UNDERSTANDING THE DEFENSES
Marshal Rommel knew he had insufficient troop strength and quality, particularly in powerful maneuver units like Panzers that had made the Wehrmacht so effective in earlier years. He was well aware that the Atlantic Wall was paper thin, and given Allied control of the local air, moving reinforcements to a breach would result in many losses before combat began. He concluded that an invasion would have to be stopped on the beaches.
Beaches in Normandy had high tides (17 to 21 feet) and long gradients (as much as 500 yards difference between high and low water marks at Omaha). The Field Marshal believed the Allies would land at high water to minimize exposure to small arms fire from German troops in positions directly defending the beaches.
Based upon that assumption he created a ‘Devil’s Garden’ of passive defenses that would be under water, invisible and unavoidable, at high tide. These defenses would snag landing craft, rip out their bottoms, blow them up, cause them to swamp or swing sideways to fire from the shore, and snarl the way for subsequent vessels. They would also force heavy-laden troops into water from waist deep to over their heads.
Allied troops expected to encounter bunkers, occupied trenches, tank traps, artillery, machine-gun positions, even armor. Some of them had faced all that before in North Africa and Italy, many hadn’t. The off-shore beach obstacles were something new. They ranged from simple posts to concrete or steel shapes. All were intended to make it as difficult as possible for troops to struggle to the beach against mortar, machine-gun and anti-tank gun fire. Mines were frequently added to obstacles to multiply the damage.
The more elaborate off-shore obstacles featuring steel and welding, poured concrete and complex installation, were the earliest efforts, occurring in the most obvious landing sites. Urgency caused by the clearly impending invasion resulted in an increased use of wooden posts. Those were sunk on beaches and just inland by the hundreds of thousands.
Most of the following photos of beach obstacle types were taken near Cherbourg by OSS teams after the city fell to the Allies, but all the shapes were known and understood by Allied planners because of photo recon before the invasion.
The most elaborate beach defense in wide use was the ‘Belgian Gate’. Well braced, welded steel, these were solid enough to stop even a large landing craft ramming into them. In lower tides, landing craft would be slowed, making better targets as they tried to thread a path through the gates. With high tides, the ‘gates’ would be under water. Landing craft would be caught, hull possibly holed, in water too deep for troops to disembark.
‘Belgian Gates’ were most effective when used in large numbers, forming a zone with considerable depth, leaving no clear avenues to the beach. Note a wide area of open beach beyond the ‘gates’. They were of less value when uncovered by a receding tide – except that they tended to force landing craft to stop well short of dry land.
‘Gates’ were well anchored, but, on D-Day, experience showed a heavily loaded, large landing craft with good speed might ram through one. The only way to get rid of the ‘Gates’ was for Engineers to blow them up.
This appears to be a photo of pre-fabricated ‘Belgian Gates’ faces awaiting installation. The gravel access road hints at many more of them here at one time. They are stored between steel rail posts and a barbed-wire field designed to frustrate an airborne landing.
This type of elaborate and expensive barrier may have only occurred at one site. Pre-shaped rails in the foreground indicate it was still under construction and it appears to be a very labor-intensive job. Perhaps the plan was to eventually move them off-shore. Location above the high-water line is hard to explain (perhaps as a tank barrier?).
More common concrete pyramids are along the same beach scarp in the background. Note, the tide is in and there is almost no beach at the bottom of the scarp.
‘Pyramids’ were pre-formed concrete sections. Six wired together created the shape. These were easy to make and easy to assemble but they were not well anchored, depending upon their weight and shape for resistance. Here they are seen backed by rows of angling posts, some topped with Teller Mines. This whole defense field would slow, but probably couldn’t stop, a determined landing.
A closer look at ‘Pyramids’ shows their construction. Given a few minutes, Engineers could easily blow-up or disassemble this type of defense.
Designed to hole a landing craft, ‘Czech Hedgehogs’ were particularly effective. Made of steel rails in a shape similar to medieval Caltrops, like the other obstacles they were sited to be just below the surface at high tide to rip the bottom out of landing craft and dump troops into ‘killing zones’ in deep water. Though not anchored, they always presented several sharp arms if bumped or rolled. These were some of the most prevalent defenses at Omaha Beach. Ironically, some landing troops pinned down short of the beach by heavy fire from the cliffs were able to shelter behind the steel rails of ‘Hedgehogs’ and survive.
Both photos show how hedgehogs looked in partial flood and how they were placed in rows and close-spaced. Being relatively low they could be a hazzard close in to shore.
The same beach at higher tide shows hedgehogs at water’s edge, some of the out-lying obstacles going underwater.
Pressure to block more beaches quickly resulted in simply driving wooden posts into the sands. Vertical posts were fast and easy to seat. Angling made them more likely to withstand the shock of a landing craft. Note at least five are topped with mines, seemingly installed at random.
The foreground shows three ‘Pyramids’ either ready for installation or recently disassembled by Allied Engineers.
Concrete ramps, often topped with mines, were intended to tip a landing craft or turn it broadside. An approaching landing craft would be coming from the right.
This photo shows the three pre-formed concrete shapes and how the ramp was sited just past rows of posts. Landing craft might go over the posts but ramps were often higher. Note some ‘Pyramids’ in the background.
More primative wooden ramps were quickly created and could be quite substantial, standing higher–judging from the man, about 9-10 feet high. Perhaps the height indicates an unusually large tidal rise at this site. This ramp is topped by a mine. Enough of these crude devices and approaching a beach would be quite hazardous.
This beach hadn’t received the complete treatment yet. The posts are too few and too far apart to be much of an impediment. Almost submerged in the water are prefabricated ‘Pyramids’ of a different design. A partly disassembled/destroyed ‘Pyramid’ is at the far right.
Some beach defenses were either really basic, or perhaps done by local workers who didn’t understand the requirements. The posts are hefty enough but sparsely placed couldn’t have much effect. I can’t tell if those are explosive charges or simply ‘spacers’ between the posts.
Some beaches had mines above the high-water mark, perhaps even a little way off-shore. Mines buried in deeper water would be made useless by a few tidal changes. Beaches seeded with mines would be neutralized by ‘flail tanks’ using rotating drums with heavy chains to beat the surface and, hopefully, detonate mines harmlessly ahead of the vehicle. Other vehicles designed to solve specific problems getting beyond the beaches were: tanks with heavy mortars or flame-throwers to take out bunkers; tanks with fascines to fill in anti-tank ditches or unroll matting to give tanks and trucks purchase on loose beach shingle; tanks with ‘dozer’ blades or small assault bridges; and tanks that could ‘wade’ in deep water or ‘swim’ ashore (Duplex Drive M4 ‘Sherman’ tanks). Collectively they were called ‘Hobart’s Funnies’ after their commander, Maj. Gen. Percy Hobart.
This Matilda Flail was photographed in North Africa where the technique was first successfully employed.
Invasion planners had the daunting task of balancing a bewildering series of variables against the probabilities of success and the lives of men. Landing at low tide would expose all the beach obstacles for avoidance, but would force the men to transit up to 500 yards of open ground under fire just to reach the shore berms. High tide landings would result in losses from running into the obstacles. Then there was the requirement for a surprise night attack with enough moonlight to permit precise parachute and glider landings. It was finally decided that the best combination of tides and moon was met on 5 June 1944.
Operation Overlord beach landings would be made just after dawn, about an hour after low tide. Many beach obstacles would be visible and rising tide would float off hard-beached landing craft to clear the beach and make other trips possible. Once on the land, forces would rapidly thrust inland to create a defense perimeter while sappers and engineers would begin destroying the off-shore obstacles, creating safe lanes to the beaches for subsequent landings by larger vessels bringing more men, heavy vehicles and equipment. By the next low tide (1725 hrs.), Bulldozers and explosive charges were expected to have made short work of beach defenses below the high-tide mark.