Infantry weapons

The common infantry soldier had three weapons at his disposal in the trenches: the rifle, bayonet, and grenade.

The standard British rifle was the .303 Short Magazine Lee-Enfield, which was originally developed as a cavalry carbine and had an effective range of 1400 yards, though in the hands of the average soldier, 200 yards was about the limit of accurate fire. British infantry training emphasised rapid fire rifle shooting rather than accuracy. Early in the war, the British were able to defeat German attacks at Mons and the First Battle of Ypres using massed rifle fire, but as trench warfare developed, opportunities to assemble a line of riflemen became rare.

The British soldier was equipped with a 21-inch sword bayonet, which was too long and unwieldy to be particularly effective in close quarters combat. However, bayonet use was safer than firing the rifle which, in a melee, might strike an ally instead of an enemy. British figures recorded that only 0.3% of wounds were caused by bayonets, however, a strike from a bayonet was highly likely to result in death. A bayonet charge could be effective at inducing terror in an opponent, encouraging them to flee or surrender. The bayonet was used to finish off wounded enemy during an advance, saving ammunition while reducing the possibility of being attacked from the rear.

Many soldiers preferred a short handled spade or entrenching tool over a bayonet. They would sharpen the blade to a knife edge so it was just as effective as a bayonet and the shorter length made them handier to use in the confined quarters of the trenches. These tools could then be used to "dig in" after they had taken a trench.

The grenade came to be the primary infantry weapon of trench warfare. Both sides were quick to raise specialist bombing squads. The grenade enabled a soldier to engage the enemy indirectly (without exposing himself to fire) and it did not require the precise accuracy of rifle fire in order to kill or maim. The Germans and Turks were well equipped with grenades from the start of the war, but the British, who had ceased using grenadiers in the 1870s, entered the war with virtually none, such that soldiers had to improvise bombs with whatever was available. By late 1915, the British Mills bomb had entered wide circulation, and by the end of the war 75 million of them had been used.

Machine guns

The machine gun is perhaps the signature weapon of trench warfare, with the image of ranks of advancing infantry being scythed down by the withering hail of bullets. The Germans embraced the machine gun from the outset -- in 1904, every regiment was equipped with one machine gun -- and the machine gun crews were the elite infantry units. After 1915, the MG 08/15 was the standard-issue German light machine gun; its number entered the German language as an idiomatic expression for "dead plain". At Gallipoli and in Palestine the Turks provided the infantry, but it was usually Germans who manned the machine guns.

The British high command were less enthusiastic about machine gun technology, supposedly considering the weapon too "unsporting", and they lagged behind the Germans in adopting the weapon. However, by 1917, every company in the British forces was equipped with four Lewis guns, which significantly enhanced their firepower.

The heavy machine gun was a specialist weapon, and in a static trench system was employed in a scientific manner, with carefully calculated fields of fire, so that at a moment's notice an accurate burst could be laid upon the enemy's parapet or at a break in the wire. The British water-cooled Vickers machine gun required a 16 man crew and cost £30 a minute to operate. Each belt of ammunition had to be hand loaded with 250 rounds and the barrel of the gun had to be changed after two belts were fired. It was a fragile and difficult weapon to maintain and operate, but was very effective.

Mortars

Mortars, which lobbed a shell a relatively short distance, were widely used in trench fighting for harassing the forward trenches and for cutting wire in preparation for a raid or attack. In 1914, the British fired a total of 545 mortar shells. In 1916, they fired over 6,500,000 shells.

The main British mortar was the Stokes mortar, which was the precursor of the modern mortar. It was a light mortar, but was easy to use, and capable of a rapid rate of fire by virtue of the propellant cartridge being attached to the shell. To fire the Stokes mortar, the round was simply dropped into the tube, where the cartridge was ignited automatically when it struck the firing pin at the bottom.

The Germans used a range of mortars. The smallest were grenade-throwers(granatenwerfer) which fired "pineapple" bombs. Their medium trench-mortars were called mine-throwers (minenwerfer), dubbed "minnies" by the British. The heavy mortar was called the ladungswerfer which threw "aerial torpedoes", containing a 200 lb (90 kg) charge, over 1000 yards. The flight of the missile was so slow and leisurely that the men on the receiving end could make some attempt to seek shelter.

Artillery

Artillery dominated the battlefield of trench warfare in the same way the air power dominates the modern battlefield. An infantry attack was rarely successful if it advanced beyond the range of its supporting artillery. In addition to bombarding the enemy infantry in the trenches, the artillery would engage in counter-battery duels to try to destroy the enemy's guns.

Artillery mainly fired shrapnel, high explosives or, later in the war, gas shells. The British experimented with firing incendiary "thermite" shells to set trees and ruins alight.

Artillery pieces were of two types; guns and howitzers. Guns fired high velocity shells over a flat trajectory and were often used to delivershrapnel and to cut barbed wire. Howitzers lofted the shell over a hightrajectory such that it plunged into the ground. The biggest artillerywere usually howitzers. The German 420 howitzer weighed 20 tons and couldfire a one ton shell over six miles.

A critical feature of modern artillery pieces was the hydraulic recoil mechanism which meant that the gun did not need to be re-aimed after each shell was fired. Initially each gun would need to register its aim on a known target, in view of an observer, in order to fire with precision during a battle. The process of gun registration would often alert the enemy that an attack was being planned. Towards the end of 1917, artillery techniques were developed enabling guns to be aimed accurately without the need for registration.

Gas

See main article: Use of poison gas in World War I

Tear gas was first employed in August 1914 by the French but this could only disable the enemy. In April 1915, chlorine was first used by Germany at the Second Battle of Ypres. A large enough dose could kill but the gas was easy to detect by scent and sight. Those that were not killed on exposure could suffer permanent lung damage.

Phosgene, first used in December 1915, was the ultimate killing gas of World War I — it was 18 times more powerful than chlorine and much more difficult to detect. However, the most effective gas was mustard gas, introduced by Germany in July 1917. Mustard gas was not as fatal as phosgene but it was hard to detect and lingered on the surface of the battlefield and so could inflict casualties over a long period. The burns it produced were so horrific that a casualty resulting from mustard gas exposure was unlikely to be fit to fight again. Only 2% of mustard gas casualties died, mainly from secondary infections.

The first method of employing gas was by releasing it from a cylinder when the wind was favourable. Such an approach was obviously prone to miscarry if the direction of the wind was misjudged. Also the cylinders needed to be positioned in the front trenches where they were liable to be ruptured during a bombardment. Later in the war, gas was delivered by artillery or mortar shell.

Helmets

During the first year of the war, none of the combatant nations equipped their troops with steel helmets. Soldiers went into battle wearing simple cloth or leather caps that offered virtually no protection from the damage caused by modern weapons. German troops were wearing the traditional leather pickelhaube (spiked helmet), with a covering of cloth to protect the leather from the splattering of mud. Once the war entered the phase of trench warfare, the number of lethal head wounds that troops were receiving from shrapnel increased dramatically.

The French were the first to see a need for greater protection and began to introduce the first steel helmets in the summer of 1915. The Adrian helmet (designed by August-Louse Adrian) replaced the traditional French kepi and was later adopted by the Belgian and Italian armies.

At about the same time the British were developing their own helmets. The French design was rejected as not strong enough and too difficult to mass produce. The design that was eventually approved by the British was the Brodie helmet (designed by John L. Brodie) This British helmet had a wide brim to protect the wearer from falling objects but offered less protection to the neck of the wearer.

The traditional German pickelhaube was replaced by the stahlhelm or "coal-scuttle helmet" in 1916.

Other

The fundamental purpose of the aircraft in trench warfare was reconnaissance and artillery observation. The role of the fighter was to protect his own reconnaissance aircraft and to destroy those of the enemy, or at least deny them the freedom of his airspace. This involved achieving air superiority over the battlefield by destroying the enemy's fighters as well. Spotter aircraft would monitor the fall of shells during registration of the artillery. Reconnaissance aircraft would photograph trench lines, monitor enemy troop movements, and locate enemy artillery batteries so that they could be destroyed with counter-battery fire.

The Germans employed flame throwers (flammenwerfer) during the war but the technology was not mature so they were more effective at inducing terror than inflicting casualties.