Why were Rommel's tanks blowing up?
As the Desert Fox's panzers churned through the Libyan desert in May 1942, they were confident of victory. For more than a year, despite being outnumbered by the British Eighth Army, the German armor had time and again emerged victorious.
Now the Afrika Korps was on the offensive against the British fortified line at Gazala, aiming to capture the vital port of Tobruk, and then move on to seize the Suez Canal and perhaps even the vital Middle East old fields.
But on May 27, the Afrika Korps ran into a deadly surprise. Its tanks were being destroyed from long range, something that had never happened before. Until Gazala, the Afrika Korps had only faced the 2-pounder (40-millimeter) guns on British tanks and 37-millimeter cannon on American Lend-Lease Stuarts used by Britain, both of which frequently bounced off the frontal armor of German Mark III and Mark IV tanks. Yet now the panzers were being picked off by 75-millimeter cannon that outranged their own 50-millimeter tank guns.
Rommel discovered the cause soon enough. It was the M-3 Grant , an American-made tank sent to the British under Lend-Lease. As Rommel wrote in “The Rommel Papers”, “Up to May of 1942, our tanks had in general been superior in quality to the corresponding British types. This was now no longer true, at least not to the same extent.”
The M-3 (known as the Lee in American service, but called the Grant when used by the British) was as ugly a tank as ever rolled on treads. Vaguely resembling the Army Surplus Special in the 1960s cartoon “ Wacky Races ,” the 30-ton Grant stood an incredible 10 feet tall (compared to 9 feet for a Sherman and 8 feet for an M-1 Abrams).
The Grant's layout was truly bizarre. The M-3 consisted of a hull with a 75-millimeter cannon stuck into a sponson on the right front hull, which meant the gun could only engage targets to the front. On top of the vehicle was a second turret that could traverse to fire at targets to the flanks and rear. Unfortunately, the second turret only contained a small 37-millimeter cannon. While most World War II tanks had a crew of five, the two-gun Grant had a crew of seven.
The genesis of the Grant sprang less from inspiration and more from desperation. In 1939, the U.S. Army had just 400 tanks, mostly M-2 light tanks and a few M-2 mediums, neither of which would have fared well against heavier German armor. After Hitler's panzers smashed France in the summer of 1940, the U.S. Army realized that it desperately needed a more modern vehicle. The M-4 Sherman was its tank of choice, but Detroit's factories needed time to retool from automobile to armored vehicle production.
In the meantime, America needed a tank that could fit a 75-millimeter cannon. The result was the M-3, whose big gun was mounted in the front hull because U.S. industry couldn't make a turret big enough to hold a 75-millimeter gun. Before the M-3, American tanks were built with armor plating connected by rivets, which flew around the vehicle like shrapnel when hit. Cast or welded armor was stronger, but American industry wasn't yet geared to manufacture them. Thus early versions of the Grant had riveted armor, or a giant one-piece cast armor upper hull.
With two inches of frontal armor and a speed of 26 miles per hour, the M-3 Grant compared favorably with existing German tanks in protection and mobility. However, the lack of a turret for the 75-millimeter meant that the tank had be pointed in the direction of the target, similar to German and Soviet assault guns that also mounted their weapons in the hull.
But at least assault guns traded a turret for a lower silhouette, which meant a smaller target. The Grant had the worst of both worlds: a fixed main gun and a huge silhouette. "The M3 medium tank came as quite a shock when first issued to the new U.S. armored divisions because of its sheer size compared to the more familiar light tanks," writes author Steven Zaloga in his book Armored Thunderbolt: The U.S. Army Sherman in World War II .
But losers can't be choosers, and the British in early 1942 couldn't wait for the perfect tank to take on Rommel's panzers. Besides being mechanically unreliable, British tanks were not equipped with high explosive shells for their 2-pounder guns, leaving them only short-range machine guns to take out infantry and anti-tank weapons. However, the Grant's 75-millimeter and 37-millimeter cannon could both fire armor-piercing shells against tanks and against high explosive shells effective against soft targets. Coupled with the superiority of the 75-millimeter over the 37-millimeter and 50-millimeter guns on most German armor in North Africa, the Grant was quite deadly.