For example, the US sent the tanks without their most capable armor upgrades. The tanks were older versions and the US, in line with policy requirements, downgrades export models to protect its sensitive technology.

In a brutal war where combat vehicles are often targeted by artillery and drones, among other threats, Ukraine’s tanks need all the protection they can get. That’s why Ukraine is now beefing up the Abrams and other American vehicles with additional armor to increase their survivability.

Nicholas Drummond, a former British Army officer who now works as a land warfare analyst, told Business Insider: “The depleted uranium armor the Americans are using is top secret, and the last thing they want is for it to fall into Russian hands.” But without top-notch armor, Ukraine will have to come up with its own solutions, he said.

Designing new protection

The tanks Ukraine received from its Western allies, as well as the Soviet tank arsenal, have been repeatedly fitted with new types of armour, in particular cage armour.

A Ukrainian company has created new protective shields for the Abrams and Bradley infantry fighting vehicles.

Colonel Hamish de Bretton-Gordon, former commander of the UK’s Joint Chemical, Biological, Radiological and Nuclear Forces, described these innovations to BI as “very, very simple, but actually very effective.”

He described the enhancements as necessary because “the Americans had removed some of the secret armor,” a change that “makes them more vulnerable to direct fire.”

It is unclear how effective the more advanced armor would be against a mass deployment of exploding drones, but the improved protection would still help Ukraine counter the proliferation of various Russian threats to its armor on the battlefield.

The US Abrams tanks feature composite armor containing depleted uranium, an often misunderstood material also used in tank shells. The details of the armor are kept secret.

Three people with knowledge of the plans told Politico in January 2023, months before the tanks were shipped, that the U.S. planned to send the newer M1A2 Abrams but with the secret depleted uranium armor removed. The U.S. removes the armor from all tanks it exports to allies and partners, the report said.

The Ukrainian military also indicated that it planned to replace the depleted uranium in the composite armor of the M1A2 Abrams with conventional armor-plating steel.

But plans changed. The U.S. decided instead to send older M1A1s, because they could get to Ukraine faster. Pentagon spokesman Pat Ryder said that surplus hulls the U.S. already had would be refurbished and modified to make M1A1s that could be sent to Ukraine. These older tanks lack the best armor upgrades.

When asked about the tanks, Pentagon spokesman Lt. Col. Charlie Dietz told BI that the Defense Department “can’t provide details, but can confirm that these were export variants.” That confirmation indicates that the armor on the Abrams tanks, among other things, had degraded prior to delivery.

A different kind of war

This war is a particularly intense conflict and unlike the conflicts the West has fought, with drones being used more than in any other conflict in history and a huge amount of missiles and artillery in play. Combat vehicles of all types have had a hard time.

Some Ukrainian soldiers have said that the armor fitted to the Abrams tanks is “not sufficient at the moment” with so many drones attacking from above. Drones have been used to damage and destroy tanks, and to guide other weapons to hit the vehicles.

According to De Bretton-Gordon, many of Ukraine’s additions “focus primarily on drones, as the mass use of drones is new to this conflict.”

Innovations like cage armor are seen as necessary, as many Western and Russian tanks, even with newer armor upgrades, have much thinner protection on the top than elsewhere on the tank hull. Ukraine often reinforces these with reactive armor extensions to create an additional layer of defense.

“Nobody really expected an attack from above, that’s why they’re so vulnerable,” de Bretton-Gordon said. The Abrams was designed and built primarily to fight Soviet tanks, not to evade air attacks, and it earned much of its reputation in close-air combat.

He said the vulnerability of tanks has changed now, with drones able to attack directly or drop devices such as hand grenades onto tanks — something that has caused Russian tanks to blow up, often by burning up the ammunition inside. Western tanks such as the American Abrams are better designed to prevent this, but the vehicles still have vulnerabilities.

Tanks in this war are also threatened by artillery and anti-tank missiles, making the battlefield more dangerous for tanks.

Drummond said: “The Russians are equipped with a lot of anti-tank weapons and when you attack an enemy position you are overwhelmed by anti-tank weapons, so you need armor.” Ukraine needs as much armor as possible.

Not enough western tanks

He described Russia and Ukraine as a kind of race, as is usual in war. “As soon as someone comes with an advantage, someone else comes back with a countermeasure,” he said.

Both Russia and Ukraine have modified some of their tanks and other armored vehicles by putting cages on them. The Russian innovations included a strange-looking structure that led to their tanks being called “turtle tanks.”

This war has been a tough one for tanks. Russia had lost more than 3,000 by February, the International Institute for Strategic Studies reported at the time. And Ukraine has lost tanks, too, including at least five of its 31 Abrams.

According to many experts, the fact that Ukraine has so few of them is a difficult issue for Ukraine. The country needs to keep the few tanks it has intact, and it does not have enough to carry out a large-scale offensive.

Bretton-Gordon said that if Ukraine had more Abrams and Challenger tanks, “they would use them differently.” But instead, “drip-feeding equipment” to Ukraine means “they have been fighting with one hand behind their back.” Ukrainian President Volodymyr Zelenskyy has complained about the limited number of Abrams.

The Bradleys are considered more successful and can even take on Russian tanks.

Part of the explanation may be that Ukraine has received more of them, more than 300. Bretton-Gordon said it was important that Ukraine “has a lot of them.” Ukraine has used the vehicles as a kind of light tank.

He praised the Ukrainians for their “very innovative” way of protecting against drones on the battlefield, and said Western militaries would keep an eye on Ukraine to see what they could learn from it.

Ryan Pickrell contributed to this report.