PzKpfw III

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From 1935 onwards the collective knowledge gained during the design and development of the PzKpfw I and PzKpfw II tanks enabled the German tank-building industry to produce its own design ideas. The PanzerKampfwagen III was planned from the beginning as the standard medium battle tank of the German armored formations. It was to be equipped with an armor-piercing gun, as well as bow and turret machine-guns, while the PzKpfw IV was to have a large-caliber low velocity gun and be used as a support vehicle. The PzKpfw III was intended to equip three of the panzer battalion's four companies, with the PzKpfw IV as the equipment of the fourth or heavy company.

Senior tank officers like General Guderian preferred to arm the first versions of the PzKpfw III with a 50mm gun, a sensible provision at a time when the British were beginning to fit a 40mm gun into their Cruiser tank series and the Russians were employing a 45mm gun in their BTs and T-26s. However the Ordnance Department objected, pointing out that the infantry was already in possesion of the 37mm anti-tank gun, which was in production, and the convenience of standardization. The PzKpfw III was therefore armed with a short barrel 37mm gun, but it proved to be a blessing in the later years that the size of the turret had been designed large enough, which allowed to mount a 50mm gun without major structural modifications.


Ausf. A pre-serie vehicle from Daimler-Benz	PzKpfw III Ausf. D with 8-wheel running gear during the Polish campaign in 1939

The first development contracts for the so-called 'medium tractor' or Zugkraftwagen (platoon leader's vehicle) were issued in 1934 to the firms Daimler-Benz, MAN, Rheinmetall-Borsig and Krupp, requiring a 15-ton armored vehicle. The two largest motor car firms in Germany, Ford and Opel, were deliberately excluded from the tank programme because of their American ownership. The drive sprockets were to be in the front, with the advantage of the self-cleaning of the tracks before they reached the drive sprockets, and short steering lines. The first prototypes appeared in 1935, and Daimler-Benz was contracted for series productions. Their vehicle, the PzKpfw III Ausf. A, had five road wheels, sprung by coil springs, and two return rollers. Armor was between 5 and 14.5mm thick and the overall weight was 15 tons. A total of 150 rounds was carried for the 37mm main gun and 4500 rounds for the three machine-guns, two of which were co-axial to the main armament, in the turret.


A PzKpfw III Ausf. F with 50mm KwK in North Africa	A dirty PzKpfw III armed with a 50mm gun

Later test series were fitted with eight road wheels, which were mounted in pairs sprung by a longitudinal leaf spring (Ausf. B-D), and return rollers were increased to three. All had troubles with the suspension. Ausf. D had increased armor to 30mm all round, raising the total weight to about 19 tons. The question of German road bridge limitations determined that the maximum permissible fighting weight of the PzKpfw III be 24 tons. Fifty-five examples of this version were produced. The crew consisted of five men: commander, gun layer and loader in the turret, and driver and wireless operator in the forward compartment. The commander had a raised seat, between the aimer's and loader's places in mid-turret, with his own cupola, allowing an all-round view. Throat microphones were to be used for communication among the crew members and also for the radio link from tank to tank, while on the move. The PzKpfw III underwent its baptism of fire in Poland and proved well despite the low numbers available. All the pre-production machines (Ausf. A-D) were used in the campaign if in only nominal numbers; nevertheless valuable combat experience was gained.


PzKpfw III Ausf. E crossing a bridge	PzKpfw III Ausf. J with the 50mm KwK 39 L/60 gun

The final (test) production vehicle (Ausf. E) appeared in late 1939, and were in service by spring 1940. There were now three return rollers and six road wheels, sprung on transverse torsion bars. Each road wheel turned on an axle that was pressed into a swinging arm mounted to the hull. A torsion bar spring contacted the swinging arm, while the other end was held on the opposite side of the hull. The upward movement was limited by rubber contact blocks. The coupled machine-guns (MG34s) in the turret were replaced with a single machine-gun. By early 1940 one hundred of these machines had been built and they were rushed into service to provide the main hitting power of the panzer divisions.

On 10 May 1940, only 349 PzKpfw IIIs of all kinds were available for operations in France and Flandern. The few suitable tanks available to the British Expeditionary Force, as well as the French battle tanks, were more than a match for the PzKpfw III. This was demonstrated when the British Matilda's counter-attacked Rommel's panzers at Arras on 21 May 1940. Rommel lost three PzKpfw III's and six PzKpfw IV's, while the British reported that one Matilda took as many as 14 hits from 37mm guns with only the slightest damage of the armor plates. Though lacking speed and size, the invincibility of the well armored Matilda showed the desirements for better German tanks in the future. Hitler ordered the following versions of the PzKpfw III to be up-armored by fitting spaced armor plates, despite loss of speed and an increase in weight.


Panzer III Ausf. F were prepared for Operation 'Sealion'...	...and were used to cross the river Bug in 1941

After the French campaign in 1940, 54 PzKpfw III were adapted for crossing water, which should be used in Operation Seelöwe (the invasion of England). All exterior openings of the vehicle were sealed with a water-tight compound, and the gap between the hull and turret was closed by an inflatable rubber ring. Rubber sheeting covered the commander's cupola, the mantlet and the hull machine-gun, but this could be blown away from inside the vehicle by means of an electrical detonator. Air was supplied to the engine by a flexible 18-metre long hose (200mm in diameter), which was held on the surface by a buoy, exhaust gases being carried upwards through two tall vertical pipes fitted with non-return valves. Maximum safe diving depth of the Tauchpanzer was 15 metres.

These 'diving tanks' were intended to be deployed from freight barges, and a command boat should provide course directions. These vehicles were used later in Russia to cross the many rivers which were delaying obstacles for the panzers. Instead of the rubber snorkel, the tanks were fitted with a 3.5 meter steel pipe as an air intake. On June 22, 1941, these vehicles crossed the Bug underwater, with no need for the building of bridges for the surprise attack.

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