As soon as the French headquarters realized the need for a trench artillery, a request was made to develop a mine thrower able to fire heavy power shells, in addition to the 58mm trench mortars. This gave birth, in 1915, to the 240 mm mortars.

The very first weapon of this series was the 240 CT mortar ('240 Court de Tranchée' - '240 short trench mortar'). It was a heavy equipment (1003 kg with its platform), appearing on the battlefields at the middle of 1915, and giving satisfactory results particularly during the September 1915 Champagne offensive. The terrifying effects of its 87 kg bomb (45 kg of explosive) created terror and devastation in the German trenches.

Its modest range (1025 m) induced the development of a new '240 LT trench mortar' (Long), that would have a very successful career. This model was able to send fin tailed 86 kg (42 kg of explosive) shells that were entirely introduced into the tube, at more than 2000 m, causing terrible destructions. Unhopefully, its set-up before firing was long and difficult, and the weight of its platform materials quite heavy. It appeared on the front in July 1916.

The concept was used afterwards by the British (9.45 inches 'Flying Pig') armies and the Italian armies, copied by the German engineers with the famous 24 cm IKO and Albrecht minenwerfers, and developped to the incredible 340 mm caliber by the French armies (firing a 195 kg bomb !)

Main characteristics :

• Weight in firing position : 3500 kg (including 2500 kg wooden platform)
• Calibre : 240 mm
• Tube length : unknown
• Projectile weigth : 85 kg
• Initial velocity : unknown
• Maximum range : 2150 m
• Direction range : 36 degrees (practical)
• Elevation range : 54 to 75 degrees