Panzerkampfwagen III

When Germany began secretly rebuilding its armoured force in the 1930s, doctrine called for two complementary medium tanks: a gun-armed vehicle to fight enemy tanks, and a heavier support tank firing high-explosive. The first of these became the Panzerkampfwagen III, designed under Daimler-Benz from 1936 and intended as the standard battle tank of the Panzer divisions.

Crucially, the design was laid out around a five-man crew — commander, gunner, loader, driver and radio-operator/hull gunner — with the commander in a dedicated cupola, free to observe rather than serve the gun. This division of labour, rare among contemporaries, gave German tanks a decisive edge in command and gunnery efficiency, and the layout became the template every modern tank would follow.

Early production models (Ausf. A–F) carried a 37 mm KwK 36 L/46.5 gun and only 15–30 mm of armour. Combat in Poland and France showed both to be marginal, and the design was rapidly improved: armour on the Ausf. F–J was thickened to 30–50 mm (often with 30 mm bolt-on plates), and the gun was upgraded first to the 50 mm KwK 38 L/42, then to the high-velocity 50 mm KwK 39 L/60 on the Ausf. J/L/M.

The standard powerplant was the Maybach HL 120 TRM, a 12-cylinder petrol engine of about 300 hp, giving the ~23 t tank a road speed near 40 km/h and a range of around 155 km. Torsion-bar suspension on six road wheels per side delivered a stable, comfortable ride that aided accurate gunnery on the move.

By 1942 the Panzer III had reached the limit of its turret. The 50 mm KwK 39 L/60 was the largest gun it could take, and against the T-34 and the KV-1 that was not enough, so the anti-tank role passed to the Panzer IV. Production of the gun tank ran to roughly 5,770 vehicles across more than a dozen marks, from the Ausf. A of 1937 to the Ausf. N of 1943.

The Blitzkrieg legend rests on a tank that was barely present for it. Only 98 Panzer III had been completed by 1 September 1939, and Poland was overrun by the Panzer I and Panzer II — machine-gun and 20 mm vehicles that the Panzer III had been designed to replace. Eight months later, for the attack in the West in May 1940, there were 349 of them among 2,439 German tanks: roughly one in seven.

What made them decisive was not how many there were but where they were put. Concentrated in the leading panzer divisions instead of spread along the front, they formed the armoured tip at Sedan and in the race to the Channel. France had more tanks in total and better-armoured ones — the Char B1 bis carried 60 mm against the Panzer III Ausf. F’s 30 — but distributed them among infantry-support units, in vehicles whose commander also aimed and loaded the gun he was supposed to be directing.

On 22 June 1941 the invasion force included 965 Panzer III. Figures as high as 1,440 appear in print, and the gap is a matter of accounting rather than of dispute: authors differ over whether the count covers gun tanks with the invading formations, or every Panzer III on strength including command variants and the replacement pool. On either count it was the most numerous German gun tank in the East, and for four months it did what it had done in France.

Then came the T-34 and the KV-1. The 50 mm KwK 38 L/42 could not defeat either from the front. Nor could the L/60 that replaced it: firing PzGr 39 it penetrated 67 mm at 100 m and 44 mm at 1,000 m against plate set at 30°, while a T-34’s glacis was 45 mm laid back at 60° — close to 90 mm of effective thickness. The gun that had been sufficient in France could reach a T-34’s 45 mm flank at normal battle range and nothing on its front at any range.

North Africa was the theatre where the Panzer III fought its longest campaign as a first-line tank, and the balance sheet at Gazala on 26 May 1942 shows what Rommel was working with. His front line held 232 Panzer III with the short L/42 and only 19 with the long L/60, together with 40 Panzer IV and 228 Italian tanks, mostly M13/40 and M14/41 — 560 in all. Facing them the British had 849 tanks in the line and a further 145 Grants and Stuarts in reserve.

The nineteen counted for more than their number. The British called them Mark III Specials, and the L/60 gave them a chance against the M3 Grant that the L/42 versions did not have, at a moment when the Grant’s hull-mounted 75 mm had just taken the measure of the earlier German tanks. Rommel broke the Gazala line and took Tobruk with an armoured force two-thirds the size of the one opposing it, and with fewer than twenty tanks in it that could be called modern.

One variant deserves its own account. For Operation Sealion, the invasion of England, the Germans needed tanks that could be put over the side of a barge and drive ashore along the seabed. Between June and October 1940 some 160 Panzer III Ausf. F, G and H — with eight command tanks and 42 Panzer IVs — were sealed for underwater running: every hatch, joint and mantlet gasketed, the engine fed through a long floating hose held up by a buoy, and the exhaust fitted with non-return valves. They were tested at depths between 6 and 15 metres.

Sealion was cancelled and the Tauchpanzer were left with nothing to wade into. In early 1941 the floating hose was replaced by a rigid 3.5 m snorkel, which turned an invasion vehicle into a river-crossing one, and on the morning of 22 June 1941 they were used at the opening of Barbarossa: the 18. and 3. Panzer-Division put them across the River Bug at Patulin, driving submerged from one bank to the other. The equipment built to reach England was expended, in a single morning, entering the Soviet Union.

The last combat version reversed the tank’s entire development. Some 700 Ausf. N were built carrying the short 75 mm KwK 37 L/24 — the low-velocity gun that had originally armed the Panzer IV as the support half of the original pair. Unable to fight tanks with a 50 mm, the Panzer III was handed back the job the other vehicle had started with, seven years after the two had been specified as complements.

From 1943 the Ausf. N served as close escort to the Tiger battalions, screening them at short range against infantry and anti-tank teams, targets on which the 8.8 cm was wasted. The tank built to be the panzer division’s main battle tank ended its front-line career as bodyguard to the vehicle that had replaced it.

The gun tank was withdrawn; its hull was not. The same chassis, running gear and Maybach HL 120 TRM underpinned the Sturmgeschütz III, and the StuG was built in greater numbers than any other German armoured vehicle of the war — over 10,000, against the 5,770 Panzer III gun tanks that gave it its running gear. A turretless casemate could carry the long 7.5 cm the turret could not, which is why the design outlasted the tank it came from.

Other conversions used the same hull: the Flammpanzer III flamethrower, and the Befehlspanzer command and observation vehicles that gave panzer regiments their radio nets, fitted with extra sets in place of the main gun’s ammunition. Panzer III components stayed in front-line production until the last months of the war, years after the last Ausf. N left the assembly line in 1943.

The Panzerkampfwagen III is less celebrated than the Tiger or the Panther and was far more important to Germany’s early victories: a sound 23-tonne medium with five men, good optics and a commander free to command. What ended it can be stated as a measurement. Its turret ring was 1,520 mm in diameter against the Panzer IV’s 1,680 mm, and the long 7.5 cm KwK 40 L/48 needed 505 mm of recoil travel that the smaller turret could not give it.

A hundred and sixty millimetres of ring diameter decided which of the two 1930s medium tanks had a future. The Panzer IV was re-gunned in 1942 and fought to the end of the war; the Panzer III could not be, and was relegated to secondary fronts, training units and the escort role by 1943, just as the T-34 and the Sherman were reaching full production. Its components fought on under a different silhouette, in the 10,000 StuG III that the same hull made possible.

• Peter Chamberlain & Hilary L. Doyle, Encyclopedia of German Tanks of World War Two (Arms & Armour Press).
• Thomas L. Jentz & Hilary L. Doyle, Panzer Tracts No. 3: Panzerkampfwagen III.
• Robert Forczyk, Desert Armour: Tank Warfare in North Africa — Gazala to Tunisia, 1942–43 (Osprey, 2023).