Wednesday 10 March 2021

Extra Protection

The tendency to increase armour protection was one of the most notable features of the German tank building school. No nation in the world increased protection without a radical change to the chassis. For instance, the Pz.Kpfw.III more than tripled the thickness of its front armour compared to its initial form. The Pz.Kpfw.IV set a record, quadrupling the thickness of the front hull compared to that of the B.W. This wasn't it, as the Germans still worked on improving protection of tanks that were already build. This article will cover those methods.

First wave of reinforcement

Such a significant increase in protection usually leads the general public to some conclusions that are not entirely correct. The increase in armour is not just a sign that the chassis had reserves to spare, but also that the tank's armour was insufficient to oppose methods used against it.

The design of the Zugführerwagen (future Pz.Kpfw.III) and Begleitwagen (future Pz.Kpfw.IV) began in 1934. At the time tanks still had bulletproof armour. The new German tanks had armour 14.5 mm thick, same as the light La.S. (Pz.Kpfw.I) and La.S.100 (Pz.Kpfw.II) tanks. This was no different than what other nations did.

In September of 1939 the Pz.Kpfw.II, one of the Wehrmacht's main tanks, had armour that could at best protect it from rifle caliber bullets. This armour was not a problem for Polish anti-tank rifles.

The situation changed in late 1938 when the first battles took place between German tanks and the Soviet T-26 in Spain. The Pz.Kpfw.I's machine guns could penetrate the T-26 only at point blank range with armour piercing bullets, whereas the T-26 had a 45 mm cannon that could defeat the German tank at any range. However, most nations misunderstood the lesson of the Spanish Civil War. The main enemies of the tank in that war weren't 37-45 mm cannons, but heavy machine guns and light autocannons. These systems penetrated 20-25 mm of armour, and many nations increased requirements to that level. Soviet A-20 and A-32 tanks had 25 mm of armour, American light tanks had first 22 and then 25 mm, the British increased the protection of their future tanks to 28 mm. The Germans raised their standards to 30 mm.

Medium tanks were also short on armour. The existence of Polish 37 mm anti-tank guns was an unpleasant surprise for the Germans.

This upgrade was not made to all German tanks. The Pz.Kpfw.II kept its old armour and no one thought of modernizing the Pz.Kpfw.I. The reason was simple. Not everyone understands what a tank really is. It's not just a tub on tracks with the thickest armour and biggest gun that fits. A tank is a fighting machine that operates at the limits of its capacity. It has to meet tactical-technical requirements that include mass, power to weight ratio, range, armament, ammo capacity, crew number, etc. Designers need to fit all this into a fighting machine and are often forced to make compromises. The resulting tank has some modernization potential, but make no mistake, this limit is very finite, especially in some parameters. When some parameters do not fit the requirements, these limits are reduced. Take for instance the Pz.Kpfw.I tank that was supposed to weigh 3 tons but ended up weighing 5.4 tons, prompting a redesign of the chassis and a new engine. The result was the Pz.Kpfw.I Ausf.B with a weight of 5.8 tons. There was no reserve for improving the armour. With the Pz.Kpfw.II the initial goal was a 6 ton tank, but the prototype weighed 7.6 tons and production tanks weighed 8.9 tons. MAN saw what was happening, redesigned the suspension, and added a more powerful engine, but at first there was also no attempt to improve the armour.

The first German tanks with applique armour turned up in France in May of 1940.

The situation with medium tanks was often simpler. The Pz.Kpfw.III had such bad armour to begin with that the tank had to be redesigned. The Z.W.38 had 30 mm of armour from the start. The Pz.Kpfw.IV increased in mass only by half a ton, plus the Pz.Kpfw.IV Ausf.B had a more powerful Maybach HL 120 TRM engine, thanks to which the power to weight ratio improved. The Pz.Kpfw.IV tank was also the only one that met weight requirements. However, everything was going well only on paper. The Red Army had its wake up call when it came to tanks protected from autocannons at Khalkin-Gol in 1939. The Germans had theirs a little later, on September 1st, 1939. The Germans ran into Polish anti-tank guns that dealt with 30 mm of armour without an issue. The sides of the Pz.Kpfw.IV tank were also too thin. One of Sergeant Orlik's victims was a Pz.Kpfw.IV tank. After the Polish campaign the Germans started to think about applique armour for their tanks.

Medium tanks did not get applique armour by the French campaign. The first instances of using spare tracks as armour were spotted in France.

Applique armour for the Pz.Kpfw.II was ready in the fall of 1939. Extra armour 15-20 mm thick was attached with bolts to the front of the turret and turret platform. The front hull received 20 mm thick spaced armour, also held on bolts. Sets of armour were sent to units in February of 1940, but they were produced quite slowly, and most tanks that fought in France didn't have it. This armour protected only from small caliber autocannons and obsolete guns. British 2-pounders and French 47 mm guns could penetrate this armour easily. However, the armour could not be made any thicker, as the tanks already weighed 9.5 tons. Also it's important to understand that applique armour is not the same as one solid plate.

Out of pre-war medium tanks only the Pz.Kpfw.IV received applique armour. There was little modernization reserve, and only the front hull was reinforced.

The situation with medium tanks was different. The Pz.Kpfw.III Ausf.A-D were not even considered, as they were hopeless. The Pz.Kpfw.IV and Pz.Kpfw.III Ausf.E-F were not initially considered either. Work on improving the armour of the Pz.Kpfw.IV Ausf.D began only in the spring of 1940. Krupp finished the first set of armour on May 15th, 1940. 20 mm of armour was added to the front of the hull, other places covered the center of the sides where the fighting compartment was. 30 mm thick armour was bolted to the front of the turret platform and 20 mm plates were bolted to the sides. The turret received no additional armour. The tank's mass increased to 20 tons even without it. Installation of applique armour began on June 25th, after the fighting in France ended.

Applique armour of the Pz.Kpfw.III Ausf.G and H tanks.

Theoretically this made the front hull impenetrable to 25-40 mm guns. However, this armour was more suitable for the September 1939 campaign. The French had some SA Mle.1937 anti-tank guns that had no problems with this armour, plus medium and "battle" tanks had 47 mm cannons that might have been somewhat weaker than the towed versions, but also had no problems with the German applique armour. The Germans well understood that applique armour was not the same as a monolithic plate, plus the armour remained unprotected. Starting with July of 1940 the Pz.Kpfw.IV Ausf.E had improved armour. The front hull and turret were 50 mm thick without applique armour. The weight of the tank grew to 22 tons, close to the chassis' limit.

The applique armour theoretically made the tank immune to 37-45 mm guns.

While the Armaments Department thought about improving the thickness of armour, the army acted on its own. The French campaign was the first where spare track links were carried on tanks en masse. The discovery that this works as additional armour was an accident. Likely someone had a positive experience and distributed the idea among the tank forces.

The applique armour installed on the Pz.Kpfw.III Ausf.E-F was different, as the driver's observation device had a different design. As a result, the armour was installed with a gap from the main armour.

This solution had its merits. It was tested in 1944 at the NIBT proving grounds on a T-34 tank. Trials showed that spare tracks have no effect at medium distances (500-600 m), but at a range of 1000 meters and out the minimum distance of penetration decreased by 200 meters. These trials were conducted with the 75 mm Pak 40, while calibers in use in 1940 were smaller. Of course, this was not a complete solution, but it was a field expedient one.

Extra weight was a big drawback. Installing applique armour and a new gun raised the weight of the tank by two tons.

Mass applique armour installation on the Pz.Kpfw.III began in December of 1940. By then the early Pz.Kpfw.IV received partial applique armour on their front hull. The Pz.Kpfw.III received 30 mm of armour on the front hull, front turret platform, and upper rear hull. The methods of installation were different, for instance the Pz.Kpfw.III Ausf.E-F had spaced armour but the Pz.Kpfw.III Ausf.G-H had the applique armour right up against the main plate. The cost for this armour was weight. The front plates weighed 555 kg, and that's not including the bolts. The applique armour was introduced alongside the 50 mm KwK 38 L/42. The tank's weight increased from 19.5 to 21.5 tons. The suspension had to be changes as a result. The torsion bars and shock absorbers were reinforced and 400 mm wide track links were introduced.

Trials showed that the applique armour could weather 5-7 hits from 37-45 mm guns. After that, the bolts fell apart.

Theoretically, the 60 mm thick composite hull guaranteed protection from 40-45 mm guns. In reality, this was not the case. As mentioned above, applique armour is not the same as a thicker monolithic plate. For instance, trials held at the NIBT proving grounds in October of 1942 showed that after 4 hits (2 from a 2-pounder and 2 from a 45 mm gun) the bolts holding the applique armour burst and it fell off. The applique armour was not very long lived.

The Pz.Kpfw.IV Ausf.E with a full set of applique armour.

There were some benefits from applique armour, especially in North Africa where the British had only 40 mm anti-tank guns. However, this was armour suitable for 1940 at best.

Composite applique armour was not a good idea. Only a few hits were enough to destroy it.

Interestingly enough, the front hull armour of the Pz.Kpfw.III and Pz.Kpfw.IV was increased, but not their turrets, even though the turret is a priority target for tank and anti-tank gunners. It was logical to improve the protection of the turret with applique armour. The British did this with the Cruiser Tank Mk.IV, the Soviets did it with the T-34 and KV-1, but not the Germans. The Pz.Kpfw.IV Ausf.E had thicker turret armour, but the late Pz.Kpfw.III Ausf.G and H still had just 30 mm. Only the Pz.Kpfw.III Ausf.J had 50 mm thick front turret armour, but no applique armour. The only known example of turret applique armour was the Vorpanzer kit installed on the Pz.Kpfw.IV Ausf.D, E, and F. These massive plates were not common. Officially, this kind of armour was forbidden.

The Vorpanzer was one of the few cases where additional armour was installed on the turret. This solution overloaded the tank and was not well received.

The explanation for this odd situation is the chassis. As said above, the total weight of the additional armour for the Pz.Kpfw.III was a ton and a half, and it mostly stressed the front road wheels. The front turret armour would have put another 200-250 kg of load on the front road wheels. Nothing good could have come from this increase.

At the limits of the chassis

The invasion of the USSR on June 22nd, 1941, brought many unpleasant surprises. German losses may not have been great in June, but increased drastically in July. The Wehrmacht's tank forces were still chiefly made up of tanks built in 1939-1940. Although some of them went through modernization and had applique armour, not all tanks had it. The issue was partially solved using spare track links. It was clear that the actions taken to reinforce the armour were insufficient.

German tanks were quickly covered in garlands of spare track segments.

Practice showed that the Red Army fought German tanks with all manner of artillery. Typically anti-tank artillery was used against tanks, but in a pinch battalion, divisional, and even corps level artillery was used. The same tendency could be seen on the German side. It was clear that applique armour and 50 mm of main armour were not enough. At the moment it was not enemy tanks, but artillery, that was the tank's main enemy. Meanwhile, German generals began to spot KV-1 and T-34 tanks, which slowly became the main types of Soviet tanks. The armour of German tanks was no challenge for their 76 mm guns.

50 mm of armour used on the Pz.Kpfw.III Ausf.J and Pz.Kpfw.IV Ausf.F was insufficient against 76 mm guns.

This situation was unsatisfactory for German tankers. Armour was supplemented with spare track links in the summer of 1941. The most common installation was in front of the front hull armour. More advanced layouts included augmenting the turret platform front. Nobody thought about how much this increased the tank's mass.

Spaced armour used on the Pz.Kpfw.III.

The Germans thought of further increases in armour in the summer of 1941. This was not caused by Operation Barbarossa, but by combat in North Africa where the British were expected to use more and more powerful anti-tank guns. The idea of another wave of applique armour was first voiced on July 7th, 1941. This time Hitler initiated the conversation, suggesting spaced armour for the Pz.Kpfw.III Ausf.J. It would be installed at a distance of 100 mm in front of the main armour. This allowed the plate to be made thinner, just 20 mm. The plate weighed 110 kg compared to a 155 kg 30 mm plate. Like before, it was held on with bolts.

The reserve of the chassis was enough to install spaced armour on the turret and turret platform front. The front hull did not receive additional protection.

Work on the new applique armour dragged on. Meanwhile, experience on the Soviet-German front showed that the main enemies of tanks were 76 mm guns with the ballistics of the USV divisional gun. The USV could penetrate 70-72 mm of armour. The spaced armour would be able to protect against this gun, but it was only put into production in late spring of 1942. This armour covered the front of the turret platform and turret. The plates weighed 250-300 kg: less than applique armour used on older tanks. However, the front hull did not receive additional protection and remained at 50 mm. THe Pz.Kpfw.III Ausf.J already weighed 21.6 tons, and it was close to 22 tons with the extra armour. Another half a ton came thanks to the 50 mm KwK 38 L/60 gun. This brought the tank's weight to its limit, not to mention that the extra 900 kg of mass was loading the front road wheels.  

Note that the applique armour did not really help this tank.

The Pz.Kpfw.IV went through a similar process, but it was somewhat different. The additional armour was 30 mm thick, not 20. Additionally, it was not spaced. The applique armour was either bolted or welded on right up against the main armour. Third, the layout was different. The extra armour was applied to the front of the hull and turret platform. There was no reserve left for the turret front, as the applique armour was first installed in May of 1942, when the Pz.Kpfw.IV with long guns was already in production. The mass grew from 22.3 to 23.6 tons. Later, on the Pz.Kpfw.IV Ausf.H, the armour was produced from 80 mm thick plates rather than with applique armour. The Pz.Kpfw.IV's reserves were depleted.

The Pz.Kpfw.IV's front hull and turret platform were reinforced. There was not enough modernization reserve to improve the turret armour.

There was a third vehicle that received applique armour in 1942. This was the StuG III assault gun. Like the Pz.Kpfw.IV, it had the potential to receive long 75 mm guns and also thicker armour. 30 mm thick plates were welded on to the front hull and casemate of the StuG 40 Ausf.F (that was the name given to the vehicle after the 7.5 cm StuK 40 was installed). The total thickness of the armour was 80 mm.

Applique armour used on the StuG 40 Ausf.F.

The most numerous vehicle of the series, the StuG 40 Ausf.G, also had applique armour. Instead of welding, they were bolted on. The front of the hull was made from 80 mm thick plates starting in the fall of 1943, but the applique armour near the driver's visor remained until the end of production. Cement was also often applied to the front of the casemate tha acted as extra protection.

Early StuG 40 Ausf.G vehicles had bolted on applique armour.

Soviet reports on "second wave" German applique armour are interesting. A report made in 1943 claims that the Pz.Kpfw.III's spaced armour offers complete protection against 76 mm AP and HEAT shells. The same conclusion was made with the StuG 40, but this armour was not as reliable as one might think. Hits from 75-76 mm shells destroyed the plate and its attachments. 2-3 hits were enough to fully destroy the applique armour.

A StuH 42 with applique armour.

Starting with the second half of 1942 when the main Soviet tank was the T-34 and American tanks with 75 mm guns appeared in North Africa, the applique armour was at most a chance to return fire. The tanks also slowly lost mobility and suspension life. These factors were the cause of cancellation of applique armour for T-34 tanks in late February of 1942. The Germans went in a different direction, which led to both positive and negative results.

Trials showed that the applique armour was not enough to save even from the 45 mm gun. 30+50 mm of armour were penetrated by subcaliber shot.

Trials held in September of 1943 at the NIBT proving grounds showed the mixed effectiveness of the applique armour. A StuG 40 Ausf.G with applique armour on the front hull and casemate was delivered for trials. The 45 mm gun was used first. The AP shell could not penetrate the front hull, but the APCR shot could. This could be done at only a minimal range (150 m), but also showed that calculations claiming that the armour was enough to offer complete protection were incorrect.

Destruction of the applique armour from two hits with 57 mm shot.

The results of shooting the StuG with a British 57 mm tank gun were no less interesting. The armour was not penetrated at 300 meters and only a 7-8 mm deep dent was formed. The second shot broke off a potion of the applique armour and six bolts that held it on. Larger caliber guns were not used, but it is unlikely that the plate would have held more than 3-5 hits from 75-76 mm guns.

Covering the sides

As you probably noticed, the Germans increased the protection of their tanks mainly by thickening the front of the hull and turret. This process can be observed in other nations' tank building schools as well. Variable armour became standard and quite pronounced by the end of WWII. However, the Germans and others also missed a radical improvement in infantry anti-tank weapons, namely anti-tank rifles.

A Pz.Kpfw.III Ausf.N tank with skirt armour. 

At the start of WWII, the Germans considered 30 mm of side armour to be enough. This was indeed enough to resist armour piercing rifle bullets and light autocannons. However, infantry often had more anti-tank weapons than expected, and tanks were often taken out from the sides. The speed of the Polish and French campaigns did not permit for a thorough analysis of the situation, nor did the first few months of the Great Patriotic War offer enough information.

Skirt armour was installed on early production tanks, for instance this Pz.Kpfw.III Ausf.G. This photo shows the drawback of skirt armour: only the commander can see side to side.

The situation started to change in early 1942 when the use of PTRD and PTRS anti-tank rifles became widespread. These rifles could easily penetrate 30 mm of armour. The PTRD and PTRS couldn't penetrate the latest German medium tanks in the front, but ideal tank battles where tanks only take hits to the front armour do not exist. Anti-tank rifles were much more mobile than anti-tank cannons, and so concentrated fire at flanks was quite common. This wasn't the case just for German tanks, according to a report on survivability of the T-34 prepared by NII-48 in 1942, more than half of all hits came from the sides. This is a big number even if you consider the observation qualities of Soviet medium and heavy tanks. Interestingly enough, this is when the observation of German tanks started to get poorer, partially due to the use of anti-tank rifles. Observation ports in the sides of the hull and turret were easy targets, and so they were removed. This improved the protection offered by the armour, but increased the chances of being unexpectedly hit from the side. Soviet anti-tank rifles could penetrate their side armour from 300-500 meters, quite a common engagement distance.

Skirt armour on the Pz.Kpfw.IV Ausf.H. They were also installed on earlier models.

Anti-tank rifles reached peak production in 1942. This kind of mass adoption could not go unanswered. Even if anti-tank rifles couldn't penetrate the tank's armour, they still dealt major damage to the running gear and could immobilize the tank. Development of a countermeasure was imperative by early 1943. Similar looking spaced armour was developed for the Pz.Kpfw.III and Pz.Kpfw.IV. A complex system of rails was attached to the side of the hull and fenders. 5 mm thick plates were attached to these rails. 10 mm thick plates with doors opposite the tank's turret hatches were installed on the turret. Skirt armour was also developed for the StuG 40 Ausf. G.

A StuG 40 Ausf.G with skirt armour. This armour was also used on other vehicles on the Pz.Kpfw.III and Pz.Kpfw.IV chassis.

Trials were held on February 20th, 1943. It turned out that the PTRD could penetrate the skirt armour from 100 meters, but only a dent was made on the main armour. Orders were given to install skirt armour on tanks and StuG assault guns. They were installed on newly produced tanks starting in April of 1943. Kits for retrofitting early production tanks were also produced. Vehicles with this armour were issued starting in May of 1943 and were first used en masse at Kursk.

Trials held in September of 1943 showed that the skirt armour protects from anti-tank rifles, HE and HEAT shells, and anti-tank grenades.

This novelty was not ignored by the GBTU. A StuG 40 Ausf.G and Pz.Kpfw.III Ausf.N with the skirt armour arrived at the NIBT proving grounds by September of 1943. Trials were held with the 20 mm RES anti-tank rifle. The range of penetration was reduced to just 100 meters. The 14.5 mm Blum anti-tank rifle could not penetrated the main armour at all if skirts were present.

The skirt armour was not an obstacle for anti-tank cannons.

Larger calibers showed a different result. 45 mm AP penetrated the side of the StuG 40 with skirt armour from 900 meters. The range of penetration with APCR shot was reduced to 600 meters. The 6-pounder gun could penetrate it from 900 meters, and that was not the limit. The penetration was not affected by the skirt armour. The same thing happened with armour piercing shells fired from the 75 mm M3 gun and 76 mm F-34 gun.

The best the skirt armour could do was slightly reduce the range of penetration, most noticeably against APCR shot.

There was another interesting effect that the skirt armour's creators did not anticipate. The plates protected against HE and HEAT ammunition. The shells destroyed the skirt armour plate but the damage to the main armour was insignificant.

Many tankers took off the side armour since it impeded the tank's mobility on rough terrain.

Like many technical novelties, at first the skirt armour was introduced on as many tanks and SPGs as possible. However, by the end of 1943 in many cases the skirts were either not installed at all or only installed partially. There were good reasons for this. One was that the skirts resulted in additional load for the chassis. For instance, the mass of the Pz.Kpfw.IV Ausf.H increased to 25 tons. Second, the already declining visibility dropped even more. Only the commander of the tank could look sideways. Finally, the skirt armour had a tendency to snag on terrain, trees, and other obstacles and then tear off. As a result, it was preemptively removed.

The mesh armour was about as effective as the solid armour, but much lighter.

Naturally, the skirt armour was constantly improved. Improved skirt armour with new mounting rails and plates installed at an angle was introduced in the fall of 1943. Mesh armour was introduced in the fall of 1944. They worked no worse than solid plates, but they were much lighter. However, the issues with the design were never resolved, and some units experimented with their own skirt armour of lesser size or installed at different angles.

A StuG 40 Ausf.G with skirt armour installed at an angle.

It's interesting to explore the situation with skirt armour on German tanks after the war. These tanks were used by many nations for many years, but the skirt armour was removed. The whole idea was treated with skepticism. The USSR experimented with German style spaced armour, but no more than that. The only other nation who made use of skirt armour were the British, which is not surprising, as they experimented with skirts for a long time. However, the skirt armour used on the Centurion was different, simpler, and much lighter than what the Germans used.

A questionable paste

In conclusion, let us raise the issue of another protection method characteristic of the Germans. This was Zimmerit: a special paste used en masse starting in the fall of 1943. Discussions on why this was necessary continue to this day and many nations had their own interpretations of what it was used for. This also applies to the USSR, which initially made the wrong conclusions on why Zimmerit was applied.

Field applied Zimmerit coating. Having analyzed what was happening, the Germans decided to apply it at the factory.

In March of 1943 the 6th Department of the Armaments Directorate initiated the development of a special paste that would be applied to tanks and SPGs. There were two requirements in the tender: resistance to fire and good coverage. There are different opinions on why this was done. Various theories are voiced, up to the claim that it helped the armour resist penetration. In reality even a 1947 report by the Ministry of Transport Machinebuilding gives the correct reason: protection from magnetic grenades and mines. The issue is that the development was purely preventative. 

Typical application of Zimmerit.

A number of companies took part in the tender, but victory went to Chemische Werke Zimmer & Co from Berlin. This company had a wealth of experience with similar coatings for industrial applications. The coating, named Zimmerit, was composed of five main components including barium sulfate, zinc sulfate, and sawdust. The result was a paste that could be easily applied with a putty knife. The theory was that it would be applied to vertical surfaces to impede attachment of magnetic mines. The paste couldn't prevent the magnet from attaching completely, but it would have made the enemy's life more difficult.

Even the factory applied Zimmerit incorrectly. For instance, applying it to the skirt armour just made it heavier.

The initial plan was to send Zimmerit to the units that would then apply it. This was also done with the skirt armour, where field workshops would install it. Skirt armour is one thing, and paste is another. The results of trials held by the 4th and 7th Tank Divisions in the summer of 1943 showed that effectiveness was low. Practice showed that crews slapped Zimmerit on any which way, putting too much in some places and too little in others. It was also commonly applied in places where it wasn't necessary.

Zimmerit was applied to places like the turret platform roof. It's hard to believe that an enemy soldier would climb up there with a magnetic mine.

As a result it was decided that Zimmerit would be applied directly at the factory. In September-October of 1943 it was applied to all medium and heavy tanks as well as the StuG. A process of applying Zimmerit was also developed. The first layer was divided into squares with a putty knife. After a day, a second textured layer was applied. This wavy texture reduced the effectiveness of magnets.

The Zimmerit pattern could vary between factories.

In theory, instructions for each factory were the same. In practice, the application was not identical. Each factory's application was different and the differences were sometimes quite pronounced. Barrels of Zimmerit still made it to the front lines, and at that point it was up to each individual commander's discretion. Zimmerit was applied to vehicles where it made no sense, like halftracks. The practice of applying Zimmerit to surfaces where it was useless continued.

A full set of protection: Zimmerit, skirt armour, track armour.

The USSR noticed that Zimmerit appeared on tanks in late 1943. In March of 1943 Zimmerit samples were studied by the NIIKS (Scientific Research Institute of Cinema Construction). They managed to correctly identify the composition of the paste, but incorrectly guess the temperature at which it melted (1100 C), as a result of which they assumed it was applied to protect the tank from incendiary fluids. The GBTU made the same conclusion, even though German POWs revealed the real reason for the application of Zimmerit. As mentioned above, the Red Army did not use magnetic mines, so the GBTU suspected there was another reason.

British experiments with Zimmerit.

The Germans stopped applying Zimmerit in September of 1944 as nobody used magnetic mines against their tanks and SPGs. Enemy infantry had much more effective means of combating tanks. As for using analogues of Zimmerit, the British got the furthest, but still did not progress past frontline improvisations and experimental work.

1 comment:

  1. A fascinating read, thank you. Small <> in para 4, though:

    'Soviet A-20 and A-32 tanks had 25 mm of armour, American light tanks had first <<22 and then 22>> mm, the British increased the protection of their future tanks to 28 mm.'