Terrain and Weather Factors
Between September 1939 and May 1941, German panzer divisions had encountered no serious difficulties in their campaigns due to either adverse terrain or weather conditions (other than the English Channel, which was conveniently ignored). In particular, Panzergruppe Kleist had been able to quickly pass through the `impenetrable’ Ardennes Forrest and then conduct successful opposed river crossings across the rivers Meuse and Somme in France. In April 1941, Kleist’s panzers were able to overrun Yugoslavia and Greece in less than three weeks, despite numerous rivers and mountainous terrain. The overriding impression Hitler and the OKH leadership gained from the Wehrmacht’s preceding campaigns was that terrain in itself was not a serious obstacle to the panzers. Nor did Hitler and the OKH have any useful experience with mechanized operations under winter conditions. In contrast, the Red Army had learned painful lessons about the limitations of mechanized units in forested terrain and winter conditions during the 1939-40 Russo-Finnish War and were in the process of incorporating some of the lessons learned.
Crossing rivers or large streams was an essential feature of military operations in the Soviet Union and the relative fording capabilities of tanks had a major impact on the tempo of armoured operations. Although both Germany and the Soviet Union had a small number of tanks with amphibious capabilities, such as the Pz. III and Pz. IV Tauchpanzer and the T-37, T-38 and T-40 light amphibious tanks, the majority of tanks on both sides could not ford water that was deeper than one meter (i. e. chest deep on a man). The bridging capabilities of the 1941-42 panzer divisions were rather rudimentary – a Bru” ckenkolonne B or K could construct a 50-meter long pontoon bridge in about twelve hours that could just support a Pz. III medium tank, but the Pz. IV and later Tiger and Panthers needed proper bridges to get across significant water obstacles. Indeed, the Wehrmacht lagged behind the Allies in assault bridging, having nothing like the British Bailey bridge. Soviet tank divisions of 1941 were supposed to have a pontoon bridge battalion, but most were never fully formed or quickly lost during the hectic retreats of 1941. While tanks could often cross smaller rivers at shallow fording sites, these critical locations were usually defended by anti-tank guns and mines. Larger rivers, such as the Dnieper or Volga, could not be crossed without substantial army-level engineer support. Pontoon rafts could be constructed to get small numbers of tanks across a large river, but this was usually only sufficient to defend a bridgehead against enemy counterattack. Thus, the capture of intact bridges – particularly railroad bridges, which could support the weight of tanks – was an important constant in Eastern Front armoured operations: both sides sought opportunities to seize poorly-defended bridges because they allowed tanks to do what they do best – move fast and use their shock effect to disrupt an enemy’s defenses. When bridges or fording sites were not available, armoured operations came to a full stop.
Generally, you can try to go just about anywhere with a tank – at least once – but you may regret that you tried. Armoured operations on the Eastern Front were often impeded or channelized – forced into narrow mobility corridors – due to `no-go’ terrain such as marshes or dense forests. The marshlands between Leningrad and Ostashkov in northern Russia and the Pripet marshes were particularly hazardous for armoured operations. Tanks could easily become irretrievably bogged down in marshy terrain, or forced to move along narrow tracks that made them very vulnerable to anti-tank ambushes. In the early border battles in 1941, the Red Army foolishly lost a number of precious T-34 and KV-1 tanks in water-logged areas in the Pripet Marshes. The best tank country on the Eastern Front was the steppe country of the Ukraine, although this region also had the worst mud during the rainy periods. There were areas of `slow-go’ terrain in the Soviet Union, including urban areas and the ravines along the River Don, which could cause tanks to throw track. The Germans were particularly shocked by the almost total lack of decent all-weather roads in the Soviet Union, which increased the wear and tear on all vehicles and greatly reduced their mobility.
The Germans had totally discounted the severity of the weather in the Soviet Union and were shocked in turn by the summer heat, the autumn mud and the harsh winter cold. Mud in particular is the bane of the existence of all tankers, but the idea that it only interfered with German mobile operations and that it was only a problem during the autumn and spring Rasputitsa season is an oversimplification that has been accepted for too long in Western historiography about the Eastern Front. First of all, the Eastern Front stretched over 1,700km from Leningrad to the Crimea and the weather could vary considerably across regions; a typical rain system would cover a 400-500km wide area, but other areas received no rain (or snow). Weather fronts moved from west to east across Russia, meaning that bad weather would generally hit the Germans first. Second, the summer months of June-July tended to have the most rain, but April and May were the driest months. In 1941, Heeresgruppe Süd had twice as much rain in July as it did in September-October, and mud caused significant mobility problems in the summer as well. When mud occurred, the wheeled vehicles in armoured units and towed artillery pieces were likely to be the most affected, but tracked vehicles could generally move until the mud became so deep that the tank either scraped bottom or the roadwheels became too fouled with mud. When the supply trucks couldn’t make it through the mud, armoured operations ground to a halt from lack of supplies and ammunition. Oftentimes, SPW half tracks had to be diverted from their primary combat tasks of transporting infantry to making supply runs through muddy areas or going to pull mired trucks out. Routine track maintenance became much more difficult when everything was caked in thick, gooey mud. Soviet tankers also complained about the mud and it significantly affected their operations as well. The main Soviet tanks in 1941 – the T-26 and BT-7 – had even narrower tracks and less engine power than the German Pz. III, meaning that most Red Army tank units in 1941 were more prone to being impeded by muddy roads. Since Soviet tank brigades in 1941-42 consisted of mixed vehicle types, the superior T-34s would still have to travel at the rate of the slower light tanks.
The first snow arrived over the Eastern Front in October 1941, but in most areas it consisted of only 5cm and turned to rain within twenty-four hours. There were only two or three days with snow in October, with more falling in the humid Ukraine than around Leningrad. Snowfall in November jumped to about 20cm in central Russia, but the heaviest snowfalls did not occur until December- February. German equipment was designed to operate in temperate areas and proved unsuited to cold-weather operations in Russia. Panzer crews were particularly shocked to find that their tracks could literally freeze to the ground in winter months or their batteries crack when the fluid inside froze. The Czech-built Pz. 35(t) used a hydraulic system that literally froze in October 1941, bringing that vehicle’s career to an abrupt end. When the German expectations of a short campaign were unfulfilled, the panzers were forced to conduct operations under all weather conditions, for which they were not psychologically or materially equipped.
Doctrinal and Technological Influences
During the interwar period, there were two contending schools of thought among major armies in regard to the proper employment of tanks. The dominant school was that tanks were best suited for the infantry support role and should be attached directly to infantry units. More revolutionary was the concept of armoured units that could operate independently, which was inspired in part by the theories of the British armour theorist, J. F. C. Fuller, and his Plan 1919. Fuller’s theories of mechanization, expounded in his interwar writings, attracted followers in both the Reichswehr and the Red Army. The proponents of creating independent armour units argued for looking beyond the breakthrough battle and for using tanks in a long-distance, exploitation role. However, this kind of radical thinking ran head-on into the powerful cavalry lobbies in both Germany and the Soviet Union, who regarded tanks as a threat to the mounted branch’s traditional use in the exploitation role. Both infantry and cavalry officers generally opposed the creation of independent tank units or tried to place limits on the kind of role they would serve. The infantry school argued for the development of infantry support tanks with a high level of armoured protection and had a howitzer-type weapon, but speed or range were not important requirements. Cavalry officers gradually accepted that tanks would be included in their country’s armed forces, but preferred light, fast tanks that could assist the cavalry in reconnaissance and pursuit roles. These intra-service debates about tank design crossed national lines and shaped tank development in Britain, the United States, France, Germany and the Soviet Union in the 1920s and 1930s.
Armour theorists gradually recognized that in order to develop effective tanks, both the infantry support and cavalry exploitation missions needed to be reconciled in technical requirements. The utopian idea of a single `universal tank’ that could successfully accomplish all missions was quickly determined to be unfeasible and theorists recognized that more than one type of tank would be necessary in order to fulfill armour’s potential on the battlefield. The infantry support mission required a tank that was equipped with weapons capable of engaging enemy infantry entrenched in fieldworks, bunkers or buildings. Given the high threat level from enemy artillery and anti-tank weapons, it would also be prudent for infantry support tanks to possess a high level of armoured protection. However, the exploitation mission suggested a tank with the primary requirements of speed and mobility. Most armies struggled with developing the right types of tanks, with the best characteristics and in the best mix to meet these mission requirements. Both the Red Army and the Reichswehr made choices about what tanks they wanted, based upon doctrinal and technological influences in the 1930s, which would shape battlefield outcomes in 1941-45.
Since Germany was not allowed to build or possess tanks due to the restrictions of the Treaty of Versailles after the First World War, the postwar Reichswehr made covert agreements with the Red Army to establish a tank training school at Kazan in 1929. The Red Army, which only had a handful of obsolete tanks left over from the First World War, was desperate to acquire foreign tank technology and willingly cooperated with the Reichswehr. During the four years that the Kazan school was operational, the Germans tested two different tank prototypes there and determined the necessity of mounting radios in every tank in order to exercise effective command and control over an armoured unit (the importance of this was further reinforced when German observers noted the successful use of radios in British pre-war tank exercises). German officers such as Erich von Manstein, Walter Model and Walter Nehring spent time in the Soviet Union and observed Soviet tank exercises, although this apparently did little to enhance their regard for the professionalism of Soviet tankers. As part of the deal for hosting the Kazan school, the Red Army acquired several 3.7cm Pak guns and the design for a 7.5cm anti-aircraft gun from the German firm Rheinmetall, which were used to bolster Soviet research on tank armament. The Soviets also acquired fuel-injection technology from Germany, which was used to enhance Konstantin F. Chelpan’s development of an experimental diesel tank engine at the Kharkov Locomotive Works. However, the Soviet leadership believed that the Germans were not sharing their best technology and finally closed the school in September 1933.
Soviet military theorists such as Mikhail Tukhachevsky, Vladimir K. Triandafillov and Georgy Isserson had been assiduously working on a new military doctrine since the late 1920s. This doctrine, known as Deep Battle (glubokiy boy), was partly inspired by J. F. C. Fuller’s Plan 1919 and mixed it with Marxist-Leninist thinking about protracted warfare. Early on, the Red Army leadership recognized the imperative need to develop a tank force, but was reluctant to choose between the infantry support and cavalry schools. Instead, the Red Army codified its basic tank doctrine in Field Regulations PU-29, issued in October 1929. These regulations specified that PP tanks would provide infantry support, while DD tanks would push deeper into enemy rear areas to destroy their artillery. The Red Army cavalry lobby, in the form of Marshall Semyon Budyonny, also managed to retain enough influence that PU-29 was written to include joint tank-cavalry Deep Operations (glubokaya operatsiya). At the same time, the Red Army established the Office of Mechanization and Motorization (UMM) to develop the tanks necessary to fulfill the doctrine spelled out in PU-29, as well as train and organize all mechanized forces. The first head of the UMM, Innocent A. Khalepsky, decided that the Red Army also needed a heavy breakthrough tank to penetrate fortified areas, so he recommended a 60-ton tank with two 76.2mm howitzers and a 37mm cannon. From this point on, Red Army doctrine pushed Soviet industry to concurrently develop light, medium and heavy tanks.
At the start of the First Five Year Plan (1928-32), Soviet industry was unable to build indigenously-designed tank engines or tank guns and barely able to construct a few dozen light tankettes per year. Since Stalin and the Politburo were more concerned about falling behind Western tank developments than domestic economic consequences, they arbitrarily doubled the number of tanks required by the Red Army and rushed technical development in order to field the largest number of tanks possible. Three tank design bureaux were established under the plan: OKMO and SKB-2 in Leningrad and KhPZ at Kharkov. An artillery design bureau in Gorky was also tasked with developing new tank armament. At Stalin’s behest, the UMM authorized numerous tank projects, many of which proved failures, but this also jump-started the Soviet tank industry. Between the pressure of fulfilling quotas established by the Five Year Plans and the personal consequences of `obstructionism,’ the Soviet tank design bureaux were forced to develop tanks that could be built quickly and in numbers, which would prove to be advantageous in a long war. Through ruthless effort, Stalin’s regime was able to build up the Soviet Union’s defense industrial base at an astonishing rate and succeeded in producing over 5,000 light tanks under the First Five Year Plan. A generation of young Soviet engineers proved adept at using off-the-shelf components and designs acquired legally and illegally from Britain and the United States, while Soviet engineers took the idea of sloped armour from John Walter Christie’s innovative M1931 tank prototype and employed it on the BT-series light tanks. Soviet espionage was also successful in acquiring tank design information in Britain. Despite negligible experience in armoured vehicle design and fabrication, Soviet engineers were able to move from the prototype stage to series production of the T-26 and BT-series light tanks within less than two years. Although Soviet engineers were forced to use foreign-designed engine components and armament in their first generation of indigenous tanks, the design bureaux in Leningrad, Kharkov and Gorky were also given some of the best engineering talent in the Soviet Union, who were tasked with developing indigenous engines and cannon for the next generation of tanks. In particular, the talented Konstantin F. Chelpan made excellent progress – with the backing of Khalepsky, the head of UMM – in developing a practical diesel tank engine, which would have enormous implications for armoured warfare on the Eastern Front in the Second World War.
Due to the success of the First Five Year Plan, the Red Army had sufficient tanks by 1932 that it could afford to create both an independent tank force and separate tank brigades for direct infantry support. Two mechanized corps were formed – three years before the Germans fielded their first panzer divisions. The mechanized corps were intended for independent Deep Operations, up to 250km in three days. While the T-26 was intended to fulfill the NPP role, the BT-series fast tank (Bystrokhodny tank) was built for speed and mobility for the DD exploitation role. The Red Army formed separate heavy tank brigades with the new T-35 heavy tank and independent mechanized brigades to support the infantry and cavalry. During 1932-33, the Red Army began testing the Deep Battle concept in field maneuvers with the new tank units. When the Red Army had difficulty in actually conducting field exercises according to Deep Battle doctrine, the innovative Aleksandr I. Sediakin, deputy chief of the general staff, was put in charge of combat training and transforming the new doctrine into a practical reality. By 1934, Sediakin had developed a Deep Battle `playbook’ for Soviet commanders that instructed them how best to employ a combined arms attack using armour, mechanized infantry, artillery and airpower. Sediakin and his staff intensively studied and tested Deep Battle doctrine, using the mechanized corps as test beds, and one of his crucial findings was the logistical difficulties of getting fuel to tank units that achieved a deep penetration. The Military Academy of Mechanization and Motorization (VAMM) in Moscow also worked to train battalion and regimental-level armour leaders in the new doctrine. In 1936, Deep Battle became the official doctrine of the Red Army in Field Regulations PU-36. It is important to note, however, that Sediakin’s `playbook’ approach to Deep Battle was in line with the Marxist preference for prescriptive training, which encouraged junior leaders to follow a checklist by rote, rather than employ initiative on the battlefield.