The M3 medium tank was viewed by some as an interim solution for the US until it could make a tank equipped with a 75 mm gun in a fully traversable turret. The U.S. Armored Force Board received five options to choose from in April of 1941. The simplest design (called the T6 medium tank) placed a turret onto a modified M3 hull and chassis. A preproduction model was delivered to Aberdeen in September of 1941. The hull was welded (like the later M3s) and featured a side hatch which was eliminated from production models. There was no machine gun cupola, either. The T6 became standardized as the M4, and production began in October 1941.
The M4 Sherman Medium Tank
Delivery schedules called for 1,000 M4 Shermans per month in 1942 through the effort of eleven different manufacturers. The first production model was designated the M4A1. Its hull was made from the largest armor castings available. Production ended for the M4A1 in 1944 after 6,281 were made. Thousands of these were rebuilt with improvements before D-Day.
The original M4 was powered by a Wright R-975-C1 radial, 9-cylinder engine. The aircraft industry placed high demand on these engines for aircraft, however, so gasoline and diesel engines were substituted in the tanks. The M4 had a crew of 5 and weighed in at over 30 tons; some models weighed as much as 40 tons. The tank exerted a ground pressure of over 14 pounds per square inch. The M4 had a road speed of 26 miles per hour with a range of about 100 miles. It could surmount vertical obstacles 2 feet high, climb a 60-degree gradient, ford depths of 3 feet, and cross trenches 7.5 feet wide.
The M4 earned nicknames like "Ronson" because the ammunition in early models had a tendency to catch fire when the tank was hit. (Ronson manufactured cigarette lighters with the advertising slogan, "Lights the first time.") The Germans called them "Tommy Cookers" -- a reference to a small field stove. Appliqué armor was added to the sides of the upper hull in an effort to protect ammunition stowage areas. Spare track pieces were frequently welded to hulls and turrets or sandbags added to help protect against German hollow charge weapons. Wet stowage for ammunition was added in an attempt to combat fires. Thirty-eight gallons of water mixed with antifreeze and an anti-corrosion product called "ammudamp" was needed for 100 shells. The suffix 'W' indicated this modification, as in M4A3(75)W.
Early models had twin hull machineguns and direct vision blocks on the hull front.
The M4A2 was powered by twin GMC diesels but otherwise was the same as the M4A1. Of the more than 11,000 M4A2s produced, 8,053 were armed with the 75 mm gun and 3,230 were armed with the 76 mm gun. The Marines were the only American users, but many were lend-leased to the USSR, where it wasn't popular because of its thin armor and high silhouette. In the UK, the M4A2 was named the Sherman II.
The M4A3 was the most prolific version of the Sherman. Many were supplied to the Soviets and the British (where it was known as the Sherman IV). M4A4s had welded hulls and were powered by the 370-horsepower Chrysler Multibank engine. The M4A5 was a rarely used designation assigned to the Canadian Ram tank, which was not a Sherman at all.
A suffix letter marked British variations of the Sherman. For example, the Sherman IVA had a 76 mm gun with wet stowage and the IVB had a 105 mm gun. The IVC was the famous Sherman Firefly with a 17-pdr gun, as was the VC based on the M4A4. The Firefly lay the gun on its side and extended the turret to accommodate the big gun's breech, which limited the crew to four. The Firefly was the only tank that could meet German Tigers and Panzers on nearly equal terms on D-Day. One Firefly was available for every four British tanks for the rest of the war.
The M4A3E2 "Jumbo" was a limited production model with extra-heavy armor. In mid-1944, horizontal volute spring suspension (HVSS) was adopted because it was stronger and allowed the changing of individual wheels. It also reduced the vehicle's ground pressure.
The M4A3E8 was the last production version. It was nicknamed "Easy Eight" because the HVSS gave it a smoother cross-country ride than other tanks.
Production of the M4 ceased in 1945. Many sub-variants and special purpose variants were built, including the M32 tank recovery vehicle and the T-34 Calliope rocket launcher system. There were many British specialized-use versions, which are often called "funnies" -- such as the DD (duplex drive) or swimming tanks used on D-Day.
Production of all models of the Sherman tank exceeded 55,000, making it the most numerous tank design of all time apart from the T-34.
The British introduced the Sherman to combat at El Alamein in October 1942. British Shermans also saw action during the Italian campaign. In the Pacific, the M4 was far superior to any Japanese tank.
The Sherman was exported to many countries after the war, and some remained in service well into the 1990s. Sherman tanks appeared in almost every armored conflict between 1945 and the late 1970s.
Other articles in this series:
The Humber Scout Car
Carro Armato M13/40
German Crew Served Weapons