Specifically designed (although derived from an existing mortar) for the Maginot line, the breech loading 81mm mortar was installed in both turrets and casemates at a fixed angle of 45 degrees.
The mortar’s task was to shell enemy forces by indirect fire in hilly terrain or, in general, defiladed positions near or in front of ouvrages or casemates. The mortar was well suited for this task, since the shells had a strongly curved trajectory.
|¹ When the FA model RF 1936 shell was used|
|Max. range||3600 m ¹|
|Rate of fire||13 rpm|
The 81mm mortar model 1932, was derived from the infantry mortar model 1927/31 of the same calibre made by the company Stokes-Brandt. It was a standard-setting design that was widely copied or licenced for manufacture worldwide. It had a smoothbore barrel and was breech loading.
When installed in a casemate, the 81mm mortars were usually located in a firing chamber below ground on the bottom level of the casemate.
At Block 3 of PO Coume-Sud, there is a rather unique situation in which the mortars do not fire in the same direction as the block's 47mm AT gun and machine guns.
To load the mortar, a shell was placed on the loading tray extending down from the mortar breech. The breech block was then manually slid upwards and rotated to the right using a handle. This action moved the projectile into the tube and sealed the breech.