Hitler Thought His Atlantic Wall Was Indestructible. It Wasn't.

June 16, 2021 Topic: History Blog Brand: The Reboot Tags: World War IID-DayU.S.GermanyFrance

Hitler Thought His Atlantic Wall Was Indestructible. It Wasn't.

The German Atlantikwall was formidable, though. 

In terms of permanent fortifications, the Germans continued to concentrate a substantial portion of their heavy construction work near the major ports.  Hitler went so far as to declare 11 of the ports “Fortresses” (Festungen) on January 19, 1944. 

Singled out were Ijmuiden and the Hook of Holland in the Netherlands; Dunkirk, Boulogne, and Le Havre in the Fifteenth Army sector along the Channel; Cherbourg, St. Malo, Brest, Lorient, and St. Nazaire in the Seventh Army area; and the Gironde River estuary that led to Bordeaux in the First Army area. 

During February and March, OKW added three more—the Channel Islands and the harbors of Calais and La Pallice-La Rochelle.  Designation as a Festung was rather hollow since most of them had already been declared defense areas in 1942, and had therefore already been given considerable attention.

Inside both the fortresses and the coastal strongpoints, engineering troops and OT workers proceeded to improve the heavy infantry weapon positions, the command posts, and even machine-gun nests as well as many of the coastal artillery batteries that were exposed. OT also began moving artillery pieces to make the guns less susceptible to Allied air and ship bombardments, and worked to camouflage existing batteries and construct dummy positions.

Local commanders lent a hand by reducing the number of hours that troops spent in combat training and had them assist in construction efforts. The soldiers worked to improve strongpoints using sea walls, ship canals, and old ramparts—filling in the gaps between with field defenses, preparing real and bogus minefields, setting up barbed-wire entanglements, and digging antitank ditches.

By effectively utilizing the men and materiel at their disposal, the Germans made considerable strides in building up defenses prior to the Allies’ D-Day.  During the first four months of 1944, the number of cubic meters of concrete laid by OT doubled from 357,000 to 722,100 per month. From 1941 to the end of 1943, the Germans had erected some 8,478 concrete structures along the Channel and Atlantic coasts, but from January to May 1944, over 4,600 hardened fortifications were erected, including those on the French Mediterranean coast.

Rommel’s Beachhead Obstacles

Rommel also introduced his own ideas about beach obstacles, which were to be covered by light and medium guns and machine guns in order to turn every foot of shoreline into a killing ground. He placed a premium on laying minefields and beach obstacles based on the impressions that had been made on him by the British defensive positions along the Gazala Line in Libya in 1942.

Rommel promoted a program that stressed the use of field hindrances, which von Rundstedt supported, and included a variety of measures to disrupt an Allied landing, such as laying large numbers of land mines, flooding low-lying areas, and placing foreshore obstacles and tall stakes called “Rommel asparagus” just behind the coast. 

The latter were simple antiairborne and antiglider devices made from a pointed pole driven into the ground and spaced so that the flat, open terrain was turned into a field of deadly wooden spears.

Rommel’s most important upgrade of the Wall’s defenses was the use of foreshore obstacles. Placed along the beaches, these obstacles were designed to fill the gaps between strongpoints, protect the more remote beaches, and delay an Allied landing, even if only for a short time.

Rommel ordered underwater obstacles planted in three to six rows along the beaches to disrupt an amphibious operation, whether at high or low tide. 

The obstacles consisted of various devices. The simplest was an 8- to 10-foot wooden stake or concrete pole driven into the beach sand and angled toward the sea.  Some of the stakes had mines or grenades attached, and all of them, when submerged, could rip open the hull of a landing craft. 

The same was true of numerous V-shaped ramp-like structures, which the Germans sloped toward the sea and armed with mines or artillery shells designed to explode on contact.

A third type of obstacle was the concrete tetrahedron.  This pyramid-shaped object was six feet high, weighed nearly a ton, and could also be mined to sink a landing craft. 

Another hindrance was the “hedgehog” tank obstacle.  It was made of three seven-foot steel girders welded together in the middle so that the beams presented three points angled 120 degrees apart.

Finally, there were Belgian gates––heavy steel antitank structures resembling gates, about nine feet high, and nine feet across, a few with waterproof mines attached..

A tremendous amount of progress had been made. From 1941 to October 30, 1943, the Germans had laid 1,992,895 mines in the West; by May 30, 1944, the number had increased to 6,508,330.  Yet, this figure fell far short of Rommel’s estimated need of 50 million.

By mid-May 1944, there were 517,000 foreshore obstacles on the Channel beaches, 31,000 of them fitted with mines.  Farther out to sea were a variety of shallow-sea naval mines.

But, at the beginning of June, only three of the six rows of obstacles Rommel wanted had been placed along the Normandy beaches. This lack was due in part to a shortage of material in April.

Increase in Personnel on the Atlantic Wall

Yet, during the first half of 1944, there was a steady rise in personnel. On October 4, 1943, Ob West listed 38 divisions ready for combat and 13 additional divisions in the process of forming. The number of ready divisions toward the end of December increased to 41, with seven more being formed or refitted. By April 1944, the total figure had climbed to 54 divisions and would reach 58 just before D-Day.

Forty-six of the 58 divisions were positioned along the coast. The Fifteenth Army had 18; the Seventh Army had 14; First Army, on the Bay of Biscay, had four; the Nineteenth Army, on the French Mediterranean coast, had seven; and there were three in the Netherlands; two reserve divisions were located in the interior of France. 

The remaining 10 divisions were armored formations. Three panzer divisions were stationed north of the Seine, three between the Seine and Loire Rivers, and the other four in the south of France.

These forces possessed 3,300 artillery pieces, 1,343 tanks, and 1,873,000 troops.  Complementing the ground forces were five Navy destroyers in the Bay of Biscay, four torpedo boats, 29 motor torpedo boats, and 500 small patrol boats and minesweepers.  Thirty-five small submarines were located at Brest and other Atlantic harbors. The Luftwaffe’s Third Air Fleet had 919 aircraft, of which 510 were operational as of late May.

The Atlantic Wall Breached

But the chances of Rommel or von Rundstedt beefing up the Atlantic Wall defenses even more was at an end.  On the cold, gray dawn of June 6, 1944, time had run out.

The Atlantic Wall achieved at least a partial success. Almost from the Wall’s inception, the Wehrmacht regarded the Allied capture of an important harbor as a necessary prerequisite for sustaining an invasion front so, by June 1944, the Germans had transformed the harbors into fortresses.  Cut off and dependent on their own resources, many of these beleaguered German garrisons held on tenaciously before finally surrendering.  These actions helped to produce a logistics crisis for the Allies during the late summer and fall of 1944.

Though the Wall was weak in many places, there were enough artillery pieces distributed in key locations to possibly impede an invasion. All the major ports were defended to some degree against an attack from the sea and most were prepared with all-around defense. None of the large or medium-size ports were so vulnerable that an invasion force could capture them easily.

Beside causing logistics problems after the landing, the Wall dissuaded the Anglo-Americans from directly attacking the Pas de Calais and convinced them not to undertake a cross-Channel invasion until 1944.  Given just a bit more time and a few more resources, it could have been much worse for the Allies.

Yet, in spite of all the money, manpower, and effort expended, in the end, thanks to information provided by British intelligence and the French Underground, a bit of luck, and many determined soldiers, the Allies breached the “impregnable” Atlantic Wall in a matter of hours on June 6, 1944.

They found its weaknesses, exploited them to drive wedges into the openings, and then rapidly forged their beachheads.

This article first appeared at the Warfare History Network.

Image: Flickr.