2 inch Medium Mortar

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2-inch Vickers Medium Trench Mortar
British troops loading a 2 inch trench mortar with attached periscope post. Balkan front World War I.
Type	Medium mortar
Place of origin	United Kingdom
Service history
In service	1915 - 1917
Used by	British Empire
Wars	World War I
Production history
Manufacturer	Vickers
Specifications
Weight	105 lbs ^[1]
Barrel length	36 inch (bore) 40.85 inch (total)^[2]
Crew	5 per mortar; 25 per battery of 4^[3]

Shell	HE 51 lb^[4] Smoke
Calibre	2 inch (mortar barrel, not bomb)
Effective range	100 - 570 yards depending on charge
Filling	Amatol or Ammonal
Filling weight	12.5 lb^[5]

The 2 inch Vickers Medium Trench Mortar, also known as the 2-inch Howitzer, and nicknamed the "Toffee Apple" or "Plum Pudding" mortar, was a British SBML medium trench mortar in use in World War I from late 1915 to early 1917.

1 History
2 Combat use
3 Use as anti-tank mines
4 See also
5 Surviving examples
6 Image Gallery
7 Notes
8 References
9 External links

[edit] History

Introduced late 1915.

Replaced by the Newton 6 inch Mortar from February 1917 onwards. Some Australian units retained them for projecting smoke screens.

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[edit] Combat use

Typical mortar pit, Mesopotamia 1917, with firing lanyard laid out

The weapon was initially operated by joint infantry and artillery detachments, eventually it became the responsibility of the Royal Field Artillery.^[6] A typical infantry division was equipped with 3 batteries designated X, Y, Z, each with 4 mortars.

It fired a spherical cast-iron iron bomb "the size of a football"^[7] painted dirty white filled with Amatol (identified by a painted green band) or Ammonal (identified by a painted pink band)^[8] attached to the end of a pipe ("stick"), hence the nicknames "Toffee Apple" and "Plum Pudding". Weights of bombs as delivered without fuzes varied. Light bombs, from 39 lb 14 oz to below 40 lb 10 oz, were marked with a stencilled "L". Heavy bombs, above 41 lb 10 oz to 42 lb 6 oz were marked with a stencilled "Hv".^[8] Hence the total fuzed weight with stick of 51 lb is only an average.

2-inch refers to the mortar barrel's bore and the projectile stick inserted into it, not the much-larger bomb itself which remained outside the barrel. It was comparable in explosive power if not range to other 6-inch mortars.

Its primary use was in cutting barbed wire defenses^[9] and attacking enemy front line trenches, such as in the July 1916 attack on the Somme^[10]. The spherical shape and relatively low velocity brought the benefit that the bomb did not penetrate the ground before exploding. The short range was a disadvantage as it could only be used if no man's land (between the British and enemy front line) was relatively narrow. It was used to fire some White Star (50%-50% Chlorine and Phosgene) gas bombs during the Battle of the Somme ^[11] but only as a stopgap measure until other specialised longer range projectors became available.

Cordite charges appropriate to the required range were dropped into the barrel before the bomb was loaded. Charges and ranges^[12]:-

1.5 ounces : 100 - 220 yards (dangerous due to propensity for incomplete burn and hence to fall short^[13])
2.5 ounces : 180 - 340 yards
3.5 ounces : 300 - 500 yards

A Lee-Enfield bolt mechanism and chamber was screwed into a socket in the top of the barrel near the base.^[2] A special blank rifle cartridge was loaded and fired via a long lanyard from a sheltered position if possible due to the risk of bombs falling short^[14]. This ignited the propellant charge and launched the bomb.

In early use it was situated in frontline trenches but this tended to attract enemy fire onto the troops manning them. Standard procedure became to locate the mortars separately from frontline trenches, in unoccupied trenches or in saps running off the frontline. This had the benefit of drawing enemy fire away from troops manning the front line^[15].

Estimated rounds required for various targets, with instantaneous percussion fuze 107 :^[16]

Fuze No. 107

Cutting barbed wire : 1 round per 10 sq. yards
Cutting loose wire : 1 round per 6 sq. yards
Destroy trenches frontally : 5 rounds per yard
Destroy trenches in enfilade : 2.5 rounds per yard
Destroy a machine-gun emplacement with top cover not more than 3 feet of earth : 80 rounds

Provision was made for attachment of the "Temple Silencer" at the muzzle,^[2] but it is unknown whether this was used in combat.

British Mk V tank disabled by anti-tank mine, Ronssoy October 3 1918. Unexploded bombs are visible

[edit] Use as anti-tank mines

In Spring 1918 many of the by-then obsolescent bombs were buried on the Western Front under metal plates as anti-tank mines in expectation of attack by German tanks. This led to some later confusion as to whether unearthed bombs were unexploded mortar projectiles ("Duds") or undetonated mines.

These minefields were inadequately documented. This caused the British problems in the closing months of the war when they had to advance again over territory they had previously abandoned, and also prevented full clearance of the minefields after the war. This led to some French farmers being blown up in the 1930s when they started using tractors e.g. around Gouzeaucourt.

[edit] See also

[edit] Surviving examples

Please help improve this section by expanding it.
Further information might be found on the talk page or at requests for expansion.

[edit] Image Gallery

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2 inch Medium Mortar

Diagram showing bomb dimensions

Royal Army Ordnance Corps men playing cards on bomb dump, Acheux, July 1916, Battle of the Somme. Sticks not yet attached. Note wooden retaining blocks attached to bombs

Men carrying mortar bombs by their attached carrying straps

Men of the 37th Division pose with bombs, Hamel, c1916

[edit] Notes

^ "Appendix D. Details of Trench Mortars". Mortar=105 lb; Bed=50 lb; Elevating Stand=50 lb; Tool Box=60 lb; Periscope box=70 lb; Temple silencer=47 lb; Rifle mechanism=5 lb; Total Weight for Transport = 497 lbs
^ ^a ^b ^c Handbook of the M.L. 2-Inch Trench Mortar. Mark I. 1917, page 1
^ "No. 351/38. Medium Trench Mortar Battery (Consisting of four mortars)". War Establishments, General, 1916. September 18 1916.
^ "Appendix D. Details of Trench Mortars". 51 lb was the total projectile weight as fired, including filled bomb, fuze, and stick
^ "Appendix E. Details of Ammunition"
^ Clarke 2004, page 16
^ Pratt 1965
^ ^a ^b Handbook of the M.L. 2-Inch Trench Mortar, Mark I. 1917, page 13
^ Ruffell
^ Pratt 1965
^ Jones 2007, page 27
^ Ruffell
^ Ruffell
^ Ruffell
^ Pratt 1965
^ Artillery in Offensive Operations, January 1917