The Mortier de 270 mm modèle 1889 sur affût G was a heavy mortar originally employed as

coastal artillery Coastal artillery is the branch of the armed forces concerned with operating anti-ship artillery or fixed gun batteries in coastal fortifications. From the Middle Ages until World War II, coastal artillery and naval artillery in the form of ...

and later converted to the

siege artillery Siege artillery (also siege guns or siege cannons) are heavy guns designed to bombard fortifications, cities, and other fixed targets. They are distinct from field artillery and are a class of siege weapon capable of firing heavy cannonballs or ...

role. Mle 1889 mortars were used in both the

First World War World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

and

Second World War World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

History

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 The 155 mm calibre is widely used for artillery guns. Land warfare Historic calibres France - 1874 The caliber originated in France after the Franco-Prussian War (1870–1871). A French artillery committee met on 2 February 1874 to dis ...

, 240 mm) and two mortars ( 220 mm, 270 mm) were ordered by the

French Army The French Army, officially known as the Land Army (, , ), is the principal Army, land warfare force of France, and the largest component of the French Armed Forces; it is responsible to the Government of France, alongside the French Navy, Fren ...

. The mle 1889 was advanced for its time due to being built completely of steel instead of a steel liner and

cast iron Cast iron is a class of iron–carbon alloys with a carbon content of more than 2% and silicon content around 1–3%. Its usefulness derives from its relatively low melting temperature. The alloying elements determine the form in which its car ...

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.

Variants

Coastal Artillery

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 A parapet is a barrier that is an upward extension of a wall at the edge of a roof, terrace, balcony, walkway or other structure. The word comes ultimately from the Italian ''parapetto'' (''parare'' 'to cover/defend' and ''petto'' 'chest/brea ...

. The Vavasseur mounts allowed high angles of elevation with 300° of traverse. The mount was traversed by a

worm gear A worm drive is a gear train, gear arrangement in which a worm (which is a gear in the form of a Screw thread, screw) meshes with a worm wheel (which is similar in appearance to a spur gear). Its main purpose is to translate the motion of two p ...

which attached to the base. The mle 1889 was

breech loaded A breechloader is a firearm in which the user loads the ammunition from the breech end of the barrel (i.e., from the rearward, open end of the gun's barrel), as opposed to a muzzleloader, in which the user loads the ammunition from the ( muzzle ...

with a de Bange obturator, and

separate loading Ammunition, also known as ammo, is the material fired, scattered, dropped, or detonated from any weapon or weapon system. The term includes both expendable weapons (e.g., bombs, missiles, grenades, land mines), and the component parts of oth ...

bagged charges and projectiles. The recoil system for the mle 1889 consisted of a U-shaped gun cradle which held the

trunnion A trunnion () is a cylinder, cylindrical Boss (engineering), protrusion used as a mounting or pivoting point. First associated with cannons, they are an important military development. In mechanical engineering (see the Trunnion#Trunnion bearin ...

ed 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)''.

Siege Artillery

Although the majority of combatants had heavy field artillery prior to the outbreak of the First World War, none had adequate numbers of heavy guns in service, nor had they foreseen the growing importance of heavy artillery once the Western Front stagnated and

trench warfare Trench warfare is a type of land warfare using occupied lines largely comprising Trench#Military engineering, military trenches, in which combatants are well-protected from the enemy's small arms fire and are substantially sheltered from a ...

set in. Two sources of heavy artillery suitable for conversion to field use were

coastal fortifications A coast (coastline, shoreline, seashore) is the land next to the sea or the line that forms the boundary between the land and the ocean or a lake. Coasts are influenced by the topography of the surrounding landscape and by aquatic erosion, su ...

and surplus naval guns. Suitable field and rail carriages were built for these guns in an effort to give their forces the heavy field artillery needed to overcome trenches and hardened concrete fortifications. Although an older design the need for heavy artillery on the Western Front was so pressing that 86 mortars were converted to field use as siege mortars between 1915 and 1917. The conversion consisted of the steel firing platform of the coastal gun being placed on top of a platform made from wooden beams in the field. The mle 1889 could be broken down into three loads for rail transport. Once at a rail station behind the front the mortars could be transferred to narrow gauge rail wagons for the final leg to their firing positions. These narrow gauge tracks were also used to re-position the mortars and bring up their ammunition and supplies. Once the firing platform had been assembled the mortar could be assembled in two hours by cranes and block & tackle.

Photo Gallery

File:Cuperly. Mortier de 270 - Fonds Berthelé - 49Fi520.jpg, Stereo view of a mle 1889 being transported to the front. File:Vailly. Pièce et obus de 270 - Fonds Berthelé - 49Fi1114.jpg, Stereo view of a mle 1889 in a heavily camouflaged position. File:Reservegeschütze (27 cm-haubitzen) im Lager von Mailly.jpg, Mle 1889's at a reserve depot captured by the Germans.

Weapons of comparable performance and era

* 28 cm howitzer L/10 - A similar Japanese howitzer * 28 cm Haubitze L/12 - A similar German howitzer * 24 cm Mörser M 98 - A similar Austro-Hungarian mortar

References

{{DEFAULTSORT:Mortier de 270 mm modèle 1889 Artillery of France World War I artillery of France World War II weapons of France World War I guns Siege artillery Coastal artillery