“Enemy forces that have succeeded in landing must be destroyed or thrown into the sea by immediate counterattacks.”
Führer Directive No. 40, March 23, 1942.
Hitler’s directive of March 23, 1942, marked the official birth of the Atlantic Wall even though the actual work had started much earlier. Unfortunately, since Hitler had no clear concept of defense, a rift arose between those German military leaders who advocated mobile defense and counter attacks to drive the allies back into the sea, and those who preferred a static defense system designed to prevent enemy disembarkation in the first place which would commit most field units to the coast. Eventually the proponents of the static defense concept prevailed, and the Atlantic Wall became reality.
One of the most ambitious coastal defense systems ever undertaken, the Atlantic Wall was built in an astoundingly short period of time. It extended for over 2,600 km from North Cape in the Arctic Circle to the Spanish border. Later it was expanded toward Petsamo in Finland. The Mediterranean, which included the coastal defenses of France, Italy, and Greece, could be considered, in a manner of speaking as an extension of the Atlantic Wall.
The German coastal defense system began with the creation of the Army Coastal Artillery in 1940, with its new coast artillery battalions (HKAA). The mission of the Army Coastal Artillery was to support the Navy Coastal Artillery, which could not expand sufficiently to meet the demands of such a long front. The Wehrmacht began to devote its full attention to coastal defense in 1942. However, in the following years, construction workers and equipment were diverted to work on other defensive lines such as the Gothic Line in northern Italy and the Panther Line in the
Soviet Union. In addition, the East Wall had to be resurrected and reinforced late in the war. However, most of the land positions built by the Germans were overshadowed by the Atlantic Wall, which attracted the world’s attention thanks to propaganda and the epic battle for Normandy.
Norway’s coastline was the longest of all the territories occupied by the Germans. The mountainous terrain and lack of roads, hindered the movement by land of reinforcements from one point to another. Only the entrances to the fjords and the major cities on the fjords that also served as ports offered potential invasion sites. As a result of this peculiar topography, every important fjord had to be defended but the remainder of the mountainous coastline was left almost unprotected.
Belgian and French Coast to St. Malo
The stretch of coastline between Brittany and Belgium was considered the most likely place for an Allied invasion because of its proximity to Great Britain. Its varied topography favored defense in some areas and offense in others. The area between Zeebruge in Belgium and Le Tréport in France, dominated by sandy beaches and dunes, was unfavorable to deep-sea shipping and the logistic support necessary for amphibious landing. The only breaks in this low coastline occurred at river mouths and near Cap Gris Nez where the beaches turned into cliffs. The littoral between Tréport and Carentan in France, consisted of cliffs cut by valleys opening onto beach areas. Along the eastern Cotentin Peninsula there was little relief behind the coast, which gave easy access to the interior. However, the lowlands of the peninsula were easily flooded. The northern part of the Cotentin, on the other hand, was dominated by cliffs that gave way, on the western side, to smaller beaches that extended, with some breaks, up to St. Malo in Brittany.
Some of the most important French ports on this front were Cherbourg, Le Havre, and Rouen, a major inland port. In Belgium, Antwerp had to be defended since it was the gateway to the interior. In addition, the Atlantic Wall encompassed several smaller Channel ports that had to be defended as well. Naturally, the Germans took advantage of the pre-existing fortifications erected by the French. An invader faced the difficult proposition of winning control of the mouth of the Seine to take Rouen and the mouth of the Schelde to capture Antwerp.
French Coast from St. Malo to Bayonne
The front between St. Malo and Bayonne included the Brittany Peninsula, dominated by hills punctuated by a few potential invasion beaches and several easily defended ports. Further south, on the Bay of Biscay, numerous open beaches gave way to low hills. In a few areas the cliffs reached the shoreline. Some of the key ports of this front were the naval bases of Brest and Lorient, already well protected, and the ports of St. Nazaire and La Rochelle-La Pallice. The major inland port of Bordeaux could not be put in use without control of the mouth of the Gironde.
The Dutch, German and Danish Coasts
The sandy beaches and dunes of Flanders continued along the shores of the Netherlands. The low lands behind them, including the islands of the Schelde, were easily flooded, negating any advantage of a seaborne assault. The major port of Rotterdam was useless without control of the mouth of the Rhine, while Amsterdam could not be put in service without control of both sides of the Great Dike on the Zuider Zee.
The Frisian coast of the Netherlands extended into north-western Germany, where it was masked by many large islands. The only major ports in the area were located in Germany and were difficult to capture because of their location and the protection of the off-shore islands.
The Danish coastline offered few ports on the lowlands of western Jutland. Its beaches faced shallow waters, unfavorable to the logistical support necessary for amphibious invasions. Operations against northwest Germany or Denmark would be limited to action against individual islands and offered few advantages.
French Mediterranean Coast
The Mediterranean coast of France was not, strictly speaking, part of the Atlantic Wall and is sometimes referred to as the Southern Wall. The area west of the Rhône included no major ports, but consisted of many low beaches difficult to defend.
The east of the Rhône, the port of Marseilles and the major naval base of Toulon were well protected by the terrain, and had been heavily fortified by the French. Most of the remainder of this coast presented a rugged appearance devoid of beaches. However, it also included a few stretches of long beaches opening into the hinterland.
The eastern portion of this coast formed the French Riviera, famous for its beaches dominated by the Maritime Alps. It extended into the Italian Riviera where the number of good invasion sites rapidly diminished.
After the fall of France in June 1940, the Germans moved to the coast in preparation for the invasion of England. While the Wehrmacht worked on plans for the next offensive, the first positions of the Atlantic Wall were being established. The Germans took over the French coastal defenses and moved heavy artillery to the coast, in the region of the Pas de Calais.
The mission of the heavy and medium gun batteries brought to the coast, was to protect Axis shipping in the channel and perform long-range bombardment. The medium batteries consisted of 150-mm guns and railway weapons like the navy’s Gneisenau Battery that had four guns with armored shields. The heavy batteries included large railway guns with calibers of 210-mm, 240-mm, and 280-mm.
When the invasion was indefinitely postponed, the Germans began to work on permanent artillery positions. The first large concrete ”Dome Bunkers” for a heavy rail gun, began to go up in September 1940. By the end of 1941, seven concrete battery positions were completed in France, one in the Netherlands, and four in Norway. These were Battery Graf Spee (4 x 280-mm guns) at Brest, Battery Hamburg (4 x 240-mm guns) and Battery Brommy (4 x 150-mm guns) at Cherbourg, Battery Friedrich August (4 x 305-mm guns) at La Trésorie, Battery Schleswig Holstein (3 x 406-mm guns) at Sangatte, Battery Oldenburg (2 x 240-mm guns) at Calais, Battery Kurfürst (4 x 280-mm guns) and Battery Prinz Heinrich (2 x 280-mm guns) at Framzelle, and Battery Tirpitz (3 x 280-mm guns) at Hoek van Holland. Most of these batteries had been brought from the northwestern German sities at Sylt, Nordemey, Borkum, Wangerooge, and Kiel. Battery Kurfürst and Prinz Heinrich came from Pillau, Battery Brommy from Memel, and Battery Schleswig Holstein(renamed Lindemann in 1942) from Hela on the Baltic. In addition, Norway received Battery Skagerrak (4 x 240-mm guns), Battery Goeben (4 x 280-mm guns), Battery Grosser Kurfürst (4 x 280-mm guns), Battery Yorck (4 x 170-mm guns), and Battery Goeben (3 x 170-mm guns).
The Norwegian defenses were given priority in 1941 in order to secure the Reich’s northern flank before the beginning of the Russian Campaign. The rugged terrain restricted the number and location of air bases, making a defense based on large-scale air attacks impractical. Large stretches of the coastline could only be watched by occasional patrols. However, these isolated areas did not provide a good foothold for any force larger than a raiding party.
Almost all the construction material for the fortifications in Norway was shipped from Germany, which limited the number of concrete positions that could be built, especially when construction had to be speeded up. To save on construction materials, the Wehrmacht had to adapt many caves along the coastline to accommodate artillery positions. The Wehrmacht also borrowed the idea of using large rocks as anti-tank obstacles from the Finns.
In France, in the meantime, a series of Allied commando raids between 1940 and 1942 exposed the weaknesses of the Atlantic Wall. The 1941 raid on St. Nazaire in particular disturbed Hitler, who ordered his engineers to complete the submarine pens and protect more efficiently those still under construction. After all, the U-boats were the only remaining weapons that would allow him to take the war to the enemy after 1941, since the Luftwaffe was fully engaged in the East. That is why Hitler was anxious to secure the U-boat bases not only with massive concrete pens, but other defenses as well.
When the army groups withdrew from France between the fall of 1940 and the spring of 1941 in preparation for the invasion of the Soviet Union, only the newly formed Army Group D remained. Its commander, Field Marshal Erwin Witzleben, also assumed the position of Commander-in-Chief West (OBW) after Field Marshal Gerd von Rundstedt moved Army Group A to the East. As OBW, Witzleben was responsible for the defense of the French and Belgian coasts and came directly under the High Command of the Armed Forces (OKW). A newly appointed Inspector of Land Fortresses in the West was attached to OB West and his headquarters were moved from Metz to Paris in the same year. The High Command of the Army (OKH) was removed from the chain of command in the West and took control of the Eastern Front. The Armed Forces Command Netherlands had authority in Dutch territory, but fell under OBW’s tactical command in the event of an invasion. Denmark and Norway were placed under separate commands.
While the Wehrmacht command in the West was in the throes of reorganization, the construction of battery positions proceeded and the heavy batteries at the Pas de Calais exchanged fire with British artillery in the Dover area. Plans were drawn for the defense of key areas of the coast, but by the end of 1941 only the ports had any significant defenses.
The first major German defensive projects on the Atlantic Wall were set in motion on the occupied British Channel Islands. The reinforced 319th Infantry Division, which eventually reached a strength of about 40,000 men, set up positions on the islands in mid-1941. Men from the office of the Inspector of Land Fortresses in the West had already surveyed the sites by that time. In October Hitler decreed that the islands must be turned into “impregnable fortresses.” The Todt Organization (OT) arrived soon afterwards to begin the construction. The OT offices, fixed at St. Malo on the mainland, devoted their full attention to the defenses of the islands until October 1943.