Monday, March 23, 2015

Semovente 75/18

An Italian artillery Colonel named Sergio Berlese (who designed the Obice da 75/18 modello 34) suggested that Italy should create an armoured fighting vehicle similar to the German StuG III, which had been successful in the French campaign. 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).

Structurally 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 typical Italian design fashion, in a separate structure, which was sloped, 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, itself a quite modern divisional artillery piece. It 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, which was quite low by contemporary self-propelled gun standards (even though in the North African theatre some crews used to store some 100 shells by removing their seats and filling the space with the extra rounds.[1]) A model RF1 CA with interphone radio was usually fitted.

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