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M4 Medium Tank Sherman
Specifications
Mass	30 tonnes
Length	5.92 m
Width	2.62 m
Height	2.74 m
Crew	5

The M4 Medium Tank was the main tank designed and built by the United States for allied forces in World War II, totaling roughly 50,000 tanks plus thousands more derivative vehicles under different model numbers with different abilities. In the UK lend-lease M4s were dubbed M4 General Sherman after Union General William Tecumseh Sherman, continuing a practice of naming American tanks after famous Generals. The name is often shortened to M4 Sherman or simply Sherman, and quickly became popular in the US as well. M4 tanks made in Canada up to 1943 were given the name Grizzly. In the USSR it was nicknamed Emcha. After WWII, Shermans served the US (in the Korean War) and many other nations world-wide and saw combat in many wars in the late 20th century.

Production history

see also M4 Sherman variants

The U.S. Army Ordnance Department designed the M4 medium tank with a 75 mm gun in a traversing turret on the chassis shared with the interim M3 Medium Tank known as "Lee". During the production period, the U.S. Army's seven main sub-designations, M4, M4A1, M4A2, M4A3, M4A4, M4A5, and M4A6 (British terms differed), did not necessarily indicate linear improvement (A4 is not meant to indicate 'better than' A3). Instead, these sub-types indicated standardized production variations (often manufactured concurrently at different locations) that differed mainly in terms of engine, although M4A1 differed from M4 by its fully cast upper hull rather than by engine; M4A4 had a longer engine system that also required a longer hull, longer suspension system, and more track blocks; M4A5 was an administrative placeholder for Canadian production; and M4A6 also elongated the chassis but totaled fewer than 100 tanks. Only the M4A2 and M4A6 were diesel while most Shermans were gasoline. "M4" might refer specifically to the single 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 throughout production life without an "advance" to the tank's basic model number; more durable suspension units, safer "wet" (W) ammuntion stowage, and stronger armor arangements such as the M4 Composite which had a cast front hull section mated to a welded rear hull.

Early Shermans mounted a 75 mm medium-velocity general-purpose gun. Later M4A1, M4A2, and M4A3 models received the larger T23 turret with a high-velocity 76 mm M1 gun (a hybrid formed from the 3 inch gun of the M10 Wolverine tank destroyer and the breech of the 75 mm), which traded reduced HE and smoke performance for improved anti-tank performance. Later M4 and M4A3 were factory-produced with a 105 mm howitzer and a new distinctive mantlet in the original turret. The first standard-production 76mm-gun Sherman was an M4A1 accepted in January 1944 and the first standard-production 105mm-howitzer Sherman was an M4 accepted in February 1944.

The US accepted in June-July 1944 a limited run of 254 M4A3E2 "Jumbo" Shermans with very thick armor and the 75 mm gun in a new heavier T23-style turret in order to assault fortifications. The M4A3 was the first to be factory-produced with the new HVSS suspension with wider tracks for lower ground pressure and the smooth ride of the HVSS with its experimental E8 designation led to the nickname "Easy Eight" for Shermans so equipped.

The British devised a late-WWII post-production conversion called the Firefly that mounted the even more potent British QF 17 pounder (76.2 mm) anti-tank gun in the standard turret by moving the radio to a new bustle on the turret rear and by turning the long-recoiling AT gun on its side. The conversion was carried out on M4, M4Composite and M4A4 Shermans, some Canadian licence built M4A1s (Grizzlies) were also converted to Firefly standard but were used only for training. The British offered the 17 pounder with its significant armour penetration but a significant initial (later rectified) HE shortcoming to the Americans but the US Ordnance Department was working on a 90 mm tank gun and declined.

Under Major-General Percy Hobart, "Hobart's Funnies", specialist function tanks, were designed specifically for Operation Overlord ("D-Day") and the Battle of Normandy. Some of these were based on Shermans. These vehicles included the "swimming" Duplex Drive Sherman tanks and the Sherman 'Crab', (a Sherman tank with a flail in front of it which destroyed landmines without damage to the tank) both of which were necessary for the initial beach assault. A very unusual modification was the Sherman BARV which had a welded superstructure attached to the top in place of the turret. It was used to recover stranded vehicles at the water's edge. The crew included one diver who could attach towing cables underwater. As part of the deception plan of Operation Fortitude that drew German attention to the Pas de Calais rather than Normandy, inflatable rubber Shermans were manufactured and deployed across fields in Kent alongside plywood artillery pieces, another vesion of dummy Sherman was made from painted canvas over a steel frame and could be built over a Jeep and driven to simulate a moving tank.

The M4 Sherman's basic chassis further undertook all the sundry roles of a modern, mechanized force, totaling roughly 50,000 Sherman tanks plus thousands more derivative vehicles under different model numbers. Rocket-firing tanks, bulldozer tanks, "tow truck"-style recovery tanks with winches and booms, artillery prime movers, self-propelled artillery, and upgunned tank destroyers were among the many other M4 Sherman variants.

Service History

During World War II, the M4 Sherman served with the US Army and US Marine Corps, as well as the allied forces of the United Kingdom (including Commonwealth), Soviet Union, Free French government-in-exile, Polish government-in-exile, and China.

The first Shermans to see battle were with the British 8th Army at the Second Battle of El Alamein in October 1942. British and Commonwealth use in Europe was comprehensive, the Sherman replaced the M3 Grant and Lee variants and was in the majority by 1944 - the other main late-war tanks being the Churchill and Cromwell. The British largely used M4, M4A1, M4A2, and later became the primary user of the M4A4. The Sherman Firefly variant was converted mostly from M4 and M4A4 Shermans supplied from the U.S.A, and was used both in Sherman-equipped and Cromwell-equipped units to add extra anti-tank capability.

Although the US Marine Corps used the diesel M4A2 in the Pacific and the US Army Tank Destroyer Command used the diesel M10 tank destroyer (based on the M4A2 chassis) also in Africa and Europe, the US Army Chief of the Armored Force Lt. Gen. Jacob L. Devers ordered that no diesel-engined Sherman tanks be used outside the Zone of Interior (ZI). The first US Shermans in combat were the M4 and M4A1 used for Operation Torch in November 1942 and Shermans replaced M3 Lees in tank battalions over the course of the North African campaigns. Although the M4 and M4A1 continued in combat units throughout the war, the US Army preferred the M4A3 with its more powerful 500 hp engine for the rest of the war. The first 76 mm gun Sherman to enter combat in summer 1944 was the M4A1 followed by the M4A3. By the end of the war, half the US Army Shermans in Europe had the 76 mm gun for better anti-armor work while half had the 75 mm gun for better HE and smoke work, and some units intentionally kept a mix of both guns. The first HVSS Sherman to see combat was the M4A3E8(76)W in late 1944.

The Soviet Union preferred the diesel Shermans because its native tanks such as the T-34 were also diesel. Consequently, it was the second largest user (after the United Kingdom) of the diesel M4A2 Sherman with 75 mm gun and the largest use of the M4A2 with 76 mm gun. Unlike the case of the British, the M4A2 accounted for nearly all Soviet Shermans.

Free French forces used many types of which M4A2 represented a relatively high proportion.

Post-WWII, the US kept the M4A3E8 "Easy Eight" in service with either 76 mm gun or 105 mm howitzer. The Sherman remained a common US tank in the 1950-1953 Korean War.

After the war, Shermans served many nations world-wide and saw combat in smaller wars in the late 20th century. Upgraded versions included the Israeli M50 "SuperSherman" with French 75 mm gun and M51 "Isherman" with 105 mm gun, a shorter (L/44) version of that used in the AMX-30, both these tanks mounted the main armament in the large T23 turret. The Sherman fought on both sides of the Second Kashmir War and Indo-Pakistani War of 1971. Latin-America used the Sherman for a long time after the war; the Chilean army used active-duty Shermans into 1989, and Paraguay was the last country in Latin America to use the Sherman.

Combat performance

Preface: Doctrine

Stephen Ambrose states in Citizen Soldiers that, in accordance with U.S. Army doctrine at the time, the tank was designed to help infantry exploit a breakout rather than to engage in armor vs. armor combat. In defense, Allied armies deployed infantry anti-tank guns, tank destroyers, artillery fire and airpower to wear down the German armor before launching an armored counter-attack. In armored offense, American commanders were able to bring overwhelming numbers and airpower to bear.

The United States Army was influenced by the German Panzer tanks, used successfully in the Blitzkrieg tactics in the 1939 Polish Campaign to support fast-moving infantry (though this was not the first time such tactics were used in warfare). According to US doctrine the role of defeating German armour fell to tank destroyers such as the M10 Wolverine rather than the medium tanks.

Although the US Combined Arms team included exceptional close air support, artillery, and engineer components, the tank component was weakened by the Tank Destroyer concept. This is most closely identified with the Chief of Army Ground Forces, General Leslie McNair who believed towed 57 mm AT guns, hand-held Bazookas and thinly armoured Tank Destroyers to be superior to friendly tanks for fighting enemy tanks. Under this doctrine, tanks were supposed to avoid tank-vs-tank combat as much as possible, leaving enemy tanks to the tank destroyers. In actual combat, McNair's doctrine led to US tanks having weaker guns and less armor protection than their German counterparts.

Armament

Early models are often criticized for the 75 mm gun chosen by the artillery branch of the US Army. To some extent this criticism is unfounded. The standard Sherman, armed with a 75 mm cannon, was not even specifically intended for anti-tank work. Nevertheless, at the time it first saw combat, the Sherman's 75 mm gun, inherited from the M3, could kill any German tank then in service at normal combat ranges. The problem was the failure to upgrade tank guns to keep pace with the heavier German tanks being introduced later in the war. While it was an effective weapon in 1942, by the Normandy landings of 1944 the Sherman lacked effectiveness against the medium Panther and heavy Tiger I tanks, against which the Sherman's 75 mm gun could not achieve a frontal penetration at any range. The 75 mm gun was a solid weapon against infantry and other targets, even if it was outmoded for anti-tank use later in the war.

The 75 mm gun was replaced in time with a much improved higher-velocity 76 mm M1 gun giving it firepower comparable to the Soviet T-34/85 and many of the AFVs it encountered, particularly the Pz III, Pz IV, and StuG vehicles. The 76 mm armed vehicles first saw combat in Normandy, where half the German tanks encountered were the 45-ton Panther. With a regular APBC ammunition the 76 mm could reliably knock out a Panther only with a shot to its flank. Firing later HVAP ammunition, the 76 mm could penetrate the frontal armor of the Panther but this was usually in short supply. By the end of the war 50% of Sherman tanks were equipped with the superior 76 mm gun. The 75 mm gun remained superior for HE and smoke and thus most medium battalions intentionally kept a 75 mm armed Sherman to fulfil the role of smoke layer.

Because there were relatively few Tigers and Panthers, they could be defeated by weight of numbers or superior tactics, using up-gunned Shermans working with tank destroyers such as the M36 Jackson (with a 90 mm anti-tank gun) and the M18 Hellcat (a mobile, fast tracked vehicle with the same 76 mm gun). US crews and commanders such as LTC Creighton Abrams or Sergeant Lafayette Poole were able to knock out dozens of German tanks each.

The best anti-tank weapon that was mounted on the Sherman was the British QF 17 pounder (76.2 mm) gun, a very high-velocity weapon firing APDS shells capable of defeating the heavier German tanks. The 17 pounder had already shown its value in 1943, in Africa as a wheeled anti-tank gun. It proved an effective weapon against German AFVs. With the APDS developed for the 17 pounder, the Firefly's performance was increased again. Although the 17-pounder was an excellent anti-armor weapon, initially the HE shell provided was weak, making it a poor general-purpose tank gun but the HE shell issue was resolved later. A 1944-pattern British armored company had one Firefly per troop (platoon) of 4 Shermans. Later when the Sherman was being replaced in British service by the Cromwell, the Firefly was retained until the introduction of the Comet which carried the 77 mm HV a form of cutdown 17 pdr.

In the relatively few Pacific tank battles, even the 75 mm gun Shermans outclassed the Japanese in every engagement. The use of HE (High Explosive) ammunition was preferred because anti-tank rounds punched cleanly through the thin armor of the Japanese tanks (light tanks of 1930s era design) without necessarily stopping them.

Post WW2 Shermans saw a revolution in armament, many supplied to Israel saw conversion with a French 75mm , as used in the French light tank AMX13(Developed from that in the Sherman's old adversary the Panther). This gun was mounted in the large 76mm turret and Shermans modified to this standard were classed as the M50. This turret also proved able to accommodate a suitably modified 105mm gun fitted with a huge muzzle brake and characteristic Infra Red lamp over the gun mantlet, this modification was known as the M51 or 'Super Sherman'.

Armor

It must be remembered that from the outset the Sherman was designed to withstand a 37mm anti-tank gun and by the end of the war it was facing the 75mm guns of the German Panthers and Panzer IVs and even the 88mm KwK43 L/71 of the King Tiger. The Sherman had armor protection levels comparable to other medium tanks of 1942. By 1944, this level of protection was no longer adequate. While Shermans were able to take on the Panzer III medium tanks in the North African campaigns, they were unable to withstand the weapons mounted on late-model Panzer IV, and Panther and Tiger tanks encountered in Italy and Normandy. Armor was more evenly distributed and thicker at the side than the PzIV; the top armor was equal to that of the Tiger.

Early Sherman models were prone to burning at the first hit. US Army research proved that the major reason for this was the use of unprotected ammo stowage in sponsons above the tracks. The common myth that the use of gasoline (petrol) engines was a culprit is unsupported; most WW2 tanks used gasoline engines, petrol was unlikely to ignite whenhit with AP shells. This vulnerability increased crew casualties and meant that damaged vehicles were less likely to be able to be repaired for reuse. At first a partial remedy was found by welding one-inch thick applique armour plates to the vertical sponson sides over the ammunition stowage bins. Later models moved ammunition stowage to the hull floor, with additional water jackets surrounding the main gun ammunition stowage. This decreased the likelihood of "brewing up".

A particularly unfortunate design defect meant that if the main turret gun came to rest at the wrong angle it blocked one or the other of the two front hatches from being opened, thus potentially trapping the crew member inside. Eye witness accounts have recorded the horror of hearing the screaming of the man trapped inside while he burnt to death, and being helpless to rescue him. Unfortunately this was a common flaw in many WW2 tanks including the British Cromwell, German Panzer IV, and German Tiger I. The M4 and T-34 had an escape hatch on the hull bottom to help minimize this problem, but it was not a complete solution, particularly if a crewman was wounded.

The Sherman gained grim nicknames like 'Tommycooker' after a World War I portable stove, or "Ronsons" after the cigarette lighter with the slogan "Lights up the first time, every time!" Progressively thicker armour was added to hull front and turret mantlet in various improved models, while field improvisations included placing sandbags, spare track links, or even logs to increase protection against shaped-charge rounds.

General George S. Patton, informed by his technical experts that the standoff produced by sandbags actually increased vulnerability to shaped-charge weapons (a controversial opinion) and that the machines' chassis suffered from the extra weight, forbade the use of sandbags and instead ordered tanks under his command to have the front hull welded with extra armour plates, salvaged from knocked-out American and German tanks. Approximately 36 of these up-armored Shermans were supplied to each of the armored divisions of the Third Army in the spring of 1945.

The diesel-engined M4A2 ("emcha") used by the Red Army were considered to be much less prone to burn and explode than the Soviet T-34. The M4A2 also saw use with other Allied forces, such as the US Marine Corps in the Pacific.

The (rare) M4A3E2 Sherman Jumbo variant had thicker frontal armor than the Tiger and Panther.

Mobility

Strategic Mobility

The U.S. Army required the Sherman not to exceed certain widths and weights so that the tank could use a wide variety of bridge, road, and rail travel for strategic, industrial, logistical, and tactical flexibility. Eisenhower demanded an improved tank from Army Chief of Staff George C. Marshall, who explained that he couldn't move a larger tank along the rail tracks to the East coast for shipping to Europe. The comparatively compact size of the Sherman also made it suited for transportation across the Atlantic and for amphibious operations. According to Ambrose, General George C. Marshall favored the M4 because two Shermans could be loaded on to an LST while only one larger tank could be accommodated.

Operational Mobility

Spares were readily available, an important consideration when more tanks were lost to mechanical failure than any other cause, including enemy action. Jim Dunnigan, a military analyst and war game designer, states that the number of tanks lost to mechanical failure in American, Soviet, and German armies in World War Two was in the ratio of one to five to ten. This is a striking testimony to the performance of the Sherman and highlights the relative mechanical unreliability of German tanks such as bedeviled the Tiger. The spectacular Allied mobility of 1944-45 could not have been achieved with tanks as unreliable as the Tiger or Panther, nor could the spectacular German mobility of 1939-41.

Tactical Mobility

The Sherman had good speed both on and off-road for the era. Off-road performance varied. In the desert, the Sherman's rubber tracks performed well. However, US crews found that on soft ground, such as mud or snow, the narrow tracks gave poor floatation compared to wide-tracked second-generation German tanks such as the Panther. Extended end connectors or 'duckbills' were a stopgap solution. Soviet experiences were similar and tracks were modified to give grip in the snow. The M4A3E8 'Easy Eight' Shermans and other late models with wider-tracked HVSS suspension corrected this problem, but formed only a small proportion of all tanks in service even in 1945. In the confined, hilly terrain of Italy, the Sherman could often cross terrain German tanks could not.

Summary

The Sherman tank was comparatively fast and maneuverable, mechanically reliable, easy to manufacture and service, and produced in many special-purpose variants whose capabilities differed greatly. It was effective in the infantry support role.

The Sherman performed well against WWII Japanese tanks, Italian tanks, and the most common German tank of WWII, the Panzer IV medium series. However, the typical Sherman was inferior in both armor and armament to the later German Panther "medium" (heavy by US standards) and Tiger heavy tanks. Sherman Crews would sometimes hide or drive instead of confronting a Tiger. In the Normandy campaign it could take between four to five Shermans to knock out a single Tiger tank, and then by maneuvering to find its weaker flank or rear armor.(The Soviet T-34s fared similarly against the German tanks, as previously the German PzIII had against the Soviet heavy tanks.) Increasing numbers of upgunned Shermans with better ammunition after Normandy reduced the imbalance against the heavier German tanks.

The majority of losses of Shermans were not in battle with other tanks, but from mines, aircraft, infantry anti-tank weapons and, on occasion, friendly fire. This should not be surprising considering that the entire strategy of blitzkrieg, as practiced first by the Germans and later the Allies, was to strike the enemy where they are weakest and wreak havoc in their rear areas, rather than attempting brute-force frontal attacks like the Germans attempted in the Battle of Kursk. Thus although their tanks were less powerful, this turned out to be as irrelevant to the ultimate outcome of the final half of World War Two as the French and Russian superiority in tank forces was in the first half. US armoured forces ultimately triumphed over their German counterparts because of numerical superiority, a more consistent supply of fuel and ammunition, and the responsiveness and quality of the US combined-arms team as a whole.

According to Belton Y. Cooper's memoir of his 3rd Armored Division service, the Shermans were "death traps"; the overall combat losses of the division were extremely high. The division was nominally assigned by table of organization 232 medium tanks (including 10 M26 Pershing tanks that made it into combat). It lost 648 tanks totally destroyed in combat, and a further 1,100 needed repair, of which nearly 700 were as a result of combat. According to Cooper, the 3rd Armored therefore lost close to 1,350 medium tanks in combat, a loss rate of 580%. Cooper was the junior officer placed in charge of retrieving damaged and destroyed tanks. As such, he had an intimate knowledge of the actual numbers of tanks damaged and destroyed, the types of damage they sustained, and the types of repairs that were made. His figures are comparable to those given in the Operational History of 12th U.S. Army Group: Ordnance Section Annex.

The only other Second World War tank produced in comparable numbers to the Sherman was the Soviet T-34 series, which had lower ground pressure and sloped side armor while the M4 had advantages over the T-34 including an auxiliary generator and (on late models) fire-resistant "wet" ammunition stowage. During the Korean War, Shermans performed well against their T-34/85 adversaries. In later wars, upgraded Shermans sometimes performed well against post-WWII designs including some Patton tanks.

Characteristics

M4A2

• Length: 19 ft 5 in (5.92 m)
• Width: 8 ft 7 in (2.62 m)
• Height: 9 ft (2.74 m)
• Weight: 30 tons
• Speed: 30 mph (48 km/h)
• Range: 150 miles (240 km)
• Crew: 5
• Armament:
  • Primary: 75 mm or 76.2 mm gun
  • Secondary:
    • One .50 cal (12.7 mm) M2 machine gun
    • Two .30 cal (7.62 mm) Browning M1919
• Power plant: Two General Motors 6046 six-cylinder inline diesels of total 375 hp (280 kW) output

Firefly Similar to standard Sherman except

• Crew: 4
• Armament:
  • Primary: 17 pounder (76.2mm) Gun
  • Secondary:
    • One .50 cal (12.7 mm) M2 machine gun
    • One .30 cal (7.62 mm) Browning M1919

See also

• List of vehicles of the U.S. Armed Forces
• Vickers Tank Periscope MK.IV
• Sherman Firefly
• M4 Sherman variants

Further reading

• Cooper, Belton Y. Death Traps: The Survival of an American Armored Division in World War II. Novato, CA: Presidio, 1998. ISBN 0891416706. Read with caution. This book is a wonderful memoir and tribute to the men who fought in and serviced the tanks. However, when the author strays from his area of expertise (tank maintenance) he commits numerous inaccuracies to paper.
• Rodrigo Hernandez Cabos, John Prigent. M4 Sherman Osprey Publishing ISBN 1841762075

External links

• Sherman Register
• OnWar
• AFV Database
• WWII vehicles
• battlefront.co.nz
• M4(105 mm) at tamiya.com
• israeli-weapons.com

• Medium tanks
• World War II United States tanks