M4A3E2 – The Sherman with More Armor than a Tiger

It is often said that Shermans had thin armor and were little more than fodder for German tanks, so it may surprise you to learn that the US actually produced a variant of the Sherman with armor that not only rivalled the Tiger I, but exceeded it.

This was the M4A3E2, often called the “Jumbo”, and wasn’t some “variant” that is essentially a whole new design, no, this was a Sherman that literally had extra armor welded to it in the factory.

The turret was a custom job, although it still resembled the standard type, and had more armor on its sides than the Tiger I had on its front.

M4A3E2 during development.
The M4A3E2 was incredibly well armored.

The end result was one of the most heavily armored tanks to see action during the Second World War, capable of shrugging of even the German 88.

Read on to find out just how the US turned the humble Sherman into an armored fortress.

Contents

Background

Back in early 1942, long before the M4A3E2 was even on the drawing board, British and US representatives had been discussing the idea of creating a heavily armored assault tank that could replace the Churchill.

At this point it was thought that the Churchill was going to suffer from poor mobility and reliability. Therefore there were plans to replace it from the get go.

One of the earlier ideas discussed was a British suggestion to up armor the M4 Sherman, which was still in development.

Churchill VIII
At this time the Churchill was known as an assault tank, not infantry tank. Image by Alan Wilson CC BY-SA 2.0.

Then, a meeting in March 1942 resulted in both the US and UK developing their own assault tanks; the T14 from the former and A33 from the latter. The idea was that the vehicles would be tested, and Britain would select the best design for production.

None of these impressively armored tanks would come to fruition though. The US was never interested in the T14 nor the up-armored Sherman, and as it happened the Churchill turned out to be much better than expected, so the UK didn’t need them either.

Read More T-34/100 – Egypt’s Super T-34 with a 100 mm Gun

Work on a heavier tank with thick armor didn’t completely stop in the US though as they began the process of creating a successor to the Sherman in 1942. This vehicle would end up being the M26 Pershing, a tank that is about equal to the German Tiger I.

T14 assault tank's angled armor.
This is the T14, a failed attempt at creating an assault tank with similar features to the Sherman.

Experiences with powerful German anti-tank guns cemented the need for such a vehicle, and the upcoming invasion of Europe increased this further. It was hoped that the M26 would reach units by late 1944 to assist on the Continent, but it was clear this was not going to happen.

The US needed a heavily armored assault tank, so, as always, they turned to the Sherman as a stop-gap solution.

Development

In late 1943/early 1944, the General Motors Proving Ground carried out tests on an M4A3 loaded with weights to give it a total weight of 41 tons. In comparison, the weight of a standard, fully loaded M4A3 was 34 tons.

The M4A3 was the most powerful Sherman variant of the war, powered by the 18 litre Ford GAA V8. This is likely why this particular model was chosen to receive the extra weight.

The test Sherman coped surprisingly well with all that extra weight, proving that the chassis was capable of being significantly up-armored.

M4A3E2 loaded up with ballast weights.
The M4A3 loaded with weights at the General Motors Proving Ground to simulate the weight of extra armor.

So the Sherman could be beefed up, but now the US had to figure out the best way of getting them to the front. There was an initial proposal to supply kits to troops that could be fitted in the field, but in the end it was decided that the changes would be made in the factory by Fisher Body.

In March 1944 the new tank was given a name: the M4A3E2. The “E” in the name means “Experimental”, but in this case it was left in, despite entering frontline service.

In total, 254 M4A3E2s were ordered. There was such a desperation for the tank that the US government allowed the manufacturer to produce them without the usual standard checks, essentially trusting that they would build them properly.

The M4A3E2’s Armor

The extra armor plating would be applied to the front, sides and belly of the M4A3 hulls. These were the “large hatch” type, which featured bigger hatches for the driver and bow gunner.

The additional armor was not “built in” to the design, but welded on top of the normal armor of the M4A3. 38 mm thick plates were added to the upper glacis and hull sides.

M4A3E2 at Aberdeen Proving Ground, June 1944.
An M4A3E2 at Aberdeen Proving Ground, June 1944.

This brought the total armor thickness of the upper glacis to 101 mm, an amount equal to the Tiger I. On top of this, the upper glacis angle of 47 degrees meant the effective thickness of the M4A3E2’s upper plate was an incredible 150 mm.

The curved differential housing’s armor was increased too, unlike the one used on the earlier T14. The thickest part – at the very front of the housing – was now 140 mm thick, compared to 101 mm on the standard version. This extra thickness added 1.5 tons of weight, and was actually cast into the armor rather than being welded on.

Meanwhile the extra plating brought the sides up to a total of 76 mm. These plates were applied in two separate pieces to ensure it was structurally sound.

M4A3E2 front hull.
The extra armor welded to the front of the M4A3E2. Also, note the thickened final drive housing. Image by Pierre-Olivier B CC BY-SA 2.0.

The rear of the hull and the lower hull sides behind the suspension were not given additional armor, but extra plating was applied under the driver and bow gunner to increase mine resistance.

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The turret was based on the T23 turret that would later feature on 76 mm Shermans, but it was, for the most part, a completely new design, with no pistol-port and massively more armor. The front, sides and rear of the turret were all protected by an incredible 152 mm of steel. To put that into perspective, this is equal to the front glacis plate of the Tiger II.

An M4A3E2's turret.
The thickness of the turret sides can be seen here. The roof of the turret was made from two plates, welded into the gap created by the cast sides. Standard Sherman turrets were cast as a single piece. Image by Pierre-Olivier B CC BY-SA 2.0.

The gun mantlet was created by welding an additional 130 mm of steel plating onto the standard 50 mm thick mantlet for a total of 180 mm – nearly the same as the Tiger II’s turret front.

From the front the M4A3E2 was nearly immune to the Tiger I’s 88 mm gun, and some parts of the turret front could stop even the Tiger II’s long 88 mm gun.

Other Features

All M4A3E2s were built with the 75 mm M3 gun. However once in service it was found that the 76 mm M1 was in high demand, so around 100 were modified with the 76 mm. As the M4A3E2’s mantlet was originally for the 76 mm gun, the swap was quite straight forward.

As standard, the tank had a .30 caliber machine next to the main gun, and another in the front of the hull. A crew of five operated the vehicle; commander, gunner, loader, driver and co-driver.

The tank was powered by the same Ford GAA V8 as the standard M4A3, which produced around 500 hp and 1,410 Nm of torque. This is impressive, but the tank weighed almost 10 tons more than a standard A3, so the final drives were adjusted to give the tank a top speed of 22 mph.

M4A3E2 gun mantlet.
Check out the 180 mm thick gun mantlet, seen here from above. Image by Pierre-Olivier B CC BY-SA 2.0.

One issue that had to remedied with such a heavy tank was its ground pressure. The additional weight of the M4A3E2 would cause the tank to sink into the ground, so “duckbill” extensions were attached to the tracks, increasing their width.

But perhaps the M4A3E2’s biggest problem was with its suspension. The Sherman’s vertical volute spring suspension (VVSS) were designed for a much lighter tank, and were under significant strain holding the M4A3E2 up.

Duckbill end connectors.
Duckbill end connectors, as used on the M4A3E2 to spread the tank’s weight. Image by Pierre-Olivier B CC BY-SA 2.0.

They worked for the most part, but the suspension springs were easy to break if the tank hit a bump hard.

In fact, images of the tank show that the tank sits much lower, with the suspension swing arms almost level with the ground.

Service and Performance

Desperate to get the tanks into Europe as quick as possible, the M4A3E2 was already in production by May 1944. To speed the process up, the US government allowed the manufacturer to produce them without the usual standard checks, essentially trusting that they would build them properly.

Incredibly, all 254 units were completed by July 1944. This was still too late for D-Day though, and the tanks were delivered to Europe in the closing months of 1944.

M4A3E2 in Cherbourg.
Staff prepare an M4A3E2 Sherman after in arrival in Cherbourg.

When the M4A3E2 finally arrived on the frontlines in late 1944 they were immediately loved by the troops. Issued to the US First, Third and Ninth Armies, the tanks’ extra armor quickly started saving lives, and within a short period they were in high demand.

Soon after their introduction there were cases of the tanks shrugging off multiple hits from German anti-tank guns, even of the formidable 88 mm type. As a result they were thrust to the front of convoys or advances to make the most of their armor.

However despite their extra armor they weren’t invincible, and large numbers were lost – although this is likely due to them being put in the line of fire wherever possible.

A knocked out M4A3E2.
This M4A3E2 was knocked out by a landmine. It was then hit by a number of German 88 mm rounds to prevent it from being put back into service. Only one penetrated.

Still, they were an extremely useful tool for US forces in Europe, and the total of 254 M4A3E2s suddenly seemed rather small. Requests were made for more to be produced, but due to timing and complexities in the procurement process no more were built.

But their effect was so significant that General Patton himself issued an order in early 1945 for as many M4A3s to be modified in the field with extra armor in an attempt to “recreate” more M4A3E2s. Shortly after, damaged Shermans were having entire armor plates cut out and welded onto operational tanks. Even armor from knocked out German tanks was used.

Around 100 such conversions were made, and these too saved lives.

M4A3E8 with extra armor.
M4A3E8 Sherman fitted with extra armor in the field.

The majority of M4A3E2s survived the war, but after it ended they had little use. By this point the tank the M4A3E2 was created as a stop gap for – the M26 Pershing – was now in service, so the M4A3E2 was no longer needed.

They nearly had a second lease of life in the 1950s when some were refurbished for use in the Korean War, but they were never sent overseas for that conflict.

Read More The T14 Assault Tank – A Big, Fat Sherman

Today, just eight “complete” M4A3E2s exist, and, alongside tanks like the M-51, remain a testament to the Sherman tank’s excellent dependability and adaptability. So, next time someone says the Sherman had no armor, point them to the M4A3E2!