Origins of the M4 Sherman Medium Tank
Brom Kim, 1999
Axis King Tiger with Allied Sherman parked behind - an unfair fight on any day
To me, one of the greatest tragedies of World War II was that our armored troops had to fight the Germans with a grossly inferior tank compared to the heavy German panzer units. Before we went into Normandy, we had been led to believe that the M4 Sherman main battle tank was a good tank, thoroughly capable of dealing with German armor on an equal basis. We soon learned that the opposite was true. The Third Armored Division entered combat in Normandy with 232 M4 Sherman tanks. During the European campaign, the division had some 648 Sherman tanks completely destroyed in combat and we had another 700 knocked out, repaired and put back into operation. This was a loss rate of 580 percent.- Belton Y. Cooper
In the words of Belton Y. Cooper, a young lieutenant assigned to the Third Armored Division in World War II, the employment of the M4 Sherman as the U.S. army's main battle tank in Europe was 'one of the greatest tragedies ' of the war, it also poses one of the most frequently asked questions about World War II. Civilian commentators have asked since World War II why the most motorized society in the world, capable of producing such military marvels as Ultra, the jeep, the C47, the proximity fuse, and the atomic bomb, was unable to supply its armored troops with a tank that would give them a fighting chance against German armor and antitank guns. The knee-jerk answer often proposed is that U.S. tank designers were just not up to the job- German tank designers were technological geniuses who were years ahead of their American counterparts. While this answer may be satisfying to those for whom a peculiar mythology has sprung up about the Third Reich, it does an injustice to the bravery and skill of the German tank crews and the intelligence and thoughtfulness of their commanders. This answer also ignores the fact that German designs of the late war were heavily influenced by Soviet designs, which were in turn largely derived from rejected American designs. Like so many other persistent questions, the question of the Sherman tank has persisted because the easy answers really don't answer anything. A satisfying answer to the question of why U.S. troops were supplied with the Sherman cannot really be found in World War II history at all. The reasons why U.S. commanders decided to continue to use the Sherman tank when superior designs were available are located in the armored force doctrines developed during World War I and the intra-war period.
Planners who expected World War I to be a brief, glorious war of maneuver were to be horrifically disappointed. There should have been enough evidence of the superior defensive power of the machine gun from its use against recalcitrant 'primitive ' colonial subjects. There were also plenty of lessons about trench warfare that might have been derived from the Russo-Japanese war. Perhaps it was thought that the superior quality of European troops would win the day. More likely, the right people just weren't paying attention. Either way, these lessons went unheeded. The defensive qualities of the machine gun, and modern artillery made it nearly impossible to cross no man's land and attack the enemy's trenches with anything but a decimated force. Not surprisingly, after a few years of incredible slaughter, inventors began dreaming of a better way to cross the fire swept area between the trenches.
By mid-war, the first British and French tracked armored vehicles, code named tanks for secrecy, began to appear. Here was a weapon that had tremendous potential. The tank's armor was relatively impervious to enemy fire, tracks allowed the tank to carry a heavy payload of weapons, troops, or supplies across broken ground. The tank could crush barbed wire obstacles, and bring heavy firepower to bear on enemy strong points. Still, no one was quite sure how to best use this new beast.
In spite of protests from their inventors that they should be reserved for a massive breakthrough, tanks were at first thrown into battle in small groups as soon as they arrived in France. While these piecemeal attacks yielded little success, they proved that the tank had great potential. Subsequent attacks would use much greater numbers of tanks, but in differing ways. Sometimes, tanks would be ordered to stay in close contact with the infantry they supported. Other times, often on individual initiative, tank commanders would drive their machines deep behind enemy lines. Surprisingly, the German army did little to counter the tank threat, and produced only tiny numbers of their own tanks, which they employed late in the war alongside captured Allied tanks. The tank, combined with the entry of U.S. forces, provided the breakthrough that ended World War I. But the argument over what was the best way to use tanks was to go on for the next twenty years.
Some early armor theorists believed that the tank's most valuable asset was its armor. These were to become the proponents the 'tank as infantry support weapon' school of thought who believed that the tank's role should be to support the advance of the infantry. In this method of employment, the tank would rely on heavy armor for protection as it slowly moved across the battlefield methodically destroying enemy strong points.
Others believed that the tank's best asset was its mobility. Although the speed of tanks in the Great War was still quite slow, less than 10 mph, tank warfare pioneers began to wonder if tanks, with their armor and superior firepower, might replace horsed cavalry altogether, rather than simply breaching enemy defenses for the other arms to exploit. These tank pioneers would envision swarms of small, fast, mobile tanks streaming across the battlefield like cavalry of old. In the aftermath of World War I, it is not surprising that Fuller, Liddell Hart, Guderian and other reformers of their generation focused on mobility as a means to reintroduce maneuver into warfare and avoid the deadlocked slaughter of the last war.
One early proponent of tank mobility, Col. J. F. C. Fuller, chief of staff of the British tank Corps, created in 1917 drafted plans for a massive 1919 war ending attack, employing 5000 tanks for both breakthrough and exploitation. The war ended before Fuller's plan was used, but Fuller, and his younger contemporary, B. H. Liddell Hart continued to develop Fuller's plan 1919 into a theory of land war in which all components of attacking force would be mechanized. Tanks would replace cavalry, infantry would be transported by trucks, and artillery would be able to move forward rapidly on motorized carriages.
Fuller abhorred the idea of relegating a potentially fast moving, long range tank force to the pace of foot soldiers: "To combine tanks and infantry is tantamount to yoking a tractor to a draft horse. To ask them to operate together under fire is equally absurd." Apparently the British military establishment agreed, and Fuller got his way. In 1923, the British tank corps was granted royal title and made a permanent part of the British army.
While the British tank corps had existed before, its acceptance as a separate and permanent force meant that, according to Fuller and Liddell Hart's ideas, the tank corps would operate independently of the other arms, focusing on marauding breakthrough tactics rather than infantry support. In Britain at least, mobility had won out over the proponents of infantry support. The work of Fuller and Hart would influence armor doctrine worldwide, especially in Germany.
Although by the outbreak of World War II, both Fuller's and Liddell Hart's ideas were well circulated in the largely accepted within the British army, the worldwide depression of the '30s had prevented Britain from equipping her forces in accordance with the latest doctrines. What this meant in terms of British tanks at the beginning of the war was that several models had been designed, mainly of the light and medium type but very few had been perfected, and all were in short supply.
The British War Office, not unlike its American counterpart, with its shoestring budget, made the defense of the realm its highest priority, and the lion's share of funding went to the Air Force and Navy. It was then thought that France's seemingly well equipped land forces could hold their own. Britain then would need only to support with air power. Land forces, should they be needed, would be limited to a small elite mobile force, so, in 1939, the British army was still largely organized and equipped in the old fashion. Only two mobile divisions existed, one in England, one in Egypt, both poorly equipped and undermanned.
If Britain and the United States had under-equipped ground forces in the '30s, Germany should have seemed even less of a threat. After all, German industry and the German economy had been intentionally hobbled by the treaty of Versailles. But, Germany, who had put so little faith in tanks in the last war, was now freed from Versailles by Hitler and the rise of the Nazi party, and had begun work in secret on an armored force. The German-Soviet mutual assistance treaty of Rapallo, 1922, had enabled secret joint German-Soviet development of tank tactics and technology at Kazan, a remote Soviet outpost. Hitler himself was a great advocate of mechanization. At a demonstration of new tank technology, Hitler is supposed to have said "That's what I need! That's what I want to have!" The lessons in tank warfare from the last war, would soon be put to use by a man who had read, and owed much to Fuller and Liddell Hart.
German tank design and doctrine in World War II was heavily influenced by Heinz Guderian. A World War I veteran, Guderian thought little of the huge indirect fire bombardments of the last war. Guns, he said, must be brought close to the enemy line so that targets can be pinpointed and destroyed. To Guderian, the tank provided means of crossing the fire swept area between lines. Guderian condensed his own ideas, observations of World War I, and borrowed ideas from Fuller and Hart in a primer on armored warfare, Achtung-Panzer!
The first half of the book attempts to distill the lessons of armor from World War I. Guderian, like his contemporaries Fuller and Liddell Hart, criticizes the allies for having tied tanks to the pace of infantry, and not employing them en masse.
"It is patently absurd to make the conscious decision not to exploit the potential of a weapon to the full. For that reason the specifications for the ultimate development of the weapon must be set as high as seems practicable at the time. If, for example, we can possess the wherewithal to attack at speed, it seems ridiculous to force tanks to offer slow-moving targets to enemy fire, just because old-fashioned infantry would otherwise be unable to keep up with them. Now that technology can put the infantry and armored escort vehicles which can move every bit as fast as the tanks, it is the tank which must determine the speed of the infantry; the French have grasped this point and they have placed their Dragons Portes in armored carriers. Again, it makes no sense to bring a tank attack to a halt for several hours simply to enable horse-drawn artillery to change position, when it is now technically possible to tow guns by powered vehicles or mount them on armored self-propelled carriages, and to provide their gun detachments and forward observers with the mobility of armored vehicles. The tanks must not follow on the artillery, but the other way around."
Guderian's ideas differed slightly from Fuller's and Liddell Hart's however. While Liddell Hart was fascinated, somewhat fancifully, by Mongol cavalry, Guderian's ideas were more Napoleonic. German tank forces, once broken through into the enemy rear area, did not split up into small parties and attack enemy headquarters in supply, but would instead cut enemy communications, isolating enemy front-line units' from command and resupply.
Well aware that the success of his ideas in the real world depended on the machines that were employed, Guderian specified three types of tanks to carry out operations. Slow, heavily armored tanks would carry both machine guns and cannon for supporting infantry; gigantic heavy tanks with huge guns would be used to assault fixed fortifications; and, most importantly, fast, mobile medium tanks would be needed for breakthrough and exploitation.
A common feature of all three specifications is that Guderian never underestimates the threat of enemy tanks, and anti-tank weapons. While the U.S. developed doctrines based on swarms of fast light tanks protected by separate anti-tank units, Guderian was not a light tank advocate. His specifications emphasize armor protection and firepower over speed. This would have far reaching effects as when the fast, mobile, thin skinned, undergunned Sherman had to fight the lumbering German Tiger tanks.
Guderian unlike his contemporaries also took a special interest in tank vs. tank combat. Drawing lessons from the few engagements in World War I, and the Spanish Civil War, Guderian observed the a tanks greatest enemy was an enemy tank. This probably influenced German tank designers to design vehicles that would function not only as anti-personnel systems, but also antitank systems. Guderian noted that when undergunned tanks advanced against well armored opponents with weapons capable of penetrating their armor, they had no choice but to retreat. Although Guderian is referring here specifically to machine gun tanks attacking cannon equipped tanks in the Spanish Civil War, the same would hold true when the Sherman was pitted against late war German heavy tanks.
Additionally, Guderian says that when enemy tanks are encountered, the mission of tanks and support units must immediately be diverted to the destruction of the enemy tanks. This is the exact opposite of the U.S. doctrine that would state that the mission of tanks was not to fight other tanks. Enemy tanks were, in theory, supposed to be dealt with by separate anti-tank units.
Guderian's wish list may have been useful to German tank designers throughout the war, but in the late 30s Germany's still recovering economy and arms industry was not yet capable of fully delivering on Guderian's list. Even so, German tank designers had done a lot of work toward building fairly reliable tanks with good handling characteristics. As a result, many of the early designs would soldier on throughout the war either as improved models with add-on armor and bigger guns, or as gun carriage and assault gun platforms. For example, the Panzerkampfwagen IV, which began the war with a short-barreled 75 mm infantry support gun, ended the war with a high velocity long barreled 75.
Many critics of the Sherman tank fail to realize that the Wehrmacht achieved its early successes with the light and medium tanks of the Panzerkampfwagen series by skill and combined arms tactics rather than any great technological or mechanical advantage. At the time of its introduction the Sherman's gun and armor were on par with most German tanks. The heavy Panther and Tiger models of the late war appeared only after the Wehrmacht stumbled into the heavily armored Russian KV-1 heavy tank and the nimble, hard-hitting T-34. Russia was the only nation in the world to field an effective heavy tank early in the war. Ironically, the Russian tank program owed much to designs the eccentric American tank designer, J. Walter Christie, whose designs had been rejected by the U.S. military.
The development of American tank design and doctrine that would eventually lead to the M4 Sherman began in World War I. After General Pershing, commander of the AEF was favorably impressed by British and French armored operations. He directed a board of officers to perform a detailed study on tactics and equipment. They concluded that the tank would be very important in the war and that Pershing should create a separate tank department. An American tank force was formed led by Capt. George Patton of World War II fame.
Early on, Patton met with Col. Fuller, the British Tank Corps operations officer, and discussed mass employment of tanks in the recent British offensive at Cambrai, tank doctrine, and tactics. Patton's 1st tank brigade saw its first action on 12 September 1918 when they supported the U.S. 4th Corps which was slated to assault the southeastern face of the German salient at Saint-Mihiel. Although their success was limited by the rapid German retreat, Patton's men did quite well in their first action, sustaining only light casualties. In an event that was to be echoed in the next war, Patton's tankers' advance was halted only when they ran out of gas.
Meanwhile, back in the U.S., another World War II icon, then Captain Dwight D. Eisenhower was at Gettysburg, Pennsylvania in 1918, establishing a new domestic tank or training center called Camp Colt. Camp Colt was the largest training facility of its type during World War I. By the time of the armistice, Eisenhower was a Lieutenant Colonel. Patton and Eisenhower would gain valuable experience employing armor in World War I, but with the breakup of the tank corps in 1920, both would transfer out of armor.
Although it appeared at first that the U.S. Army would develop an independent mechanized force along British lines, The National Defense Act of 1920 dissolved the fledgling tank corps. This caused many promising officers, such as Eisenhower and Patton, to disassociate themselves with armor. This also meant that tanks would hereafter be assigned to the infantry. Although the U.S. Army experimented with independent tank forces throughout the '20s according to the British example, none of the experiments were deemed successful. Whether this was due to the Army's use of obsolete World War I M1917 light tanks and Mark VII Liberty heavies, or because the U.S. Army was clinging to a Civil War era strategy of annihilation, there would be no American Blitzkriegs.
In 1930, Gen. Douglas MacArthur became chief of staff of the Army. In his first annual report he said:
There have been two theories advanced to govern the application of mechanization. . . The first is that a separate mechanized force should be so organized as to contain within itself the power of earning on a complete action, from first contact to final victory, thus duplicating the missions and to some extent the equipment of all other arms. The other theory is that each of the older arms should utilize any types of these vehicles as will enable it better and more surely to carry out the particular combat tasks it has been traditionally assigned. . . . In the initial enthusiasm of postwar thought the first method was considered as the ideal one. . . Continued study and experimentation have since resulted in its virtual abandonment. . . Accordingly during the last year the independent "mechanized force" at Fort Eustis has been broken up. The cavalry has been given the task of developing combat vehicles that will enhance its powers in roles of reconnaissance, counter-reconnaissance, flank action, pursuit and similar operations. One of its regiments will be equipped exclusively with such vehicles. The infantry will give attention to machines intended to increase the striking power of the infantry against strongly held positions.
Although this was a pretty strong statement against the tactics of Fuller, Guderian, and Liddell Hart, at least McArthur did support mechanization to some extent. Tanks, called combat cars in order to circumvent the regulation assigning tanks to infantry, would become primarily the domain of the cavalry arm. Cavalry's emphasis on fast, lightweight, lightly armed vehicles designed to emulate the traditional reconnaissance and screening role of horse cavalry would have far-reaching effects on U.S. tank design.
In World War I, the prevailing doctrine of tank warfare called for heavy, slow-moving infantry support tanks. Commander of U.S. tank forces, Brigadier General S. D. Rockenbach excepted this idea, but by October 1918, perhaps influenced by Fuller he began to see the need for a faster medium tank along the lines of the British Whippet, which he called a raiding tank. In 1919, the ordinance department placed an order for the first Christie project, a 15 ton 'convertible' medium tank with removable tracks for high-speed road travel .
In what was to become an agonizingly frustrating, repeated ordeal for both the inventor and the ordinance department, Christie ran into problems when the model 1919 was delivered. This was because J. Walter Christie designed his vehicles by building them blueprintless from the ground up. Although Christie designs were innovative and usually had many points to recommend them, they always had many bugs that needed to be worked out, and never conformed to Ordinance Department contract specifications. True to the tradition of the eccentric inventor-tinkerer, Christie never really perfected any of his designs. Instead, after partially finishing one project, he would immediately start on a new, 'better' project.
By the end of 1924, the army had invested almost $1 million in Christie's various projects, none of which were deemed suitable. The ordinance department recommended the cancellation of all Christie projects. But they would not to be rid of the inventor so easily. When Christie introduced the "national defense machine" model 1928, future chief of staff General Summerall was so impressed that he circumvented the Ordnance Department and ordered the infantry tank board to test the M1928. Funding for Cunningham light tanks was redirected to the procurement of six Christie models. Meanwhile, seeking a more appreciative audience, Christie began discreetly negotiating to sell his tanks to the Soviet Union and Poland.
The model 1928 was truly revolutionary. It introduced what became known as Christie suspension, which employed large road wheels with long traveling independent helical springs. The design was a major advance, providing a more stable gun platform when moving, and greatly improved mobility in uneven terrain. But, circumventing the ordnance apartment proved not to be a good idea. Because the vehicle had not yet been tested, after considerable debate, the original order was scaled back to just one vehicle all, a model 1930 at $55,000. And even this was not to be. When the vehicle failed to pass the cross-country testing, a thousand dollars was deducted from the agreed price. Christie became enraged and sold the tank chassis to the British government.
For his next project, the model 1931, Christie decided to circumvent the army altogether, and lobby Congress for the contract. Although this alienated his supporters in the military, congressional pressure resulted in the contract for seven model 1931 tanks. The mechanized cavalry version was designated CCT1; the infantry support version designated T3.
The competition against the Christie vehicle was the ordnance department designed CCT5, which employed a volute spring suspension system. Although the CCT5 proved to be more maneuverable than the Christie vehicle, its flotation was so poor, i.e., the ride was so bumpy, that accurate marching fire was deemed impossible. Although farsighted armor officer Gen. Adna Chaffee lobbied for the convertible CCT4, the decision was made to acquire the lighter, less expensive CCT5. Capt. H. H. D. Heiberg, commander of a tactical combat car platoon that had experience with Christie vehicles would later recall that the decision to adopt the CCT5 was made in the war department "by officers [who had] probably never ridden in a tank, much less fired from one."
The rejection of the Christie design would have far reaching effects. The CCT5, was standardized for production as the combat car M1, featuring the Ordnance Department designed volute suspension system. It would define the characteristics of U.S. tanks until late in World War II. The combat car M1 provided the basis for an enlarged version, the M2 medium, forerunner of the M4 Sherman.
A few years later, during the Spanish Civil War (1936-39), U.S. Army attaches reported favorably on the Soviet supplied BT fast tanks they saw in action there. Machine-gun tanks, then the mainstay of U.S. armored forces, were unable to overcome the Soviet BT type tanks armed with 45 mm cannon. These are the tanks that Guderian refers as being impervious to machine gun tanks in Achtung-Panzer! The Soviet vehicles were the BT fast tank type directly derived from the Christie tank, and forerunners of the T34. The next U.S. design to use Christie suspension was the M18 Hellcat. Although very lightly armored, it had a remarkable top speed of 55 mph. One crewman described the M18 as "a tanker's dream"[…]"real quiet and very fast."
The result of all this, in terms of U.S. tank designs at the beginning of World War II was that, given the cavalry's ascendancy as the new tank arm, U.S. tanks at this time consisted primarily of light, fast models. A medium model, the M2, was available, but it was under-gunned and already obsolete. Had the war been fought with light tanks, the U.S. Army would have been well equipped. The 14 ton M3 Stewart was capable of moving at 36 mph, had a maximum armor thickness of 1.75 inches, and mounted a 37 mm anti-tank gun, which while producing respectable muzzle velocity, fired a puny 1.92 lb. shot. Although the Stuart was already somewhat obsolete, the fast, mobile light tank would be well received in the field.
Anyway, the war was fought predominantly with medium and, later, heavy tanks and U.S. Army, owing to its own preferences had nothing satisfactory on hand in 1940. A year earlier in 1939, Belton Cooper, then a young OTC candidate who would later serve with the 3rd armored division in Europe, was shocked to find that the total tank research and development budget for that year was only $85,000.
In order to supply the Army with the desperately needed medium tank, a committee of cavalry, artillery, and armor officers decided on specifications for a temporary expedient, the 30 ton M3 medium variously called the General Grant or Lee. As a result of its committee design, the M3 ended up being a motley collection of guns and turrets more reminiscent of a World War I tank, rather than the newest and best effort of the greatest industrial power in the world. The M3 mounted a 75 mm cannon in its riveted hull, and a 37 mm antitank gun in the turret. On top of all this sat a commanders turret mounting a .30 caliber machine-gun. Additionally, two more .30 caliber guns were mounted in the hull.
Armored and Calvary officers favored mounting a large caliber high velocity antitank gun in the turret, but artillery won out, arguing that the main gun should be capable of firing 7500 service rounds. In order to achieve this, the low velocity short-barreled 75 mm gun was chosen. Cooper is highly critical of short-barreled 75, and remarks, "Apparently, it hadn't occurred to anyone that there was only a remote possibility that a tank would last long enough in combat to fire 5000 rounds."
The M3, with its ridiculous layer cake of turrets and guns provided a huge target for enemy gunners, especially since it was impossible to fire the 75mm gun from a hull down position. Worse yet, although it had a respectable 2.25 inches of armor, the rivets it was constructed with would ricochet with deadly effect around the crew compartment when struck by even small caliber armor piercing bullets. Still, while the M3 was hardly an elegant design, it at least gave Allied troops in North Africa the ability to shoot back at Rommel's panzers with some success, while work on its successor, the M4 Sherman was finished.
The first Sherman tanks were delivered by Chrysler and the Fisher tank arsenal in July 1942, and the army began phasing out the M3 medium tank. The Sherman was actually a fairly well designed vehicle that could hold its own with any medium tank on the battlefield at that time. It was more mechanically reliable and had a greater rate of fire than German tanks. A fast power turret traverse, and long wearing rubber tracks were also assets. A Sherman's tracks lasted for 2500 miles compared with something like 500 miles for the Panther and Tiger. The Sherman's narrow rubber tracks also made it quiet and fast on hard surfaces. The Sherman used half the gasoline of a larger tank and had twice the range. Two Shermans could fit in the space required by one larger tank on a L. S. T., or a cargo ship.
But there were, of course, problems. Essentially a product of the cavalry arm, the Sherman was no assault tank, nor was it an antitank system. Even in 1942, German high velocity guns could penetrate the Sherman's relatively light armor with a single shot from well over a mile away. There were instances of Shermans knocked out by German gunners shooting through a brick wall, and in at least one case by shooting through another Sherman. The Sherman had to get within 600 yards of the Panther and score a flank hit in order to knock it out. The Panther with its high velocity 75 mm long barreled gun could knock out Sherman at 2000 yards head-on.
But the Sherman was designed to go fast and far, not to slug it out with antitank guns and tanks. Originally, the so-called G. H. Q. heavy tank battalions were supposed to be equipped with a heavy assault tank with sufficient frontal armor to enable it to withstand enemy antitank fire. The German version of an assault tank was the Pzkw. VI Jagdtiger, with thirteen inches of frontal armor, mounting a 128 mm high velocity anti-tank gun. Ordnance tank experts consistently argued for heavy tanks but the infantry and cavalry branches opposed the idea. So the Sherman ended up being used in the assault role.
U.S. policy was oriented towards defending the nation against invasion, not for sending and expeditionary force overseas to attack strongly fortified positions. Critics of heavy tank advocates mocked the need for heavy tanks by reminding heavy tank advocates that neither Canada nor Mexico had erected Maginot lines. But Germany's successes in the spring of 1940 came with exaggerated reports of the size of German tanks, so in 1940, at the same time the specifications for the M3 medium were laid down, the Chief of Infantry asked for a heavy tank.
The resulting design was remarkably advanced for 1940, and was at least a step toward the assault tank the army needed. The M6 featured a cast hull and turret, a 1000 horsepower gasoline engine, a 3 inch gun mounted coaxially with a 37 mm gun, volute spring suspension, Hydra-Matic automatic gearbox, and two .50 and two .30 caliber machine guns in the hull. President Roosevelt's plan called for the building of 500 M6 heavy tanks in 1942 and 5000 in 1943. Fisher tank arsenal and Baldwin locomotive Co. were contracted to build them at their combined rate of 250 per month.
But, the Armored Board turned down the M6. The Board said that the M6 lacking in firepower, although at the time it probably had the most powerful tank gun in the world. They said that the transmission and suspension were faulty, which was somewhat true, but the first prototype did cover over 3500 miles on its first set of tracks. Additionally, they said that the fire control equipment was supposedly defective, although it was the same equipment was used in the new M4 Sherman, and that the crew compartment was badly laid out.
Admittedly, the M6 heavy tank still needed a lot of work to improve its suspension, transmission, brakes, and other vital parts. So, the Ordnance Department asked for a full tabulation of the armored Board's objections so that modifications could be made. An experimental model was produced with a redesigned crew compartment, and a powerful 90 mm gun. Additionally, fifteen M6's were modified to carry a 105 mm gun in the turret, in the belief that such a powerful tank would be of value in Europe, but both were refused by the Armored Board. According to Ian Hogg, in the Jane's publication Armor in Conflict, "the full story of the M6 will probably never be unveiled, but what little is known seems to indicate a level of political in-fighting and personality clashes which, in the end, work to have serious effects on American armored effectiveness." This situation would be worsened because at about this time, work on the 63 ton German Tiger heavy tank was nearing completion.
Still, the Board's objections were not entirely unjustified. The M6 had been intended for the ideal tank country of North Africa where bridges were not a problem, but by early 1943 the end of the North African campaign was in sight. The Armored Board had made up its mind that the war would be won on the Sherman. All they required was that the Sherman be periodically modified to keep it up to date. While this greatly simplified logistics, it meant that the Sherman would continue to be the main battle tank of U.S. forces in Europe, employed in a role for which it was never intended.
The main modifications of the Sherman for the war in Europe consisted of a new gun, and a better engine. By the time of the Normandy invasion, the high velocity 76 mm T1 gun, replaced the old short 75 on about one in ten tanks of Cooper's 3rd armored division. Thereafter, because of the unacceptable loss rate of the Sherman, nearly all replacements to the 3rd came with the high velocity gun.
The Sherman's original engine was a surplus Continental Radial aircraft engine designed to operate at high constant speed. In a tank, which spent a lot of time idling, the spark plugs of the radial engine would become oil fouled. The new Sherman tank engine was a Ford produced version of the British Rolls Royce Merlin engine (used in the Spitfire fighter) cut down to eight cylinders. The new 550 horsepower V8 engine was about 25 percent more powerful than the old radial engine and improved the speed, reliability, and mobility of the Sherman.
Although these modifications, especially the new gun, marginally improved the Sherman's performance, it still had nowhere near the amount of armor necessary to stop German antitank weapons. This situation was worsened by Norman hedgerow country. Thousands of dense hedges provided a natural anti-tank defense, and an ideal conditions for German ambushes. What's more, German infantry was now a serious threat to allied tanks. The Panzerfaust (tank fist) and Panzerschreck (tank terror) were infantry antitank weapons inspired by the American bazookas the Germans captured in Russia. Even the lowly disposable recoilless grenade launcher, the Panzerfaust could easily knock out a Sherman if the German infantryman was brave enough to get within range.
The Sherman was woefully under armored for the use it was put to. Cooper discusses welding supplementary armor patches onto the Sherman's hull to provide extra protection for the drivers, fuel tanks, and ammunition storage. Although these may have provided some extra protection, German gunners are said to have used these patches aids to aiming. Eventually, an assault version of the Sherman, the M4A1E3 nicknamed the Jumbo Sherman was issued with extra frontal armor. This model was still not proof against the 88, and the extra weight further hampered the Sherman's cross-country performance. Also, this model still mounted the old low velocity 75 mm gun.
The vulnerability of the Sherman's fuel tanks and amunition earned it the German nickname of the "Tommy cooker" and the Allied nickname the "Ronson" (lights on the first try every time). Later model Sherman's used wet ammunition storage. Main gun rounds were stored in a mixture of water, antifreeze, and a rust preventative. Although this reduced the chance of detonation of main gun rounds, the American model Sherman's gasoline filled fuel tanks were still prone to explosion. German tanks, and the British and Russian variants of the Sherman used diesel.
Cooper says that American tank crews, with the desperation of "drowning men", took every means available to reinforce the front glacis plate of their tanks. They stored spare track links and wheels on the glacis plate, others used sandbags, logs in an attempt to stop German hollow charge antitank rounds. Some even poured a layer of concrete over the glacis plate. While these makeshift measures were probably effective in stopping Panzerfaust and Panzershreck hits, they would be all but useless against German solid shot. Only when Patton ordered all Sherman tanks in his army to have an additional 2 1/2 inches of armor plate, salvaged from wrecked tanks, put on the forward hull was the Sherman able to withstand a hit from the 88, although this must have seriously hampered cross country performance.
While these modifications improved the Sherman's performance, it quickly became clear that American tankers were dying for lack of a better tank. Because the Sherman was unable to counter German armor, a combined arms approach had to be quickly improvised. Cooper says, "only through the combined efforts of our armored infantry, self-propelled artillery, tank destroyer units, and pinpoint bombing by the P. 47's were our great tank losses partially offset. In fact, it may be that Operation Cobra became necessary only because of the inability of the Sherman to breakthrough German defenses.
Of course the German forces by now, were hardly in an ideal situation either. They had failed to stop the Allied invasion on the beaches, which Rommel said was their only hope. The Sherman greatly outnumbered German tanks in Europe, and about half of the German tanks in Normandy were the old twenty-six ton Pzkpfw. IV's, albeit upgunned and with added armor. On the German situation, George Friedman, author of The Future of War offers this description:
Blitzkrieg is a form of risk-taking imposed by weakness, a game for the numerically inferior side. The weaker power concentrates his forces at a certain point along the enemy front, crafting a localized superiority, and ruptures it. He then moves to the rear of enemy formations, cutting lines of supply and communications and seizing strategic points. The larger force is immobilized by the shock and effectiveness of the maneuver-and the result is victory. However, should the initial blow failed to break the enemy, the danger of an extended war of attrition looms.
By this time, it should have been clear to Hitler that the military situation was not looking good. But Hitler held out on hopes that the truly spectacular new wonder weapons, the Elektro-boat long range electric submarine, rocketry, jet aircraft, and the atomic bomb might yet turn the tide. And in fact these weapons, especially the atomic bomb probably reinforced Allied commanders' decision to invade France as soon as possible with whatever they had. Either way, without a political solution in sight, Allied armored forces still had a long war ahead of them.
Because of the relative weakness of most U.S. tank and tank destroyer guns, in a return to World War I tactics, Cooper cites concentrated plunging fire from the past firing self-propelled 105 mm howitzers as U.S. Army's most effective weapons against German armor at the time. Not including tanks repaired and put back into action, the 3rd Armored Division's total losses of them for German tanks after penetrating five miles into France were 87. These losses were unacceptable and could not be sustained. Requests immediately went to Washington to reverse the decision to focus on the and for and get the and 26 heavy tank into the E. T. O. as soon as possible.
If the armored board was correct in denying U.S. troops a heavy tank because of bridging and logistical problems, it might have at least approved the use of the new M26 Pershing in Europe, which was actually a medium tank reclassified has a heavy following the cancellation of the M6. The M26 Pershing tank weighed 47.5 tons and had four inches of armor on the glacis plate. The power to weight ratio of the M26 was 12 horsepower per ton compared to 10 horsepower per ton on the Sherman. This meant that the Pershing tank had equal or greater speed on the highway, and because of the wide track and modified Christie suspension, it had much better maneuverability off road. The M26 mounted a 90 mm antiaircraft derived gun similar to the German 88 capable of firing a projectile at 2850 fps.
The M26 was greeted enthusiastically by field officers and combat commanders who had actually fought the Germans in North Africa. Brigadier General Maurice Rose, who had encountered the German Pzkpfw. VI Tiger was strongly in favor of deploying M26 as soon as possible. But it was not until June 1944, that ordinance finally got approval of its plan to mount the 90 mm gun on the experimental T26. In the end, only 50 were built in 1944, 700 before the end of the war in 1945, and few saw service.
Cooper lays the blame for the delay in the fielding of the M26 on Lt. Gen. George Patton. He believes that Patton's insistence on following Army regulation to a 'T' led him to reject the Pershing tank on the grounds that the role of tanks was not to fight other tanks, but to bypasses them and attack the enemy rear. Gen. Rose and other field commanders resisted Patton on this. Their experiences at Kasserine Pass and Sicily convinced them of the need for a heavy tank to offset German armor, but Patton prevailed and the M26 was downgraded. As Cooper says, Patton had an extreme flair for getting his way.
When an improved model of the M26, the Super M26A1E2 Pershing tank finally arrived in 1945, it had the most powerful tank gun in Europe at the time. The T15E1 high velocity gun 70 caliber had a muzzle velocity of 3850 fps, some 600 fps greater than the 88 mm Kwk43 gun mounted on the King Tiger. Cooper and his colleagues tested the M26's experimental gun on a knocked out Pzkpfw. IV assault gun. The armor piercing round penetrated four inches of armor, a five inch driveshaft, the rear partition of the fighting compartment, the 5.5 inch crankshaft of the Maybach engine, the one inch rear armor plate, and dug itself into the ground so deeply it could not be located. Clearly the United States had the ability to field a better tank then the Sherman. It simply chose not to.
Cooper believes that had the U.S. Army deployed the M26 Pershing earlier, the 1944 offensive east of Aachen would have been much more successful. The German buildup in the Ardennes might have been outflanked, and the battle of the Bulge might not have occurred, thereby ending the war months earlier. Of course this is only conjecture. What is truly regrettable is that American troops were sent into the field with a weapon that was not really up to the job they had to perform. Cooper says that before he arrived in Europe, he knew nothing of the German heavy armor, aside from some newspaper articles he had read about the Tiger tank in North Africa. It would seem that the U.S. should have learned something from the Russian experience fighting German heavies, often in lend-lease Shermans.
Still, in defense of the M4 Sherman, it was as the armored board had predicted, the tank that won the war. Commentator Christopher R. Gabel writes:
Memory tends to be selective. Postwar commentators tended to remember the dashing, blitzkrieg-type operations rather than the slugfests in the Normandy hedgerows or the streets of Aachen. They tended to remember the Sherman tank’s weaknesses as an antitank system, while forgetting that 70 percent of the rounds fired by the Sherman were high-explosive, not antitank ammunition. Day in, day, out armor’s chief contributions were in functions that armor doctrine said tanks should avoid: fighting in cities, reducing pillboxes, and generally operating at the pace of the infantry. The blitzkriegs stand out precisely because they were the exception rather than the rule.
Certainly by the time the U.S. arrived in Europe, the blitzkrieg had lost its lightning, and it was this war of attrition that hordes of the mass-produced Sherman, like its namesake, the Civil War general, proved adept at winning. But, it is equally true that this justification would have been cold comfort to the Sherman tanker who had to face the German zoo (Panther, Tiger) in his thin skinned, undergunned tank.
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