Stokes mortar with example of his WWI mortar and bombs It was not until the
Stokes mortar was devised by Sir
Wilfred Stokes in 1915 during the First World War that the modern mortar transportable by one person was born. In the conditions of
trench warfare, there was a great need for a versatile and easily portable weapon that could be manned by troops under cover in the trenches. Stokes' design was initially rejected in June 1915 because it was unable to use existing stocks of British mortar ammunition, and it took the intervention of
David Lloyd George (at that time
Minister of Munitions) and Lieutenant Colonel J. C. Matheson of the Trench Warfare Supply Department (who reported to Lloyd George) to expedite manufacture of the Stokes mortar. The weapon proved to be extremely useful in the muddy trenches of the
Western Front, as a mortar round could be aimed to fall directly into
trenches, where artillery shells, because of their low angle of flight, could not possibly go. . The Stokes mortar was a simple muzzle-loaded weapon, consisting of a smoothbore metal tube fixed to a base plate (to absorb recoil) with a lightweight
bipod mount. When a mortar bomb was dropped into the tube, an impact sensitive
primer in the base of the bomb would make contact with a
firing pin at the base of the tube and detonate, firing the bomb towards the target. The Stokes mortar could fire as many as 25 bombs per minute and had a maximum range of , firing the original cylindrical unstabilised projectile. A modified version of the mortar, which fired a modern
fin-stabilised streamlined
projectile and had a
booster charge for longer range, was developed after World War I; this was in effect a new weapon. By
World War II, it could fire as many as 30 bombs per minute and had a range of over with some shell types. The French developed an improved version of the Stokes mortar as the
Brandt Mle 27, further refined as the
Brandt Mle 31; this design was widely copied with and without license. These weapons were the prototypes for all subsequent light mortar developments around the world.
Mortar carrier heavy siege mortar in August 1944 M113 mortar carrier showing the placement of an 81 mm mortar
Mortar carriers are vehicles which carry a mortar as a primary weapon. Numerous vehicles have been used to mount mortars, from
improvised civilian trucks used by
insurgents, to modified
infantry fighting vehicles, such as variants of the
M3 half-track and
M113 armored personnel carrier, to vehicles specifically intended to carry a mortar. Simpler vehicles carry a standard infantry mortar while in more complex vehicles the mortar is fully integrated into the vehicle and cannot be dismounted from the vehicle. Mortar carriers cannot be fired while on the move, and some must be dismounted to fire. There are numerous
armoured fighting vehicles and even
main battle tanks that can be equipped with a mortar, either outside or inside of the cabin. The Israeli
Merkava tank uses a mortar as a secondary armament. The
Russian army uses the
2S4 Tyulpan self-propelled heavy mortar which is one of the largest mortars in current use.
Gun-mortars Gun-mortars are breech-loaded mortars usually equipped with a
hydraulic recoil mechanism, and sometimes equipped with an
autoloader. They are usually mounted on an armoured vehicle and are capable of both
direct fire and
indirect fire. The archetypes are the
Brandt Mle CM60A1 and
Brandt 60 mm LR, which combine features of modern infantry mortars together with those of modern cannon. Such weapons are most commonly smoothbore, firing fin-stabilised rounds, using relatively small propellant charges in comparison to projectile weight. While some have been fitted with rifled barrels, such as the
2S31 Vena and
2S9 Nona. They have short barrels in comparison to guns and are much more lightly built than guns of a similar calibre – all characteristics of infantry mortars. This produces a hybrid weapon capable of engaging area targets with indirect high-angle fire, and also specific targets such as vehicles and bunkers with direct fire. Such hybrids are much heavier and more complicated than infantry mortars, superior to
rocket-propelled grenades in the anti-armour and
bunker-busting role, but have a reduced range compared to modern gun-
howitzers and inferior anti-tank capability compared to modern anti-tank
guided weapons. However, they do have a niche in, for example, providing a multi-role anti-personnel, anti-armour capability in light mobile formations. Such systems, like the Soviet
2S9 Nona, are mostly self-propelled (although a towed variant exists). The
AMOS (Advanced Mortar System) is an example of an even more advanced gun mortar system. It uses a 120 mm automatic twin-barrelled, breech-loaded mortar turret, which can be mounted on a variety of armoured vehicles and attack boats. A modern example of a gun-mortar is the
2B9 Vasilek.
Spigot mortar A spigot mortar consists mainly of a solid rod or
spigot, onto which a hollow tube in the projectile fits—inverting the normal tube-mortar arrangement. At the top of the tube in the projectile, a cavity contains
propellant, such as
cordite. There is usually a trigger mechanism built into the base of the spigot, with a long firing pin running up the length of the spigot activating a
primer inside the projectile and firing the propellant charge. The advantage of a spigot mortar is that the firing unit (baseplate and spigot) is smaller and lighter than a conventional tube mortar of equivalent payload and range. It is also somewhat simpler to manufacture. Further, most spigot mortars have no barrel in the conventional sense, which means ammunition of almost any weight and diameter can be fired from the same mortar. The disadvantage is that while most mortar bombs have a streamlined shape towards the back that fits a spigot mortar application well, using that space for the spigot mortar tube takes volume and mass away from the payload of the projectile. If a soldier is carrying only a few projectiles, the projectile weight disadvantage is not significant. However, the weight of a large quantity of the heavier and more complex spigot projectiles offsets the weight saved. A near-silent mortar can operate using the spigot principle. Each round has a close-fitting sliding plug in the tube that fits over the spigot. When the round is fired, the projectile is pushed off the spigot, but before the plug clears the spigot it is caught by a constriction at the base of the tube. This traps the gases from the propelling charge and hence the sound of the firing. After World War II the Belgium Fly-K silent spigot mortar was accepted into French service as the TN-8111. launcher on display. Note the exposed spigot on the lower left launcher. Spigot mortars generally fell out of favour after World War II and were replaced by smaller conventional mortars. Military applications of spigot mortars include: • The petard mortar used on the
Churchill AVRE by Britain in World War II. • The
Type 98 mortar used by Japan in World War II to some psychological effect in the battles of
Iwo Jima and
Okinawa • The
Blacker Bombard and
PIAT anti-tank launchers used by Britain in World War II. • The
Hedgehog launcher, used from the deck of a ship, used 24 spigot mortars which fired a diamond pattern of anti-submarine projectiles into the sea ahead of the ship. A sinking projectile detonated if it struck a submarine, and the pattern was such that any submarine partly in the landing zone of the projectiles would be struck one or more times. Non-military applications include the use of small-calibre spigot mortars to launch lightweight, low-velocity foam dummy targets used for training
retriever dogs for bird hunting. Simple launchers use a separate small primer cap as the sole propellant (similar or identical to the cartridges used in industrial
nail guns).
Improvised Insurgent groups often use improvised, or "homemade" mortars to attack fortified military installations or terrorise civilians. They are usually constructed from heavy steel piping mounted on a steel frame. These weapons may fire standard mortar rounds, purpose-made shells, repurposed gas cylinders filled with explosives and shrapnel, or any other type of improvised explosive, incendiary or chemical munitions. These were called "
barrack busters" by the
Provisional Irish Republican Army (PIRA).
Syrian civil war Improvised mortars used by insurgents in the
Syrian civil war are known as
hell cannons. Observers have noted that they are "wildly inaccurate" and responsible for thousands of civilian deaths.
Sri Lankan civil war Improvised mortars used in the
Sri Lankan civil war by the rebel
Tamil Tigers are known as "Pasilan 2000", also known as a "rocket mortar" or "Arti-mortar" like the cannon, successor to the
Baba mortar used by the LTTE for ground operations since the 1980s. As Baba mortar rounds contained tar, they caused a fire when they hit the ground. The Baba, the prototype mortar, was crude. But with time the weapon has improved. The Pasilan 2000, the improved version, has been developed with characteristics similar to a rocket launcher. The Pasilan 2000 was a heavy mortar fired from a mobile launcher mounted on a tractor. The shell does not emit constant muzzle flares like
artillery or MBRL. This is ideal for LTTE's camouflage and conceals attacking style. Once a round is fired, forward observers/spies/civilian spotters can correct the fire. The way the tube is installed is similar to the positioning of rocket pods. The length and calibre of the barrel indicate Pasilan 2000 system has common features to the Chinese made Type 82 30-tube MLRS (introduced by the Palestinian Liberation Army (PLA) in the early 1980s) rather than rail-guided Katyusha variants such as the Qassam Rocket. The warhead weight is and it is filled with TNT. It had a range of . The rocket has since then undergone some modifications. The Pasilan 2000 was more lethal than Baba mortar. But it was not heavily used for ground attacks during the
Eelam War IV. ==Modern==