The ‘Door Knocker’

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It has become fashionable in much post WWII literature to almost ridicule some of the early anti-tank (AT) weapons from WWII. For some reason their comparatively weak performance is often compared to more modern tanks which they were never designed to defeat. I am not sure why AT guns (and tanks) in particular come in for this type of treatment, but it is unfortunate because it often interferes with a more objective examination of a weapon’s true historical worth. The German 3.7cm Panzerabwehrkanone 36 (PaK 36) is an excellent example of this phenomenon.

The 3.7cm Panzerabwehrkanone 36 (PaK 36)

The Pak 36’s Real Overall Combat Performance as Late as 1941


The 3.7cm Panzerabwehrkanone 36 (PaK 36)

The German standard issue AT Gun from 1939 to 1941 was the 3.7cm Panzerabwehrkanone 36 (PaK 36). The PaK 36 was developed by Rheinmetall in 1933 and was first issued in 1936. At the time the PaK 36 was considered an excellent design, and it was subsequently extensively copied by other nations, notably the USA and Japan. By 1941 over 20 000 PaK 36s had been built with many sold abroad, notably to the Soviet Union. The Soviets used the basic PaK 36 carriage design for their 45mm M1937 AT gun.

The PaK 36 could penetrate 29mm of 30 deg slopped homogeneous armour at 500m, 22mm at 1000m, and 19mm at 1500m using its standard AP shot. Some sources give the Pak 36 an even better penetration figure of 36mm at 500m in the same conditions, but caution should be used with this figure. In the period 1936 to 1939 this performance was quite acceptable for dealing with contemporary tanks. However by 1940 the PaK 36’s performance was becoming inadequate, and in the French campaign the PaK 36 showed that it could not easily stop the latest Allied medium and heavy tanks.

Its reputation is not helped by the fact that the German soldiers dubbed the PaK 36 the ‘door knocker’ due to its ineffectiveness against Allied heavy tanks in France in 1940. Consequently many post-war commentators criticize the PaK 36 (to the point of ridicule) as obsolescent by 1939 and completely obsolete by 1941. This is based on the idea that it was ineffective against tanks such as the British Matilda, the French Char B, and the Soviet T-34 and KV tanks.

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The Pak 36’s Real Overall Combat Performance as Late as 1941

In reality, Matilda, Char B, T-34 and KV tanks represented a very small fraction of the world’s tank park from 1939 to 1941, and in 1941 the PaK 36 was still quiet capable of dealing with the vast majority of existing tanks. In addition the PaK 36 retained some very beneficial attributes. The PaK 36 had superior optical aiming devices, it was extremely mobile and could be brought very rapidly into action (weighing only 432 kg it could be manhandled by as few as two men), it was small and easy to conceal, and it could maintain a very high rate of fire. Against light tanks and most tanks built prior to 1940, the PaK 36 remained highly effective.

As a case in point let us examine the Red Army’s tank park in June 1941. On 22nd June 1941 the Soviets had
23 295 tanks in service (including non-operational tanks in various states of repair in rear areas). This represented by far the largest tank force in the world in 1941: a force well over twice as large as the rest of the world’s combined tank forces! This force included 10 661 T-26s, 2 987 T-37/38/40/50s, 59 T-35s, 442 T-28s, 7 659 BTs, 957 T-34s, and 530 KVs.(1) Firing its standard AP shot (Pzgr 39) the PaK 36 could penetrate the following tanks frontally:(2)

  • T-26B-2 (model 1937), T-38 (Model 1937), T-60 (Model 1941), and BT-5 (Model 1932), at ranges over 1500m.
  • BT-7-2 (Model 1936) at ranges between 500 and 1000 metres.
  • T-35-2 (Model 1935), T-28B (Model 1938) at ranges under 100m.

Firing its standard AP shot (Pzgr 39) the PaK 36 could penetrate the following tanks from the side:(3)

  • T-26B-2 (model 1937), T-38 (Model 1937), T-60 (Model 1941), BT-5 (Model 1932) and BT-7-2 (Model 1936) at ranges over 1500m.
  • T-28B (Model 1938) at ranges between 1000 and 1500 metres.
  • T-35-2 (Model 1935) at ranges between 500 and 1000 metres.

At the optimum (for the PaK 36) combat ranges between 400 and 1000 meters, we can see from this analysis that the PaK 36 could easily destroy over 91% of the existing Soviet tank park in June 1941.

In addition, the PaK 36 engaged and destroyed many Soviet tanks at ranges beyond 1000 metres.(4) Not bad for a ‘door knocker’! The only ‘old’ generation tanks which presented a problem at all were the T-28 and T-35, and these were still very vulnerable from the side. The fact that the PaK 36 was almost helpless against the latest T-34 and KV tanks, which represented only 6% of the Soviet tank park, should not totally divert attention from the PaK 36’s deserved overall position in history. The prevalence of the PaK 36 ensured that of the rather incredible 20 500 tanks lost by the Soviets in 1941, the large majority were destroyed by PaK 36s in the AT battalions of German infantry divisions.

(1) Refer to Part IV 6. 18) a. – ‘The Soviet Armed Forces from June – December 1941: the Soviet Fully Integrated Land and Air Resource Model - The Actual Strength of all Soviet Land Combat Units in a Deployed (D) State on 22nd June 1941 - The Soviet ‘Tank Deployment Matrix’ - The Deployment and Composition of Red Army and NKVD Armoured Forces on 22nd June 1941’ for the full details on these figures.
(2) Based on armour thickness of the tank’s superstructure front AND an impact angle of 30 degrees or less. Data taken from Part IV 2. 6) – ‘The Soviet Armed Forces from June – December 1941: the Soviet Fully Integrated Land and Air Resource Model - The Soviet Personnel and Equipment Resource Database – Tanks’ table 'Sov Res Database 2'.
(3) Ibid. Based on armour thickness of the tank’s superstructure side AND an impact angle of 30 degrees or less.
(4) This is particularly irksome in tactical-operational simulations where the 45mm M1937 is given effective AT combat ranges over 1000 metres and the PaK 36 is not. This is common in war games with scales of around 1hex per km. In these simulations the effects of superior optics and fire control are often ignored, and the PaK 36 can only engage the enemy at literally point blank range.

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