Appendix 5: A Note on Tanks, Armour, and Anti-Tank Guns in 1941
(See page 173)
1. The German terms used in this note are as follows:
Panzerkampfwagen (Pzkw), or tank
Panzerabwehrkanone (Pak), or anti-tank gun
Kampfwagenkanone (Kwk), or tank gun
Flugabwehrkanone (Flak), or anti-aircraft gun
Sprenggranate (Spgr), or high explosive shell
Panzergranate (Pzgr), or armour piercing shell or shot.
Special attention is drawn to the ‘Pzgr 40’ which was a special light armour-piercing shot with a core of tungsten carbide.
2. By August 1940 the Germans had tested the British tanks and weapons captured in France. They were particularly impressed by the armour on the Matilda II tank, which in front of the hull was 78 mm thick, and noted that only the 88-mm Flak gun would penetrate it at the longer ranges. (This gun had been designed for both low angle and high angle fire). They had decided to replace the 37-mm gun of all Pzkw IIIs by a 50-mm gun, and, in accordance with their general policy of making the frontal armour of a tank capable of resisting its own gun at a given range, they had also decided to increase the armour of the Pzkw III and IV. The first German tank units which went to Libya in February 1941 included Pzkw IIIs armed with the 50-mm gun, although the British did not realize for some time that all the old 37-mm Kwk had been superseded. Pzkw IV was a support tank, mounting a short 75-mm gun which fired a high explosive shell. It was not of great consequence as regards penetration of armour, though it could cause damage to British tanks at long range—3,000 yards or more.
3. The German tank and anti-tank weapons which have to be taken into account in the fighting of 1941 include:
(i) 37-mm Pak 35/36.
(ii) 50-mm Pak 38, of 60 calibres.
(iii) 50-mm Kwk, of 42 calibres.
(iv) 88-mm Flak 36. This gun had been designed for both low angle and high angle fire, and as early as 1940 the Germans were designing models to supersede it. One of these later came into service as the 88-mm Flak 41; the other—in 1943—as the 88-mm Pak 43.
4. The process of replacing 37-mm Pak by 50-mm Pak is clearly shown by a few extracts from German records. On 10th February 1941 Panzerjäger Bn 39 of 5th Light Division had twelve 50-mm Pak out of a total of thirty-three guns. On 12th March Panzerjäger Bn 33 of 15th Panzer Division had eleven out of the same total. By 15th May the 5th Light Division had fifty 37-mm and thirty-six 50-mm Pak guns, and the 15th Panzer Division had thirty-nine 37-mm and eighteen 50-mm. This was roughly the position at the time of BATTLEAXE, but by September 1941 the Germans had 158 anti-tank guns of which 96 were 50-mm Pak 38.
5. Many factors affect the behaviour of a shell or shot on striking an armour plate, and it is impossible to give a simple and categorical answer to the question whether the projectile will or will not penetrate on the battlefield. Calculations and tests serve as guides, but in battle the conditions are so variable that, except in extreme cases, only broad forecasts can be made. The figures in the accompanying table will therefore give some idea of the relative expected performance—other things being equal—of the different weapons, but they cannot be taken as a definite forecast of how any projectile will behave. For example, it may fail to penetrate and yet cause damage.
The table shows clearly (a) the great power of the 88-mm Flak 36, (b) the similarity of the performance of the British 2-pdr tank gun and the 50-mm Kwk—except when the Pzgr 40 was being used at short range, and (c) the superiority of the 50-mm Pak 38 to the British 2-pdr anti-tank gun.
Table showing expected penetration in millimetres of homogeneous armour plate
|Weapon||37-mm Pak 35/36||50-mm Pak 38||50-mm Kwk||88-mm Flak 36||British 2-pdr tank and anti-tank gun|
|Weight of shot or shell||1½ lb Pzgr||¾ lb Pzgr 40||4½ lb Pzgr||1.9 lb Pzgr 40||4¾ lb Pzgr||1.9 lb Pzgr 40||21 lb||2.375 lb armour-piercing shot|
The above figures are for an angle of impact of 30° to the normal, simply as a basis for comparison. In battle the angle of impact may be anything from 0° to 90°. As a rough guide it may be taken that at short ranges the penetration of a shot striking normally to the surface would be about one and a quarter times that of the figure given for 30°. At 60° it would be rather less than half.
6. The monthly ammunition returns of the DAK show that only a small proportion of the ammunition for their anti-tank guns—roughly 13% at first—was of the Pzgr 40 type. It is worthy of note that they asked for a great deal more, but their demands were not met in full.
In this connexion an entry in the War Diary of 15th Panzer Division headed ‘Experience gained in the defensive battle of 15–17 June 1941’ is of interest: ‘... In order to achieve surprise, all anti-tank weapons will hold their fire until it seems likely to be successful. Even if the Flak 88-mm has successfully opened fire, Pak 37- and 50-mms will remain silent in order to escape the attention of enemy tanks. They will wait until the heaviest English tanks are only a few hundred metres away before opening fire with the Pzgr 40...’
As regards ammunition for tank guns, the 50-mm Kwk, with which Pzkw III was armed, was also supplied with a small proportion of Pzgr 40 shot.
7. The performance of a projectile against armour plate is only half the story. To compare the effectiveness of the tank and anti-tank guns on both sides it would be necessary to study the complete specification of the armour, which on any given tank varied in thickness and slope from place to place. Moreover armour plates differed in quality and hardness, and there were different systems of attaching and joining them. All these matters had an effect on the power of resistance to penetration and damage. It is therefore impossible to generalize, but a few broad comparisons may be made as a general indication of the vulnerability of the tanks on both sides. The most heavily armoured of all was the British Matilda, with 78 mm in front of the hull, almost as much round the turret, and 65 mm on the sides of the hull. The thickest armour on the older cruisers was 30 mm; on the Crusader I (or cruiser Mark VI) it was 40 mm in front of the turret; in Crusader II this became 50 mm.
The German Pzkw III used in France in 1940 had no more than 30 mm of armour anywhere. This was of machinable quality, not face-hardened. Before the end of the year reports of an increase in the armour on the front and turrets of German tanks were reaching England. In April 1941 details obtained from tanks captured in the Middle East showed that this increase had been achieved by bolting extra plates in front and rear. In the Pzkw III the extra plates (32 mm thick) on the front of the superstructure projected upwards to protect the turret joint and gave the front of the tank a total thickness of 62 mm. These extra plates were found to be face-hardened to such a degree that they could keep out a 2-pdr A.P. shot at any range except the closest. Unless a shot of this type succeeded in shattering the hardened face it scarcely made any impression on the inner armour.
This method of improving the protection was an interim measure, which could be carried out without seriously affecting the output from the factories. This was Model H. The next new Model, J, differed from Model H in several respects, and the armour was of 50-mm face-hardened plate. None of Model J reached Libya until the very end of 1941.
The extra plates on Model H were not easy to detect, and it is not known how many of the tanks in BATTLEAXE carried them. But the shipping lists show that hardly any German tanks reached Libya between the end of June and 19th December 1941, and as considerable numbers of tanks with extra plates were identified as having taken part in CRUSADER (November–December 1941)
it seems that many of them must have come over with 5th Light Division and 15th Panzer Division or very soon after.
Apart from these developments various alterations were made locally from time to time. But as the introduction of a new or altered model did not mean that the older tanks immediately disappeared, there were often several different types in use together. Adding this complication to the one already mentioned of the different natures of German tank and anti-tank gun ammunition, it is plainly impossible to assess accurately the technical odds in any particular encounter. At the time it was natural to generalize from the observed results, and the fact that these were often contradictory probably accounts for the wide divergence of opinion that has been recorded of the relative performance of the British and German weapons and armour.
8. Taking into account only the basic features of the guns and armour already set out, and disregarding such important matters as the manoeuvrability of the tank, its speed, its mechanical reliability, the rate of fire of its gun, and the state of training and morale of the crew, it can be said that, from the facts as now known, the position at the time of BATTLEAXE was briefly as follows. First, the Germans had a marked superiority in anti-tank guns. Secondly, many of their Pzkw IIIs (i.e. those that had the extra armour plates) had the advantage when opposed by British cruisers. Thirdly, in the Matilda the British had a tank which the Germans had good reason to respect—and they frequently said so. However, in the 88-mm Flak they had the means of dealing with this tank, although of these guns they had only a few.
Short particulars of some British and enemy tanks in use in 1941
|Type||Weight, tons||Crew||Main armament||Secondary armament||Thickest armour||Engine BHP||Max. speed on good road* m.p.h.||Remarks|
|Light Tank Mark VI||5½||3||one 0.5 inch m.g.||one .303 inch m.g.||14 mm||88||35|
|Cruiser Mark II||14||4||one 2-pdr||one .303 inch m.g.||30 mm||150||16||Close-support type had one 3.7 inch mortar instead of gun.|
|Cruiser Mark VI (Crusader I)||19||5||one 2-pdr||two 7.92 mm m.gs.||40 mm||340||26||Close-support type had one 3.7 inch howitzer instead of gun.|
|Matilda II||26½||4||one 2-pdr||one 7.92 mm m.g.||78 mm||175||15||ditto|
|Pzkw I Model B||5.7||2||two 7.92 mm m.gs.||..||15 mm||60||25||There was a modified version used as a Commander’s tank|
|Pzkw II model F||10||3||one 20 mm||one 7.92 mm m.g.||35 mm||140||30|
|Pzkw III model G||20||5||one 50 mm (short)||two 7.92 mm m.gs.||30 mm||320||24||In Model H the thickest armour was 30 plus 32 mm|
|Pzkw IV model D||19.7||5||one 75 mm (short)||two 7.92 mm m.gs.||30 mm||320||26||Close-support tank. In Model E the thickest armour was 30 plus 30 mm.|
|M 13/40||13½||4||one 47 mm||four 8 mm m.gs.||30 mm||105||19|
* The speed across country depends of course upon the surface, but would certainly be less than half the figures here given.