Anti-tank warfare refers to military strategies, tactics and weapon systems designed to counter and destroy armoured vehicles such as tanks. Originating from the first deployment of tanks in 1916, it has since become a fundamental component of wartime strategy and doctrine. Across the 20th century, anti-tank warfare has rapidly evolved, from anti-tank guns to guided missiles and in more modern times, improvised explosive devices (IEDs), drones and loitering munitions.
Tank threat Anti-tank warfare evolved as a countermeasure to the threat of the tank's appearance on the battlefields of the Western Front of the First World War. The tank had been developed to negate the German system of trenches, and allow a return to maneuver against enemy's flanks and to attack the rear with cavalry.
The use of the tank was mainly based on the assumption that, once they were able to eliminate the German trench lines with their machine gun and infantry support gun positions, the Allied infantry would follow and secure the breach, and the cavalry would exploit the breach in the trench lines by attacking into the depth of German-held territory, eventually capturing the field artillery positions and interdicting logistics and reserves being brought up from the rear areas. Naval crews initially used to operate the installed naval guns and machine guns were replaced with Army personnel who were more aware of the infantry tactics with which the tanks were intended to cooperate. However, there was no means of communication between the tank's crew and the accompanying infantry, or between the tanks participating in combat. Radios were not yet portable or robust enough to be mounted in a tank, although Morse Code transmitters were installed in some Mark IVs at Cambrai as messaging vehicles.Macksey, K., Tank vs Tank, Grub Street, London, 1999, p.32 Attaching a field telephone to the rear would become a practice only during the next war. With greater use of tanks by both sides, it was realized that the accompanying infantry could be forced to ground by ambush fire, thus separating them from the tanks, which would continue to advance, eventually finding themselves exposed to close-assaults by German infantry and sappers.
The early tanks were mechanically rudimentary. The thick armor generally prevented penetration by small arms fire and shell fragments. However, even a near miss from field artillery or an impact from a mortar could easily disable or destroy the tank: if the fuel tank were ruptured, it could incinerate the tank's crew. A large-caliber gun was recognized as a tactical necessity for attacking machine-gun positions and defeating any infantry field pieces found in the trench lines, which could easily disable tank track with HE ammunition. This was achieved by mounting a 57 mm QF 6 pounder Hotchkiss light naval gun in the hull barbettes. Hull and track engineering was largely dictated by the terrain—the need to cross wide trenches—although the relationship between ground pressure and soil-vehicle mechanics was not resolved until the Second World War. Turrets were later introduced on medium and light tanks to react to ambushes during the advance.
First World War The tank, when it appeared on the Western Front in September 1916, was a surprise to German troops, but not the German General Staff. The French Army Staff was highly critical of the British Army's early fielding of the Mark I tanks in small numbers, as French trials had shown the armored vehicles to be highly unreliable. They judged that large numbers had to be employed to sustain an offensive despite losses to mechanical failure or vehicles foundering in intractable no man's land terrain. These losses, coupled with those from enemy artillery fire, later amounted to as high as 70% of the starters during some operations. Deploying small numbers of tanks would therefore cause the Allies to lose the element of surprise, allowing the Germans to develop countermeasures.
Anti-tank weapons Because the German Army was the only force in need of anti-tank weapons, it was the first to develop viable technology to combat armored vehicles. These technologies took three ammunition approaches: use of grenades by infantrymen, including the Geballte Ladung ("Bundled Charge") of several stick grenades bound together by pioneers; early attempts at the small-caliber anti-tank rifles like the bolt-action 13 mm Mauser 1918 T-Gewehr; 3.7 cm TaK Rheinmetall in starrer Räder-lafette 1916 anti-tank gun on a light carriage which could destroy a tankJohn Norris, Anti-tank weapons, p.7 using large-caliber armor-piercing ammunition issued in 1917 to special commands; and the existing 77 mm field guns (such as the 7.7 cm FK 16) of the infantry division's artillery regiment were also eventually issued with special armor-piercing (AP) ammunition.
Anti-tank tactics With the appearance of Allied tanks, the German Army quickly introduced new anti-tank defense detachments within the pioneer battalions of the infantry divisions. These were initially issued as 13 mm-caliber, long-barreled rifles firing solid shot. However, these suffered from fouling after 2–3 rounds and had a recoil that was unsustainable by the mechanism or the rifleman. Stick grenades were used to destroy the tracks by individual pioneers; this required accompanying machine-gunners to first separate the supporting Allied infantry line from the tanks, a task that proved difficult. Another tactic was to lure the tank beyond the German trench line, then re-establish it just as the Allied infantry approached. The divisional 7.7 cm guns brought forward would then engage the tank, attempting to disable its tracks with standard HE shells (and later AP ammunition). If the crews of the disabled tanks refused to surrender, they were engaged with flamethrowers, or a mortar would be fired on the stricken vehicle until a direct hit was achieved on the top surface, usually resulting in an internal fire. Finally, anti-tank obstacles were prepared on the likely approaches by deepening and widening existing ground cratering, the precursors of the anti-tank trench. Finally, in early 1917, the 3.7 cm TaK from Rheinmetall was rushed to the frontline and proved effective at destroying tanks despite its limited elevation and traverse.
Development between the world wars
The lack of consensus on the tank's design and use after the First World War also influenced the development of anti-tank countermeasures. However, because Germany was restricted by the Treaty of Versailles in its military capability, and there were no other challenges to France and Britain, very little development took place in anti-tank warfare until the 1930s.
The Interwar period was dominated by strategic thinking with fortified borders at its core. These included obstacles consisting of natural features such as ditches, streams and urban areas, or constructed obstacles such as anti-tank ditches, minefields, dragon's teeth, or log barriers. The pinnacle of this strategic thinking was considered to be the Maginot Line which replaced infantry-filled trenches with artillery-filled bunkers, including casemates housing 37 or 47 mm anti-tank guns, and steel turrets armed with a pair of machine guns and a 25 mm anti-tank gun, although Germany was forbidden to produce tanks. The construction was partially based on the Allied experience with the Hindenburg Line, which was breached with tank support during the battles of Cambrai and St. Quentin Canal, although German Command was more impressed by the surprise achieved by the Canadian troops at the Battle of the Canal du Nord. This influenced their planning in 1940.
The Maginot line defenses – up to deep from the forward positions to the rear line – were intended to prevent a surprise attack and delay any attack while the French Army was mobilized. Given the relative numerical inferiority of France compared to Germany, it was a more effective use of human resources. Within the line, passive anti-tank obstacles were supported by anti-infantry and anti-tank bunkers. After Belgium declared neutrality in 1936, France began work on extending the line along the Belgian border.
Improved artillery was seen as the quickest solution to anti-tank defense, and one of the earliest post-war designs was the French 25 mm Hotchkiss anti-tank gun. It was intended to replace an Atelier de Puteaux 37 mm weapon designed in 1916 to destroy machine gun positions. Rheinmetall commenced design of a 37 mm anti-tank gun in 1924 and the first guns were produced in 1928 as 3.7 cm Pak L/45,Terry Gander and Peter Chamberlain, Small Arms, Artillery and Special Weapons of the Third Reich, MacDonald and Janes, London, 1978, p.107 later adopted in Wehrmacht service as 3.7 cm Pak 36. It made an appearance during the Spanish Civil War, as did the Bofors 37 mm developed in Sweden, and used by many early Second World War combatants. The British Army accepted for service the (40 mm) Ordnance QF 2 pounder, which was developed as a tank gun. The Soviet Red Army after the Russian Civil War also begun a search for an anti-tank gun with a French Hotchkiss 37 mm L.33 tank gun, but soon upgraded this to a higher velocity L.45 Model 1935 while also making a licensed copy of the German 3.7 cm PaK 36. However, the Red Army was taught a lesson in anti-tank warfare almost immediately when a tank battalion sent to aid the Spanish Republicans in the Spanish Civil War was almost destroyed in an engagement.
At this time, the predominant ammunition used against tanks was the armor-piercing kinetic energy shell that defeated armor by direct pressure, spiking or punching through it. During the late 1930s, shaped charge ammunition was experimented with, using chemical energy to penetrate armor. The shaped charge concept is officially known as the "Munroe Effect" and was discovered by accident decades earlier by Professor Charles E. Munroe at the U.S. Torpedo Station, Providence, RI. Professor Munroe was detonating different manufactured blocks of explosives on a sheet of armor plating and observed the blocks having the manufacturing
letters recessed (vs. raised) cut an imprint of the manufacturing letters into the armor plate—the birth of the shaped-charged explosive, which focuses the blast energy caused by an indentation on the surface area of an explosive.Dr. J.R. Crittenden, "RPG-The Devil's Finger", Shotgun News, Nov. 20, 2003, P.30. Although shaped charges are somewhat more difficult to manufacture, the advantage is that the projectile does not require as high velocity as typical kinetic energy shells, yet on impact it creates a high-velocity jet of metal flowing like a liquid due to the immense pressure (though x-ray diffraction has shown the metal stays solidJOURNAL OF BATTLEFIELD TECHNOLOGY, VOL 1, NO 1, MARCH 1998, SOME METALLURGICAL ASPECTS OF SHAPED CHARGE LINERS, Alistair Doig, p.1.) which hydrodynamically penetrates the armor, killing occupants inside.Chant, Christoper, How Weapons Work, Marshal Cavendish, Ltd,, Hong Kong, 1980, p.50. The depth of the penetration, though proportional to the length of the jet and the square root of its density, is also dependent on the strength of the armor. With the development of this new ammunition, more advanced research into steel manufacturing began, and the development of spaced armor caused "jet waver" by detonating prematurely or at the wrong angle to the surface of the main armor.
The only significant attempt to experiment with the use of tanks in the late 1920s was the British Army's Experimental Mechanized Force, which influenced the future development of tanks, armored troops, and entire armies of both its future enemies and allies in the next war.