2-inch medium mortar

As the Western Front in France and Belgium stagnated into trench warfare in late 1914, British forces found themselves with no means of replying to the German minenwerfers (trench mortars) which were lobbing both small and large (over ) high-explosive shells into their frontline trenches from short range. British commanders requested an accurate short-range weapon which was manually portable in the trenches, could be safely used to attack enemy trenches as close as to the British trenches, was easily concealed and projected a reasonably large explosive charge capable of damaging protected enemy positions. The British Expeditionary Force had been expected to participate only in mobile warfare and was not equipped with any mortars. Various alternative designs for light and medium mortars were evaluated, prompted by the need to place at least some weapon into action without diverting manufacturing capacity from guns and howitzers, which weapons were given priority. Hence the emphasis was on designs for both mortar and ammunition that could be manufactured by small unsophisticated workshops unsuited to other war work: 4-inch mortar • The mortar was the only official type to enter service before the end of 1914 (12 units). It fired an pound steel bomb with studs to engage rifling grooves in the mortar barrel, similar to the German minenwerfer. The barrel was improvised by boring out a shell. Its range of and its accuracy was considered acceptable, but the shell case was expensive and was slow to load. About 40 guns and several thousand rounds were issued by June 1915, with 168 of the total 300 manufactured eventually serving in France. It was soon replaced by the Stokes mortar in its "light mortar" class. 3.7-inch mortar • The pipe gun was an early improvised mortar. Eighteen were initially made by the Indian Corps in France by December 1914. It was a smooth tube firing a "tin-pot" filled with ammonal. The fuze was a length of Bickford fuse ignited by the burning of the propellant, which made it too dangerous for long term use. By the end of June 1915, another 100 had been manufactured and sent to France and 20 to Gallipoli. Vickers 1.57-inch mortar • The Vickers trench mortar was first introduced to France in March 1915, 127 by the end of June, and about 275 were manufactured until it was withdrawn in January 1917, after being replaced by the 2-inch mortar. The 1.57-inch was similar to the eventual 2-inch model, but the particular Vickers design was complicated and expensive to manufacture. It fired either an cast-iron bomb filled with Permite (perchlorate), but the smaller bomb was considered too light and the heavier had a range of only . ==The 2-inch medium mortar==

This was designed and manufactured by the Royal Ordnance Factories in early 1915 and introduced along with the 1.57-inch mortar in March 1915. It incorporated what was known of the German prewar Krupp mortar. This was the first design to meet all the requirements, after modifications to simplify manufacture; it fired a good-sized spherical cast-iron bomb of (total projectile weight with stick and fuze), considered the largest practical size for use from trenches, at ranges from using a simple 2-inch tube as the mortar body. The mortar and ammunition could be cheaply manufactured by small unsophisticated "trade" workshops; the bomb was safely detonated by a standard No. 80 "time and percussion" artillery fuze. Drawbacks were that the steel tail was usually projected backwards towards the firer when the bomb detonated, resulting in occasional casualties and the No. 80 fuze was also required by the 18-pounder field guns which were given priority, limiting mortar ammunition supply to the front until early 1916 when a special cheap trench mortar fuze was developed. The 2-inch mortar served in limited numbers in France in 1915 from March, with early mortars and ammunition made by the Royal Ordnance Factory, with the Vickers 1.57-inch model. Mass production began with an order in August 1915 for 800 mortars from several railway workshops and agricultural machinery makers, together with an order for 675,000 bombs from numerous small firms. Manufacture of the Vickers model which was twice as expensive was ended and it was withdrawn by January 1917. It fired a spherical cast-iron bomb "the size of a football" painted dirty white filled with amatol (identified by a painted green band) or ammonal (identified by a painted pink band) Hence the total fuzed weight with stick of 51 lb is an average. The 2-inch designation 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 4-inch mortars. The 2-inch mortar was itself superseded by the Newton 6-inch mortar from mid-1917 onwards. Some Australian units retained them for projecting smoke screens. ==Combat use==

Deployment The weapon was initially operated by joint infantry and artillery detachments, eventually it became the responsibility of the Royal Field Artillery. A typical infantry division was equipped with three batteries designated X, Y, Z, each with four mortars. Use in action Its primary use was in cutting barbed wire defenses and attacking enemy front line trenches, such as in the July 1916 attack on the Somme. 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: A special blank rifle cartridge was loaded and fired via a lanyard from a sheltered position if possible due to the risk of bombs falling short. • Cutting barbed wire: 1 round per 10 square yards (8 m2) • Cutting loose wire: 1 round per 6 square yards (5 m2) • 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 Silencer Provision was made in mid-1916 for attachment of the "Temple silencer" at the muzzle, intended to reduce the flash and noise generated on firing, which at the short ranges the mortar operated at was quickly noticed by the enemy and invited artillery response. This required the use of bombs with a special piston attached to the tail which was retained in the barrel by the silencer on firing, and hence sealed the muzzle after the bomb tail left the barrel. This had the major disadvantage of causing the barrel to overheat during prolonged daylight firing, and the silencer was only used at night. Use as anti-tank mines In Spring 1918 many of these 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. ==See also==

Image:2inchTrenchMortarDiagram.jpg| Image:Bomb2InchTrenchMortarDiagram.jpg| Image:ToffeeAppleBombs1916.jpg| Image:2inchMortarBombsBeingCarried.jpg| Image:Toffee Apple 2inch Mortar Bomb, Musée Somme 1916, pic-023 (12325940504).jpg| ==Notes and references==