Here's What You Need to Know: The side with the Sherman won the war.

American tanks in World War II were generally inferior to their German counterparts. German tanks boasted better armor protection and more firepower.

But armor and lethality don’t tell the whole story. The same American tanks were superior to their rivals in other important ways. The M-4 Sherman, in particular, helped the U.S. Army win the war—even though, in battle, German tanks destroyed them en masse.

The Sherman’s inadequacies were products of its origins. Before the war, American tank design and development was bipolar—a result of the competing demands of the Army’s infantry and cavalry branches.

The infantry wanted a tank that—no surprise—could support the infantry on the battlefield. Infantry generals favored a vehicle with a big gun that could sit still and take out enemy bunkers.

The infantry walked into combat. They weren’t all that concerned about a tank’s speed.

By contrast, the cavalry—the Army’s scouts—preferred a fast-moving tank that could speed through gaps in enemy lines. The freewheeling cav didn’t fret armor protection.

Two tank philosophies, totally at odds with each other. And the Great Depression exacerbated the problem—the R&D money ran out.

The American tank force idled until the war jumpstarted it.

From Export to Expediency

Shortly after the outbreak of World War II, the United States began supplying the United Kingdom with tanks. Losing France was a staggering blow to the Allies’ industrial production—the U.K. couldn’t produce everything it needed on its own.

The British Army, partly out of desperation, bought American tanks.

The first American export, the M-3 Grant, had a 75-millimeter low-velocity gun mounted in the hull for engaging infantry, and a high-velocity 37-millimeter anti-tank gun in the turret.

That may sound impressive, but the Grant packed two guns because the Americans lacked a single gun capable of engaging both infantry and tanks. The Grant’s layout also gave it a high profile on the battlefield, making it easy to spot … and thus destroy.

The Grant’s baptism of fire was the battle of Gazala in North Africa in the spring of 1942. The British Army deployed 167 Grants against Panzer III and IV tanks from the German 15th Panzer Division.

Although the German Afrika Korps ultimately forced back the Brits, the appearance of the 75-millimeter gun—a first for the British—was a shock to the Germans.

As adequate as the Grant was, the war was forcing the creation of faster, more lethal tanks almost by the month. A new, more lethal version of the Panzer IV, the so-called “Mark IV Special,” had appeared three months before the battle.

Enter The Sherman

Back in America, tank designers were already working on a successor to the Grant. The new Sherman packed a single 75-millimeter gun. Crew was just five, compared to the Grant’s seven. The M-4 featured a host of improvements based on British experience with the Grant in North Africa.

With steady upgrades, the Sherman would be the main American tank for the remainder of the war.

Even at the time of introduction, the Sherman was really nothing to get excited about. Protection was unremarkable and required constant improvement—such as an extra inch of steel plate welded to the hull to protect main gun ammunition, plus a “wet stowage” system which bathed the ammunition in water to prevent it from detonating in the event of a direct hit.

The Sherman’s 75-millimeter gun was also nothing special. It was powerless against the latest German tanks—particularly the Tiger and Panther. The gun was more suitable for taking out less well-armed targets—half-tracks, artillery, infantry.

U.S. intelligence had assessed the Sherman as equal to the Panzer IV, the mainstay of the German tank force. America concluded the Sherman was good enough. Unfortunately, the U.S. had failed to accurately forecast production of newer, more powerful German designs such as the Panther and Tiger.

The U.S. military believed that although the Sherman was inferior to those tanks, the new German models would rarely appear on the battlefield.

That proved wrong.

Numbers, Numbers, Numbers

The Sherman wasn’t the best tank, but thanks to efficient American production methods it would be the most prolific. The United States built a staggering 49,234 Sherman tanks between 1942 and 1945.

The majority went to the U.S. Army and Marine Corps, which underwent a massive wartime expansion. Washington provided 21,959 tanks to Allied forces. The United Kingdom, Free French Forces, Poland, Brazil, New Zealand, China and the Soviet Union all deployed M-4s.

A lot of armies depended on American factories to keep them in Shermans. Assembly lines had to keep moving, no matter what. In order to maintain a high level of production, managers kept design changes to an absolute minimum.

Introducing a new tank design, or even making significant changes to the existing one, would mean fewer tanks.

The Army Ground Forces, which oversaw the ground combat branch’s equipment, kept an eye on the long game. Mindful of the Army’s poor experiences fielding equipment in World War I, the AGF wanted mature, reliable vehicles. Tanks built in Detroit only to break down in France were worse than worthless.

The Army was well aware that German and Soviet tanks were getting bigger and more powerful, but the United States would have problems keeping up. German and Russian tanks on the Eastern Front could move by train, but American tanks had to be loaded onto and off of cargo ships—a much more expensive mode of transportation that imposed lots of its own constraints on vehicle design and production.

Heavier tanks would have caused problems up and down the line for the Americans.

An Ecosystem of Weapons

Finally, the Army viewed the tank force holistically within a veritable ecosystem of weapons. Infantry, tanks, artillery, engineers and planes were all part of the same team.

By this way of thinking, tanks shouldn’t take on other tanks. Instead, the armored vehicles should exploit gaps in enemy lines, rush in, start blowing up stuff. Infantry, airplanes, artillery and tank destroyers—vehicles similar to tanks, but lightly armored—would engage the enemy’s tanks while American tanks were running rampant.

There was a problem with this reasoning. Just because the Army wanted its Shermans to avoid the more powerful German Panthers and Tigers didn’t mean those encounters didn’t happen.

Making matters worse for American tankers, the Army’s inability to properly forecast German tank production—which was much higher than anyone predicted—meant there were a lot more of these tanks on the battlefield than the Army had originally counted on.

The U.S. did eventually field a new, heavier tank in early 1945. Sporting a 90-millimeter gun and thicker armor, the M-26 Pershing rectified many of the Sherman’s worst failures. In the fighting around Cologne, the M-26 bested German Panthers — even if the new American vehicle was underpowered and less reliable than the Sherman.

Postwar American tank development ensured that U.S. tankers were never again outmatched on the battlefield. The M-60 series of tanks, followed by the M-1 Abrams, were at least the equals of Soviet models.

This was largely due to the fact that American forces were by now permanently stationed in Europe and didn’t have to rush overseas in the event of war. American tank designers were limited only by their imaginations—and cost.

For its part, the M-4 was good in 1942, adequate in 1943, and totally outclassed by 1944. Unfortunately for American tankers, the war lasted until 1945.

Still—as maligned as the Sherman often is, it’s important to view it in context. The side with the Sherman won the war.

Kyle Mizokami is a defense and national security writer based in San Francisco who has appeared in the Diplomat, Foreign Policy, War is Boring and the Daily Beast. In 2009 he cofounded the defense and security blog Japan Security Watch. You can follow him on Twitter: @KyleMizokami.

This article first appeared in 2014.

Image: Wikimedia Commons