The M4 Sherman, officially Medium Tank, M4, was the most widely used medium tank by the United States and Western Allies in World War II. The M4 Sherman proved to be reliable, relatively cheap to produce, and available in great numbers. It was also the basis of several other armored fighting vehicles including self-propelled artillery, tank destroyers, and armored recovery vehicles. Tens of thousands were distributed through the Lend-Lease program to the British Commonwealth and Soviet Union. The tank was named by the British after the American Civil War General William Tecumseh Sherman.

The M4 Sherman evolved from the M3 Medium Tank, which – for speed of development – had its main armament in a side sponson mount. The M4 retained much of the previous mechanical design but moved the main 75 mm gun into a fully traversing central turret. One feature, a one-axis gyrostabilizer, was not precise enough to allow firing when moving but did help keep the gun aimed in roughly the right direction for when the tank stopped to fire.[8] The designers stressed reliability, ease of production and maintenance, durability, standardization of parts and ammunition in a limited number of variants, and moderate size and weight (to facilitate shipping and compatibility with existing bridging equipment size and weight limit restrictions). These factors, combined with Sherman's then-superior armor and armament, outclassed German light and medium tanks fielded in 1939–42. The M4 was the most-produced tank in American history, with 49,324 produced (including variants). During World War II, the Sherman spearheaded many offensives by the Allies after 1942.

When the M4 tank went into combat in North Africa with the British Army at the Second Battle of El Alamein in late 1942, it increased the advantage of Allied armor over Axis armor and was superior to the lighter German and Italian tank designs. For this reason, the US Army believed that the M4 would be adequate to win the war, and relatively little pressure was initially exerted for further tank development. Logistical and transport restrictions, such as limitations imposed by roads, ports, and bridges, also complicated the introduction of a more capable but heavier tank. Tank destroyer battalions using vehicles built on the M4 hull and chassis, but with open-topped turrets and more potent high-velocity guns, also entered widespread use in the Allied armies. Even by 1944, most M4 Shermans kept their dual-purpose 75 mm gun. By then, the M4 was inferior in firepower and armor to increasing numbers of German upgraded medium tanks and heavy tanks but was able to fight on with the help of considerable numerical superiority, greater mechanical reliability, better logistical support, and support from growing numbers of fighter-bombers and artillery pieces. Later in the war, a more effective armor-piercing gun, the 76 mm gun M1, was incorporated into production vehicles. For anti-tank work, the British refitted Shermans with a 76.2 mm Ordnance QF 17-pounder gun (as the Sherman Firefly). Some were fitted with a 105 mm gun to act as infantry support vehicles.

The relative ease of production allowed large numbers of the M4 to be manufactured, and significant investment in tank recovery and repair units allowed disabled vehicles to be repaired and returned to service quickly. These factors combined to give the Allies numerical superiority in most battles, and many infantry divisions were provided with M4s and tank destroyers. By 1944, a typical U.S. infantry division had attached for armor support an M4 Sherman battalion, a tank destroyer battalion, or both.

After World War II, the Sherman, particularly the many improved and upgraded versions, continued to see combat service in many conflicts around the world, including the U.N forces in the Korean War, with Israel in the Arab–Israeli wars, briefly with South Vietnam in the Vietnam War, and on both sides of the Indo-Pakistani War of 1965.

U.S. Design Prototype

The United States Army Ordnance Department designed the M4 medium tank as a replacement for the M3 medium tank. The M3 was an up-gunned development of the M2 Medium Tank of 1939, in turn, derived from the M2 light tank of 1935. The M3 was developed as a stopgap measure until a new turret mounting a 75 mm gun could be devised. While it was a big improvement when used by the British in Africa against German forces, the placement of a 37 mm gun turret on top gave it a very high profile, and the unusual side-sponson mounted main gun, with limited traverse, could not be aimed across the other side of the tank. Though reluctant to adopt British weapons into their arsenal, the American designers were prepared to accept proven British ideas. These ideas, as embodied in a tank designed by the Canadian General Staff, also influenced the development of the American Sherman Tank. Before long American military agencies and designers had accumulated sufficient experience to forge ahead on several points. In the field of tank armament, the American 75 mm and 76 mm dual-purpose tank guns won the acknowledgment of British tank experts. Detailed design characteristics for the M4 were submitted by the Ordnance Department on 31 August 1940, but the development of a prototype was delayed while the final production designs of the M3 were finished and the M3 entered full-scale production. On 18 April 1941, the U.S. Armored Force Board chose the simplest of five designs. Known as the T6, the design was a modified M3 hull and chassis, carrying a newly designed turret mounting the M3's 75 mm gun. This would later become the Sherman.

The Sherman's reliability resulted from many features developed for U.S. light tanks during the 1930s, including vertical volute spring suspension, rubber-bushed tracks, and a rear-mounted radial engine with drive sprockets in front. The goals were to produce a fast, dependable medium tank able to support infantry, provide breakthrough striking capacity, and defeat any tank then in use by the Axis nations.

The T6 prototype was completed on 2 September 1941. The upper hull of the T6 was a single large casting. It featured a single overhead hatch for the driver and a hatch in the side of the hull. In the later M4A1 production model, this large casting was maintained, although the side hatch was eliminated and a second overhead hatch was added for the assistant driver. The modified T6 was standardized as the M4, and production began in February 1942. The cast-hull models would later be re-standardized as M4A1, with the first welded-hull models receiving the designation M4. In August 1942, a variant of the M4 was put forth by the Detroit Arsenal to have angled, rather than rounded hull and turret armor. The changes were intended to improve the tank's protection without increasing weight or degrading other technical characteristics.

Doctrine

As the United States approached entry into World War II, armored employment was doctrinally governed by Field Manual 100–5, Operations (published May 1941, the month following the selection of the M4 tank's final design). That field manual stated:

The armored division is organized primarily to perform missions that require great mobility and firepower. It is given decisive missions. It is capable of engaging in all forms of combat, but its primary role is in offensive operations against hostile rear areas.

The M4 was, therefore, not originally intended primarily as an infantry support tank. It placed tanks in the "striking echelon" of the armored division, and placed the infantry in the "support echelon", without directing that tanks should only seek to attack other tanks, thus leaving target selection up to the field commander based on what types of units were available to him to attack. A field manual covering the use of the Sherman (FM 17–33, "The Tank Battalion, Light and Medium" of September 1942) described fighting enemy tanks when necessary as one of the many roles of the Sherman, but devoted only one page of text and four diagrams to tank-versus-tank action, out of 142 pages. This early armored doctrine was heavily influenced by the sweeping early war successes of German blitzkrieg tactics. By the time M4s reached combat in significant numbers, battlefield demands for infantry support and tank versus tank action far outnumbered the occasional opportunities of rear-echelon exploitation.

United States doctrine held that the most critical anti-tank work – stopping massed enemy tank attacks – was primarily to be done by towed and self-propelled anti-tank guns, operated by "Tank Destroyer" battalions, with friendly tanks being used in support if possible. Speed was essential to bring the tank destroyers from the rear to destroy incoming tanks. This doctrine was rarely followed in combat, as it was found to be impractical. Commanders were reluctant to leave tank destroyers in reserve; if they were, it was also easier for an opposing armored force to achieve a breakthrough against an American tank battalion, which would not have all of its anti-tank weapons at the front during the beginning of any attack.

U.S. Production History

The first production of the Sherman took place at the Lima Locomotive Works, with many early vehicles reserved for British use under Lend-Lease; the first production Sherman was given to the U.S. Army for evaluation, and the second tank of the British order went to London. Nicknamed Michael, probably after Michael Dewar, head of the British tank mission in the U.S., the tank was displayed in London and is now an exhibit at The Tank Museum, Bovington, UK.

In World War II, the U.S. Army ultimately fielded 16 armored divisions, along with 70 separate tank battalions, while the U.S. Marine Corps fielded six tank battalions. A third of all Army tank battalions, and all six Marine tank battalions, were deployed to the Pacific Theater of Operations (PTO). Before September 1942, President Franklin D. Roosevelt had announced a production program calling for 120,000 tanks for the Allied war effort. Although the American industrial complex was not affected by enemy aerial bombing or submarine warfare as was Japan, Germany, and, to a lesser degree, Great Britain, an enormous amount of steel for tank production was diverted to the construction of warships and other naval vessels. Steel used in naval construction amounted to the equivalent of approximately 67,000 tanks; and consequently, only about 53,500 tanks were produced during 1942 and 1943.

The Army had seven main sub-designations for M4 variants during production: M4, M4A1, M4A2, M4A3, M4A4, M4A5, and M4A6. These designations did not necessarily indicate linear improvement; in that "M4A4" did not indicate it was better than "M4A3". These sub-types indicated standardized production variations, which were in fact often manufactured concurrently at different locations. The sub-types differed mainly in engines, although the M4A1 differed from the other variants by its fully cast upper hull, with a distinctive rounded appearance. The M4A4 had a longer engine that required a longer hull and more track blocks, and thus the most distinguishing feature of the M4A4 was the wider longitudinal spacing between the bogies. "M4A5" was an administrative placeholder designation for Canadian production. The M4A6 had a radial diesel engine as well as the elongated chassis of the M4A4, but only 75 of these were ever produced.

Most Sherman sub-types ran on gasoline. The air-cooled Continental-produced Wright R-975 Whirlwind 9-cylinder radial gasoline engine in the M4 and M4A1 produced 350 or 400 horsepower (260 or 300 kW). The M4A3 used the liquid-cooled 450 hp (340 kW) Ford GAA V8 gasoline engine, and the M4A4 used the liquid-cooled 370 hp (280 kW) 30-cylinder Chrysler A57 multibank gasoline engine. There were also two diesel-engined variants. The M4A2 was powered by a pair of liquid-cooled GMC Detroit Diesel 6–71 two-stroke inline engines, that produced a total of 375 hp (280 kW), while the M4A6 used an RD-1820 (a redesigned Caterpillar D-200A air-cooled radial diesel engine, adapted from Wright Aeronautical's Wright R-1820 Cyclone 9 nine-cylinder radial aircraft engine.) that produced 450 hp (340 kW). A 24-volt electrical system was used in the M4. The M4A2 and M4A4 were mostly supplied to other Allied countries under Lend-Lease.

The term "M4" can refer specifically to the initial sub-type with its Continental radial engine, or generically, to the entire family of seven Sherman sub-types, depending on context. Many details of production, shape, strength, and performance improved while in production, without a change to the tank's basic model number. These included stronger suspension units, safer "wet" (W) ammunition stowage, and stronger or more effective armor arrangements, such as the M4 "Composite", which had a cheaper-to-produce cast front hull section mated to a regular welded rear hull. British nomenclature for Shermans was by mark numbers for the different hulls with letters for differences in armament and suspension: A for a vehicle with the 76 mm gun, B for the 105 mm howitzer, C for the 17pdr gun, and Y for any vehicle equipped with horizontal volute spring suspension (HVSS); eg. British operated M4A1(76) was known as Sherman IIA.

Early Shermans mounted a 75 mm medium-velocity general-purpose gun. Although Ordnance began work on the T20/22/23 series as Sherman replacements, the Army Ground Forces were satisfied with the M4, and Armored Force Board considered some features of the experimental tanks unsatisfactory. Continuing with M4 minimized production disruption but elements of the experimental designs were incorporated into the Sherman. Later M4A1, M4A2, and M4A3 models received the larger turret with a high-velocity 76 mm gun trialled on the T23 tank. The first standard-production 76 mm gun-armed Sherman was an M4A1, accepted in January 1944, which first saw combat in July 1944 during Operation Cobra. Variants of the M4 and M4A3 were factory-produced with a 105 mm howitzer and a distinctive rounded gun mantlet, which surrounded the main gun, on the turret. The first Sherman variant to be armed with the 105 mm howitzer was the M4, first accepted in February 1944.

From May to July 1944, the Army accepted a limited run of 254 M4A3E2 "Jumbo" Shermans, which had very thick hull armor and the 75 mm gun in a new, better-protected T23-style turret ("Jumbos" could mount the 76 mm M1 cannon), to assault fortifications, leading convoys, and spearhead armored columns. The M4A3 model was the first to be factory-produced with the HVSS system with wider tracks to distribute weight, beginning in August 1944. With the smooth ride of the HVSS, it gained the nickname "Easy Eight" from its experimental "E8" designation. The M4 and M4A3 105 mm-armed tanks, as well as the M4A1 and M4A2 76 mm-armed tanks, were also eventually equipped with HVSS. Both the Americans and the British developed a wide array of special attachments for the Sherman, although few saw combat, remaining experimental. Those that saw action included a bulldozer blade, the Duplex Drive system, flamethrowers for Zippo flame tanks, and various rocket launchers such as the T34 Calliope. British variants (DDs and mine flails) formed part of the group of specialized vehicles collectively known as "Hobart's Funnies" (after Percy Hobart, commander of the 79th Armoured Division).

The M4 Sherman's basic chassis was used for all the sundry roles of a modern mechanized force. These included the M10 and M36 tank destroyers; M7B1, M12, M40, and M43 self-propelled artillery; the M32 and M74 "tow truck"-style recovery tanks with winches, booms, and an 81 mm mortar for smoke screens; and the M34 (from M32B1) and M35 (from M10A1) artillery prime movers.

Service History

Allocation

During World War II, approximately 19,247 Shermans were issued to the U.S. Army and about 1,114 to the U.S. Marine Corps. The U.S. also supplied 17,184 to the United Kingdom (some of which in turn went to the Canadians and the Free Poles), while the Soviet Union received 4,102, and an estimated 812 were transferred to China. These numbers were distributed further to the respective countries' allied nations.

The U.S. Marine Corps used the diesel M4A2 and gasoline-powered M4A3 in the Pacific. However, the Chief of the Army's Armored Force, Lt. Gen. Jacob L. Devers, ordered that no diesel-engined Shermans be used by the Army outside the Zone of Interior (the continental U.S.). The Army used all types for either training or testing within the United States but intended the M4A2 and M4A4 (with the A57 Multibank engine) to be the primary Lend-Lease exports.

First Combat

Shermans were being issued in small numbers for familiarization to U.S. armored divisions when there was a turn of events in the Western Desert campaign. Axis forces had taken Tobruk and were advancing into Egypt and Britain's supply line through the Suez Canal was threatened. The US considered collecting all Shermans together to be able to send the 2nd Armored Division under Patton to reinforce Egypt, but delivering the Shermans directly to the British was quicker, and over 300 – mostly M4A1s, but also including M4A2s – had arrived there by September 1942.

The Shermans were modified for desert warfare with shields over the tracks and another stowage. The Sherman first saw combat at the Second Battle of El Alamein in October 1942 with the British 8th Army. At the start of the offensive, there were 252 tanks fit for action. These equipped the British 9th Armoured Brigade (for the battle under the New Zealand Division), 2nd Armoured Brigade (1st Armoured Division), and 8th and 20th Armoured Brigades (10th Armoured Division). Their first encounter with tanks was against German Panzer III and IV tanks with long 50 mm and 75 mm guns engaging them at 2,000 yards (1,800 m). There were losses to both sides.

The first U.S. Shermans in battle were M4s and M4A1s in Operation Torch the following month. On 6 December, near Tebourba, Tunisia, a platoon from the 2nd Battalion, 13th Armored Regiment was lost to enemy tanks and anti-tank guns.

Additional M4s and M4A1s replaced M3s in U.S. tank battalions over the course of the North African campaign.

The M4 and M4A1 were the main types in U.S. units until the fall of 1944 when the Army began replacing them with the preferred M4A3 with its more powerful 500 hp (370 kW) engine. Some M4s and M4A1s continued in U.S. service for the rest of the war. The first Sherman to enter combat with the 76 mm gun in July 1944 was the M4A1, then the M4A2, closely followed by the M4A3. By the end of the war, roughly half the U.S. Army Shermans in Europe had the 76 mm gun. The first HVSS-equipped Sherman to see combat was the M4A3(76)W in December 1944.

Eastern Front

Under Lend-Lease, 4,102 M4A2 medium tanks were sent to the Soviet Union. Of these, 2,007 were equipped with the original 75 mm main gun, with 2,095 mounting the more-capable 76 mm gun. The total number of Sherman tanks sent to the USSR under Lend-Lease represented 18.6% of all Lend-Lease Shermans. The first 76 mm-armed M4A2 Shermans started to arrive in the Soviet Union in the late summer of 1944.

The Red Army considered the M4A2 to be much less prone to catch fire due to ammunition detonation than the T-34/76, but the M4A2 had a higher tendency to overturn in road accidents and collisions or because of rough terrain than the T-34 due to its higher center of gravity.

By 1945, some Red Army armored units were equipped entirely with the Sherman. Such units included the 1st Guards Mechanized Corps, the 3rd Guards Mechanized Corps, and the 9th Guards Mechanized Corps, amongst others. According to Soviet tanker Dmitriy Loza, the Sherman was held in good regard and viewed positively by many Soviet tank crews, with compliments given to its reliability, ease of maintenance, and generally good firepower (referring especially to the 76 mm gun version) as well as an auxiliary power unit (APU) to keep the tank's batteries charged without having to run the main engine, as was required on the T-34. However, according to Soviet tank crews, the Sherman also had disadvantages, the greatest being its high center of gravity and the ease of hitting by enemy fire. The Sherman’s relatively narrow-set tracks struggled to negotiate muddy terrain compared to the wider-set tracks of the T-34 or German Panther tank.

Pacific Theater

While combat in the European theater often consisted of high-profile armored warfare, the mainly naval nature of the Pacific Theater of Operations (PTO) relegated it to secondary status for both the Allies and the Japanese. While the U.S. Army fielded 16 armored divisions and 70 separate tank battalions during the war, only a third of the battalions and none of the divisions were deployed to the Pacific Theater. The Imperial Japanese Army (IJA) deployed only their 2nd Tank Division to the Pacific during the war. Armor from both sides mostly operated in jungle terrain that was poorly suited to armored warfare. For this type of terrain, the Japanese and the Allies found light tanks easier to transport and employ.

During the early stages of combat in the Pacific, specifically, the Guadalcanal Campaign, the U.S. Marine Corps M2A4 light tank fought against the equally-matched Type 95 Ha-Go light tank; both were armed with a 37 mm main gun. However, the M2 (produced in 1940) was newer by five years. By 1943, the IJA still used the Type 95 and Type 97 Chi-Ha medium tanks, while Allied forces were quickly replacing their light tanks with 75 mm-armed M4s. The Chinese in India received 100 M4 Shermans and used them to great effect in the subsequent 1944 and 1945 offensives in the China Burma India Theater.

To counter the Sherman, the Japanese developed the Type 3 Chi-Nu and the heavier Type 4 Chi-To; both tanks were armed with 75 mm guns, albeit of different types. Only 166 Type 3s and two Type 4s were built, and none saw combat; they were saved for the defense of the Japanese home islands, leaving 1930s-era light and medium armor to do battle against 1940s-built Allied light and medium armor.

During the later years of the war, general-purpose high explosive ammunition was preferred for fighting Japanese tanks because armor-piercing rounds, which had been designed for penetrating thicker steel, often went through the thin armor of the Type 95 Ha-Go (the most commonly encountered Japanese tank) and out the other side without stopping. Although the high-velocity guns of tank destroyers were useful for penetrating fortifications, M4s armed with flamethrowers were often deployed, as direct fire seldom destroyed Japanese fortifications.

Korean War

During the Korean War, the M4A3E8 Easy Eight was the main tank force of the U.S. military until the signing of the armistice agreement.

At the outbreak of the war, the U.S. military tried to deploy the M4A3E8, a medium-sized tank of the same class, to respond to the North Korean T-34-85, but there were few tanks available for rapid deployment from the Far East due to disarmament after World War II. The U.S. Far East Command collected 58 M4A3E8 scattered throughout Japan, created the 8072nd Temporary Tank Battalion (later renamed to the 89th Tank Battalion) on July 17, and landed them in Busan on August 1. The 8072nd Temporary Tank Battalion was immediately deployed for the Battle of Masan to support the 25th U.S. Infantry Division.

Since then, a total of 679 M4A3E8 were deployed on the Korean Peninsula in 1950. The M4A3E8 and T-34-85 were comparable and could destroy each other at normal combat ranges, although the use of High-Velocity Armor Piercing ammunition, advanced optics, and better crew training gave the Sherman an advantage. The M4A3E8, using 76 mm HVAP ammunition, destroyed 41 enemy tanks from July to November 1950.

The M4A3E8 had weaker anti-tank combat capability compared to the larger caliber M26 Pershing and the M46 Patton that were operated at the same time. However, the lighter M4A3E8 became the preferred U.S. tank in the later phases of the war. It was considered more advantageous in terms of maneuverability on rough terrain and ease of maintenance due to its mechanical reliability. Because of this feature, the M4A3E8 was widely used for providing close support to infantry units, particularly during battles for high ground and mountains.

From December 1951, around 20 M4A3E8s saw service with the Republic of Korea Marine Corps during the war while the Army operated M36 GMCs as its main armored asset.

Other uses

After World War II, the U.S. kept the M4A3E8 Easy Eight in service, with either the 76 mm gun or a 105 mm M4 howitzer. The U.S. Army replaced the M4 in 1957, in favor of the M47 Patton, M48 Patton, and, M60 Patton. The U.S. continued to transfer Shermans to its allies, which contributed to widespread foreign use.

The Israeli Defense Force used Shermans from its creation in 1948 until the 1980s, having first acquired a single M4A2 lacking the main armament from British forces as they withdrew from Israel. The popularity of the tank (having now been re-armed) compared to the outdated, 1934-origin French Renault R35 interwar light tanks with their 37 mm short-barreled guns, which made up the bulk of the IDF's tank force, led to the purchase of 30 unarmed M4(105 mm)s from Italian scrapyards. Three of these, plus the original M4A2, saw extensive service in the 1948-9 War of Independence. The remainder were then serviced and rearmed with 75 mm guns and components whenever these became available, composing a large part of Israeli tank forces for the next eight years. The 75 mm-armed Shermans were replaced by M4A1 (76 mm) Shermans imported from France before the 1956 Suez Crisis after it was realized that their armor penetration was insufficient for combat against newer tanks such as the IDF Centurions as well as the T-34-85s being delivered to Egyptian forces. During further upgrades, the French military helped develop a conversion kit to upgrade about 300 Shermans to the long high-velocity 75 mm gun CN 75-50 used in the AMX-13. These were designated Sherman M-50 by the Israelis. Before the Six-Day War in 1967, the Israeli Army upgraded about 180 M4A1(76)W HVSS Shermans with the French 105 mm Modèle F1 gun, re-engined them with Cummins diesel engines, and designated the upgraded tank Sherman M-51. The Sherman tanks, fighting alongside the 105 mm Centurion Shot Kal and M48 Patton tanks, were able to defeat the T-34-85, T-54/55/62 series, and IS-3 tanks used by the Egyptian and Syrian forces in the 1967 Six-Day War.

M4A3s were also used by British forces in Indonesia during the Indonesian National Revolution until 1946 when they were passed on to the KNIL, which used them until 1949 before they were passed on to the Indonesian National Armed Forces.