The wind blows hard across the English Channel
and the Normandy peninsula
. In order to counter the winds, over the centuries French farmers planted hedgerows
of thick bushes and trees that grew together over the centuries. They didn't look like much in the photographs taken from Allied airplanes. Most analysts considered them little more than annoyance in the days leading up to D-Day
, the Allied invasion of France. But when Omar Bradley's First Army began to expand beyond the Normandy beachheads they discovered the hedgerows were more then a little problem, but a set of natural barriers which enabled three German divisions to hold up many American divisions. The Cullen hedgerow device was the best known of a number of American improvisation
s which helped the American Army to finally punch through the thin line of the German defenses and race across France.
By 1944 the Luftwaffe had been reduced to a pale shadow of the force which dominated the battlefields of 1940 and 1941. P-47 Thunderbolt and Hawker Typhoon fighters roamed the skies looking for targets. Rommel, who had experienced Allied air power in North Africa kept his divisions close to the coast for a fast response. Hitler's orders delayed them moving, which helped the Allies extend their beachhead far enough so that supplies could be unloaded unmolested. But most German armor was still intact, its officer corps and staffs dominated by combat veterans of the great tank battles North Africa and the Eastern Front. To the northeast of the beachhead near the city of Caen was open country, relatively flat with few natural barriers. Perfect tank country. The British had drawn the northern beaches on D-Day, and they're responsibility was to the north. And so the British Commander, Bernard Law Montgomery attacked their first initiating Operation Goodwood.
There he failed. After five years of war the Germans knew good tank country when they saw it. They concentrated the vast majority of their panzer divisions to defend the open country around Caen. Allied tankers faced what is often called a "target-rich environment" in the north. Another reason for Monty's defeat was the UK's relatively smaller population and four years of war led to a relative shortage of British Infantry, while America had produced plenty of Sherman tanks. Doctrine supported the 'tank only' approach. Ever since J.F.C. Fuller and Basil Liddell-Hart created British doctrine it had stressed the importance of the tank, and its ability to dominate the battlefield. So with little infantry support and Montgomery sent Richard O'Connor's VIIIth corp forward to a bloody defeat.
But the bigger reason wasn't the lack of effective combined arms operations, but rather the equipment. The M4 Sherman had been designed to resist 37mm gunfire. The King Tiger mounted the famed 88. The Panther a long 75mm and the surviving Pzkw IVs and Stug III assault guns all carried long 75mm guns, and the open country allowed the Germans to engage to the extent of their equipment. The 88mm gun on a Tiger could penetrate a Sherman's frontal armor at 3,000 meters. The M3 75mm gun mounted on early Shermans could penetrate the frontal armor of a King Tiger at zero meters. German armor had months to learn the terrain and on defense could prepare hull-down fighting positions. The Brits got to shoot at thickly armored turret faces while the Germans could hit the entire tank. Fortunately for the Brits, Canucks and Poles the Germans had only two companies of Tigers, but Panther's could kill Shermans at 2,000 meters versus 100 meters from the American tank at no point did a straight gunnery duel favor the Allies. The Brits did have some Sherman Firefly tanks equipped with the OQF 17-pounder. The 17 pounder could penetrate German armor at range, but the Sherman lacked the armor to fully match up against the newer German tanks. Worse, the long barrel and counterweight made it easy to identify a Firefly so the Germans shot at them first.
Now add in some of what Clausewitz called "friction', the inevitable problems and mistakes of war with some poor planning, the inability to support those operations which had been successful and the skill of the German defense led Montgomery's troops to fail in their drive East along with enormous tank losses. Bad as things were in the north the problem of the American troops in the south seemed even worse. Granted the Americans faced only 3 German divisions, but this was the bocage country, the hedgerows. The countryside was divided up by thick green fences of hedges, bushes and other plants that spanned two or three meters and had grown together for centuries. Each one divided an area about the size of an American Football field, but often smaller. Because the hedgerows had not been plowed for centuries, they each had an earthen berm several feet higher then the field and particularly the sunken roads leading between villages.
Naturally the Germans had noticed all of this. Step one: Mine the roads so you have to clear them before using them. Since all that shrubbery provides good cover, you support the minefields with a few anti-tank guns, machine guns and panzerfausts, so clearing the roads is pretty darned dangerous. Then you install booby-traps in the foliage for good measure.
Of course the Americans quickly tried moving off the road. But it wasn't so easy to infantrymen into the field and try and clear out the guns. The Germans put a machine gun in one corner of the squarish fields, where it could easily shoot anything that moves. If the infantry called for a tank to defeat the machine guns, but to do that they had to cross the hedgerows. Crossing lifted up the Sherman's nose exposing its belly. Tank bellies are armored, but lightly. Even the smallest anti-tank gun or panzerfaust can cut through the thin belly armor leaving a burning tank up on the hedgerow. The bocage was perfect defensive country. Which is why the Germans figured they could afford to put most of their troops up north against Montgomery.
Tanks like open country, where they can maneuver. Down south the hedgerows all but eliminated such mobility, canalizing the Americans onto easily defended roads. The bocage even gave Germans plenty of cover from the ground and sky, negating much of the Allied advantage in air power and artillery. American soldiers had to clear each hedgerow, one at a time, using infantry, which was expensive in men, equipment, and time-consuming to boot.
The solution was something that could allow a tank to push through the hedgerow rather then around it. One solution was the dozer tank, which is really nothing more then a tank with a bulldozers blade and hydraulics grafted on. Each battalion had only five, and available dozer tanks had many responsibilities, including mine clearing. Something new was needed so the Army began experimenting.
The first solution was known as the salad fork. The salad fork consisted of two logs attached to the front of a tank like horns on a steer. The tank was supposed to ram them into the hedgerow then back out, leaving two holes which could be filled with explosives. A gap would then be blown in the hedgerow. That idea showed promise, but the forks often broke off. The salad fork was a beginning, but something more was needed. Next came an improvised blade, that helped, but wasn't good enough.
Then a Sergeant in the 2nd Armored Division got an idea. Curtis G. Culin identified the problem as the tank raising up to present its belly when hitting a hedgerow. The problem wasn't going through it so much as keeping the tank down. The Germans had left thousands of steel tank-traps (called Rommel's asparagus) on the beaches of Normandy before D-Day and these devices were now being cleared and were useless. Culin cut them up and welded them on the transmission cover of a Sherman. They stuck out like a row of gapped teeth on the lower front of the tank, angled downward to dig in when rammed into a captured hedgerow. The 32 ton tank stayed planted and bulled its way through rather then over the berm and foliage. The pile of dirt piled on the tank's glacis even improved its level or protection until the vehicle passed through. As soon as the gun barrel cleared a high explosive round would be fired into each corner of the hedgerow, destroying any German guns placed in that ideal spot. Infantry would follow the tank in and worked with the tank to clear the field.
Patton attended a demonstration of the device and was impressed. Bradley ordered the devices installed, and they were welded onto the fronts of all types of Allied tanks and tank destroyers. He also ordered the device not be used until the outset of Operation Cobra which began on July 25, 1944. Patton pointed out that if Bradley couldn't bring many troops to bear in the bocage country, neither could the Germans. He said "Once you're through, you're through." Operation Cobra was intended to clear a corridor through the bocage country and permit First Army (and the newly forming Third Army under Patton) out south and into Brittany to sieze its ports. Bradley did not want to give the Germans time to devise a counter-measure to Sgt. Culin's hedgerow cutter. While the Americans prepared Montgomery continued his attacks toward Caen, keeping the German's eye firmly fixed on him.
The measure worked. Attacking near St. Lo, the US 2nd Armored and 1st Infantry Divisions were able to force a corridor past German lines. The measure allowed the U.S. to re-establish tactical mobility, as US Armor (but not German) was no longer road-bound. The small fields negated the long range advantage held by the Panther's long gun. In fact the wide Panther with its long gun and wide body had a harder time maneuvering down the narrow lanes then the lighter Sherman. While the Culin device wasn't used everywhere, its mere existence greatly multiplied the German defense problem because they never could predict where American armor might strike next. Expanding the attack to include all of the VIII Corps within a week the German flank had largely crumbled and their troops were in full retreat. US 1st and 3rd Armies sprang east toward Paris, and then north to try and trap the German armies in the Falais pocket. Canadian and Polish troops launched Operation Tractable and began to attack east to try and close the other end of the pincers, which was closed by 22 August. While 100,000 German troops escaped to fight another day, they did so without their equipment. Fifty thousand German soldiers were taken prisoner and another 10,000 slain in the pocket. The Germans retreated in disarray and were not able to re-establish an effective front until that fall when they stood on the borders of Germany, and only then because Allied armies outran their supply lines.
If Sgt. Culin's hedgerow cutter helped lead to such an enormous success why don't we see them today? First of all, the hedgerow cutter didn't do the trick by itself. The first few weeks after D-Day taught that the infantry supporting a tank and the tank crew needed to communicate directly, which led to new radios and telephones being mounted on the back of each tank. Most of the traffic did use the roads once the thin German line had been punched through. The biggest reason was the bocage represented a unique tactical problem. Tanks are required to cross all types of country, not simply bull their way through thick hedgerows. Imagine crossing a ditch with a few of those prows sticking out the front! Once past the bocage no new devices were installed. As tank casualties were substantial during the last year of the war many rhino equipped tanks did not survive the war or had the Culin device cut off during maintenance. But in July and early August 1944, Sgt. Culin's bright idea did its part in punching Allied armies through the thin German defence and forward to liberate Europe.