42 cm Gamma Mörser

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
42cm Gamma-Gerät
42 cm Gamma Mörser AWM A02560.jpeg
A Gamma-Gerät in 1914
TypeSiege artillery
Place of originGerman Empire
Service history
In service1909–18, 1945
Used byGerman Empire
Nazi Germany
WarsWorld War I
World War II
Production history
Weight150 t (150 long tons)
Length13.5 m (44 ft)
Height4.25 m (13.9 ft)
Diameter420 mm (17 in)

Elevation+43° to 66°
Maximum firing range14,200 m (46,600 ft)

The 42cm kurze Marinekanone L/12, or Gamma-Gerät and Gamma Mörser (Gamma Device and Mortar respectively) was a German siege mortar built by Krupp AG. The Gamma-Gerät's barrel diameter was 42 centimetres (17 in), making it one of the largest artillery pieces ever fielded. It was designed from 1906 to 1910, then used by the Imperial German Army in Belgium, France, Poland, and Serbia. A single Gamma-Gerät survived World War I and saw limited use in World War II to attack the Maginot Line and Sevastopol. Because of the Gamma-Gerät's extreme weight, 150 t (150 t), it was a Bettungsgeschütz (bedding gun) and took 24 hours to emplace. Mostly immobile, it saw limited effectiveness on either the Western and Eastern Fronts of World War I, and only ten were built.

Development and design[edit]

Design of a fortress by Henri Brialmont
A design of a Belgian fortress by Henri Alexis Brialmont

The quick advancement of artillery technology beginning in the 1850s provoked an arms race between artillery and military architecture. Rifled artillery could now fire out of range of fortress guns, so military architects began placing forts in rings around cities or in barriers to block approaching armies. However, these forts were vulnerable to new artillery shells, which could penetrate earth to destroy masonry underground. In response, star forts evolved into polygonal forts, mostly underground and made of concrete with guns mounted in armoured, rotating casemates. Combining rings and barriers, France created a vast fortified zone on their border with Germany. Meanwhile, Belgium began construction of the National Redoubt in 1888.[1][2]

The German Empire also fortified its borders, but Chief of the General Staff Helmuth von Moltke the Elder desired to break through Franco-Belgian fortifications.[3] Although German artillery had been effective during the Franco-Prussian War, by the 1880s the diameter of the German Army's most powerful gun, 21 centimetres (8.3 in),[4] had become the standard thickness for fortress concrete.[5] Moltke began requesting more powerful guns that same decade, which then became essential to his successor, Alfred von Schlieffen, who planned to quickly defeat France by sweeping through Belgium in response to the 1893 Franco-Russian Alliance. That same year, the German Army's Artillerieprüfungskomission (Artillery Test Commission, APK) formed a secret partnership with Krupp AG to supervise development of a weapon that could break Franco-Belgian fortresses. Acting on a study that showed that a 30.5-centimetre (12.0 in) shell could penetrate modern fortresses, Krupp designed and built a 30.5cm mortar, the Beta-Gerät. The Beta-Gerät was adopted into service in 1897 as the schwere Küstenmörser L/8, a cover name concealing its true purpose,[a] making it Germany's first large artillery piece to have a breech and a recoil system. Further studies conducted by the APK in the mid-1890s showed that the Beta-Gerät could not penetrate the armor of modern Franco-Belgian forts, even with revised shells. Interest in an improved siege gun waned until the Russo-Japanese War, during which the Japanese Army used coastal mortars brought from Japan to end the 11-month long Siege of Port Arthur.[7]

Helmuth von Moltke the Younger, now Chief of the General Staff, saw the utility of a newer, larger siege gun. In 1906, he instructed the APK to conduct further evaluation of the Beta-Gerät. The resulting study suggested a siege gun with a caliber as large as 45 centimetres (18 in), but the German Army opted for a 30.5cm howitzer and a 42cm gun. The howitzer, the Beta-Gerät 09, had a greater range and accuracy than the Beta-Gerät. However, the Beta-Gerät 09 was heavy and difficult to transport, and could not penetrate fortress concrete. Only two were produced. Meanwhile, the 42cm gun was designed as a mortar in 1906 and its first model was delivered for testing in May 1909. After initial difficulties with penetration, the gun was accepted into the German Army in 1910 as the kurze Marinekanone L/12, or the Gamma-Gerät. The Gamma-Gerät was essentially an enlarged Beta-Gerät 09 weighing 150 metric tons (150 t), ensuring that it could only be emplaced near permanent railways in a process that took a total of 24 hours. With a maximum range of 14,000 metres (46,000 ft) and a high degree of accuracy, the Gamma-Gerät was Germany's most powerful siege gun of World War I. A total of five Gamma-Gerät mortars and 18 barrels were produced by Krupp.[8]

To emplace the Gamma-Gerät, all nearby vegetation was cleared and a rectangular 2.25 metres (7.4 ft) pit, reinforced timber and steel, was dug to form the bedding. At the same time, a rail spur was spun off the nearest permanent line to the site. Then, a 25 metric tons (25 t) rail-mounted gantry crane unloaded and used to assemble all seven, 20–25 metric tons (20–25 t) portions of the Gamma-Gerät. Fully emplaced, the Gamma-Gerät stood 4.25 metres (13.9 ft) and 13.5 metres (44 ft) long. Standard rate of fire for an Gamma-Gerät mortar was one shell every seven minutes, eight in an hour. The fastest recorded rates of fire were 19 shells an hour for a single Gamma-Gerät and 30 shells an hour for a two-gun battery.[9]

"Gerät" siege artillery variants[6]
Name Calibre Weight Range Rate of fire Time to emplace (hours)
M-Gerät "Big Bertha" 42 cm (17 in) 42.6 t (41.9 long tons; 47.0 short tons) 9,300 m (30,500 ft) 8 shells an hour 5–6
Gamma-Gerät 150 t (150 long tons; 170 short tons) 14,000 m (46,000 ft) 24
Beta-M-Gerät 30.5 cm (12.0 in) 47 t (46 long tons; 52 short tons) 20,500 m (67,300 ft) 7–8
Beta-Gerät 09 45 t (44 long tons; 50 short tons) 12,000 m (39,000 ft) 12 shells an hour 12
Beta-Gerät 30 t (30 long tons; 33 short tons) 8,200 m (26,900 ft) 15 shells an hour


Photograph of a 42cm shell
A 42cm projectile in 1918

German siege artillery had three types of projectiles: Panzergranate (Armour-piercing), Langgranate (High explosive), and kurze Haubengranate (Intermediate). The armour-piercing shell was designed to smash through concrete and metal armour, but was largely ineffective against reinforced concrete. High explosive shells were fitted with two charges and could be set to have no delay or a short or a long delay. If set to "no delay," then the shell burst on impact. 42cm high explosive shell craters could be as wide as 9 m (30 ft) and as deep as 6 m (20 ft). If set to a delayed detonation, it could penetrate up to 12 m (39 ft) of earth. Finally, the intermediate, or "short shell," weighed half as much as the high explosive shell and was fitted with a ballistic tip for range and accuracy. 42cm shells were generally 1.5 m (4.9 ft) long, weighed between 400–1,160 kg (880–2,560 lb), and were propelled via primer loaded into the gun with a brass casing. Siege artillery shells were produced in limited runs, ensuring a gradient in their quality. Beginning in early 1916, German siege guns began to suffer internal explosions due to faulty ammunition. As a result, crews were required to disembark from the gun before firing.[10]

Service history[edit]

The kurze Marinekanone (KMK) Batteries that formed with Gamma-Gerät guns were 1 (2 August 1914), 2 (2 August 1914), and 4 (October 1914). In April 1916, Batteries 1 and 2 were split to form additional batteries: 8, 9, and 11. When Battery 8 had its guns destroyed by internal explosion in 1917, it was outfitted with two Beta-M-Gerät mortars, converted from the destroyed Gamma-Gerät guns.[11]

World War I[edit]

With the start of World War I, all siege gun batteries were mobilised and assigned to the Western Front. KMK Battery 2 was sent north to Namur, but could not arrive in time to participate in the Siege of Namur, while KMK Battery 1 was assigned to the 6th Army in Lorraine. As part of the 6th Army, it participated in the siege of the Fort de Manonviller from 25–27 August 1914. During the 52-hour siege the battery had technical troubles and had to stop firing. KMK Battery 1 finally arrived to the 2nd Army at Maubeuge in early September and joined the siege guns already present in obliterating Forts Leveau, Héronfontaine, Cerfontaine, and Sarts. On the tenth day of battle, with only two forts in French hands, Maubeuge surrendered.[12]

Picture of a shell crater at Maubeuge, 1914
42cm shell crater at the Fort de Boussois

The German defeat at the First Battle of the Marne prevented the siege guns at Maubeuge from being sent against Paris, so they were sent back into Belgium to Antwerp.[13] The Belgian Army, which had retreated to the city on 20 August following the fall of Liège, had made attacks on the German flank on 24–25 August and 9 September. In response, the III Reserve Corps, from the 1st Army, was sent to reduce the city.[14] The Corps arrived at Antwerp on 27 September, partially surrounding it and massing at its southern side. The next day, KMK Battery 2 opening bombardment against the Fort de Wavre-Sainte-Catherine, which was destroyed on 29 September by a magazine detonation cause by a 42cm shell. KMK Battery 2 then shifted its fire to the Fort de Koningshooikt, which surrendered on 2 October.[15] Beginning on 7 October and lasting the next two days, Antwerp's defenders began withdrawing from the city, which then surrendered on 10 October.[14] With the fall of Antwerp, KMK Battery 2 was attached to the 4th Army to aid in its capture of the Channel ports, and occasionally shelled Nieuport, Ypres, and Dixmude.[16]

On 27 February 1915, KMK Battery 1, with the 8th Army, joined the ongoing attack on Osowiec Fortress. Although the fortress was made of masonry, it survived, intact, because the artillery had no spotters and because of effective counter-battery fire from the fortress. After five days, the siege guns were withdrawn and the fort was besieged until August. On 8 August, KMK Batteries 1 and 4 fired on Kaunas Fortress to support the XXXX Reserve Corps. While slow, the bombardment was highly effective because of outdated masonry construction, and the Germans took four forts altogether on 16–17 August. The Russians evacuated from the city and fortress the next day. The last action for Gamma-Gerät mortars in the East was the German Invasion of Serbia. On 6 October 1915, KMK Batteries 1 and 4 opened fire on Serbian fortifications east of Belgrade to support the crossing of the 11th Army, made the next day. Battery 1 briefly fired on Smederevo Fortress, but the fortress was undamaged when it surrendered on 11 October.[17]

KMK Batteries 1 and 4 were transferred back to the Western Front in early 1916. The latter bombed Forts Douaumont and Vaux without effect while the former inflicted serious damage on a French railway viaduct east of Belfort. At the beginning of that year, all 42cm guns were assigned to the 5th Army for the upcoming Battle of Verdun.[18] The battle began on 21 February with an intense, nine-hour artillery barrage.[19] The 42cm guns were tasked with bombarding Forts Douaumont, Vaux, Souville, and Moulainville, the most modern fortresses at Verdun, to silence their guns and prevent French units from rallying at them. However, despite heavy shelling by all thirteen 42cm guns, the forts were only lightly damaged. At the same time, French counter-battery artillery and internal explosions plagued German siege guns; KMK Batteries 2, 8, and 9 lost a Gamma-Gerät each. In July, siege batteries began to be withdrawn north to the Battle of the Somme, and east to Romania. KMK Battery 4 remained at Verdun, while Battery 1 attacked Arras and Loos-en-Gohelle in June and July.[20]

In the last two years of the war, siege guns saw limited use and negligible effect on the Western and Eastern fronts. For the Spring Offensive, KMK Battery 4 was assigned to the 17th Army on the Somme. When the time for Germany's final offensive operation came in July, the gun was assigned to the 1st Army at Reims and had little effect in the battle. KMK Battery 4 survived the reorganization of the German Army in Autumn 1918, but with a single gun.[21]

World War II[edit]

A single Gamma-Gerät survived World War I and its aftermath, disassembled and hidden in Krupp's Meppen facilities. The gun was reassembled in the late 1930s and was used in 1940 to bombard both the Maginot Line and the city of Liège. Later, it was employed at Sevastopol in 1942 and then to Kronstadt, but did not fire a single shot there. The gun returned to Germany and its post-war fate is unknown.[22]

See also[edit]


  1. ^ Comparable large-scale mortars were termed Küstenmörser, "Coastal mortars," as they were used in coastal artillery batteries.[6]


  1. ^ Donnell 2013, pp. 6-8
  2. ^ Romanych & Rupp 2013, pp. 5–6
  3. ^ Donnell 2013, pp. 8–9
  4. ^ Romanych & Rupp 2013, p. 6
  5. ^ Donnell 2013, p. 8
  6. ^ a b Romanych & Rupp 2013, p. 7
  7. ^ Romanych & Rupp 2013, pp. 6, 7–8
  8. ^ Romanych & Rupp 2013, pp. 10–11, 15
  9. ^ Romanych & Rupp 2013, pp. 11–12, 14, 15
  10. ^ Romanych & Rupp 2013, pp. 22–23
  11. ^ Romanych & Rupp 2013, p. 25, 44
  12. ^ Romanych & Rupp 2013, p. 26, 28, 31
  13. ^ Romanych & Rupp 2013, p. 34
  14. ^ a b Tucker 2014, p. 118
  15. ^ Romanych & Rupp 2013, pp. 35–36
  16. ^ Romanych & Rupp 2013, pp. 36–37
  17. ^ Romanych & Rupp 2013, p. 37, 39, 42
  18. ^ Romanych & Rupp 2013, pp. 41–42
  19. ^ Tucker 2014, p. 1616
  20. ^ Romanych & Rupp 2013, pp. 43–44
  21. ^ Romanych & Rupp 2013, pp. 46–47
  22. ^ Romanych & Rupp 2013, p. 47


  • Donnell, Clayton (2013). Breaking the Fortress Line 1914. Pen and Sword. ISBN 9781473830127.
  • Romanych, Marc; Rupp, Martin (2013). 42cm "Big Bertha" and German Siege Artillery of World War I. Illustrated by Henry Morshead. Osprey Publishing. ISBN 978-1-78096-017-3.
  • Tucker, Spencer, ed. (2014). World War I: The Definitive Encyclopedia and Document Collection. ABC-CLIO. ISBN 978-1-85109-964-1.

Further reading[edit]

  • Joachim Engelmann & Horst Scheibert: Deutsche Artillerie 1934–1945: Eine Dokumentation in Text, Skizzen und Bildern: Ausrüstung, Gliederung, Ausbildung, Führung, Einsatz. C. A. Starke. OCLC 5673937
  • Terry Gander & Peter Chamberlain: Weapons of the Third Reich: An Encyclopedic Survey of All Small Arms, Artillery, and Special Weapons of the German Land Forces, 1939–1945. Doubleday ISBN 0-385-15090-3
  • Ian V. Hogg: German Artillery of World War Two. Greenhill Books. ISBN 1-85367-480-X
  • Herbert Jäger: German Artillery of World War One. Crowood Press. ISBN 1-86126-403-8
  • Hermann Schirmer: Das Gerät der Artillerie vor, in und nach dem Weltkrieg: Das Gerät der schweren Artillerie. Bernard & Graefe. OCLC 29133423
  • Gerhard Taube: Die schwersten Steilfeuer-Geschütze, 1914-1945: Geheimwaffen "Dicke Berta" und "Karl". Motorbuch Verlag. ISBN 978-3-87943-811-2