Carro Armato M11/39

The specification the Italian army issued in the late 1930s asked for a medium tank with a crew of three, a 37 mm gun mounted in the hull, and two 8 mm machine guns in the turret. Fiat–Ansaldo built exactly that, and the result is one of the clearest design errors of the war: the weapon that could fight another tank could not be traversed, and the mounting that could traverse could not fight anything armoured.

It was not a uniquely Italian mistake — the American M3 Lee repeated the essential part of it three years later, with a 75 mm in a hull sponson. But the Lee at least put a 37 mm gun in its turret as well, so it could shoot at armour in whatever direction it was looking. The M11 could not. Turning the turret changed nothing about where the gun pointed.

The 37 mm Vickers-Terni L/40 sat in the front of the hull with a few degrees of traverse either side. To engage anything outside that arc the driver had to turn the whole tank, which takes time, raises dust, and presents the side of the vehicle to whatever is being aimed at — the exact sequence a tank crew spends its training learning to avoid.

The commander, meanwhile, sat in a turret with two machine guns and no way to influence the main armament except by telling the driver to steer. In a meeting engagement the M11 had to solve with the whole vehicle a problem that every other medium tank of 1940 solved by turning a turret ring.

Protection ran from 6 to 30 mm, and it was riveted rather than welded. Riveted armour has a failure mode of its own: a hit that does not penetrate can still shear the rivet heads and send them through the fighting compartment at lethal speed, so the crew can be killed by their own tank without the plate being pierced.

Thirty millimetres was adequate against machine guns and light automatic weapons in 1939. By the time the M11 met the British in the Western Desert it was facing 2-pounder anti-tank guns and Matilda IIs, and it was proof against neither.

The type’s war was decided in a single morning. On 9 December 1940 — the opening day of Operation Compass — British and Indian troops attacked the fortified camp at Nibeiwa, held by the Maletti Group, and came in from a direction the defenders had not prepared.

Around two dozen M11/39s were caught encamped, many with their engines cold, and were overrun where they stood. It was not a tank battle: the tanks never got to be tanks. General Maletti was killed in the fighting, and the accounts of how differ: one has him shot down as he emerged from his dugout, another has him directing the fire of a 47/32 anti-tank section on the northern perimeter at about nine in the morning. The camp fell in a few hours, taking with it the larger part of the M11 force in Africa.

What happened next is the part worth remembering. From 10 April 1941, during the siege of Tobruk, the 6th Australian Division Cavalry Regiment put the captured M11s back into service — together with several M13s — because they had no tanks of their own and these were available.

They painted large white kangaroos on the hulls so that their own side would not shoot at them, and drove them against the Italian positions in what became the first tank action ever fought by the Australian army. Only seven of them completed the approach march without breaking down, and the rest were used until the diesel ran out and there was no more to be had.

Production stopped at 100 vehicles. The design was already being superseded as it entered service, and the replacement was the same tank with the mistake removed: the M13/40 took the hull, put a 47 mm gun in a proper turret and moved the machine guns to the hull — which is where they had belonged from the start.

That the correction was available so quickly says the fault was understood before the first vehicles reached Africa. What the M11 bought Italy was a year of production capacity, a hundred hulls that could not fight, and the crews who took them into the desert in 1940.

The M11/39 is the vehicle by which Italian armour is most often judged, and unfairly so — it was superseded in 1940 and the M13/40 and the Semoventi that followed were competent designs. But the judgement contains something true. The M11 was not badly built; it was badly conceived, to a specification that asked for the gun and the turret to be in the wrong places.

A hundred were made. Around two dozen were lost in one morning at Nibeiwa without fighting, and a number of the survivors finished their service under Australian colours, with kangaroos painted on them, being driven against the army that had built them.

• Nicola Pignato & Filippo Cappellano, Gli autoveicoli da combattimento dell’Esercito Italiano (Ufficio Storico dello Stato Maggiore dell’Esercito).
• Filippo Cappellano & Pier Paolo Battistelli, Italian Medium Tanks 1939–45 (Osprey, New Vanguard).
• Barrie Pitt, The Crucible of War: Western Desert 1941 (Jonathan Cape).