Allied Engineers Plan for D-Day
by Joseph Balkoski
Posted April 14, 2014

Rommel had kept the German garrison in Normandy busy—so busy, in fact, that when photos snapped by Allied reconnaissance aircraft along the Calvados coast in early April 1944 were forwarded to OVERLORD planning staffs, a shock wave promptly rippled through Eisenhower’s command. The Allies had already churned out mammoth D-Day plan books, but this latest intelligence revealed something entirely new: for weeks the enemy had been working fervently to erect thousands of obstacles on the Normandy shoreline, an alarming development that would force the Allies to rethink their invasion methods just two months before D-Day.

Hardly prime examples of Germany’s capability to produce Wunderwaffen—wonder weapons—the contraptions Rommel’s men had begun to embed in the Normandy sands appeared absurdly antiquated, little different from war matériel employed by Alexander or Caesar: logs propped at a forty-five-degree angle, facing seaward; iron rails welded together at crazy angles, known as “hedgehogs” by the Allies; gate-like contraptions, nicknamed “Belgian barn doors” by intelligence staffs. One could scarcely believe that such archaic devices would seriously impede a modern army, but, as of April 1944, no enemy activity in Normandy worried Ike more. Fixed on tidal flats, at low water the German obstacles were fully exposed, but they would be submerged little more than three hours hence as the volatile Norman tide rose with its astonishing rapidity. At high tide, when the obstacles were underwater and invisible, Allied coxswains guiding their landing craft shoreward risked impaling their vessels far short of the beach or, much worse, ramming an obstacle topped with a Teller mine—a catastrophic event that would surely kill or wound most passengers.