Fiat M13/40

The Fiat-Ansaldo M13/40 was an Italian medium tank ("M" for Medio (medium) according to the Italian tank weight standards at the time: 13 tonnes was the scheduled weight and 1940 the initial year of production), designed to replace the Fiat L3, the Fiat L6/40 and the Fiat M11/39 in the Italian Army at the start of World War II. The design was influenced by the British Vickers 6-Ton and was based on the modified chassis of the earlier Fiat M11/39. Indeed, M11/39 production was cut short in order to get the M13/40 into production. Although designated a medium tank, the M13/40 was closer to contemporary light tanks in armor and firepower.

Specifications
The M13 was constructed of riveted steel plates as follows: 30 mm front (as M11), 42 mm on turret front (30 mm for M11), 25 mm on the sides (M11 had only 15 mm), only 6 mm bottom (that made it very vulnerable to mines) and 15 mm on top. The crew were housed in a forward fighting compartment, with the engine at the rear and transmission at the front. The fighting compartment accommodated the crew of 4: driver and machine-gunner/radio operator in the hull, and gunner and commander in the turret.

The Vickers-derived running gear had two bogie trucks with eight pairs of small wheels on each side, using leaf-spring suspension. The tracks were conventional skeleton steel plate links, and were relatively narrow. Together, this system was thought to allow good mobility in the mountainous areas in which future combat was expected. In the desert where most M13s were actually employed, mobility was less satisfactory. The tank was powered by a 125 hp diesel engine. This was an innovation that many countries had yet to introduce. Diesel engines were the future for tanks, with lower cost, greater range and reduced danger of fire compared to gasoline-powered engines.

The tank's main armament was a 47 mm gun. It could pierce about 45 mm of armor at 500 meters. This was sufficient to penetrate the British light and cruiser tanks it would face in combat, though not the heavier infantry tanks. One hundred four rounds of armor-piercing and high explosive ammunition were carried. The M13 was also armed with three or four machine-guns: one coaxially with the main gun and two in the forward, frontal ball mount. A fourth machinegun was sometimes carried in a flexible mount on the turret roof for anti-aircraft use. Two periscopes were available for the gunner and commander, and a radio was also theoretically available as standard equipment.



Operational use
The M13/40 was used in the Greek campaign in 1940 and 1941 and in the North African Campaign. The M13/40 was not used on the Eastern Front; Italian forces there were equipped only with Fiat L6/40s and Semovente 47/32s. Beginning in 1942, the Italian Army recognized the firepower weakness of the M13/40 series and employed the Semovente 75/18 self propelled gun alongside the tanks in their armored units.

First actions
The first of over 700 M13/40s were delivered following a rate of production of about 60-70 a month, before the fall of 1940. They were sent to North Africa to fight the British. Its baptism of fire came with a special unit, the Babini Brigade. Arriving too late to fight in the September offensive, this unit was ready the next December, for Operation Compass. Further action took place in Derna, where the V battalion had just arrived. Tanks of III battalion were also present near this position, at Bardia. In 2 days of fighting ( January 3-4 1941), the Australians suffered 456 casualties, the Italians lost 45,000 men captured. On February 6-7, the British offensive penetrated so far that the Babini Brigade sought to open a breach in the British lines at Beda Fomm in an effort to allow cut-off Italian troops to retreat along the Libyan coast. The brigade's action was unsuccessful and all their tanks were lost. The last six surviving tanks entered a field near the local British command post. They were destroyed one after another by a single 2pdr (40 mm) anti-tank gun. Many tanks were lost in this campaign to artillery fire rather than other tanks. A number of captured M11 and M13s were re-used by the 6th Australian Division Cavalry Regiment and the 6th battalion, Royal Tank Regiment, until the spring of 1941, when their fuel ran out and they were destroyed.

The M13s also fought in Greece, in difficult terrain. Subsequently, in April, 1941, M13s of the Ariete division took part in the Siege of Tobruk, with little success against British Matildas. The first successful action for the M13 was the Battle of Bir-el Gobi.

Later use in the desert war
In April 1941, at the time of the arrival of the Afrika Korps, the Italians had around 240 M13 and M14 tanks in first line service. In 1942, as the allies began deploying Grants and Crusader IIIs, along with towed 6 pounder anti-tank guns in their infantry units, the weaknesses of the M13 were exposed. The Italians equipped at least one company in each tank battalion with more heavily-armed Semovente 75/18 assault guns. In an attempt to improve protection, many crews piled sandbags or extra track links on the outside of their tanks, but this made the already underpowered vehicles even slower and added to maintenance problems.

The Second Battle of El Alamein saw the first appearance of the M4 Sherman, while some 230 M13s were still in front line service. In several days of battle, the Ariete and Littorio divisions were used to cover the Axis retreat. The Centauro Division was virtually destroyed fighting in Tunisia.

Strengths and weaknesses
The M13/40 was a conventional light tank of the early war period, similar in capability to other Vickers-derived designs such as the Polish 7TP and Soviet T-26. With a weight of 13 tons, it carried armor comparable to its opponents of 1940-41, and sufficient firepower to engage the British tanks of 1940-41. The main gun's HE round was useful against towed guns and infantry. The diesel engine was an advantage, and the simplicity of production suited the state of Italian industry.

However, the tank also had shortcomings: the engine gave good range, but reliability was a problem. The M13's engine was the same as the M11's, but the newer tank was heavier, which resulted in lower speed and more strain on the power-plant. The suspension and tracks were reliable enough, but resulted in relatively low speeds, not much better than infantry tanks such as the Matilda. Armament was sufficient for 1940-41 but did not keep up with the increased armor and firepower on Allied or German tanks. The method of construction, using rivets, was outdated. Most tanks of the era were switching to the use of welding for construction, since rivets can shear off when hit, becoming additional projectiles inside the tank. The two-man turret was less efficient in combat than the three-man turrets used in many other tanks of the era. Radios were not fitted to many tanks.

Despite heavy operational attrition, the M13 were present at the war's end and a few even managed to survive into the post-war period.



Variants
The M13/40 series was Italy's most-produced tank of the war, including later variants such as the M14/41, over 3,000 were built. The last version was the M15/42 tank produced in 1943, with a better petrol engine and a longer 47/40 gun. The Semovente 75/18 self-propelled gun was built by utilizing the M13/40 or M14/41 chassis.

The Fiat M14/41 was a variant of the same tank with a more powerful 145 hp engine and better air filters for operations in North Africa. The Semovente Comando M40 was an M13/40 tank with the turret replaced by a large multi-piece hatch. The hull housed additional radios and other communication equipment.