needed to be fully replaced, and the few BT7s upgraded to a 50mm main gun. This at least would match the Pzr III that was the mainstay of the German Panzer divisions in Poland and France. However, the BT7 had been designed for speed and the evidence, both from Finland and analysis of the German campaign in France, was that the armoured arm would have to break through enemy defences before they could exploit in depth.
(BT7 crossing a river at Khalkin-Gol, they were very effective against lightly armed opponents, but lacked the armour or main gun for modern tank warfare)
Doctrine
On the offensive, deep exploitation remained key to Soviet armoured doctrine. In effect, once the front was broken, the disruption would spread deeper and deeper into the enemy’s rear:
“If we break through to a depth of 8 km, we will paralyse the front to a depth of 30 km, if we break through to a depth of 30km, then we paralyse the front to a depth of 100km, if we break through 100km, the enemy loses control of the front”.
In the summer of 1941, the RKKA was learn the truth of those words. Not least as far too little attention was paid to the role of armour on the defense and the RKKA lacked the anti-tank weapons needed to deflect German armoured offensives.
If there was agreement as to the goal of mobile warfare, the question was how to achieve this.
Equipment
One solution was in terms of equipment. Thus, first the T-26s were replaced by the BT7 in all the tank formations.
Then, since the BT7 was essentially built for speed, it too was being phased out by the new T-34. On the eve of the German blow, the T-34 accounted for roughly one third of the Soviet medium tank establishment.
(a protype T-34 undergoing factory tests, in this case to determine if it was fire proof)
To improve the punch of the Tank Divisions, some were allocated additional organic artillery. The first versions were the zis-30, essentially an adapted tractor chasis, that first saw action at Velikiye Luki.
(zis-30, effectively a gun on top of a tractor, with flaps to provide stability)
To increase the number of armoured formations allocated to the infantry armies, small numbers of tank destroyers were produced, It was envisaged that in defensive actions these would enable infantry to hold their ground against German armoured attacks.
(SU-76 tank destroyer, as with the zis-30 this was a hastily designed solution and the crew were very vulnerable to enemy fire)
Finally came the question of whether or not specialist armour was needed for breakthrough operations. The role of such heavy tanks was not resolved before the German invasion, in part due to the inadequacies of the KV1 as a tank, in part due to the limited numbers (only 2 brigades were deployed by July 1941) and in part for doctrinal reasons.
(KV1 in the Ukraine, Summer 1941)
(not all Soviet tank drivers were as careful as they should have been)
Organisation
The second solution was in terms of military organisation. Zhukov won part of the battle and the armoured formations were allocated to the main armies, however, they were concentrated into their own corps. The plan was to develop two related formations:
A tank corps of 2 tank divisions (2 med arm, 1 mot) and 1 mechanised division (1 light arm, 2 mot);
A mechanised corps of 1 tank division and 2 mechanised.
The problem was on the eve of war, the mechanised corps were often significantly below strength, in particular lacking in tank divisions.
By June 1941, the Soviet armoured forces were organised as:
West Front – 2 Tank Corps, 14 Mech Corps, 5 Mech Corps (1 div) & 3 Mech Corps (2 div);
South Front – 1 Tank Corps, 3 Tank Corps, 8 Mech Corps & 2 Mech Corps (1 div)
So of the Mech Corps only 2 (5 & 8) were at full establishment, giving the RKKA a total of 8 Tank Divisions split 3 in Bielorussia and 5 in the Western Ukraine.
The 11 mechanised divisions were based on 1 light armour brigade (at this stage mostly T-60s) and 2 of motorised infantry.
The T-60 light tank was seen as ideal in conditions of high mobility, but lacked the equipment to either break a defended zone or to deal with enemy armour. Unfortunately in the summer of 1941, such divisions often had to fend off German armoured blows, due to the lack of tank divisions in the Soviet army.
(the T-60 was effectively a better equipped armoured car)
A handful of motorised infantry divisions existed without light armour and these were mostly treated as conventional rifle divisions. In addition, 5 cavalry divisions were allocated to the reserve armies at Kharkov and Moscow.
(Soviet cavalry in the Ukraine, 1941)