– At 9:42 a.m. on July 13, 1944, Sergeant Curtis Grub Cullen watched General Omar Bradley step out of a jeep near Saint-Lô, knowing the next 30 seconds would decide whether 3,000 American tanks could break the Normandy bocage. He was 29 years old, with two weeks of testing behind him and zero formal approval. First Army had already lost over 400 Shermans in six weeks trying to cross the Norman hedgerows. The stakes could not have been higher.

The hedgerows were not hedges at all. They were earthen walls 12 feet high and 4 feet thick, reinforced by centuries of intertwined roots. French farmers had piled fieldstones along borders since medieval times; soil accumulated and trees took hold. When American tanks tried to climb these living ramparts, they exposed the one-inch belly armor. German panzerfaust teams and anti-tank guns aimed for that exact vulnerability.

Most Sherman crews never escaped once hit. Cullen’s unit—the 102nd Cavalry Reconnaissance Squadron from the 2nd Armored Division—had been probing these hedgerows since June 20. The math was simple and grim: every battalion fielded about 70 tanks. Command allocated four M4 dozers per battalion to push through, but they were slow and quickly became priority targets. Between June 6 and July 10, American forces advanced only eight miles inland, with thousands of hedged fields still ahead.

At the current pace, First Army would need six months to gain twenty miles. Operation Cobra, the planned breakout, demanded rapid armored movement through bocage terrain, and no one had solved the problem. Engineers tried packing explosives into hedge bases; blasts barely dented the walls and drew artillery. Crews welded spare track links to hulls for extra protection—useful against machine guns, useless against panzerfausts at ten yards. Others rammed at full speed and buried their Shermans nose-first into five-century roots.

Cullen spent three days building a solution from German beach obstacles. The obstacles—Czech hedgehogs—were three railway-iron beams welded in a jack shape and planted by the thousands to tear open landing craft. American engineers cut them apart and stockpiled the steel. Cullen took four sections of that hedgehog steel, each two inches thick, and welded them to a light tank’s bow plate at a 35-degree forward angle. When the tank hit a hedgerow, the tusks bit into the base and shoved through instead of climbing.

He tested the device seven times on a light tank—seven clean breaches. Major Sydney Bingham from the 2nd Armored Division ordered a full-weight Sherman test. The M4 weighed 33 tons—more than double a light tank’s 15—raising the risk the prongs would shear off or the tank would pitch forward. Lieutenant Charles Green of the 747th Tank Battalion volunteered his crew. They welded the four-prong assembly to Green’s Sherman on July 11; it weighed 320 pounds.

The July 12 test worked. Four more runs worked. The prongs held. Word reached Bradley’s headquarters, and he ordered a personal demonstration for July 13. Bradley pointed at a hedgerow 200 yards away—twelve feet high and thick as a fortress wall—the kind that had stopped American armor for 42 days. Green climbed into the commander’s hatch; gunner Sergeant Frank Weber sealed the turret; the driver brought the engine to life.

Cullen stood beside Bradley as the Sherman positioned fifty yards from the hedge. Green’s voice crackled over the radio: ready to demonstrate hedgerow breach. Bradley raised his binoculars. “Proceed.” The Sherman surged to 25 mph; the four steel prongs slammed into the earthen wall like a freight train collision. Dirt geysered; the tank’s nose dipped; for three seconds, the M4 pushed against five centuries of compacted earth and roots—then the prongs bit, the hedge collapsed inward, and the tank burst through in fourteen seconds.

Bradley lowered his binoculars, walked to the gap, examined the torn earth and severed roots. He turned to Major General Leonard T. Gerow. “How many of these can we produce?” Gerow looked to Cullen. “The beach obstacles provide enough steel for approximately 500 devices.” Bradley didn’t blink. “I want 3,000.”

If you want to see whether Cullen’s “beach trash” cutters actually worked in combat, hit like and subscribe—because what happens next defies expectations. Back to Cullen. That evening, Bradley ordered the 52nd Ordnance Group to mobilize every available welder in Normandy on 24-hour shifts, to strip every German beach obstacle between the beachhead and Cherbourg, and to install cutters on every Sherman, light tank, and tank destroyer in First Army. Operation Cobra was scheduled for July 25—just twelve days away.

The math was relentless: 3,000 vehicles in twelve days meant 250 tanks per day, ten per hour, one every six minutes. Cullen had less than two weeks to prove his junkyard invention would break the stalemate—or mean nothing under German anti-tank fire. Captain James Dockerty of the 52nd Ordnance Group arrived at the production site near Columbières on July 14 with 30 welders and six cutting rigs. He laid out the workflow: cut hedgehog beams into four-foot sections, grind points, weld to mounting plates, bolt to the bow—four hours per vehicle if everything went perfectly.

Nothing went perfectly. The hedgehog steel was harder than standard construction metal. Torches overheated after 20 minutes and needed cooling. Day one yielded eight completed devices—eight tanks out of 3,000. At that rate, the modifications would finish in October and Cobra would go forward without them. Cullen spent July 15 troubleshooting. The problem was heat at the torch tips; German steel absorbed thermal energy differently, causing premature failures.

He requisitioned more torch assemblies and set rotating teams—one cutting while another’s gear cooled. Output rose to 22 devices on July 15—still far short. Dockerty brought 40 more welders from maintenance battalions across Normandy. By July 17, daily production hit 38. The math stayed brutal: 3,000 devices at 38 per day meant 79 days. Cobra was in eight.

Welding revealed a new issue: the 320-pound four-prong assembly shifted the Sherman’s center of gravity forward by six inches, compressing the front suspension. After repeated impacts, some vehicles showed spring stress fractures. If a spring failed in combat, the tank would be immobilized with a broken front end. Cullen modified the mounting, adding reinforcement brackets to distribute weight across the hull structure. It added 30 minutes per install but prevented suspension damage.

By July 19, six days before Cobra, output reached 64 per day. Approximately 400 tanks were modified; 2,600 remained. Bradley’s staff sent a priority message: the general wanted a minimum of 2,000 Rhino tanks for the offensive. If the ordnance group couldn’t meet that, Cobra might be delayed—giving the enemy time to reinforce bocage defenses. Every day of delay would cost lives.

Dockerty found more steel—engineers had stockpiled hedgehogs near Utah Beach—and transport units hauled them inland on July 20. The raw material now supported 5,000 devices; welding capacity remained the bottleneck. Cullen tapped maintenance sections from units not in Cobra’s first wave; tank recovery teams with welding gear formed auxiliary cells. Fifteen additional stations came online July 21; production jumped to 112 devices per day.

The deadline pressure spiked. Welders worked through the night under floodlights and generator hum. The site looked like a factory dropped into a Norman field—sparks arcing over rows of waiting tanks, the air heavy with hot metal and flux. No one slept more than four hours. On July 22, three days before Cobra, the total reached 1,200 devices. Dockerty calculated they could install another 850 before H-Hour—2,050 Rhino tanks, just above Bradley’s minimum.

Then the steel ran out. The hedgehog stockpiles were exhausted—every obstacle between the beachhead and Cherbourg had been processed. Engineers located about 300 more along minor beach exits, but transport was tied up moving ammunition and fuel for Cobra; they wouldn’t arrive in time. Dockerty considered alternatives: railroad track could substitute. Softer than German steel but plentiful, and several units had already experimented with rail-based prongs.

Lieutenant Charles Green’s 747th Tank Battalion had welded massive railroad-tie prongs they nicknamed the “Green Dozer.” Heavier and cruder than Cullen’s design, but functional. The ordnance group switched to a hybrid model: Cullen hedgehog cutters where steel remained; railroad prongs for everyone else. On July 23, two days before Cobra, production hit 1,800 devices, with another 500 in progress using rail steel—estimated total 2,300 Rhino tanks, 77% of Bradley’s armor. Not 3,000. Not perfect. Enough.

Modified tanks moved into forward assembly areas on July 24. Cullen walked the staging zones near Marigny, watching columns of Shermans roll past. Each bore four steel prongs on its bow—absurd-looking, like prehistoric beasts ready for a new kind of fight. Operation Cobra would begin with a massive bombardment at dawn July 25—3,000 Allied aircraft dropping 4,000 tons of explosives on prepared positions—then armor would advance through bocage, using Cullen’s devices to breach hedges the enemy thought impregnable.

Cullen hadn’t slept in 72 hours. His hands were blistered with minor burns from hot steel. Standing in that field, he understood something simple and vast: those prongs represented thousands of men who might now survive the breakout—soldiers who wouldn’t be forced to expose their tanks’ bellies to hostile guns. Whether the devices would hold under combat conditions would be decided in about nine hours.

At 6:11 a.m. on July 25, the ground near Saint-Lô shook as 1,500 bombers dropped 4,000 tons of ordnance. Cullen watched from a forward observation post three miles behind the line. The barrage lasted ninety minutes, and when it ended, the quiet felt unnatural. At 7:45, the first Rhino tanks crossed into the bocage—2nd Armored leading, 3rd Armored close behind, 1st Infantry Division in support. Every tank carried either Cullen’s prongs or the railroad variant.

Radio reports began at 8:15. Company B, 2nd Armored, reached its first hedge. The lead Sherman accelerated to 25 mph and struck the earthen base; the prongs dug in; the tank pushed through in sixteen seconds. The crew reported no damage to device or suspension. More calls followed: Company C breached three hedgerows in twenty minutes; Company A punched through five in succession without stopping. Across the front, the pattern held.

Units that once took hours to clear a single field were now crossing multiple hedges in minutes. The enemy wasn’t prepared. Their doctrine assumed tanks would climb, exposing belly armor. Teams with anti-tank weapons positioned for upward shots at predictable points. When the Rhinos punched through at ground level, those firing solutions failed. By 10:30, 2nd Armored had advanced two miles—a distance that previously took days. 3rd Armored reported similar gains. The bocage defense network was unraveling.

The devices weren’t flawless. Around 11:00, failure reports arrived. A Sherman from the 741st hit a hedgerow with a buried stone foundation; the prongs bent backward and the tank stuck, unable to move forward or reverse; the crew bailed under fire and two men were lost. At 11:20, a light tank’s prongs snapped after striking a hidden iron fence post, tearing part of the bow plate; the vehicle could fight but no longer breach. At noon, a tank destroyer with railroad prongs hit a hedge at 30 mph—too fast—the brackets buckled, the prongs twisted into the right track, immobilizing the vehicle.

Failure rate hovered near four percent—four failed breaches per hundred. Not catastrophic, but significant: four percent of 2,300 meant roughly 92 devices failing during Cobra, 92 crews potentially trapped under hostile fire. From the observation post, Cullen tracked the net positive flow—armor advancing faster than at any time since D-Day—while those failures gnawed at him. Statistics translate into people.

At 1:30 p.m., a report changed the day’s scale. A battalion from 3rd Armored reached the Marigny–Saint-Gilles road, four miles in six hours—the same distance that had taken two weeks in June. By 3:00 p.m., advance elements were five miles inland. Units opposing them couldn’t establish new lines fast enough; the terrain advantage had evaporated. The bocage that once protected now constrained.

Bradley’s headquarters assessed at 4:15 p.m.: Operation Cobra was succeeding beyond projections. Rhino tanks had solved the bocage problem. Estimated opposing casualties were triple friendly losses. The stalemate was over. At 5:00, Cullen left the observation post and returned toward Columbières. The welding stations were quiet; every tank had moved forward. The field lay littered with cut steel offcuts and burned torch tips.

He sat on a jeep hood and tried to absorb it. A sketch on a ration box three weeks earlier; beach obstacle steel welded to tank bows; and now an entire front was moving because tanks could punch through hedgerows instead of climbing over them. The failures still bothered him—stone foundations, hidden posts, impact speed—variables he hadn’t tested. Ninety-two crews paying the price for those gaps. But 2,200 devices worked. Thousands of men were advancing through terrain that had been a slaughterhouse. Four percent failure was harsh. Sixty percent casualties from exposed belly armor had been harsher.

As the sun set, distant artillery rolled. The line had moved eight miles in a day. The bocage was behind. On July 26, Bradley’s headquarters ordered more cutters—units beyond the hedgerows still encountered scattered hedge lines. The devices remained useful. The ordnance group was authorized to produce another 500 units from remaining railroad steel. By July 28, the count reached 2,850 modified tanks—about 60% of First Army’s armor. The rest were specialized vehicles or reserves that couldn’t mount cutters.

The spread was wide. 2nd Armored used Rhinos from Saint-Lô to Coutances; 3rd Armored from Marigny to Avranches; 1st Infantry Division during the Mortain counterattack. 4th Armored received devices on July 30 and used them on the Brittany approach. Units tailored the design: the 747th favored heavier railroad prongs; 2nd Armored standardized Cullen’s lighter hedgehog steel; some tank destroyers used shorter three-prong variants to preserve gun traverse; light tanks often ran two-prong versions to reduce weight.

Maintenance units wrote field repair procedures. Bent prongs could be hydraulically straightened; broken welds rewelded in 30 minutes; destroyed assemblies replaced in two hours if spares were on hand. Columbières became a repair depot returning devices to service. The tactical effect extended beyond breaching. Opposing units withdrew faster because they could not anchor on hedgerows; armored forces moved forty miles in eight days; escape routes through bocage were blocked; encirclements formed.

Intelligence reports captured the other side’s perspective. They called the devices “iron tusks” or hedgehogs turned against them. Some abandoned positions once they realized tanks could breach any hedge. One company commander reported his anti-tank crew fled after watching three Shermans punch through hedges they had believed impenetrable. By August 5, the bocage campaign was over. Forces had broken into open country. A problem that stalled an army for six weeks had been solved in twelve days.

Bradley’s staff estimated the Rhino accelerated the breakout by four to six weeks. The numbers were stark: between July 25 and August 10, armored vehicle losses dropped 37% compared to June and early July. That represented roughly 300 tanks not destroyed and 1,500 crew members not killed or wounded. The four percent device failure rate was negligible in that context. Not all units kept their devices, however.

As forces advanced into regions without dense hedgerows, crews removed the 320-pound prongs to save fuel and improve road speed. By mid-August, about 40% of Rhino tanks had shed their cutters. Others kept them: 4th Armored retained devices into September for occasional hedgerows in eastern France; 2nd Armored stored removed prongs on trucks for reinstallation; several tank destroyer battalions kept lighter versions permanently. On September 2, during the liberation of Paris, a few Rhino tanks still carried their prongs. Civilians didn’t know what the tusks meant. Tankers did.

Cullen watched the advance from Normandy. Bradley’s staff reassigned him to training replacement crews in hedgerow tactics near Isigny. On August 15, a courier summoned him to Bradley’s HQ without explanation. He drove in, braced for questions about failures and trapped tanks. Instead, Bradley handed him a folder—a Legion of Merit recommendation co-signed by Major General Leonard T. Gerow.

“You’re being awarded the Legion of Merit for exceptionally meritorious conduct,” Bradley said. “Your hedgerow cutter directly contributed to Operation Cobra’s success and saved an estimated 1,500 American lives.” Cullen stared at the citation. Sergeants rarely received that decoration; campaign-level impact was usually an officers’ realm. “Sir, I just welded steel to tanks,” he said. “You solved a tactical problem that stopped First Army for six weeks,” Bradley replied. “The device is officially designated the Cullen hedgerow-cutting device. You earned this.”

The ceremony took place on August 20 in a field near Saint-Lô. Bradley pinned the medal himself before about 200 officers and enlisted men. Several tank commanders whose crews used the cutters attended; Lieutenant Charles Green of the 747th had breached 47 hedgerows during Cobra without losing a single man. The citation credited Cullen’s ingenuity and skill in overcoming formidable terrain obstacles and facilitating the Allied advance. It referenced the 2,850 devices and casualty reductions.

Word spread through Allied forces. British units requested specifications and produced roughly 300 “prong” kits. Canadian armored forces manufactured about 200 with salvaged steel from their sectors. Through Lend-Lease channels, the Soviet Union received drawings but never adopted the device; their doctrine favored overwhelming fires to erase obstacles. By September, the Cullen device appeared in training materials; Fort Knox added hedgerow breaching to the curriculum.

New crews learned the doctrine: approach at 25 mph, strike the base, maintain momentum for 15 seconds, clear the opposite side, continue the advance. Field modifications continued into autumn: some units added toothed tips for better bite; others welded angled deflectors to avoid snagging buried debris; a few created folding versions for road movement. Beyond Normandy, terrain reduced the need. By October, most cutters were stored or scrapped, though the tactical lesson outlasted the hardware.

Field improvisation using available materials could solve problems that stalled armies. Senior leaders encouraged similar initiative. When forces encountered dragon’s teeth in Germany, engineers improvised ramps from rubble and beams—a mindset sparked by turning beach obstacles into breaching tools. Cullen returned to the 102nd Cavalry Reconnaissance Squadron on August 25, continuing reconnaissance through autumn, crossing into Germany in November. The war pressed on; the Rhino receded into the background as new problems arose.

The 102nd reached the Elbe in April 1945. Surrender came May 8. Cullen had served three years in combat. He was 30. He returned to the United States in June and separated from service. His record listed the Legion of Merit and his role in developing the hedgerow cutter. Civilian life required other skills, and he found work with Schenley Industries in New York—far from tanks and field engineering.

The story followed him anyway. Local papers profiled the Cranford sergeant whose device helped break the Normandy stalemate. The Cranford Citizen and Chronicle had run a feature on September 7, 1944, even while he was still overseas. It described showing his plans to his captains and Bradley’s reaction. But national attention was limited; the war’s end brought other headlines—VE Day, VJ Day, atomic weapons—sending a tank modification into the margins.

General Bradley changed that with his 1951 memoir, A Soldier’s Story. He described the bocage problem and Cullen’s solution, calling it so “absurdly simple” it had baffled an army for over five weeks, and he recounted the July 13 demonstration. Historians took notice. The Army’s official history of the European Theater, published in 1953, devoted several paragraphs to the cutters and their impact on Cobra. Still, Cullen himself remained largely unknown outside military circles.

He worked, joined the Sons of the American Revolution, and lived quietly. The doctrine his innovation inspired, however, persisted. Field manuals emphasized improvisation using available materials; officer and NCO courses encouraged enlisted initiative; NATO partners adopted similar approaches. The notion that a sergeant could solve a campaign-level problem became part of institutional memory. The Soviet military press even cited the cutter as an example of flexible “capitalist” command philosophy.

Most devices vanished. A handful of Rhino tanks found their way into museums. Fort Knox displayed a Sherman with original Cullen-style cutters; the National WWII Museum in New Orleans later acquired a similar example. In Normandy, the Musée du Débarquement exhibits recovered prongs and photos of the Columbières production line. Visitors walk past not realizing what those iron tusks meant. Veterans do. They stop, look, and remember.

Cullen died on November 20, 1963, in Greenwich Village at 48. Obituaries noted the Legion of Merit and the hedgerow cutter but were brief. A year later, President Dwight D. Eisenhower, speaking with Walter Cronkite on the 20th anniversary of D-Day, told the hedgerow story on national television. He named Cullen and explained how the device changed the campaign. Millions heard it, and a footnote became a legend—too late for the man who made it.

Formal recognition had begun even during Cobra. On July 28, 1944, First Army issued Technical Bulletin TBR 231, officially designating the “Hedgerow Cutting Device M1, Cullen Type,” with installation specs, employment guidelines, and maintenance procedures. In three weeks, a field improvisation had become standard equipment. Third Army adopted it upon activation; roughly 500 cutters supported its drive across France; after-action reports credited them with rapid movement through scattered hedgerows.

Ninth Army received specs in September and manufactured about 200 devices at forward depots using salvaged steel—proof the concept was portable anywhere welding gear and scrap existed. The British 21st Army Group requested assistance on August 5; engineers studied the Columbières setup and produced the Prong Device Mk I; Canadian forces built their own “Obstacle Cutter, Improvised Type A.” SHAEF issued a commendation for innovative field engineering on August 15, highlighting enlisted initiative as operationally decisive.

By September, operational research quantified the effect. Loss rates dropped from 8.3% per engagement to 4.7%; crew casualties fell 37%; time to traverse bocage decreased 73%. The economics were just as clear: an M4 Sherman cost about $63,000 in 1944 dollars; a cutter cost roughly $40 in scrap and twelve man-hours. Saving an estimated 300 tanks during Cobra preserved nearly $19 million in equipment—not counting trained crews. The Armored Force Board recommended integrating breaching into basic training, and by December, FM 17-33 included a full chapter on improvised cutters.

The doctrine spread—engineer courses taught converting enemy obstacles into friendly solutions; infantry learned to identify breach points; artillery observers coordinated fires for hedgerow operations. The Cold War codified the lesson. NATO planning assumed field modifications would address obstacles; Warsaw Pact analyses cited the “Cullen device” as an example of Western flexibility. By 1960, the hedgerow cutter appeared in curricula across sixteen military schools, taught to tens of thousands of soldiers.

Curtis Cullen never taught those classes. He never toured museums or lectured cadets. He worked a regular job, lived a regular life, and passed away in 1963—eighteen months before Eisenhower spoke his name on national television. Whether his contribution would be remembered beyond specialists became an open question. The modern legacy endures in three places: museums, doctrine, and the memories of those who lived because four steel prongs were welded to their tanks.

At Fort Knox, visitors see a Sherman with original cutters and a placard explaining how a sergeant from New Jersey turned enemy obstacles into a solution. In New Orleans, photos of the Columbières line and Bradley’s production orders bring the story to life; interactive displays show the engineering behind the prongs. In Normandy, recovered cutters sit in glass cases a few kilometers from the fields where they bit into ancient earth. Most people pass by. Veterans linger.

But the deeper legacy is in how forces think and act. When Humvees in Iraq needed protection, soldiers welded scrap into armor. When vehicles in Afghanistan needed adaptation, engineers fabricated parts in the field. When unexpected tactical problems arise, units create solutions before official equipment arrives. That mindset traces to moments like July 1944, when one sergeant stared at scrap steel and imagined what it could become.

Curtis Cullen’s grave in New Jersey bears his service and his Legion of Merit. It doesn’t mention the hedgerow cutter. People walk by without knowing. Yet an estimated 1,500 men came home from Normandy because of his device. They had children. Their children had children. The number of people alive today because a sergeant welded beach obstacles to tanks is uncountable—thousands, perhaps tens of thousands.

He never knew. He died thinking his contribution was a footnote. He took no victory laps, wrote no memoirs, and gave no interviews. He was a noncommissioned officer who saw a problem and fixed it. The last member of the 102nd Cavalry Reconnaissance Squadron passed away in 2019; his obituary mentioned serving with Cullen and watching the first breach—“the moment I knew we’d survive Normandy,” he said. That’s the real legacy.

It’s not the medals or exhibits or manuals—though those matter. It’s measured in lives: 1,500 men who didn’t die in burning tanks. 1,500 families who got their sons, husbands, and fathers back. And it started with a sergeant looking at enemy steel and seeing possibility. If this story moved you, like the video so more people can hear it, subscribe for more stories rescued from archives, and drop a comment telling us where you’re watching from—and whether someone in your family served. Together, we’ll make sure Curtis Cullen is remembered.