Mark IV Tank

1. Lead

The Mark IV was the British heavy tank of 1917, and the most numerous tank of the First World War. It was an improved version of the Mark I tank, with thicker armour, a shorter 6-pounder gun, Lewis machine guns in place of the Vickers guns, and a fuel tank moved outside the fighting compartment, and it was the tank that fought the great tank battles of the war: Messines, Third Ypres, Cambrai and Amiens.

At Cambrai on 20 November 1917, nearly 500 tanks, most of them Mark IVs, broke through the Hindenburg Line in the first great tank attack in history, and the Mark IV became the symbol of the tank in the First World War.

About 1,220 Mark IVs were built, in Male, Female and supply versions, and the type remained in service until the end of the war, when it was replaced by the Mark V tank.

The Mark IV’s importance lies in its numbers and in its use. The Mark I had been an experiment, built in small numbers and used in small groups, but the Mark IV was built in large numbers and used in mass, in the first great tank attacks, and it showed what the tank could do when it was used properly.

The Mark IV’s crews were volunteers, and they learned to drive, to maintain and to fight in the tank, and to use it in conjunction with the infantry and the artillery, and they developed the tactics that the Tank Corps used for the rest of the war.

The Mark IV was also the first tank to be used by the Germans, who captured a number of Mark IVs and used them against the British, and it was the first tank to fight another tank, when British Mark IVs met German A7Vs at Villers-Bretonneux in April 1918.

2. Key Facts

Type	Heavy tank
Origin	Britain
Designers	William Tritton and Walter Wilson
Manufacturers	Metropolitan Carriage, Wagon and Finance Co.; William Foster & Co.; others
In service	1917–1918
Produced	1917; about 1,220 built (420 Male, 595 Female, 205 supply)
Weight	About 28–29 tonnes
Length	About 8.1 m
Width	About 4.1 m (Male, with sponsons)
Height	About 2.5 m
Crew	8 (commander, driver, two gearsmen, four gunners)
Armour	6–14 mm
Main armament (Male)	Two 6-pounder (57 mm) guns; four Lewis machine guns
Main armament (Female)	Five Lewis machine guns
Engine	Daimler six-cylinder petrol, 125 hp
Top speed	About 6 km/h on level ground
Range	About 56 km

3. Background and Development

The lessons of the Mark I

The Mark IV was developed from the experience of the Mark I tank, which had first fought at Flers-Courcelette in September 1916. The Mark I had proved the idea of the tank, but it had also shown its weaknesses: its armour was thin, its Vickers machine guns were unreliable, its 6-pounder guns were too long and caught on the ground, its fuel tank was inside the fighting compartment and caught fire when the tank was hit, and its crew worked in appalling conditions, with the engine inside the fighting compartment filling the tank with heat and fumes.

The Tank Corps, which had been formed in 1916, asked for a tank that corrected these faults, and the result was the Mark IV, which was designed by William Tritton and Walter Wilson, the designers of the Mark I, and which was built by the Metropolitan Carriage, Wagon and Finance Company and by Foster’s of Lincoln.

The Mark IV’s improvements were practical and important. Its armour was thicker, up to 14 mm on the front and on the sponsons, which gave the crew better protection against German machine-gun fire and against the armour-piercing rifle bullet. Its 6-pounder guns were shorter, which made them easier to use in the sponsons and which prevented them from catching on the ground.

Its machine guns were Lewis guns, which were more reliable than the Vickers guns and which could be removed from the tank and used by the infantry. Its fuel tank was moved outside the fighting compartment, to the rear of the vehicle, which reduced the risk of fire, and its unditching beam, a large wooden beam carried on the roof, could be used to free the tank when it became stuck in the mud.

The Mark IV was still slow, still difficult to drive and still uncomfortable, but it was a considerable improvement on the Mark I, and it was the tank that the British Army needed in 1917.

Production in large numbers

The Mark IV was built in large numbers, and it was the first tank to be built in mass production. About 1,220 Mark IVs were built in 1917, by the Metropolitan Carriage, Wagon and Finance Company, by Foster’s of Lincoln and by other firms, and they were built in three versions: the Male, armed with two 6-pounder guns and four Lewis machine guns, of which 420 were built; the Female, armed with five Lewis machine guns and no cannon, of which 595 were built; and the supply tank, which carried supplies, ammunition and water to the infantry, of which 205 were built.

The Mark IV’s production was a remarkable achievement, given the state of British industry in 1917, when the factories were working day and night to produce tanks, guns and ammunition for the war, and when materials and labour were in short supply. The Mark IV’s production was the first mass production of tanks in history, and it showed that tanks could be built in large numbers, like guns and shells.

The fascine and the unditching beam

The Mark IV was fitted with two devices that became characteristic of the British heavy tanks: the fascine and the unditching beam. The fascine was a large bundle of brushwood, carried on the front of the tank and dropped into a trench to fill it, so that the tank could cross it, and it was used at Cambrai in 1917, where the tanks crossed the wide trenches of the Hindenburg Line.

The unditching beam was a large wooden beam, carried on the roof of the tank and chained to the tracks, which could be used to free the tank when it became stuck in the mud: the beam was placed under the tracks, and the tank drove over it, lifting itself out of the mud.

The fascine and the unditching beam were simple devices, but they were effective, and they showed how the British Army had learned to use the tank in the conditions of the Western Front, where the ground was wet and broken and where the trenches were wide and deep.

4. Design

The rhomboid hull and the tracks

The Mark IV kept the rhomboid shape of the Mark I tank, and for the same reason: to cross trenches. Its tracks ran around the whole body of the vehicle, so that the front of the track could climb out of a trench and the rear could push the vehicle forward, and the Mark IV could cross a trench about 3.5 metres wide, climb a slope of about 45 degrees and crush barbed wire under its tracks.

The tracks were made of cast steel links, and they were driven by a Daimler engine through a gearbox that was so difficult to operate that the tank needed two men — the driver and the commander, or the driver and one of the gearsmen — to change gear.

The Mark IV’s hull was of riveted construction, with armour up to 14 mm thick on the front and on the sponsons, which was thicker than the Mark I’s armour and which gave the crew better protection against German machine-gun fire and against the armour-piercing rifle bullet, although it was still not enough to stop German artillery.

Armour and armament

The Mark IV’s armour was thicker than that of its predecessor: 14 mm on the front and on the sponsons, 12 mm on the sides and 6 mm on the rear and on the roof. It was enough to stop rifle bullets and machine-gun fire, and it gave the crew better protection than the Mark I’s 12 mm, but it was not enough to stop the German armour-piercing rifle bullet at close range, and it was certainly not enough to stop German artillery.

The Male’s armament was two 6-pounder (57 mm) guns, mounted in sponsons on the sides of the vehicle, and four Lewis machine guns, and the Female’s armament was five Lewis machine guns. The 6-pounder guns were shorter than those of the Mark I, which made them easier to use in the sponsons and which prevented them from catching on the ground, and they fired high-explosive shells against infantry and armour-piercing shells against German strongpoints, while the Lewis machine guns swept the German trenches with fire.

The crew and conditions inside

The Mark IV’s crew of eight worked in conditions that were better than those of the Mark I, but still harsh by any later standard. The fuel tank had been moved outside the fighting compartment, which reduced the risk of fire, and the engine was still inside the fighting compartment, filling the tank with heat, noise, fumes and carbon monoxide.

The temperature inside the tank could reach 50 degrees Celsius, and the crew wore goggles and masks to protect themselves from the fumes and from the splinters that flew off the inside of the armour when it was hit. The tank was steered by the driver, who controlled the tracks with levers, and by two gearsmen, who worked the gearbox, and changing gear required the driver and the gearsmen to work together, which made the tank very difficult to drive.

The crew communicated by hand signals, because the noise of the engine made speech impossible, and the tank’s speed, about 6 km/h on level ground, meant that it moved at walking pace.

5. Variants

Variant	Year	Key features	Production
Mark IV Male	1917	Two 6-pounder guns; four Lewis machine guns	420
Mark IV Female	1917	Five Lewis machine guns; no cannon	595
Mark IV supply tank	1917	Carried supplies; sponsons removed	205
Mark IV Tadpole	1917	Lengthened tail for crossing wider trenches	Small numbers
Mark IV Composite	1917	One Male sponson and one Female sponson	Small numbers

Male, Female and supply tanks

The Mark IV was built in three versions, and the difference between them was their armament and their role. The Male carried two 6-pounder guns and four Lewis machine guns, and it was intended to destroy German machine-gun posts, strongpoints and artillery, while the Female carried five Lewis machine guns and no cannon, and it was intended to protect the Male from German infantry.

The supply tank, which had its sponsons removed and its interior fitted out to carry supplies, ammunition and water, was used to carry supplies to the infantry in the front line, and it was the ancestor of the armoured supply vehicles of the Second World War.

The three versions were built in large numbers, and they fought together, with the Male and the Female in pairs and the supply tanks following them into the captured German trenches. The supply tanks were unarmed, and their crews were unprotected, but they were essential to the infantry, who depended on them for ammunition, water and food.

The Tadpole and the Composite

The Mark IV Tadpole was a lengthened version of the Mark IV, with a tail fitted to the rear of the vehicle, which allowed it to cross wider trenches, up to 4 metres wide, and it was built in small numbers for use at Cambrai, where the trenches of the Hindenburg Line were wider than those of the Somme.

The Tadpole’s tail was a simple extension of the hull, and it was fitted to a small number of Mark IVs, which were used to cross the wide trenches at Cambrai and to carry fascines. The Mark IV Composite, or “hermaphrodite”, was a tank with one Male sponson and one Female sponson, and it was built when a Male sponson was damaged and replaced with a Female sponson, or vice versa, and it was used in the same way as the Male and the Female, although it was less common than either.

6. Operational History

Messines and Third Ypres, 1917

The Mark IV first saw action at Messines in June 1917, where it supported the British attack on the German lines, and it fought at Third Ypres in the summer of 1917, where it fought in the mud of Passchendaele.

At Messines, the tanks were used in larger numbers than at the Somme, and they helped the British to capture the German positions, but many broke down or became stuck in the mud, and the battle was not the breakthrough that had been hoped for.

At Ypres, the tanks were almost useless: the ground was so wet and so broken by shellfire that the tanks sank into the mud and could not move, and many were abandoned in no-man’s-land. The Mark IV’s experience at Ypres showed that the tank could not be used in wet and broken ground, and that it needed to be used on dry ground and in conjunction with the infantry and the artillery.

Cambrai, 20 November 1917

At Cambrai on 20 November 1917, the Mark IV fought its greatest battle, and the first great tank attack in history. Nearly 500 tanks, most of them Mark IVs, were used in a surprise attack on the Hindenburg Line, without a preliminary bombardment, and they broke through the German lines, advancing up to 8 kilometres on the first day and capturing thousands of German prisoners and guns.

The tanks were supported by the infantry, who followed them into the captured German trenches, and by the artillery, which fired on the German positions, and by the aircraft, which attacked the German guns. The battle at Cambrai was a triumph for the tank, and it showed what the tank could do when it was used in large numbers and in a coordinated attack, but it was also a warning: the British had no reserves to exploit the breakthrough, and the Germans counter-attacked and recaptured much of the ground that had been gained.

The breakthrough and the counter-attack

The breakthrough at Cambrai was achieved by the tanks, which crossed the wide trenches of the Hindenburg Line on fascines, crushed the wire under their tracks, and destroyed the German machine-gun posts with their 6-pounder guns. The infantry followed the tanks into the German trenches, and they captured the German positions, and the British advanced 8 kilometres on the first day, the greatest advance on the Western Front since 1914.

But the British had no reserves, and the Germans, who had been surprised by the attack, recovered and counter-attacked on 30 November, recapturing much of the ground that had been gained, and the battle ended in a draw. The lessons of Cambrai were clear: the tank could break through the strongest defences, but it needed reserves to exploit the breakthrough, and it needed to be used in conjunction with the infantry, the artillery and the cavalry.

Cambrai remains one of the most studied battles of the First World War, and it is taught in military academies around the world as an example of the tank’s potential.

The first tank-versus-tank battle

At Villers-Bretonneux on 24 April 1918, the Mark IV fought the first tank-versus-tank battle in history, when three British Mark IVs met three German A7Vs. The British tanks, which were armed with 6-pounder guns, destroyed one A7V and damaged another, and the third A7V withdrew, and the battle showed that the tank could fight other tanks, and that the 6-pounder gun was an effective anti-tank weapon.

The battle at Villers-Bretonneux was a small action, but it was important because it was the first time that tanks had fought each other, and it was a rehearsal for the tank battles of the Second World War, when tanks fought each other in large numbers.

The Mark IV’s role in the first tank battle has made it one of the most famous tanks of the First World War, and it is remembered as the tank that fought the first tank battle. The German A7V, which the Mark IVs met at Villers-Bretonneux, was a large and cumbersome vehicle, and only 20 were ever built.

Amiens and the Hundred Days, 1918

In 1918, the Mark IV fought at Amiens on 8 August, where it spearheaded the attack that began the Hundred Days Offensive, and it fought in the battles that followed, at Albert, at Bapaume and at the Hindenburg Line, where it crossed the St Quentin Canal and broke through the strongest German defences.

The Mark IV was joined by the Mark V tank in 1918, and the two tanks fought together in the great offensives of the last year of the war, and they helped the British to break through the German lines and to advance across France.

The Mark IV’s last battles were fought in the autumn of 1918, and by then the type was being replaced by the Mark V, which was better armed and better armoured, and the surviving Mark IVs were used for training or converted to supply tanks.

The Mark IV’s service in 1918 was the culmination of two years of development, and it showed that the tank had become a mature weapon of war.

7. Performance and Specifications

Specification	Mark IV Male	Mark IV Female
Main armament	Two 6-pounder (57 mm) guns	Five Lewis machine guns
Armour (maximum)	14 mm	14 mm
Armour (front)	14 mm	14 mm
Weight	About 28–29 tonnes	About 28–29 tonnes
Engine	Daimler, 125 hp	Daimler, 125 hp
Power-to-weight	About 4.3 hp per tonne	About 4.3 hp per tonne
Top speed	About 6 km/h	About 6 km/h
Trench crossing	About 3.5 m	About 3.5 m
Range	About 56 km	About 56 km
Crew	8	8
Number built	420	595

Firepower and protection

The Mark IV’s firepower was better than that of the Mark I, because its 6-pounder guns were shorter and easier to use, and because its Lewis machine guns were more reliable than the Mark I’s Vickers guns. The Male’s 6-pounder guns could destroy German machine-gun posts, strongpoints and field guns, and they could fire high-explosive shells against infantry and armour-piercing shells against German strongpoints, while the Female’s Lewis machine guns swept the German trenches with fire and protected the Male from German infantry.

The Mark IV’s armour, at most 14 mm thick, was thicker than the Mark I’s 12 mm, and it gave the crew better protection against German machine-gun fire and against the armour-piercing rifle bullet, although it was still not enough to stop German artillery, which remained the main threat to the tank.

The Mark IV’s real protection was its size and its novelty, and the fact that the German infantry had never seen such a machine and did not know how to fight it.

Mobility and reliability

The Mark IV’s mobility was poor by any later standard, and its reliability was worse. Its top speed was about 6 km/h on level ground, and much less across broken ground, and its range was only about 56 km, which meant that it could not operate far from its start line.

Its engine, a Daimler six-cylinder petrol engine of 125 horsepower, was underpowered for a vehicle that weighed 28 tonnes, and its gearbox was so difficult to operate that the tank needed two men to change gear. The Mark IV broke down constantly: at Cambrai, of the nearly 500 tanks that went into battle, many broke down before they reached the start line, and many more broke down during the battle.

The Mark IV’s tracks, which were made of cast steel links, wore out quickly, and the tank’s steering, which was done by braking one track and driving the other, was difficult and unreliable, and the tank’s crew had to work hard to keep it moving.

8. Operators

Britain: the Tank Corps

The Mark IV was used by Britain, and it was the standard heavy tank of the Tank Corps in 1917 and 1918. The Tank Corps, which had grown from a few hundred men in 1916 to more than 20,000 men by 1918, operated hundreds of Mark IVs in the great offensives of the war, and it became one of the most important arms of the British Army.

The Mark IV’s crews were volunteers, and many of them were engineers, mechanics and drivers who had joined the army to work on the new machines, and they learned to drive, to maintain and to fight in the tank, and to use it in conjunction with the infantry and the artillery.

The Tank Corps’ success in 1917 and 1918 was due in large part to the Mark IV, and to the tactics that the Tank Corps had developed for its use, and the Mark IV remained the standard tank of the Tank Corps until it was replaced by the Mark V in 1918.

Germany: captured Mark IVs

The Germans captured a number of Mark IV tanks, and they used them against the British, under the designation Beutepanzer. The Germans captured Mark IVs at Cambrai in 1917, where they captured more than 100 tanks, and they repaired them and used them in their own tank units, which were equipped with captured British tanks and with the German A7V.

The German Beutepanzer units fought at Villers-Bretonneux in April 1918, where they met British Mark IVs in the first tank-versus-tank battle, and they fought in the German offensives of 1918, where they were used to support the German infantry. The Germans also studied the captured Mark IVs carefully, and they learned from them, although they did not build a tank of their own in large numbers, and they believed that the machine gun and the artillery were more important than the tank.

The German use of captured Mark IVs was the first use of captured tanks in warfare, and it set a precedent that was followed in the Second World War.

9. Legacy and Influence

The tank of Cambrai

The Mark IV’s legacy is that it was the tank of Cambrai, and the tank of the first great tank attack in history. At Cambrai on 20 November 1917, nearly 500 Mark IVs broke through the Hindenburg Line, and they showed what the tank could do when it was used in large numbers and in a coordinated attack, and they changed the course of the war.

The Mark IV’s role at Cambrai has made it one of the most famous tanks of the First World War, and it is remembered as the tank that proved the tank, and as the tank that showed the way forward for tank warfare.

The Mark IV’s design, with its rhomboid shape, its sponsons and its tracks running around the whole body of the vehicle, became the classic image of the First World War tank, and it has remained the most recognisable image of the tank of that war.

The Mark IV in history and memory

The Mark IV is remembered today as the most numerous tank of the First World War, and as the tank that fought the first tank-versus-tank battle, at Villers-Bretonneux in April 1918. Its role at Cambrai and at Villers-Bretonneux has made it a symbol of the British Tank Corps, and of the invention of the tank, and it is remembered in Britain as a triumph of British engineering, and as a weapon that helped to win the war.

The Mark IV is also remembered in the towns where it stands as a memorial: at Ashford in Kent, where a Mark IV Male stands in the town centre, and at Lincoln, where Foster’s built the first tanks, and at the Tank Museum in Bovington, where the Mark IV is displayed alongside the other tanks of the war.

Historians have qualified the judgement that the Mark IV won the war, but its contribution to the Allied victory in 1918 was real, and it was the tank that made the tank a weapon of decision.

10. Surviving Examples

The Tank Museum, Bovington

Several Mark IV tanks survive, and the best-known examples are held at the Tank Museum in Bovington, England. The museum holds a Mark IV Female, which was presented to the museum after the war, and which is displayed alongside the museum’s other First World War tanks, including the Mark I, Mark II and Mark V.

The museum also holds a Mark IV Male, and the two tanks are displayed in the order in which they were built, so that visitors can see how the tank developed from the Mark I to the Mark IV. For most visitors, the easiest way to see a Mark IV is at Bovington, where the museum’s First World War tanks are displayed together, and where the Mark IV’s rhomboid shape and its sponsons can be seen in full, and where the museum’s guides explain the tank’s role at Cambrai and at Villers-Bretonneux.

The museum’s Mark IV is one of the most popular vehicles in its First World War collection, and it is regularly photographed by visitors from around the world.

Ashford, Brussels, Canberra and Saumur

Other surviving Mark IVs are held in several places around the world, and they are among the most famous tanks of the First World War. At Ashford in Kent, a Mark IV Male stands in the town centre, where it has stood since 1919, when it was presented to the town as a memorial to the men of Ashford who died in the war.

At Brussels, the Royal Museum of the Armed Forces holds a Mark IV Male, which was captured by the Germans and used by them, and which was later recaptured by the British. At Canberra, the Australian War Memorial holds a Mark IV Female, known as “Grit”, which was presented to Australia after the war.

At Saumur in France, the Musée des Blindés holds a Mark IV Male, and at Lincoln, the Museum of Lincolnshire Life holds a Mark IV Female, known as “Flirt II”, which was built by Foster’s in the town.

Frequently Asked Questions

What is the Mark IV tank?
The Mark IV was a British heavy tank of 1917, an improved version of the Mark I with thicker armour, a shorter 6-pounder gun and Lewis machine guns. About 1,220 were built.

How many Mark IV tanks were built?
About 1,220 Mark IV tanks were built in 1917 — 420 Male, 595 Female and 205 supply tanks — making it the most numerous tank of the First World War.

What happened at Cambrai?
On 20 November 1917, nearly 500 tanks, most of them Mark IVs, broke through the Hindenburg Line at Cambrai in the first great tank attack in history, advancing up to 8 kilometres on the first day.

What is the difference between a Male and a Female Mark IV?
The Male was armed with two 6-pounder guns and four Lewis machine guns, and the Female was armed with five Lewis machine guns and no cannon. The Female was intended to protect the Male from German infantry.

What was the first tank-versus-tank battle?
At Villers-Bretonneux on 24 April 1918, three British Mark IVs met three German A7Vs. The British destroyed one A7V and damaged another, and the third withdrew.

Where can I see a Mark IV today?
Mark IVs survive at the Tank Museum in Bovington, England, at Ashford in Kent, at Brussels, at the Australian War Memorial in Canberra and at Saumur in France.

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Sources

1. Wikipedia, “Mark IV tank” — production of about 1,220, specifications, Cambrai and Villers-Bretonneux.
2. The Tank Museum, Bovington, “Mark IV” — the development of the Mark IV and the surviving examples.
3. David Fletcher, British Mark IV Tank (Osprey Publishing, 2007) — design, development and the Cambrai attack.
4. Paddy Griffith, Battle Tactics of the Western Front (Yale University Press, 1994) — the tank at Cambrai and Amiens.
5. John Glanfield, The Devil’s Chariots (Sutton Publishing, 2006) — the Tank Corps in 1917 and 1918.
6. Tank Encyclopedia, “Mark IV” — specifications, variants and surviving examples.