The Mortier de 270 mm modèle 1889 sur affût G was a

heavy mortar A mortar is usually a simple, lightweight, man-portable, muzzle-loaded weapon, consisting of a smooth-bore (although some models use a rifled barrel) metal tube fixed to a base plate (to spread out the recoil) with a lightweight bipod mount and a ...

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 c ...

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 (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

and

Second world war World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

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 155 mm (6.1 in) is a common, NATO-standard, artillery caliber. It is defined in AOP-29 part 1 with reference to STANAG 4425. It is commonly used in field guns, howitzers, and gun-howitzers. Land warfare The caliber originated in France after ...

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

French Army The French Army, officially known as the Land Army (french: Armée de Terre, ), is the land-based and largest component of the French Armed Forces. It is responsible to the Government of France, along with the other components of the Armed For ...

. 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 more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impuriti ...

reinforcing

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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 Belt armor is a layer of heavy metal vehicle armor, armor plated onto or within the outer hulls of warships, typically on battleships, battlecruisers and cruisers, and aircraft carriers. The belt armor is designed to prevent projectiles from p ...

. 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 extension of the 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/breast'). Whe ...

. 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 arrangement in which a worm (which is a gear in the form of a screw) meshes with a worm wheel (which is similar in appearance to a spur gear). The two elements are also called the worm screw and worm gear. The terminolo ...

which attached to the base. The mle 1889 was

breech loaded A breechloader is a firearm in which the user loads the ammunition (cartridge or shell) via the rear (breech) end of its barrel, as opposed to a muzzleloader, which loads ammunition via the front ( muzzle). Modern firearms are generally breech ...

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

trunnion A trunnion (from Old French "''trognon''", trunk) is a cylindrical protrusion used as a mounting or pivoting point. First associated with cannons, they are an important military development. Alternatively, a trunnion is a shaft that positions a ...

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 Western Front or West Front may refer to: Military frontiers *Western Front (World War I), a military frontier to the west of Germany *Western Front (World War II), a military frontier to the west of Germany *Western Front (Russian Empire), a majo ...

stagnated and

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

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

coastal fortifications The coast, also known as the coastline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. The Earth has around of coastline. Coasts are important zones in n ...

and surplus

naval guns A navy, naval force, or maritime force is the branch of a nation's armed forces principally designated for naval warfare, naval and amphibious warfare; namely, lake-borne, riverine, littoral zone, littoral, or ocean-borne combat operations and ...

. 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