St Chamond (tank)

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St Chamond
early model St Chamond
General characteristics
Crew	8 (commander-driver, gunner-loader, assistant gunner, mechanic, three machine gunners, reserve crewman)
Length	8.7 m
Width	2.7 m
Height	2.4 m
Weight	22 tonnes
Armour and armament
Armour	11–19 mm
Main armament	75mm gun
Secondary armament	four 7.92mm Hotchkiss M1914 machine guns
Mobility
Power plant	4-cylinder Panhard-Levassor (petrol) 90 hp (70 kW)
Suspension	coil spring
Road speed	12 km/h
Power/weight	4 hp/tonne
Range

The St Chamond was the second French heavy tank of the First World War. Overall an inadequate design born of commercial rivalry, the war ended before it was replaced by British heavy tanks.

1 Development
2 Description
3 Variant
4 See also

[edit] Development

Originally the tank produced by Saint Chamond was meant to be identical to the Schneider CA. Early 1916, the proposed definitive prototype of this latter tank was prepared in an army workshop. Private Pierre Lescure designed the fighting compartment. Lieutenant Fouché lengthened the suspension to improve trenchcrossing abilities. In this form the prototype of the Schneider was called the Tracteur A - not for security reasons, but because nobody knew exactly how to call such vehicles; the word char was not yet applied to tanks. However Eugène Brillié, the chief designer working for Schneider Company, rejected this prototype. He had invented a tail giving a shorter chassis the same crossing abilities for a lesser weight.

While Brillié began to design a second prototype (based on his earlier work on the Schneider CA), Schneider's main competitor, the arms manufacturer Saint Chamond, was given a second order for 400 tanks. First they intended to build the same tank as Schneider. However Brillié refused to share his patented invention for free and Saint Chamond refused to pay. So the latter company, not even having been given the blueprints of the new Schneider prototype, had to base its design on the original Tracteur A. Because of this the designs of the two companies began to diverge already, as the Tracteur A was longer.

One of Saint Chamond's technical directors was "Colonel" Émile Rimailho, a former artillery officer, who had become very disgruntled over the meagre benefits he had received in reward for designing the famous 75mm field gun before the war in service of the army. For Saint Chamond he had produced a similar gun, the L12 Canon de Tir Rapide ('Rapid Fire Cannon'), receiving a percentage for every piece sold. This was too good an opportunity to let pass and Rimailho induced one of his "friends" at the Ministry of War to change the specification of their order so that the vehicle would be able to mount his gun, even though the army had never asked for such a capacity. For this a much longer hull was needed. The first prototype, now very different from the Schneider, was ready in September 1916.

As a result of Rimailho's manipulations, the new tank had become a very cumbersome vehicle. It had no turret, but a large overhanging front compartment housing the long 75 mm gun, protruding from the nose.

[edit] Description

The Char St Chamond showing the overhanging front hull and the later M.1897 75mm field gun

Within the forward fighting compartment was the driver, who was also the vehicle commander, on the left. On the right a machine gunner operated the front machine gun. This gunner was also responsible for traversing the main gun and the breech operation of the same which he could only do by getting out of his seat and using his left hand. A loader (referred to in some sources as the gunner) adjusted the gun elevation, observing the target through a large hatch in the front of the tank, which left him vulnerable and many were killed by enemy fire. A second fighting compartment at the back held one machine gunner next to the secondary driver position, from where the tank could be driven backwards by the mechanic in an emergency. Between these two compartments was the 90 HP engine over the tracks, partly protruding through the roof. Narrow passageways either side of the engine connected the compartments, each also containing a machine gun position.

Despite weighing 23 tons, the tank could manage a top speed of 12 km/h. This speed was seldom achieved in the field as the long nose was prone to dig into the ground. The relatively high speed was made possible by a petro-electric transmission. This also gave the tank simple controls, allowing for perfect gradual steering. However it tended to overheat, and breakdowns were very common.

Due to the short tracks and large body, the vehicle had much trouble crossing obstacles.

[edit] Variant

Originally the crew of 8 were protected by 11 mm of steel armour. The addition of an extra layer of spaced 8 mm armour on the front and the sides improved protection. The roof was also redesigned with a slope so that satchel charges and grenades slid off. The original observation cylinders on the top were therefore done away with, but were later replaced in the field with some low look-out turrets.

The very first St Chamonds were modified as recovery vehicles able to tow the lighter Schneider tanks. The first action as a fighting tank was 5th May 1917, mostly getting stuck in various trenches. Twelve units in total were formed with the St Chamond: Artillerie Spéciale No's 31-42.

Production petered out in March 1918, when at least 377 had been manufactured. Surprisingly, in action towards the end of the war the tank was more useful, as in a more mobile situation it was quite effective at destroying German gun emplacements (Nahkampfbatterien).

After the 165th vehicle the common, and cheaper, Model 1897 field gun was used instead of Rimailho's (profitable) L12 gun. About the same time a wider track was introduced. This version was later sometimes called the Modèle 17; this identifier was not in use at the time itself though.

After the war 54 were rebuilt as munition carriers; the remainder scrapped. There are unsubstantiated stories about Poland using the tank against the Red Army in 1920. If true these specimens were in all probability not from the Soviet Army - the latter never had been supplied with them and the French Expedition Forces to Russia were only equipped with FT-17's. Possibly they were bought from French scrap dealers.

One vehicle can be viewed, alongside other examples of the French tanks of WWI, in the Musée des Blindés at Saumur.