Tanks had been used in World War I since the Somme in 1916, but for more than a year, they never accomplished more than limited local successes. They had been designed to break the stalemate of trench warfare, but clearly, they were not being used effectively enough. Responding to the suggestions of Colonel J.F.C. Fuller, General Sir Julian Byng resolved to give the Tank Corps a proper opportunity to demonstrate the power of their weapon. The Battle of Cambrai became the first battle to use tanks in large numbers, operating in concert with each other and being supported by the infantry.
Essentially, the Battle of Cambrai was a recognition of failure in the Battle of Passchendaele, which followed conventional infantry assault tactics on a massive scale. Significantly, Byng began his planning with only two objectives: to see what the tanks could accomplish, and to hurt the enemy. With no grander objectives in mind, he selected a stretch of the Hindenburg Line outside of the city of Cambrai as his target. This area had seen little fighting previously, and in fact, the troops stationed there were often units that had fought in other sectors and were brought to Cambrai to rest. The area offered the additional virtue of terrain that was well-suited to tank use.
The British “Tank Corps” in late 1917 comprised nine battalions organized under three brigades. It had 378 new Mark IV tanks for the main effort and a further 98 older tanks, mostly Mark I and II, that remained suitable for support tasks, including one tank per battalion equipped with a radio for communications purposes. Brigadier Hugh Elles commanded this force, all of which was used at Cambrai, with Fuller as his chief of staff. Determined to make the best possible use of their tanks, they planned meticulously to maximize the impact of three key factors: terrain, mass of force, and surprise.
In general, the terrain already favored the use of tanks; this was one of the main reasons for the choice of this section of the line. It was, however, important to ensure that the artillery barrage that opened the attack did not undo this advantage by breaking up the landscape into a series of ridges and craters. While the artillery still had a role to play, it was the tank that was to be the primary disruptor of organized resistance. When the attack began, the artillery barrage was to be short, and targets were selected based on map coordinates rather than using the observation of live fire.
The massing of tanks for a heavy blow was another major priority. The entire Tank Corps was brought to the battle, and tanks would lead the attack, with the infantry following in their wake to secure and hold the ground that was gained. The tanks were to advance in groups of three for mutual support and to facilitate the crossing of up to three lines of trench. On the larger scale, the number of such teams (14 per battalion, or 126 along a line of roughly six miles) ensured the thorough disruption of the German defenders.
Surprise operated on many levels. At the most basic level, the tank was still a relatively new weapon and few German soldiers involved in the battle had encountered them before. Moreover, they had not been used in such concert when they had been used previously, and in the initial wave of the attack, the defenders would have few options for resisting such an assault. Elaborate measures were undertaken to conceal the preparations for a major offensive. The tanks were moved into place at night, driving at a slow speed to keep the sounds of their engines from alerting the Germans. False preparations, including the use of dummy tanks, were undertaken in nearby sectors, and the local infantry was kept unaware of their commanders’ plans. Soldiers captured during routine trench raids were unable to provide useful intelligence because they did not know, themselves, what was planned.
Even the weather was a factor. While specific conditions for the day of the attack could not be guaranteed, misty conditions were expected, and this held true in the event. Not only did the mist veil the ground attack, but it also discouraged aerial reconnaissance on the German side. (For their part, the British sent up planes in large numbers, to reassure their commanders that their attack had not been detected prematurely.) Finally, the brevity of the artillery barrage contributed to surprise at Cambrai. As Guderian has observed in his analysis of the battle in Achtung, Panzer!, the Germans took cover when the barrage began, expecting it to last for several hours, during which they could wait in relative safety before the attack began in earnest. Instead, the tanks emerged from the mist while most were taking cover, and only a few sentries occupied forward positions.
The tactics used in the attack were highly original and well-suited to the circumstances. Each team consisted of one “male” tank (carrying two cannons and four machine guns) and two “female” tanks (carrying six machine guns), with a large bundle of wood tied to the top. They approached the trench in a triangle formation with the “male” in front. This lead tank turned left before it reached the trench, firing into it with all weapons on its right side. The first of the “females” followed, dropping the bundle of wood into the trench and using it as a bridge for crossing over to the other side. Then it turned left and fired at the garrisons in the trenches on both sides of it. The second “female” crossed over the first bridge, dropped its bundle of wood into the support trench, and crossed it.
By this point, the supporting infantry was reaching the trenches, helping to finish off the remaining defenders and taking possession of the earthworks. By following the tanks, they were able to move much more quickly; the tanks had been far more effective at flattening and dragging away the barbed wire than artillery barrages had ever been. With the infantry in position, the first two tanks were able to cross over the bridges and rejoin the third; where a third trench line was in place, the first tank had a bundle for crossing that line. In this way, the tank teams were able to gather for further action.
The result was a spectacular success. The first day’s fighting had won as many as five miles of territory in some places; comparable results were the result only of several months of heavy fighting in other battles. Much to Byng’s frustration, however, he was unable to build upon this victory in the days ahead. The attack had accomplished all of his original goals, but as his preparations advanced, he began to envision the great breakthrough that Entente commanders had been seeking for three years. He increased the forces dedicated to the original attack, and left little in reserve to exploit the breakthrough that he hoped to achieve. Some cavalry units had been kept for this purpose, but on November 20, the day the battle opened, they were not in position to participate until late in the day, and when they did, they were unable to make any headway.
179 tanks were unable to continue the attack the next day. Many of these were salvaged and repaired later, but this robbed the Tank Corps of much of its mass in the next days of fighting. Furthermore, the course of battle had separated units, frustrating efforts at organized command, and as Fuller noted, the effective coordination of tanks and infantry ceased as well. On the German side, the element of surprise was gone, and German forces were looking for ways to combat the tanks arrayed against them. By the 23rd, the Tank Corps’ effective strength was reduced to 92. With neither mass nor surprise on its side, the Tank Corps had ceased to be a major contributor to the fighting before Cambrai, which assumed the characteristics of an infantry battle. On November 30, the Germans counterattacked, reclaiming about half of the territory they had lost.
The tank contribution at Cambrai offered the Tank Corps valuable lessons, inspiring improvements to the Mark IV and the creation of a lighter tank, the Whippet, to replace the cavalry in the exploitation of a breakthrough. Commanders on both sides were also compelled to reassess the tank as a weapon, although the spectacular gains of the first day were partially obscured by subsequent losses. Allied leaders failed to envision an independent role for the tank; the Germans concentrated on ways to neutralize tanks, but after the war was over, they would study battles like Cambrai and use those lessons to restore mobility to the modern battlefield.
Sources:
Guderian, Heinz. Achtung – Panzer! The Development of Tank Warfare. Cassell Military, 2007
Hart, Stephen. Atlas of Tank Warfare: From 1916 to the Present Day. Amber Books, 2012
Livesey, Anthony. Great Battles of World War I. Smithmark Publishers, Inc. 1997
Ibid. The Historical Atlas of World War I. Henry Holt, 1994.
Simkins, Peter. Essential Histories: The First World War (3): The Western Front 1917-1918. Osprey, 2002
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