The Semovente da 75/18 was an Italian self-propelled gun of the Second World War. It was built by mounting the 75 mm Obice da 75/18 modello 34 mountain gun on the chassis of a M13/40, M14/41 or M15/42 tank. The first 60 were built using the M13/40 chassis and a subsequent 162 were built on the M14/41 chassis from 1941 to 1943. A total of 190 were built utilizing the M42 chassis before the armistice and an additional 55 were built afterwards. The Semovente da 75/18 was intended to be an interim vehicle until the heavier P40 tank could be available.
History
Italian artillery Colonel Sergio Berlese, who also designed the Obice da 75/18 modello 34, howitzer suggested that Italy create an armoured fighting vehicle similar to the German StuG III assault gun, which had been successful in the French campaign in 1940. The first prototype was quickly assembled and delivered, on February 10, 1941, only 13 months after the first M13/40 tank upon which it was based. After that, 60 more examples were ordered. They were delivered in 1941, and were then shipped to North Africa in January 1942. This initial batch was based on the M13 chassis, with its weak 125 hp engine (later to be replaced by one of 145 hp, with the M14 chassis).
Design
This self-propelled gun was built with riveted steel plates, which were thicker but also less sloped than in the original tank (50 mm as against 42 mm max). Frontal armour was almost vertical, but it consisted of two plates that strengthened it when compared to a simple homogeneous steel plate.
The vehicle had its crew compartment and drive section forward, in a large and low casemate; the engine was situated behind it, in a separate structure (typical of Italian designs), which was sloped and somewhat smaller, and had inspection panels on the roof. The chassis was identical to that of M13/40 tanks, with eight small wheels in four trolleys which were joined in pairs by two arms. Suspensions were of the leaf spring type, which was reliable but didn't allow for high speeds. The transmission was located in the forward part of the vehicle, and the crew consisted of only three members: driver, loader/radio operator, and tank commander/gunner.
The main gun was a derivative of a 75 mm L/18 gun. This was 18 calibers long, with 40° traverse and −12/+22° elevation. The gun had a muzzle brake, and there were several observation and aiming systems (binoculars, periscopes and others) for the crew. The low muzzle velocity (around 450 m/s) meant a relative short range, 9,500 m at best elevation of 45 degrees, but the installation allowed only 22° and so the range was limited to around 7–8 km. The range in direct fire mode was also limited, especially against moving targets, for the same reason. Only one roof-mounted machine gun was fitted for close defence, though sometimes it was omitted. Initially this was a 6.5 mm Breda, later upgraded to an 8 mm model. Ammunition load was typically 44 75 mm shells and 1,108 8 mm cartridges. In the North African theatre some crews stored up to 100 shells by removing their seats and filling the space with the extra rounds. A model RF1 CA with interphone radio was usually fitted.
Service
Although these machines were not widely known, the vehicle performed well in its role. Though it was technically similar to the StuG III, it had a totally different role, serving as divisional artillery instead of a pure assault gun. The organic structure consisted of two artillery groups for every armoured division, with two batteries each (four 75/18 each and a command vehicle). The total was of 18 75 mm L/18 (included two in reserve) and 9 command vehicles, which were characterized by additional radio equipment and a Breda 13.2 mm heavy machine gun mounted instead of the main gun. The number originally ordered, 60 total, was enough for the three armoured divisions.