The Grant Medium Tank

The Grant Medium Tank M3 was an American tank used during World War II. In Britain the tank was called by two names based on the turret configuration. Tanks employing US pattern turrets were called the “Lee”, named after Confederate General Robert E. Lee. Variants using British pattern turrets were known as “Grant”, named after U.S. General Ulysses S. Grant.

Grant

Design commenced in July 1940 and the first M3s were operational in late 1941. The U.S. Army needed a good tank and coupled with the United Kingdom’s demand for 3,650 medium tanks immediately, the Lee began production by late 1940. The design was a compromise meant to produce a tank as soon as possible. The M3 had considerable firepower as it was well armed and provided good protection, but had certain serious drawbacks in its general design and shape, such as: a high silhouette, an archaic sponson mounting of the main gun, riveted construction, and poor off-road performance. Its overall performance was not satisfactory and the tank was withdrawn from front line duty (except in the remote areas of the Asian Theater by British forces as late as mid – 1944 or later) as soon as the M4 Sherman became available in large numbers.

In 1939 the U.S. Army possessed approximately 400 tanks, mostly M2 Light Tanks, with less than a hundred of the discontinued M2 Medium Tanks. The U.S. funded tank development poorly during the interwar years, and had no infrastructure for production, little experience in design, and poor doctrine to guide design efforts.

The M2 medium tank was typical of armoured fighting vehicles (AFVs) many nations produced in 1939. When the U.S. entered the war, the M2 design was already obsolete with a 37mm gun, 32mm frontal armour, excessive machine gun secondary armament and a very high silhouette. The Panzer III and Panzer IV’s success in the French campaign led the U.S. Army to order immediately a new medium tank armed with a 75mm gun in a turret. This would be the M4 Sherman. Until the Sherman reached production, an interim design with a 75mm gun was urgently needed.

The Grant

The M3 was the solution. The design was unusual because the main weapon – a larger caliber, low-velocity 75mm gun – was in an offset sponson mounted in the hull with limited traverse. (The sponson mount was necessary because at the time American tank plants were incapable of casting a turret big enough to hold the 75mm main gun). A small turret with a lighter, high-velocity 37mm gun sat on the tall hull. A small cupola on top of the turret held a machine gun. The use of two main guns was seen on the French Char B, the Soviet T-35, and the Mark I version of the British Churchill tank. In each case, two weapons were mounted to give the tanks adequate capability in firing both anti-personnel high explosive ammunition and armour-piercing ammunition for anti-tank combat. The M3 differed slightly from this pattern having a main gun which could fire an armour-piercing projectile at a velocity high enough for efficiently piercing armour, as well as deliver a high-explosive shell that was large enough to be effective. Using a hull mounted gun, the M3 design could be produced faster than a tank featuring a turreted gun. It was understood that the M3 design was flawed, but Britain urgently needed tanks.

The M3 was tall and roomy: the power transmission ran through the crew compartment under the turret cage to the gearbox driving the front sprockets. Steering was by differential braking, with a turning circle of 37ft. The vertical volute suspension units included a return roller made with self-contained and readily replaced units bolted to the chassis. The turret was power-traversed by an electro-hydraulic system in the form of an electric motor providing the pressure for the hydraulic motor. This fully rotated the turret in 15 seconds. Control was from a spade grip on the gun. The same motor provided pressure for the gun stabilizing system.

The 75mm was operated by a gunner and a loader. Sighting the 75mm gun used an M1 periscope – with an integral telescope – on the top of the sponson. The periscope rotated with the gun. The sight was marked from zero to 3,000 yds with vertical markings to aid deflection shooting at a moving target. The gunner laid the gun on target through geared handwheels for traverse and elevation.

The Grant M3

The 37mm was aimed through the M2 periscope, though this was mounted in the mantlet to the side of the gun. It also sighted the coaxial machine gun. Two range scales were provided: 0-1,500 yd for the 37mm and 0-1,000 yd for the machine gun.

Though not at war, the U.S. was willing to produce, sell and ship armoured vehicles to Britain. The British had requested that their Matilda and Crusader tank designs be made by American factories, but this request was declined. With much of their equipment left on the beaches near Dunkirk, the equipment needs of the British were acute. Though not entirely satisfied with the design, they ordered the M3 in large numbers. British experts had viewed the mock-up in 1940 and identified features which they considered flaws – the high profile, the hull mounted main gun, the lack of a radio in the turret (though the tank did have a radio down in the hull), the riveted armour plating (whose rivets tended to pop off inside the interior in a deadly ricochet when the tank was hit by a non-penetrating round), the smooth track design, insufficient armour plating and lack of splash-proofing of the joints. The British desired modifications for the tank they were purchasing, including the turret being cast rather than riveted. A bustle was to be made at the back of the turret to house the Wireless Set No. 19 radio. The tank was to be given thicker armour plate than the original U.S. design, and the machine gun cupola was to be replaced with a simple hatch. With these modifications accepted the British ordered 1,250 M3s. The order was subsequently increased with the expectation that when the M4 Sherman was available it could replace part of the order. Contracts were arranged with three U.S. companies. The total cost of the order was approximately 240 million US dollars. This equaled the sum of all British funds in the US. It took the Lend-Lease act to solve the United Kingdom’s shortfall.

The prototype was completed in March 1941 and production models followed with the first British specification tanks produced in July. Both U.S. and British tanks had thicker armour than first planned. The British design required one fewer crew member than the US version due to the radio in the turret. The U.S. eventually eliminated the full-time radio operator, assigning the task to the driver. After extensive losses in Africa and Greece the British realized that to meet their needs for tanks both the Lee and the Grant types would need to be accepted.

The U.S. military used the “M” (Model) letter to designate nearly all of their equipment. When the British Army received their new M3 medium tanks from the US, confusion immediately set in as the M3 medium tank and the M3 light tank were identically named. The British Army began naming their American tanks after American military figures, although the U.S. Army never used those terms until after the war. M3 tanks with the cast turret and radio setup received the name “General Grant”, while the original M3’s were called “General Lee”, or more usually just “Grant” and “Lee”. The M3 brought much-needed firepower to British forces in the North African desert campaign.

The chassis and running gear of the M3 design was adapted by the Canadians for their Ram tank. The hull of the M3 was also used for self-propelled artillery and recovery vehicles.

North African theatre

Of the 6,258 M3s produced by the U.S., 2,855 M3s were supplied to the British Army, and about 1,386 to the Soviet Union. The American M3 medium tank’s first action during the war was in 1942, during the North African Campaign. British Lees and Grants were in action against Rommel’s forces at the Battle of Gazala on 27 May that year. Their appearance was a surprise to the Germans, who were unprepared for the M3s 75mm gun. They soon discovered the M3 could engage them beyond the effective range of their 5cm Pak 38 anti-tank gun, and the 5 cm KwK 39 of the Panzer III, their main medium tank. The M3 was also vastly superior to the Fiat M13/40 and M14/41 tanks employed by the Italian troops, whose 47mm gun was effective only at point blank range, while only the few Semoventi da 75/18 self-propelled guns were able to destroy it using HEAT rounds. Grants and Lees served with the British in North Africa until the end of the campaign. Following Operation Torch (the invasion of French North Africa), the U.S. also fought in North Africa using the M3 Lee. The U.S. 1st Armored Division had given up their new M4 Shermans to the British prior to the Second Battle of El Alamein. Subsequently, a regiment of the division was still using the M3 Lee when they arrived to fight in North Africa. The M3 was generally appreciated during the North African campaign for its mechanical reliability, good armoured protection and heavy firepower.

In all three areas, the M3 was able to engage German tanks and towed anti-tank guns. Yet the tall silhouette and low, hull mounted 75mm were tactical drawbacks, since they prevented fighting from a hull down firing position. The use of riveted hull superstructure armour on the early versions led to spalling, where the impact of enemy shells caused the rivets to break off and become projectiles inside the tank. Later models were built with all welded armour to eliminate this problem. These lessons were applied to the design and production of the M4. The M3 was replaced by the M4 Sherman as soon as the M4 was available, though several M3s saw limited action in the battle for Normandy as armoured recovery vehicles; their armament replaced with dummy guns.

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