To Halt Ambushes, the U.S. Army Once Covered Cargo Trucks With Landmines

Talk about an accident waiting to happen

Joseph Trevithick
War Is Boring

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by JOSEPH TREVITHICK

Since World War I, trucks have been an essential military tool to help move critical supplies and gear around the battlefield. But especially in wars where there are no front lines, the unarmored cargo haulers are prime targets for ambushes.

In 1963, as fighting in Southeast Asia began to suck in more American forces, the U.S. Army started working on a new way to protect the vehicles and their drivers. Engineers proposed covering the trucks with land mines to brush off attackers.

Unfortunately, the idea didn’t turn out to be as great as it seemed at first. Strapping dozens of explosive charges to the vehicles made them just as dangerous to friendly troops — and innocent bystanders — as the enemy.

“Success is determined by an immediate and violent reaction to the ambush,” one Army manual for tankers headed to Vietnam declared. “The outcome of the ‘battle’ will be determined in the first few seconds.”

The ground combat branch felt the same way when it came to Viet Cong ambushes on supply convoys. American and South Vietnamese commanders were both desperate for ways to guard against these sudden attacks.

While simply adding armor was one option, the Army was interested in the possibility of truckers fighting back. The deadly M-18 Claymore mine offered a simple and readily available solution.

Still in use more than four decades later, the Claymore consists of C-4 explosive sitting behind a sheet of steel balls held together by epoxy. When the mine goes off, the main charge sends the deadly hail in one direction.

A slight curve in the body creates a 60-degree kill zone out to at least 50 meters. Unlike most land mines, a soldier can set off the M-18 manually or rig it up to a tripwire.

Weaponeers at the Army’s Limited War Laboratory — aka LWL — built a mount to hold these mines to the bumpers of standard cargo trucks. In an ambush, the driver could fire the weapons from the cab.

Above and at top — prototypes of the Claymorette system on a U.S. Army truck. Army photos

But Army engineers also cooked up a smaller design — nicknamed the “Claymorette” — to go along with the full-sized mines on the bumpers. Special racks held the tiny bombs to the side of the trucks.

Each of these two-inch explosive squares spewed out more than 70 fragments, according to a test report published three years after the project began. The complete setup weighed nearly 400 pounds and contained more than 20 Claymorettes.

While each mine was small, setting off so many at once was … extremely loud. Engineers told “personnel in the truck cab to wear ear protection or to cover their ears when firing the system,” another progress report noted.

At the same time, LWL tested arrays of 12-gauge shotgun barrels, grenade launchers, miniature rockets, tear gas projectors, incendiary pellets and even a clusters of .22-caliber rifle barrels each loaded with a single bullet. Engineers even tried to mount this final system on transport helicopters.

Of these varied concepts, the Army judged the mine rack to be among the most useful. American commanders also expressed interest in bolting the weapons to armored personnel carriers and river boats.

With money from the Pentagon’s Advanced Research Projects Agency, LWL hired contractors to make five mounts and more than 2,000 Claymorettes to go along with them. A shipment of faulty detonators from a subcontractor briefly held up production.

A close-up view of one of the Claymorettes. U.S. Army photo

But after replacing the broken parts, LWL finally sent the completed prototypes to Vietnam. The Army dubbed the system the “Convoy Defense Mechanism,” or simply “CDM-1A.”

We don’t know the exact results of the tests, but troops apparently weren’t too impressed. Truckers probably weren’t thrilled about driving around with racks full of explosives on top of their cargoes of fuel and ammunition.

The indiscriminate nature of the Claymorettes would have been dangerous to friendly troops, too. And if a convoy was ambushed in a village, setting off the mines could have killed innocent civilians.

Five years after starting work on the miniature bombs, the LWL quietly dropped the project. Army engineers refocused their efforts onto the .22-caliber weapon and cannons that spewed hundreds of flaming magnesium-teflon pellets.

Similar safety concerns killed these projects. In the end, regular Army troops, military police and truckers in heavily-armed, improvised “gun trucks” guarded supply convoys in Vietnam.

Airmen drive an EM-113A2 REV around Camp Bucca in 2008. U.S. Air Force photo

Some 30 years later, Army engineers revived the idea of attaching mines to vehicles during the occupation of Iraq. But the new arrangement was significantly less dangerous.

In the chaos that followed the fall of Saddam Hussein’s regime, American troops took control of a number of prisons. As the Abu Ghraib scandal showed, U.S. soldiers who had ran these facilities tortured and abused prisoners.

A little over a year after news of that scandal appeared in the press, Iraqi detainees rioted at another prison called Camp Bucca. In the ensuing violence, American troops killed four inmates and injured six more.

Afterwards, the Army’s Picatinny Arsenal in New Jersey began work on a special vehicle that troops could use to help quell similar riots. The result was the EM-113A2 Rapid Entry Vehicle, or REV.

Based on a standard M-113 armored personnel carrier, the REV had bullet-proof windows and firing ports on each side. Troops inside the vehicle could fire tear gas or incapacitating “bean-bags” from specially modified 12-guage shotguns.

On top of that, the EM-113A2s had four M-5 Modular Crowd Control Munitions next to these firing positions.

These weapons are less threatening versions of the M-18. Instead of the Claymore’s steel projectiles, the M-5 launches rubber pellets with a reduced explosive charge. To prevent confusion, the projectiles’ bodies are made of a lighter green plastic. But the M-5s still have the trademark “Front Toward Enemy” marking showing troops where to point them.

More than a year after the riot, Picatinny sent the vehicles to soldiers and airmen stationed at Camp Bucca. The Army later declared the device one of the “top 10 greatest inventions of 2006.”

But by the time the U.S. withdrew the bulk of its forces from Iraq, the REVs were gone. American commanders had turned over their prisons to authorities in Baghdad.

“There are no plans for developing similar vehicles, as they were urgently fielded rapid prototypes that fulfilled a mission-specific user need,” a public affairs official at Picatinny told War Is Boring. The idea of attaching actual mines to vehicles doesn’t appear to be making a comeback either.

We don’t know where the REVs themselves ended up, but hopefully one of these unique vehicles is headed for a museum.

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Joseph Trevithick
War Is Boring

Freelance Journalist for @warisboring and others, Historian, and Military Analyst. @franticgoat on Twitter