The German invasion of the Soviet Union through Operation Barbarossa (June 1941) taught the Germans that their current-generation tanks were not up to the challenge of disabling better-armored Soviet ones. As such, much work and expense was placed on devising battlefield tank-killing solutions and this spawned many projects involving conversions of existing tracked vehicles. Among these was the" Marder" series of converted vehicles led by the Marder I series.
After the Fall of France in June 1940, the German Army was able to secure a stock of about 37 or so FCM 36 tanks and these were taken into service under the designation of Panzerkampfwagen 737 FCM(f). From there, some ten of the fleet were modified as tank destroyers under the "Marder I" name in 1943, their primary armament becoming the 75mm PaK 40 series ant-tank gun and this installed within an open-air superstructure. The Marder I became a generic name for first-generation conversions like this that also included about 170-180 built atop the chassis of the French "Lorraine" tractor and the Hotchkiss H39 tank.
Those FCM 36 tanks converted to the tank-killer role were formally designated 7.5cm PaK 40(Sf) auf Geschutzenwagen FCM (f) and became generally recognized as "Marder I". The conversion work was handled in Paris, France.
As with other conversions of this type, the turret of the FCM 36 tank was completed removed and over this space was fitted a thin-walled hull superstructure with an open top. The PaK 40 L/46 gun protruded from the frontal face of the superstructure and the three-man gunnery crew used this are as a workspace. The area also held the 50 rounds of 75mm projectiles at-the-ready. The rear of the superstructure allowed the crew to jettison spent shell casings. The driver managed the tank from within the hull and the original track-and-wheel and drive components (including engine) were retained from the French tank. Power was from a Ricardo-Berliet 4-cylinder diesel-fueled unit outputting 91 horsepower at 1,550rpm. Maximum road speed was 17mph and range was out to 124 miles.
Armor protection reached up to 40mm. Self-defense armament included a single 7.92mm MG34 machine gun with 2,000 rounds afforded to it. Beyond these were any personal weapons carried by the crew.
Dimensions included a running length of 4.7 meters, a width of 2 meters and a height of 2.2 meters.
As crude as the vehicle may have appeared, it was a needed commodity on World War 2 battlefields where more and more enemy tanks were heavily armored and pitched tank-versus-tank battles became the norm. With Germany's current-generation tanks not up to the challenge, conversions like the Marder I were required of the Army service. From 1943, the FCM 36-based Marder Is were stationed in, and fought, across northern France as part of Panzer divisions. In June of 1944, they were deployed against Allied forces during the Invasion of Normandy.