Warfare in the Trenches: Petersburg to Cambrai

Battle of Petersburg

June 1864 the massive Union army commanded by General Grant arrived outside Petersburg, VA intent on cutting off Richmond and end the American Civil War. General Lee lie in wait intent on holding this vital city. Known as the Siege of Petersburg, it was not a classic siege, in which a city is usually fully surrounded and all supply lines are cut off. Instead was ten months of trench warfare in which the Union forces assaulted Petersburg unsuccessfully and then constructed trench lines that eventually extended over 30 miles around the eastern and southern outskirts of the city.

The siege only ended when Lee abandoned the city when his supply lines were finally threatened. His retreat ended at Appomattox Courthouse and marked the end of the American Civil War. The Siege of Petersburg foreshadowed the trench warfare that would be common in World War I.

The Battle of Petersburg was a costly campaign for both sides. The initial assaults on Petersburg in June 1864 cost the Union 11,386 casualties, to approximately 4,000 for the Confederate defenders. The casualties for the siege warfare that concluded with the assault on Fort Stedman are estimated to be 42,000 for the Union and 28,000 for the Confederates.

Wikipedia has a great timeline of the campaign to include maps! Check it out at: Siege of Petersburg.

Age of Colonialism

Over the next 50 years numerous wars raged around the world most of them were fairly localized affairs between indigenous people and their colonial masters. Trench warfare was almost nonexistent in these fights but glimpses of the deadly effectiveness of holding ground with entrenched infantry are prevalent. The Spanish held San Juan Hill, okay not so successfully but the Boer inflicted crippling losses against the British at Magersfontein. The bloodbath during the Siege of Port Arthur during the Russo-Japanese War would be repeated a few years later all over Europe.

World War I

In August 1914 Europe exploded in war, most armies prepared for a brief war whose strategy and tactics would have been familiar to Napoleon. Indeed, a number of horse cavalry units were brought to the front by train, commanded by officers who did not imagine the factors that would render them useless. Most of these units were never deployed. However, as war broke out, German and Allied (mostly French and British) forces soon learned that with modern weapons even a shallow scrape in the soil could be defended by a handful of infantry. To attack frontally was to court crippling losses, so an outflanking operation was essential. After the Battle of the Aisne in September 1914, an extended series of attempted flanking moves, and matching extensions to the fortified defensive lines, soon saw the celebrated "race to the sea"; German and Allied armies produced essentially a matched pair of trench lines from the Swiss border in the south to the North Sea coast of Belgium. Trench warfare prevailed on the Western Front from September 16, 1914, until the Germans launched their "Spring Offensive", Operation Michael, on March 21, 1918.

To break the stalemate, both sides sought technological advantages resulting in a hell on earth.

Gas

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.

Wire

The use of barbed wire was decisive in slowing infantry traveling across the battlefield. Without it, fast moving infantry (or cavalry) might cross the lines and reach the enemy machine gun posts and artillery. Slowed down by the barbed wire, they were much more likely to be shot down by machine guns or rifles. Liddell Hart identified barbed wire and the machine gun as the elements that had to be broken to regain a mobile battlefield. Wiring was usually done at night, to avoid casualties in no man's land. The screw picket, invented by the Germans (and later adopted by the Allies) during the war, was quieter than driving stakes, and thus helped decrease the amount of noise working parties would create. Methods to defeat it were rudimentary. British and Commonwealth forces relied on wire cutters, which proved unable to cope with the heavier gauge German wire. The Bangalore torpedo was adopted by many armies, and continued in use past the end of World War II.

Aircraft

The fundamental purpose of the aircraft in trench warfare was reconnaissance and artillery observation. Aerial reconnaissance was so significant in exposing movements, it has been said the trench stalemate was a product of it. The role of the fighter was to protect friendly reconnaissance aircraft and destroy those of the enemy, or at least deny them the freedom of friendly 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 map trench lines (first with hand-drawn diagrams, later photographs), monitor enemy troop movements, and locate enemy artillery batteries so that they could be destroyed with counter-battery fire. Some ingenious pilots would carry bricks with them when going on flights in order to drop on the enemy, before dropping bombs became more commonplace. As the war progressed bomber aircraft would take to the sky and attempt to destroy enemy rear areas.

Flame Throwers

The Germans employed flame throwers (Flammenwerfer) during the war but as the technology was in its infancy, its value was mostly psychological.

Mining

One of the first instances of trench mining occurred in the American Civil War during the Battle of the Crater on July 30, 1864. Union engineers tunneled beneath Confederate trenches in a failed attempt to break through to the city of Petersburg, Virginia. The dry chalk of the Somme was especially suited to mining, but with the aid of pumps, it was also possible to mine in the sodden clay of Flanders. Specialist tunneling companies, usually made up of men who had been miners in civilian life, would dig tunnels under no man's land and beneath the enemy's trenches. These mines would then be packed with explosives and detonated, producing a large crater. The crater served two purposes: it could destroy or breach the enemy's trench and, by virtue of the raised lip that they produced, could provide a ready-made "trench" closer to the enemy's line. When a mine was detonated, both sides would race to occupy and fortify the crater.

If the miners detected an enemy tunnel in progress, they would often drive a counter-tunnel, called a counter-mine or camouflet, which would be detonated in an attempt to destroy the other tunnel prematurely. Night raids were also conducted with the sole purpose of destroying the enemy's mine workings. On occasion, mines would cross and fighting would occur underground. The mining skills could also be used to move troops unseen. On one occasion a whole British division was moved through interconnected workings and sewers without German observation. The British detonated a number of mines on July 1, 1916, the first day of the Battle of the Somme. The largest mines-the Y Sap Mine and the Lochnagar Mine-each containing 24 tons of explosives, were blown near La Boiselle, throwing earth 4,000 feet into the air.

At 3.10 AM on June 7, 1917, 19 mines were detonated by the British to launch the Battle of Messines. The average mine contained 21 tons of explosive and the largest, 125 feet beneath Saint-Eloi, was twice the average at 42 tons. The combined force of the explosions was supposedly felt in England. As the Chief of Staff of the British Second Army, General Sir Charles Harrington, commented on the eve of the battle:

I do not know whether we shall change history tomorrow, but we shall certainly alter the geography.

Tanks

The stalemate on the Western Front prompted the British Army to begin research into a self-propelled vehicle which could cross trenches, crush barbed wire, and be impervious to machine-gun fire.

Originally, tanks were part of the British Navy, which would train and provide all tank personnel, and were considered "landships". The First Lord of the Admiralty, Winston Churchill, sponsored the Landships Committee, which created the first successful prototype tank, 'Little Willie', in September 1915. The vehicles were colloquially referred to as water carriers, later shortened to tanks, to preserve secrecy; the name became official in December 1915.

The first tank to engage in battle was D1, a British Mark I, during the Battle of Flers-Courcellette (part of the Battle of the Somme), on 15 September 1916, one of two to breach German lines and reach Flers, but was knocked out by friendly fire. One of these two also mistakenly machinegunned the 9th Norfolks, who were preparing to attack. The French developed the Schneider CA1 working from Holt caterpillar tractors, and first used it on 16 April 1917. The first successful use of massed tanks in combat occurred at Cambrai on 20 November 1917. Tanks were also used to great effect in the Battle of Amiens, when Allied forces were able to break through entrenched German position due to armoured support.

Germany fielded very few tanks during World War I, with the A7V being the only type produced in Germany before the end of the war, and of which only 15 were built. The first tank versus tank action took place on 24 April 1918 at Villers-Bretonneux, France, when three British Mark IVs met three German A7Vs. German forces initially lacked countermeasures, though they did (accidentally) discover solid anti-tank shot, and introduced wider trenches to limit the British tanks' mobility. However, changing battlefield conditions and continued unreliability forced Allied tanks to evolve throughout the war, producing models such as the very long Mark V, which could navigate large obstacles, especially wide trenches, more easily than their predecessors.

Initial results with tanks were mixed; significant reliability problems caused considerable attrition in combat, with up to one third breaking down due to mechanical problems unrelated to enemy fire, and their speeds were very slow, with the 13.4 km/h attained by the Whippet considered fast. Deployment in 'penny packets' also lessened their nonetheless formidable tactical value and impact. The spear-thrust type blitzkrieg-tactics were only to be developed fully in WWII, and while the tank would eventually make trench warfare obsolete, World War I came to an end before this fully came to pass.

During World War I two major types of tanks had evolved: the 'male', with large calibre guns, and the 'female', which only had machine guns. The 'female' was mainly designed as an anti-infantry platform to defend the 'male'. After World War I ended, the 'female' was largely replaced by machine gun carriers (such as the Bren carrier), and later by armoured personnel carriers.

Post War

While none of these advances proved decisive in ending the war they did spark the imagination of many great military minds. Patton, Hobart, Guderian, Chaffee, de Gaulle and Tukhachevsky would all develop armor tactical theories. Germany would put the theory into practice, and it was their superior tactics, not superior weapons, that would make blitzkrieg so formidable. Mitchell envisioned vast air armadas that would see the end of battleships and that could lay waste to industrial centers behind enemy lines. Many of these visionaries proved right just 30 years after the war to end all wars concluded on November 11, 1918.