mortar (weapon)

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mortars. A mortar is defined as a weapon which fires only at angles above 45 degrees, and, so far as the Second World War is concerned, is usually interpreted as meaning the light smooth-bore weapons employed by infantry for their own close support. The term is, however, also correctly applied to heavy rifled ordnance of the howitzer class used for coastal defence by some nations, though few ever saw use in 1939–45.

Infantry mortars were largely derived from two prototypes, the British Stokes mortar and the French Brandt mortar, both of which were developed during the First World War. In the 1920s both, but more especially the Brandt, were copied and licensed for manufacture in several countries, so that most of the world's mortars were very similar weapons in similar calibres. They fell into three groups: the light class were of 50–60 mm. (1.95–2.3 in.) calibre, the medium of 81–82 mm. (3.15–3.2 in.) calibre, and the heavy of 100 mm. (3.9 in.) calibre and above. They were almost all of similar construction; a smooth-bore barrel, the end of which rested upon a steel baseplate which spread the recoil shock to the ground and a supporting bipod or tripod which held the barrel at the desired elevation and was provided with adjustments to permit elevating and traversing the barrel.

Mortars: Mortar bomb lethal radii. Based upon standard 1939–45 period HE bombs. Based upon 70° angle of descent, average meadowland.

Ian Hogg

Mortars. The mortar is a very simple piece of artillery, essentially a firing tube, that fires a high arc and imparts its main recoil force directly into the ground through a base plate. The lack of a recoil system distinguishes this weapon from other pieces of artillery. Dating back to at least the fifteenth century, mortars became most common in World War I. With opposing forces dug in at close ranges, a simple weapon capable of high‐angle fire was needed to drop rounds in the enemies' trenches. In Britain in 1915, Sir Wilfred Stokes produced the prototype that has become the world's standard, consisting of a tube with a fixed firing pin at the breech attached to a base plate and supported at the muzzle end by a bipod. It can be adjusted in both azimuth and elevation by a screw mechanism. To fire the weapon a projectile containing the propellant and explosive is dropped into the muzzle.

After World War I, mortars passed into the hands of infantry units, while very heavy pieces remained with the artillery. The U.S. Army classifies mortars as light (60mm), medium (81mm), and heavy (120mm and above). All light and medium mortars are carried by infantrymen. They are inexpensive and easy to maintain, and can achieve a very high rate of fire. An 81mm mortar platoon can fire 196 rounds in a minute—a far greater weight of ammunition on a target than can be achieved by a field artillery battery, but one that can only be sustained over a short period of time. Concealment is easy and fire control is straightforward. With the advent of global satellite positioning systems, accuracy has been improved. The high‐angle fire associated with this weapon allows it to engage targets concealed behind cover.
[See also Weaponry, Army; World War I: Military and Diplomatic Course.]

Bibliography

The Diagram Group , Weapons: An International Encyclopedia from 5000 B.C. to 2000 A.D., 1990.
Timothy M. Laur and and Steven L. Llanso , Encyclopedia of Modern U.S. Weapons, 1995.

William F. Atwater

mortar in warfare, term originally applied to certain types of artillery with high trajectories, but later applied to an infantry weapon that consists of a tube supported by a bipod that fires a projectile at a very high trajectory. The mortar is not usually classified as artillery. Unlike standard types of artillery, mortars need no complex recoil equipment and are usually smoothbore and muzzle-loaded. Their weight is light in relation to the weight of shell delivered, but at the expense of range and accuracy. First developed by Sir Frederick Stokes during World War I, the mortar was used by infantry in trench warfare and is standard equipment in modern armies.