Mortier de 270 mm modèle 1889

The Mortier de 270 mm modèle 1889 sur affût G was a heavy mortar originally employed as coastal artillery and later converted to the siege artillery role. Mle 1889 mortars were used in both the First world war and Second world wars. The Mortier de 270 mm G mle 1885 was one of a series of heavy artillery pieces designed by Colonel Charles Ragon de Bange. On 11 May 1874 three de Bange heavy cannons (120 mm, 155 mm, 240 mm) and two mortars (220 mm, 270 mm) were ordered by the French Army. The mle 1889 was advanced for its time due to being built completely of steel instead of a steel liner and cast iron reinforcing hoops of the previous Canon de 240 mm C mle 1870-87. The mle 1889 was derived from the earlier Mortier de 270 mm modèle 1885 siege mortar and adapted to the coastal artillery role by fitting the same barrel to a different carriage. In the coastal artillery role, the mle 1889 was intended to pierce the thin decks of armored warships with high angle plunging fire, rather than piercing their armored belt. The mle 1889 was mounted on a Vavasseur mount which consisted of a large diameter geared steel ring set into a concrete slab behind a parapet. The Vavasseur mounts allowed high angles of elevation with 300° of traverse. The mount was traversed by a worm gear which attached to the base. The mle 1889 was breech loaded with a de Bange obturator, and separate loading bagged charges and projectiles. The recoil system for the mle 1889 consisted of a U shaped gun cradle which held the trunnioned barrel and a slightly inclined firing platform with hydraulic buffers. When the gun fired the hydraulic buffer slowed the recoil of the cradle which slid up a set of inclined rails on the firing platform and then returned to position by the combined action of the buffers and gravity. At the outbreak of the First World War, it is estimated there were 86 mle 1889's deployed in coastal fortifications. During the Second World War 24 guns were still in reserve. The German Army used these as coastal artillery under the name 27 cm Küstenmörser 585 (f).