240 mm trench mortar

240 mm trench mortar
240 mm trench mortar
	240 mm trench mortar, side view
Type	Heavy trench mortar
Place of origin	France
Service history
In service	1915 - 1918
Used by	France; United States; Italy; Austria-Hungary
Wars	World War I
Production history
Designer	Dumezil-Batignolles
Designed	1915
Specifications
Mass	Total: 866 kg (1,909 lb); Base: 344 kg (758 lb); Barrel & breech: 317.5 kg (700 lb); Carriage: 204 kg (450 lb);
Barrel length	2 metres (6 ft 7 in); (including breech)
Crew	7
Shell	HE 81.6 kg (180 lb); (US & France)
Calibre	240 mm (9.4 in)
Breech	Vertical sliding block
Elevation	75° to 45°
Traverse	18° left & right
Rate of fire	1 per 6 min
Muzzle velocity	145 m/s (475 ft/s); (max charge)
Effective firing range	603 - 2,071 m; (660 – 2,265 yd)
Filling	Amatol or ammonal
Filling weight	40 kg (88 lb)

The 240 mm trench mortar, or Mortier de 240 mm, was a large calibre mortar of World War I. An original French design, it was developed by Batignolles Company of Paris and introduced in 1915.

Service

The weapon was dismantled for transport, requiring four carts for the barrel, base, carriage and ammunition.

In action, a heavy timber platform was constructed embedded in the ground, on which the mortar base was immovably secured. The mortar carriage sat on the base and could traverse. The mortar barrel and breech were mounted on the carriage which provided elevation.

They were used in the "siege warfare" on the Western Front to destroy enemy strongpoints, bunkers and similar "hard" targets which were invulnerable to lighter mortars and field guns. The US Army handbook described it : "... the use for which it is primarily adapted is in the bombardment of strongly protected targets—dwellings, covered shelters, command posts, entrances to galleries, etc—or in the destruction of sectors of trenches, salients and the like.".^[1] Its effectiveness decreased late in the war as German policy changed to a lightly held frontline, hence decreasing available targets, and they became redundant when the war of movement resumed in mid-1918.

French use

The mortar was first introduced in 1915 as the Mortier de 240 mm CT (court de tranchee). It was a short barreled version which fired a 192 pounds (87 kg) bomb for 1,125 yards (1,029 m), using a propellant charge of 1 lb 9 oz (710 g).^[2]

Its first major use was in the Champagne offensive of September 25, 1915.

This was followed later by the Mortier de 240 mm LT (long de tranchée) which was a long barreled version with improved firing arrangement and breech-loaded charge which fired a 179 lb (81 kg) bomb 2,265 yards (2,071 m), using a propellant charge of 2 lb 13 oz (1.3 kg).^[2] This appears to be the bomb configuration adopted by US.

French estimates were 80 bombs needed to destroy a strong shelter with a roof of concrete or rails and concrete.^[3]

US use

US gunners loading the mortar

David Lupton's Sons Co manufactured the weapon in the United States during World War I. They were used by nine trench mortar battalions of the Coast Artillery Corps.^[4]

The US version appears to have been a direct copy of the Mortier de 240 mm LT, i.e. with longer barrel and propellant charge loaded into the breech via a brass cartridge case, was also produced late in the war but it is doubtful whether any were actually used in combat. The December 1917 manual describes the weapon as "9.45 inch" but makes clear it is the French 240 mm they are describing that the US has adopted. The bomb is described as weighing 180 lb (82 kg), with an explosive charge of 90 lb (41 kg) and range from 660 to 2,500 yards (2,300 m).^[1]

The March 1918 manual describes the Bomb, Model 1916, Type T, weight 183 lb (83 kg), explosive 93 lb (42 kg), length 1.02 m (40 in). Barrel and breech weighing 690 lb (310 kg), carriage 448 lb (203 kg), base 764 lb (347 kg), timber platform 5,720 lb (2,590 kg). Propellant charges of 800 grams Ballistite + 15 grams F-3 black powder for 750–1,400 meters, and 1250 grams Ballistite + 15 grams F-3 for 1,100–2,200 meters.^[5] This figure agrees with the charge quoted for the mortar in French use for maximum range.

"Separate loading ammunition" was used i.e. the mortar bomb was a separate unit from the propellant cartridge case, which was flanged, brass, 9.776 inches long x 6.67 inches (169 mm) diameter (248.3 by 169.4 mm).^[6] The bomb was loaded into the barrel muzzle. The cartridge containing propellant charge appropriate for the required range was loaded into the breech, similar to a howitzer.

The mortar was fired by pulling a lanyard, which triggered a primer in the base of the cartridge case and ignited the propellant charge in the cartridge. The cartridge cases could be reused after cleaning and replacing the primer.

Italian Use

Italian model with long barrel, on the Adamello glacier

Italy used both the French CT and LT versions and produced their own long barrel version.^[7]

Austro-Hungarian 24 cm Minenwerfer M.16

Some 400 were copied and manufactured by Böhler during World War I based on examples captured from Italy,^[7] although the Austrians had problems recreating the original powder mixture and their shells suffered from large dispersions.^[8]

German 24 cm s.Flügelminenwerfer

The US A.E.F. in France reported in March 1918 : "... a new pattern minenwerfer which was brought out in 1916 and looks very much like the French 240... uses a heavy bomb fitted with four vanes like the French 240 mm bombs. This bomb weighs 100 kg (220 lb) and contains 42 kg (93 lb) of explosive... ranges obtained vary from 490 to 1,310 yards (450 to 1,200 m)".^[9] The specifications appear similar to the early French 240 mm CT quoted above. It is unknown whether this was related to the French or Austrian Böhler versions.

Notes and references

1 2 ""Handbook of the 9.45-inch trench mortar matériel" United States Ordnance Department. December 1917. page 9". Archived from the original on 2012-07-07. Retrieved 2021-03-22.
1 2 Atkinson, Charles Francis (1922). "Trench Ordnance". In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 32 (12th ed.). London & New York: The Encyclopædia Britannica Company. pp. 776–777.
↑ General notes on the use of artillery. France. Ministère de la guerre. 1917 Page 43
↑ Coast Artillery Corps units in France in WWI
↑ "Manual for trench artillery, United States Army (provisional). Part IV, 240 mm. trench mortar." Prepared at Headquarters AEF France March 1918. page 9-10
↑ [""Handbook of the 9.45-inch (240 mm) trench mortar matériel" December 1917. United States Ordnance Department. page 43". Archived from the original on 2012-07-07. Retrieved 2021-03-22. "Handbook of the 9.45-inch (240 mm) trench mortar matériel" December 1917. United States Ordnance Department. page 43]
1 2 Wesley Thomas, 24cm Minenwerfer M. 16. with photographs
↑ Ortner, M. Christian. The Austro-Hungarian Artillery From 1867 to 1918: Technology, Organization, and Tactics. Vienna, Verlag Militaria, 2007 ISBN 978-3-902526-13-7, p. 480
↑ ""Manual for trench artillery, United States Army (provisional). Part I, Trench Artillery.". Prepared at Headquarters AEF, France, March 1918. page 49-50". Archived from the original on 2012-07-08. Retrieved 2022-02-06.

Surviving examples

A French LT example is displayed in the open at Place de Longueval, France
Bernard Plumier : Link to his web page which has details and photograph Direct link to photograph
The Central Museum of The Royal Regiment of Canadian Artillery, Shilo Manitoba German 24 cm minenwerfer

External links

French 240 mm

W L Ruffel, French Mortars of WW1
List and pictures of World War I surviving 240 LT mortars

US 240 mm

The US manuals for the mortar appear to be based on French manuals e.g. the soldiers depicted are in French uniform.

German 240 mm

W L Ruffel, German Mortars of WW1
"Ingenieur-Komitee" Schwerer 24 cm Flügelminenwerfer
24 cm schwere Flügelminenwerfer (in Dutch)

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[US9.45HandbookPage9-1] 1 2 ""Handbook of the 9.45-inch trench mortar matériel" United States Ordnance Department. December 1917. page 9". Archived from the original on 2012-07-07. Retrieved 2021-03-22.

[Encyclopedia-2] 1 2 Atkinson, Charles Francis (1922). "Trench Ordnance". In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 32 (12th ed.). London & New York: The Encyclopædia Britannica Company. pp. 776–777.

[3] General notes on the use of artillery. France. Ministère de la guerre. 1917 Page 43

[4] Coast Artillery Corps units in France in WWI

[5] "Manual for trench artillery, United States Army (provisional). Part IV, 240 mm. trench mortar." Prepared at Headquarters AEF France March 1918. page 9-10

[6] [""Handbook of the 9.45-inch (240 mm) trench mortar matériel" December 1917. United States Ordnance Department. page 43". Archived from the original on 2012-07-07. Retrieved 2021-03-22. "Handbook of the 9.45-inch (240 mm) trench mortar matériel" December 1917. United States Ordnance Department. page 43]

[Thomas-7] 1 2 Wesley Thomas, 24cm Minenwerfer M. 16. with photographs

[8] Ortner, M. Christian. The Austro-Hungarian Artillery From 1867 to 1918: Technology, Organization, and Tactics. Vienna, Verlag Militaria, 2007 ISBN 978-3-902526-13-7, p. 480

[9] ""Manual for trench artillery, United States Army (provisional). Part I, Trench Artillery.". Prepared at Headquarters AEF, France, March 1918. page 49-50". Archived from the original on 2012-07-08. Retrieved 2022-02-06.

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French artillery of World War I
Anti-aircraft guns	Canon de 75 antiaérien mle 1913-1917
Coastal artillery	Canon de 100 mm Modèle 1891 Canon de 19 C modèle 1870/93 Canon de 19 C modèle 1875 Canon de 24 C modèle 1876 Canon de 240 L Mle 1884 Mortier de 270 mm modèle 1889
Field artillery	Canon de 75 modèle 1897 Canon de 75 modèle 1912 Schneider Canon de 75 modèle 1914 Schneider De Bange 90 mm cannon Obusier de 120 mm C modèle 1890 Obusier de 120 mm mle 15TR
Infantry guns	Canon d'Infanterie de 37 modèle 1916 TRP
Medium and heavy artillery	Canon de 105 mle 1913 Schneider Canon de 155 court modèle 1904 Rimailho Canon de 120 mm modèle 1878 Canon de 145 L modele 1916 Saint-Chamond Obusier de 155 mm C modèle 1881 Obusier de 155 mm C modèle 1890 Canon de 155 C modèle 1917 Schneider Canon de 155 C modèle 1915 St. Chamond Canon de 155 L modèle 1877/14 Schneider Canon de 155 L Modele 1917 Schneider Canon de 155 L modèle 1918 Schneider Canon de 155 mm GPF De Bange 155 mm cannon Canon de 220 L mle 1917 Mortier de 220 modèle 1915/1916 Schneider
Mortars	Cellerier Mortar Mortier de 58 T N°1 Mortier de 58 T N°1 bis Mortier de 58 mm type 2 Mortier de 75 modèle 1915 Schneider Mortier de 150 mm T Mle 1917 Fabry Mortier de 240 mm Mortier de 270 mm modèle 1885 Mortier de 270 mm modèle 1889
Mountain artillery	Canon de 65 M modele 1906 75 mm Schneider-Danglis 06/09 Canon Court de 105 M modele 1909 Schneider
Railway artillery	Canon de 120 L mle 1878 sur affût-truc Peigné-Canet-Schneider mle 1897 Canon de 140 sur affut-truc mle 1884 Obusier de 155 C mle 1881 sur affût-truc Peigné-Canet-Schneider mle 1897 Materiel de 155 sur affut-truc Schneider Canon de 164 modèle 1893/96 TAZ Canon de 19 C modèle 1875 Canon de 19 modèle 1870/93 TAZ Obusier de 200 "Pérou" sur affût-truck TAZ Schneider 24 cm Canon G modèle 1916 Canon de 240 L Mle 1884 Canon de 240 modèle 93/96 TAZ Canon de 274 modèle 93/96 Berceau Canon de 274 modèle 87/93 Glissement Canon de 305 modèle 93/96 TAZ Canon de 305 modèle 1893/96 à berceau Canon de 305 modèle 1893/96 à glissement Canon de 32 modèle 1870/81 à glissement Canon de 32 modèle 1870/84 à glissement Canon de 32 modèle 1870/93 à glissement Canon de 340 modèle 1893 à glissement Canon de 340 modèle 1912 à berceau Canon de 340 modèle 1912 à glissement Obusier de 370 modèle 1915 à berceau Canon de 370 modèle 75/79 Glissement Obusier de 400 Modèle 1915/1916 Obusier de 520 modèle 1916
Siege artillery	Obusier de 120 mm C modèle 1890 Canon de 120 mm modèle 1878 Obusier de 155 mm C modèle 1881 Obusier de 155 mm C modèle 1890 Mortier de 220 mm modèle 1880 Canon de 240 L Mle 1884 Canon de 240 TR Mle 1903 Mortier de 270 mm modèle 1885 Mortier de 270 mm modèle 1889 Mortier de 280 modèle 1914 Schneider Mortier de 293 Danois sur affut-truck modèle 1914 Mortier de 370 modèle 1914 Filloux
Self propelled artillery	Canon de 194 GPF Canon de 220mm L Mle1917 Schneider (FAHM) Mortier 280 mm TR de Schneider sur affût-chenilles St Chamond
Armoured vehicle guns	Puteaux 37 mm SA 18 Canon de 75 modèle 1897

United States artillery of World War I
Tank guns	Puteaux SA 18 QF 6-pounder 6 cwt Hotchkiss
Small and pack guns	Canon d'Infanterie de 37 modèle 1916 TRP 37 mm Infantry Gun Model 1917 QF 2.95-inch mountain gun
Field, medium and heavy guns	3-inch M1902 field gun 75 mm gun M1897 75 mm gun M1916 75 mm gun M1917 3.2-inch gun M1897 4.7-inch gun M1906 5-inch gun M1897 6-inch howitzer M1908 6-inch gun M1903 6-inch gun M1917 155 mm GPF M1918 155 mm howitzer M1917 BL 8-inch howitzer Mk VI – VIII BL 9.2-inch howitzer 240 mm Trench Mortar
Anti-aircraft guns	75 mm gun M1897 75 mm gun M1916 3-inch gun M1917 3-inch gun M1918
Coast artillery guns	3-inch gun M1903 4.72-inch Armstrong gun 5-inch gun M1897 6-inch Armstrong gun 6-inch gun M1897 8-inch gun M1888 10-inch gun M1895 12-inch gun M1895 12-inch coast defense mortar 14-inch gun M1907 16-inch gun M1895 16-inch gun M1919 155 mm gun M1918MI
Railway artillery	7"/45 caliber gun 8-inch gun M1888 10-inch gun M1895 12-inch coast defense mortar 12-inch gun M1895MIA1 14"/50 caliber railway gun