M4 Sherman tank

Although it was not the most powerful tank made during the Second World War, the M4 Sherman was the epitome of the American fighting spirit during the time period-- maneuverable, fast, and mass-produced.

Over 50,000 M4 Sherman tanks were produced in seven different varieties in almost every allied country-- Canada produced the Ram II, while Great Britian produced a model with a 17 pounder cannon.

The standard M4 Sherman was equipped with a 75mm cannon, able to pierce through most lightly armored vehicles and tanks. It was no match for the sturdily-built Tiger and Panther tanks of the German army, which had much more powerful cannons and thicker armor.

The engine of the M4 was originally built by the Wright corporation, but, as the M4A2 and M4A3 varieties were developed during 1942-1943, the M4 was fitted with a GM diesel engine, and then later a Ford V8-- the most common variant.

As the war progressed, the M4 was upgraded to a 76mm cannon complete with a higher gun velocity. Some varieties also came with a much larger and more powerful 105mm Howitzer cannon.

The M4 first showed its battle prowess during America's (led mostly by Patton), campaign in North Africa during 1942. The Tiger and Panther tanks were not yet in full production, so the M4 fared very well against the earlier German tanks, the Panzerkampfwagen III, a light infantry support vehicle, and the Panzerkampfwagen IV, the German light/medium mainstay battle tank. The M4 was well suited to desert combat, and helped the allies push the axis out of North Africa.

America's Sherman later saw action in the invasions of Italy and Sicily in 1943 and 1944, where its maneuverability in tight urban and suburban areas gave it a slight edge over the more cumbersome German tanks.

However, the M4's most popularized role was its contribution to the D-Day invasion of Normandy in 1944, where amphibious Shermans drove ashore and help break the static German defensive positions. They were crucial in the breakout of the initial beachhead, and later proved very effective in the French hedgerows. The M4 was also heavily used in the rest of the liberation of France and throughout the drive to the Rhine-- it remained America's sturdy main battle tank throughout the war.

The M4 was a rush job, and designed by committee. The entire US tank development budget in 1939 was $85K. Utterly inadequate funding drove all the really creative people out of the War department. Then Hitler invaded Poland. Suddenly America needed tanks and needed them in a big hurry.

Needing a tank now the US rushed to build the M3 Grant. The Grant design centered on the M2 75mm cannon, a good weapon in the first few years of the war. Unfortunately, there was no time to design a turret for that weapon, so the M3 carried a casemated 75mm with limited traverse, and the 37mm turret off the M3 Stuart light tank. Despite its high silhouette and riveted construction, the M3 proved mechanically reliable and the 75mm was appreciated by Britsh tankers. But combat quickly exposed the flaws in the rushed design. The M3's silhouette was even higher than the M4, and its riveted construction was vulnerable to spalling after a hit. But it bought time for the M4's designers, and perfected the drivetrain. The design board worked with no information on any tank more advanced than the PzkW III or the early PzkW IV, armed with a short barrelled 75mm. The board assumed those vehicles would be the threat, and against them the M4 enjoyed the advantage, despite its high silhouette. The problem was that the Germans put most of their armor, including the newest Panther and Tiger tanks, into the Western Front. Worse, the more common PzKw IV proved easy to upgun.

As designed the Sherman had a crew of five, commander, gunner, loader, driver and assistant driver. This is considered a good tank crew for maintenance reasons, but was rarely achieved in combat due to casualties. The tank boasted 2 1/2 inches of armor plate on a front glacis plate inclined at 45 degrees, with 1 1/2 to 2 inches on the hull sides. Turret armor was 3-4 inches in the front, 2 on the sides, and there was a 5" mantlet surrounding the main gun. Armament for the M4 model was one short-barreled 75mm M2 cannon with a muzzle velocity of 2,050 feet per second. Later the M2 was replaced with the M3 75mm, a similar weapon. The original gun choice came out of a fight between the infantry and artillery, who felt the tank gun should have the same barrel life as an artillery weapon. That requirement mandated the selection of the low powered, short-barrelled M2, a fine peacetime weapon. US doctine at the time stated that tanks were for exploiting breakthroughs, not for fighting other tanks.That was the job of the US Tank Destroyer Force, and the US produced a number of capable vehicles in that role. Doctrine ignored that tanks are designed to fight on the front lines, while artillery pieces rarely see direct combat. When tank met tank, the M2 proved no match for the long guns installed in the Panther, Tiger, or later versions of the PzKw IV.

The M4 weighed 37 1/2 tons, and carried over the heli-coil suspension from the M3 Grant tanks. It was powered by a Continental R975C1 radial engine of 400 hp, with the transmission and final drive similar to the old M3 The continental radial was originally designed for aircraft and gave the tank a power to weight ratio of about 10 hp per ton, good for the time. The wide engine was installed at about a 45 degree angle. The driveshaft was angled and ran beneath the turret, forcing an elevated fighting compartment. The angled driveshaft gave the tank its characteristic "turtleback" silhouette.

In early 1944 Shermans began to be adapted for a 76mm gun with a muzzle velocity of 2,650 fps, in a new, much-improved turret. The 76 was an improvement, and gave the tank a fairer chance against is German opponents. But the 76 remained inadequate without HVAP ammunition. With HVAP Panthers and Tigers could be engaged at normal ranges. However, HVAP armor piercing ammunition remained scarce throughut the war, and was reserved for tank destroyer use. Tank crews were lucky to go out with two rounds on board. Even with HVAP the gun did not quite equal the German KwK75L48 on the Panther. The 76mm gun was retrofitted to the M4A1 and M4A3. The M4A3 substituted a 500HP Ford GAA V-8, which was lower, more powerful and less finicky than the Continental radial. Wet ammunition storage was introduced, which greatly reduced vulnerability to catastrophic ammunition fires after a hit. The GAA would have allowed the tank to reduce its very high profile, but the hull was not changed in order to avoid interrupting production. The GAA became the engine of choice, and the A3 was the most common variant to see action in World War II. The M4A3E8 represented the final evolution of the Sherman. The 'Easy Eight' replaced the hard riding verticle volute suspension with a horizontal volute suspension system (HVSS) and added 23" tracks, greatly enhancing mobility. It came with the T23 turret and the 76mm gun. The 'Easy Eight' was retained after the war, and saw frontline duty in Korea. American National Guard units used the tank into the 1960's.

The M4A2 used two GM 6-71 diesel engines. It fought for Russia because the US Army preferred gas engines in order to simply fuel logistics. The Marines used the M4A2 in the Pacific. There the M4 was to the (rare) Japanese tanks what the Tiger was to M4 crewmen in Europe. The 75mm proved a fine bunker buster, and the tank was well liked.   The M4A4 used a Chrysler A57 Multibank engine. The motor was cobbled together by linking five 6 cylinder auto engines. Five water pumps cooled the original versions. They were powerful enough, and proved reasonably reliable but very complex and thus required a lot of maintenance. A4's mostly went to British Service, and the Brits added one of their 17 pounder guns to the tank, creating the Sherman Firefly, which was capable of killing Panthers and Tigers at long range.

In combat the Sherman proved to be inadequately armored, as it was armored to resist the German 37mm anti-tank gun. German Panther and Tiger tanks penetrated the hull easily at range. This led to a specialized 'jumbo' Sherman which was used for assaults at the cost of speed and higher ground pressure. Panzerfausts penetrated the standard tank easily, as did the famed German 88. The Sherman's gunpower was also inadequate, meaning it could only kill Panthers or Tigers with side or rear hits, where the armor was thinner. Except for the 'Easy Eight' Shermans lacked cross-country maneuverability relative to the later German tanks, whose wide tracks had been designed with experienced gained on the Russian Front. In short, the Sherman often fared poorly against German armor. But Western tanks outnumbered their German opponents by more than 20 to 1 before the Battle of the Bulge. Afterward the mismatch grew even worse for the Germans.

The M4 was not without its virtues. It was quite reliable, provided you had spare spark plugs, which the Continental radial was notorious for fouling. The rubber track system had extraordinarily long life, and on the road it was very fast and fuel efficient. Which meant that while it was a poor weapon for creating a breakthrough, it was a fine weapon for exploiting one, the job it was designed to do. The later M26 Pershing had a high velocity 90mm gun, lower profile, lots more armor, lower silhouette and lower ground pressure. In other words, it was a superior combat weapon in every way, quite capable of taking on a Tiger. To be fair, the M26 was only available on film at the time of choosing our D-Day tank. However, British experience in North Africa had already shown the Sherman's flaws. Factories began welding on additional armor in 1943, long before the Normandy invasion.

The M4 also enjoyed two other advantage over all German tanks, a gyroscopic mount for its main gun and a powered turret. That mount allowed the tank to shoot  on the move. Unfortunately, lack of confidence in the system made shooting on the run a rare thing during the war. If more tankers had chosen to shoot on the run, the Sherman's combat record might have been better. But the powered turret meant they got the first shot off more often than not.

The Sherman chassis served as the basis for many armored vehicles. It was the basis for the M10 and M36 Tank Destroyers armed with the 76mm or the much more powerful 90mm gurn. and several self propelled artillery pieces. The most famous was the M7 Priest self-propelled 105mm howitzer, a popular and long-serving weapon. The British 17-pounder equipped Shermans were effective, but the long gun was distinctive and German gunners soon learned to shoot at the Fireflies first. The M4A3E8 with the Ford GAA engine, the horizontal volute suspension system (HVSS), wide tracks and 76mm gun was the main version retained for US service long after the war, It offered a fine ride and cross country mobility comparable to the best German tanks. The version was later shipped to Israel. The Israelis upgunned the tank to 105mm, and it served with distinction in the Six Day War.

Modified Shermans continued to serve into the 1960's and early 1970s. Today they are often found on display in front of armories and veterans organizations, usually with the 75mm gun.

Versions

1. M4-- R975 Radial engine, M2 and M3 75mm gurn
2. M4 (105) replaced 75mm with short-barreled 105mm howitzer for infantry support
3. M4A1 as above with cast hull, identified by rounded sponsons and glacis. Many were upgunned to 76mm
4. M4A2 with 2 GMC 6-71 diesel engines. Lend lease to the Soviet Union and used in the Pacific by Marines.
5. M4A3(75) Most common varient. Replaced Continnetal radial with Ford GAA V-8. Initiated wet ammuition storage, applique armor and then 47 degree glacis. One piece transmission cover.
6. M4A3(76) replaced M2 and turret with larger T23 turret and 76mm
7. M4A3E2 "Jumbo" sherman assault tank. Up armored to 4" on front glacis, turret front and 8" gun mantlet. Heavy, slow but hard even for Panthers to kill. Track extenders permanently installed to carry additional weight.
8. M4A4 same as M4 with Chrysler Multibank Engine. Sold to Great Britain.
9. M4A3E8 'Easy Eight" Same as M4A3(76) except Verticle Volute Suspension system replaced with Horizontal Volute Suspension. Tracks widened to 23" Final Sherman variant and retained in service long after the war. Saw front-line duty in Korea
10. M4A6 Very rare, and used a Caterpillar D200 (later called the Ordinance Engine RD-1820) diesel engine modified from Wright radial aircraft engine. Had a true multi-fuel capability.