All the British as well as US tank units in Italy were equipped with Shermans, except for a number of US-built M5 light tanks, which were a direct development of the earlier M3 light tanks, and the Churchill infantry tanks of the two British independent tank brigades. The same types of tanks were used by the Allied forces that landed in Normandy in June 1944, except for some British armoured units that were equipped with a new type of cruiser tank, the 27.5-tonne Cromwell, instead of Shermans.
Development that led to the Cromwell started in 1941 with the design of the very similar Cavalier and then Centaur cruiser tanks. Both were intended to be more heavily armoured successors of the Crusader, but were powered by the same Nuffield Liberty engine as the latter and were armed with the same 57mm 6-pounder as Crusader III. However, Centaur was subsequently fitted with a more powerful 600hp Meteor engine, which was a de-rated unsupercharged version of the Rolls-Royce Merlin aircraft engine that powered the Hurricane and Spitfire fighter aircraft of the Royal Air Force, and this, together with the Merritt-Brown transmission proven in Churchill tanks, converted it into the Cromwell and enabled the latter to overcome the reputation for unreliability acquired by British tanks. Except for its early versions, which were still armed with the 6-pounder, Cromwell was armed with a 75mm gun that fired the same ammunition as the 75mm gun of the Shermans.
In several respects Cromwell represented a considerable advance on earlier British tanks. However, so far as its principal characteristics – its gun and its armour – were concerned, it was no better than the Soviet T-34 that had been introduced three years earlier. When the writer brought this out some years later, the originator of the British cruiser tank development, General Martel, took exception to it and ignoring the facts claimed that the T-34 was ‘far inferior to the Cromwell’. The Russians did not think so, for when they were offered Cromwells in 1943 under the military assistance programme they turned them down. Instead they asked for more Valentines, which the Red Army was using as light tanks. A total of 2,394 of them was sent from Britain to the Soviet Union in addition to all but 30 of the 1,420 Valentines produced in Canada, although about 300 were sunk en route in Arctic convoys.
Like the Shermans, Cromwells were outgunned by the German tanks, but a more immediate problem facing British and US armies was that of landing on heavily defended beaches and then breaking through the coastal defences. This called for tanks that could be launched from ships and swim ashore, a capability foreshadowed in 1924 during a US Marine Corps exercise when an armoured amphibious vehicle built by J. W. Christie swam from a battleship to a Puerto Rican beach. In 1931 Vickers Armstrongs built two prototypes of the first successful amphibious light tanks, the A4E11 and A4E12, which were copied in the Soviet Union as the T-37 and T-38 and about 4,000 of which were produced for the Red Army between 1933 and 1939. But they were small 3-tonne two-man tanks armed with a single machine gun that could only swim in calm inland waters. Heavier tanks could not be made to float except by attaching large pontoons to them, which was not very practicable, until an ingenious system was devised in Britain by N. Straussler, a Hungarian engineer who had previously designed armoured cars for the Royal Air Force and for the Netherlands East Indies Army.
Straussler’s system involved the use of a canvas floatation screen that, when erected, provided the necessary buoyancy and when collapsed enabled a tank to operate in the usual way. In water a tank could propel itself at up to 6mph by means of two propellers driven by its tracks, which came to be called ‘Duplex Drive’ or DD, by which tanks fitted with the floatation system are generally known. The first to be modified into a DD tank was a 7.5-tonne Tetrarch light tank, which was tested in 1941. It was followed by the conversion into DD tanks of some 600 Valentines, which were only used by the British Army for trials and training, and then by the heavier 30-tonne Shermans, which in their DD form equipped three US as well as three British and two Canadian battalions or regiments that were earmarked for the assault landings in Normandy. In the event, four out of the eight units did not swim ashore but, because of rough seas, were taken directly on to the beaches by the landing craft. The fortunes of the other four units varied considerably: one of the US battalions, on Utah beach, landed all but one of the 30 tanks launched into the sea from landing craft, but of the 29 tanks launched by another US battalion 27 sank well short of the Omaha beach they were to assault.
The British, but not the US, Army also made considerable use of tanks modified to perform special tasks, and together with the DD tanks they formed the 79th Armoured Division. Its units included three regiments of Shermans fitted with mine-detonating flails, which were called Crabs, and three regiments of Assault Vehicles Royal Engineers, or AVREs, which were Churchill tanks re-armed with spigot mortars that fired large demolition charges. AVREs were also made to carry fascines, or large bundles of brushwood, which were used as in the First World War to fill trenches for crossing them, and they also carried assault bridges and rolls of hessian carpet that were unrolled over patches of soft ground that was difficult for vehicles to cross.
Tanks of the 79th Armoured Division, which led the assault in the British sector, won the fire fight on the beaches and enabled the infantry to follow on to their objectives at relatively low cost. An exception to this were three battalions of searchlight tanks, code-named Canal Defence Lights or CDL, which played no effective part in the Normandy campaign. Development of searchlight tanks began well before the Second World War and they were originally expected to dazzle the enemy, or to ‘attack by illumination’ as General Fuller described it, arguing, somewhat naively, that they were a means of winning wars. In fact, they were only used once or twice in the closing stages of the war for night illumination. Much the same applied to the CDL tanks of the US Army, which followed the British example and raised six battalions of them. But development of the CDL tanks proved to be a fiasco and the resources devoted to them would have been better spent elsewhere.
Once they created a bridgehead in Normandy the Anglo-American forces faced the reaction of the German forces and in particular of the panzer formations stationed in France. The latter had a total of 1,673 tanks and assault guns made up of 758 PzKpfw IVs, 655 Panthers, 102 Tigers and 158 StuGs. All outgunned British and US tanks, except for some Shermans armed with the British 76mm 17-pounder that outranged the 75mm L/48 gun of the PzKpfw IV and was comparable to the 75mm L/70 gun of the Panther. However, German tanks were deprived of some of their advantage by the hedgerows of the Normandy bocage, which restricted the range at which targets could be engaged. The overall effectiveness of the panzer formations was also reduced by their piecemeal deployment and by Hitler’s irrational operational orders.
Nevertheless, panzer formations inflicted severe losses on the Allied forces and checked a thrust out of the bridgehead, called Operation Goodwood, by three British armoured divisions with a total of about 700 tanks. But in the end they succumbed to the superior numbers of Allied tanks, backed by massive aerial bombardment. In the US sector, five armoured divisions with a total of about 1,500 tanks broke through at St Lô, while on their left the British Second Army attacked with three armoured divisions and two armoured brigades, or more than one thousand tanks, and a week later the First Canadian Army attacked with two more armoured divisions and two armoured brigades. In the meantime Hitler issued an order for a counter-offensive against the flank of the American advance, which proved disastrous as it exposed the attacking German forces to envelopment and led to them being trapped in the Falaise Pocket. Many of the German troops managed to escape, but most of their equipment was lost. More of what was left was subsequently lost when the remnants of seven panzer divisions retreated across the Seine under aerial attack, so that they were only able to bring out about 100 or 120 tanks.
The 11 or 12 Allied armoured divisions that broke out of the Normandy bridgehead and then advanced rapidly across France to the Belgian and German borders were all equipped with Sherman and M5 light tanks, except for the British 7th Armoured Division, which was equipped almost entirely with Cromwells, and two other British and one Polish armoured divisions, which had one regiment of Cromwells in addition to three regiments of Shermans. Both Shermans and Cromwells were armed with 75mm guns that could not perforate the frontal armour of the German Panthers and Tigers even at point blank range, while the latter could perforate theirs at 2km. To some extent Allied tanks were able to redress the balance by exploiting their numerical superiority and mobility to attack the more vulnerable sides of the German tanks. But qualitatively German tanks were superior.
The need for a more powerfully armed British tank had been recognized two years earlier and led to the development of the Challenger armed with the 76mm 17-pounder anti-tank gun. The new tank was, in effect, a lengthened Cromwell with a large, clumsy turret and did not prove entirely satisfactory. Nevertheless, 200 were ordered in 1943 and some were later used by the Cromwell equipped regiments as ‘tank killers’. In the meantime it was found that the 17-pounder could be squeezed into the turret of the Shermans, and this proved to be a better way of using it. In consequence, employment of the 17-pounder was concentrated on the Shermans and tanks re-armed with it, called Fireflies, were issued to British tank units on the scale of one 17-pounder tank to three 75mm gun tanks. Initially only 84 were actually deployed and by the end of the second month there were still only 235 of them in the field. However, by the end of the war the British 21st Army Group had 1,235 Shermans with 17-pounders compared with 1,915 others still armed with 75mm guns, and they provided it with tanks which were at last as well armed as the Panther.
The 17-pounder was made even more effective by the introduction towards the end of the campaign of Armour Piercing Discarding Sabot (APDS) ammunition with projectiles consisting of a hard high-density tungsten carbide sub-calibre shot within a pot-like aluminium carrier or sabot that separated from the shot at the muzzle. In spite of the loss of some of the kinetic energy imparted to the projectile by the gun to the sabot, most of it was still in the shot, which because of its smaller cross-sectional area penetrated more of the target than a conventional full calibre projectile.
Tungsten-cored ammunition was actually provided for the 37mm guns of German tanks as early as the 1940 campaign in France, but in their case the carrier did not separate from the shot and the velocity and penetration of the latter fell off rapidly with range. This type of ammunition was called Armour Piercing Composite Rigid (APCR), and after 1940 was used by German tank guns on the Eastern Front and in North Africa, but on a limited scale because of shortages of tungsten.
APDS ammunition was superior to APCR because its performance did not fall off as rapidly with range. It was first provided in Normandy for the 57mm 6-pounders that were still mounted in some of the Churchill tanks. However, most Churchills were by then armed with 75mm guns so this had little impact on the situation. It was only when APDS began to be provided for the 17-pounders of the Fireflies that its effectiveness began to tell. In fact, its armour penetration was 40 per cent greater at 1,000m than that of the conventional APCBC (Armour Piercing, Capped, Ballistically Capped) ammunition, although its dispersion and therefore loss of accuracy limited the range at which it could be effectively used.
For all this, the re-arming of the Shermans with the 17-pounder was only a makeshift solution that was adopted pending the development of a new and equally well-armed tank. Challenger failed to become one and before another attempt was made to develop it the General Staff opted for another stopgap, which was a derivative of the Cromwell armed with a new lower powered version of the 17-pounder called the Comet. Four regiments were equipped with it and it saw some action in the closing stages of the war. In the meantime, in May 1944, a decision was finally taken to develop another cruiser armed with the 17-pounder. Six prototypes of this 42-tonne tank called the Centurion were rushed to Germany in May 1945, which was too late for them to see any action, but the Centurion became one of the most successful British tanks ever built.
At about the time the Challenger began to be developed in Britain in 1942, US Ordnance also saw the need for tanks to be armed with a gun more powerful than the 75mm gun of the Shermans and started to develop such a gun. This led to a 76mm gun with a higher muzzle velocity and therefore greater armour penetration, but its adoption was not pursued with any urgency largely because the Army Ground Forces commanded by General L. J. McNair, which controlled the acquisition of equipment, regarded armoured forces as no more than a reincarnation of the 19th century cavalry that should be used for exploiting the successes won by other arms and not to fight enemy armoured forces. Tanks were not to be armed therefore to fight other tanks, which were to be fought instead by units of tank destroyers, such as the M10, which had a more powerful 3in. gun mounted in open-top turrets on less heavily armoured M4 medium tank chassis. The tank destroyers were much favoured by General McNair, and his views on the limited, exploitation role of tank units were shared on the eve of the landings in Normandy by some of the senior US Army commanders, including General G. Patton, who considered the 75mm gun-armed M4 tanks entirely adequate for the exploitation role.
It was eventually agreed that one third of the M4s should be armed with 76mm instead of 75mm guns, but the first of the 76mm gun tanks were only produced five months before the landings in Normandy and none took part in them. However, once US armoured units came up against German tanks, it became obvious that tanks had to be able to fight other tanks and there was an urgent demand for tanks better armed than the M4s with their 75mm guns. In consequence, M4s with 76mm guns were rushed to Europe and the commander of the US 12th Army Group even asked for tanks with the British 17-pounder. As it happens, none was available, and even when the 12th Army Group reached the Belgian border only 212 of its 1,579 M4s or Shermans were armed with 76mm guns. But by the end of the war the number of Shermans with 76mm gun deployed by the US forces in Germany rose to 2,151, out of 4,123, or to just over one half of the total.
The armour penetration of the 76mm gun was still considerably less than that of the Panther’s 75mm L/70 and of the 17-pounder, but it was at least slightly better than that of the 75mm L/48 gun of the PzKpfw IV. However, during the final months of the war its performance was improved by the introduction of APCR or High-velocity Armour Piercing (HVAP) ammunition, which increased armour penetration at 1,000m by 46 to 53 per cent compared with its standard armour-piercing ammunition.
Views responsible for the late deployment of Shermans with 76mm guns also contributed to the delays in the development of a new and more powerful US tank armed with a 90mm gun. The Ordnance Department began to consider the installation of such a gun on the Sherman in 1942 and a year later the Armored Force requested 1,000 Shermans armed with it. But Ordnance rejected this request in favour of a new tank that was still armed with a 75 or 76mm gun, while Army Ground Forces objected to it on the grounds that a powerful gun would encourage tanks to fight other tanks and thus divert them from the exploitation role!
In consequence, a series of experimental tanks was built with 75 or 76mm guns while the Army Ground Forces continued to favour Shermans armed with 75mm guns. By May 1943 Ordnance recommended that some of the experimental tanks be armed with 90mm guns, and in spite of opposition from the Army Ground Forces 50 tanks armed with them, designated T25E1 and T26E1, were built a year later. Shortly afterwards US armoured units landed in Normandy, and as the shortcomings of their tanks’ 75mm guns became painfully obvious the Armored Force requested that high priority be given to the production of the T26E1, recommending that 500 be built. Army Ground Forces refused to approve this but eventually 250 were ordered. Twenty of the first 40 to be produced were shipped to Europe in January 1945 as M26 Pershing heavy tanks, and they saw some action in the last two months of the war, by the end of which there were a further 270 in Europe. Production of the 41-tonne Pershing continued until the end of 1945, when it had reached a total of 2,428.
The 90mm gun of the Pershing represented a significant advance on the 76mm and even more on the 75mm guns of the Shermans, but in terms of its armour penetration it was still not quite as good as the British 17-pounder or the German 75mm L/70, and it was completely outclassed by the 88mm L/71 of the Tiger II heavy tank that first saw action a year earlier. But only about 100 Tigers could be mustered in December 1944 for the abortive Ardennes offensive, which was the last major effort of the panzer forces in the West. The German High Command could still assemble ten panzer divisions in March 1945 for a counter-offensive against the Soviet forces in Hungary, but the number of tanks at its disposal was generally considerably smaller than those of the opposing armies as a result of the lower scale of their production in Germany.
The differences are clearly shown by the totals of tanks produced in the different countries during the Second World War, which also illustrate the scale on which tanks were used during that conflict. Thus the total number of tanks produced in Germany from 1939 to 1945 amounted to 24,242. During the same period the number of tanks produced in Britain was 30,396. The corresponding figure for the Soviet Union was 76,186. The number of tanks produced in the United States was even higher, being 80,140.102 The total for the three countries fighting Germany was consequently 186,722 tanks, or almost eight times the number of German tanks.