The M 13-40 Medium Tank was the most important Italian tank of the Second World War, and due to the slow development of better medium tanks and the P 40 Heavy Tank had to bear the brunt of the fighting in North Africa despite being under-gunned and under-armoured by 1941-42.
The M 11-39 was the first medium tank to enter Italian service. It was developed from a series of prototypes produced in 1933-36, and carried its main 47mm gun in the superstructure, with a machine gun in the small turret. This layout must have been seen as problematic right from the start, for work began on a modified version with the main gun in the turret late in 1937, well before the M 11 had actually entered service.
The M 13-40 used the basic hull, suspension and engine (a 125hp SPA 8T diesel engine) as the M 11, but the superstructure was modified to carry a large central turret in place of the offset machine gun turret of the M 11. The 37mm gun of the M 11 was replaced with a more powerful 47mm gun while the twin turret machine guns were moved to the front of the superstructure. Armour protection was improved with the thickest armour increasing from 30mm up to 45mm. All of this extra weight was reflected in the change of designation, from the eleven ton M 11 to the thirteen ton M 13-40. There was no increase in horsepower and so performance was reduced.
The prototype of the M 13-40 was delivered to the Italian army late in 1939. A production order for 400 tanks was placed in the same year, and this eventually rose to 1,900, although many were completed as the improved M14-41. At most 800 were completed as M 13-40s but the figure is probably a little lower. They were followed by a similar number of tanks with a more powerful engine, sand filters and other modifications and that had the semi-official designation of M 14-41 .
The M 13-40 entered service in the summer of 1940 and by the end of the year 250 had been delivered. They were rushed into service where they suffered from inevitable teething troubles (much as happened with some British tanks rushed into service in the same way). Three battalions reached Libya in October 1940, but as with the M 11-39s all of these tanks were lost during Operation Compass, the first British offensive in the Western Desert. In late 1940 the M 13-40 was a capable tank, with a good gun and sufficient armour but it was underpowered giving it a low top speed in difficult terrain. Many tanks also lacked sand filters and the design was untested in desert conditions.
The M 13-40 was the main Italian tank in North Africa during 1941 and the first half of 1942. It equipped four battalions of the Ariete armoured division and one battalion each from the Littorio and Centauro armoured divisions and the Trieste Motorized Division. Some M 13-40s were still in front line service for the advance into Egypt in the summer of 1942. M 13s were amongst the first Axis tanks to reach the harbour at Tobruk on 20 June 1942, the day before the garrison surrendered. They were present at the battle of El Alamein in the autumn, but many were lost during that battle or the retreat west to Tunisia.
The M 13-40 was used extensively in the Balkans. Two companies from the 4th Battalion became the first M 13s to reach Albania in November 1940, the month after the start of the unsuccessful Italian invasion of Greece. Neither of these companies fared well. The 1st Company suffered heavy losses in the Voiussa valley in January 1941 and the second was badly hit during an attack in mountainous terrain in northern Greece.
In April 1941 the battalion took part in the Axis invasion of Yugoslavia, losing two of its medium tanks in the very first clash. After that the M 13-40s performed well, and tanks from both the Centauro and Littorio armoured divisions made their way into the heart of Yugoslavia without many problems.
Some later production was diverted to produce Semovente (self-propelled guns). Armed with heavier guns than the M 13, these self-propelled guns were rather more useful than the original tanks and were produced in a number of different versions.
Weight: 14 tons/ 30,864lb
Armament: 47mm Ansaldo 47/32 gun in turret, one 8mm machine gun in turret, two machine guns in hull, mounting for one machine gun on turret roof
Engine: 125hp SPA 8T eight-cylinder liquid cooled inline diesel
Top Speed: 19mph
Length: 16ft 1inft
Width: 7ft 6.6in
Height: 7ft 10.5in