Tourelle de mitrailleuses modèle 1899 was the name for a French armored machine gun turret, which was mainly used in the fortifications of the Système Séré de Rivières . It was a retractable tower that was installed on the ceiling of a fort in order to repel enemy infantry attacks directly from there. The model "Type GF 3" (1895) was equipped with a machine gun and the model "Type GF 4" (1899) with two machine guns.
The tower had a diameter of 1.31 meters and a total weight of 25 tons. The balanced counterweight made it possible for one man to perform a complete lift in just four seconds. In the firing position, the turret protruded 83 centimeters over the armored armor . The shooters had to perform the rotary movement with a hand crank. In order to prevent the crew from being impaired by smoke gases, manually operated fans were installed between 1912 and 1915 .
As armament of the tower type GF3 a machine gun according to the pattern served Gatling with seven pipes in the caliber of 8 mm having a cadence was 500 rounds per minute. The successor of the type GF4 was equipped with two machine guns "Hotchkiss modèle 1900" - this is already very similar to the Hotchkiss M1914 . Here, too, the 8 millimeter caliber was used, the rate of fire was 700 rounds per minute and per machine gun. These machine guns were longer than their predecessors, so they were placed on a sliding cradle and had to be moved forward to fire. The tower was made of rolled chrome steel , the ceiling was 120 millimeters, the walls 15 millimeters, then 20 millimeters thick. As soon as the tower was retracted, the rain protection plate of the roof overlapped the ring of the armored armor and thus protected the interior from the weather.
From 1905 a fire control system was installed, which made it possible to target the glacis at night or out of sight. A metal band with the relief of the existing contour lines was installed in the tower under the rifle mounts, which forced the necessary tube height to be set up when the tower was pivoted by means of a feeler arm on the mount.
Two towers intended for the forts of Belfort could not be installed until 1914. On May 26, 1913, the army command ordered 12 more towers from the “Société de construction des Batignolles”, which had not yet been delivered in July 1914.
↑ Roland Scheller: Les cuirassements dans la fortification terrestre française 1871-1918. Mémoire de maîtrise à l'Université de Strasbourg, Strasbourg 1993, chapter 4; La defense of the interval.