Atlantic Wall: Bunkers and Organization for Defence

Regelbau M162a fire-control bunker for gun battery at Frederikshavn, Denmark, in the summer of 1945. This photo was taken by Frits G. Tillisch, a Danish army officer serving in the Danish Resistance.

Cross-section of one of Mirus Battery’s gun emplacements. Modified drawing from Report on German Fortifications (Office of Chief of Engineers, US Army, 1944). (J. Kaufmann)

When the Germans went over to the defensive in the West after 1940, they increased the number of batteries to protect the ports and deter an Allied landing. However, even if the guns were able to damage some enemy ships or sink them, it is doubtful whether they alone could have stopped a raid or major landing. The Germans, therefore, had to create additional defences and protect the likely invasion beaches adjacent to or near ports and their gun batteries, which represented possible targets for an enemy landing operation. As a result, they established a complex of bunkers and other fortifications around each battery that included, in addition to the gun casemates, personnel shelters, supporting facilities and bunkers for machine-guns and other infantry weapons. Eventually this led to the formation of strongpoints (StP) and strongpoint groups. Smaller groupings of infantry bunkers and associated supporting positions formed resistance nests (Wn) charged with holding the key beaches or adding to the all-round defences for a fortress or smaller position. A variety of specialized bunkers existed for machine-guns, anti-tank guns, infantry guns and so on.66 The Tobruk pit, introduced in 1942, greatly enhanced all-around security in Wns and StPs. Each position required wire obstacles and, where possible, minefields and field fortifications.

The naval engineers determined where to deploy their heavy coastal batteries and the layout of their gun emplacements and associated supporting positions while the army engineers created the defensive scheme for protecting these batteries. In Hitler’s Atlantic Wall, Colin Partridge reveals that OB West issued Basic Order number 7 on 28 May 1942 establishing four categories of coast defences. The types of defensive positions from smallest to largest were:

1. Widerstandsnest (Wn) or Resistance Nest

2. Stützpunkt (StP) or Strongpoint

3. Stützpunktgruppe or Strongpoint Group

4. Küstenverteidigungsabschnitt and Verteidigungsbereich or Defence Area

The Widerstandsnest – often referred to on maps as ‘W’ or ‘Wn’ with a number designation – varied in size, but were the smallest defensive positions. The smallest Wn was manned by a squad-sized unit of approximately ten men, while the largest required up to a platoon-sized unit of thirty to forty men. In 1944 a German squad consisted of nine men, and a platoon comprised three squads, but many squads were not at full strength.68 Squad weapons included the squad leader’s 9mm MP-40 machine pistol (submachine-gun), a 7.92mm MG-42 light machine-gun and K-98 Mauser 7.92mm bolt-action rifles. Some units still used the older MP-38 and MG 34. Other types of machine-gun and assault rifle were issued during the war, but most went to SS units, which never served in coast defence, and to other specialized Wehrmacht formations. Three squad members served the machine-gun. These included a gunner, his assistant and an ammunition carrier. The two gunners carried pistols and the ammunition carrier a rifle. The remaining men in the squad were riflemen, so a reduced squad was short of riflemen.69 The infantry platoon also included a three-man light 50mm mortar team. Some of the troops in a Wn came from the battalion’s machine-gun company, which included three heavy machine-gun platoons (two squads, with two heavy machine-guns each) and a heavy mortar platoon (three squads, with two heavy mortars each). The heavy mortar was an 81mm mortar with a three-man crew. However, by 1944 it was replaced with a 120mm mortar in many units and the 81mm mortars were assigned to the infantry platoons to replace their inadequate 50mm mortars.

Besides mortar ammunition, the German rifle platoons needed only 7.92mm ammunition for their rifles and machine-guns and 9mm rounds for the few sub machine-guns and pistols they used. The squads stationed in a Wn or StP often ended up with foreign weapons requiring other types of ammunition. Some of the platoons were equipped with older or captured weapons instead of the standard issue, which complicated the ammunition requirements.

According to Colin Partridge, the 1942 directive called for the Wn to be manned by one or two squads with anti-tank gun, machine-gun and mortar positions. Except for the machine-gun, these weapons were not of the type found in an average German infantry squad since many were foreign-made. Since the platoon only had one mortar, these squads had to receive additional weapons. In some cases the troops in the company’s weapons platoon had to be augmented.

The crew of the smallest type of Wn, which comprised only one or two bunkers and associated field fortifications, consisted of a squad-sized formation. Probably half of the men took up posts in the weapons bunker and the remainder manned the rest of the bunkers and/or field fortifications in the complex. The squad often had a second machine-gun. A resistance nest, consisting of several bunkers and field fortifications, required up to a platoon. This type of position could include an antitank gun or cannon. Except for the Tobruks – most of which were one-man open firing positions – weapons bunkers normally needed three to eight men. A typical Wn comprised a personnel shelter (often with an associated Tobruk), an artillery or infantry observation bunker, a bunker for an anti-tank gun and one or more Tobruks. These resistance nests served individually in an interval between stronger sectors or were associated with other Wns to create a defensive barrier along a section of coast.

The Stützpunkt (StP) or strongpoint consisted of several Wns. The 1942 directive ordered the StP to provide protection for artillery or flak positions. This entailed a higher command system and usually required a company-sized unit. Field fortifications surrounded the entire position and often consisted of a couple of personnel bunkers, three or more weapons bunkers and associated Tobruks. The StP were armed with anti-tank guns, light anti-aircraft guns and multiple machine-guns for defence. Often heavy coastal batteries were incorporated into a strongpoint.

The Stützpunktgruppe (StP Gr) or Strongpoint Group was a collection of several strongpoints and Widerstandsnests that often required from two companies to a reinforced battalion-sized force. Generally this type of position included a bunker for the battalion headquarters for command and communications, a medical bunker, flak positions and/or other supporting facilities. Many coastal batteries were surrounded by a strongpoint group or were part of it. The strongpoint group covered a vulnerable landing area or held a key position like a small port.

These three types of defensive position could be grouped into an even larger fortified position known as a Verteidigungsbereich (VB) or Defence Area. In Der Atlantikwall, Rudi Rolf points out that ‘fortress construction work’ was begun on the sectors encompassed by the ports of Calais, Boulogne, Le Havre, Cherbourg and the area around Cap Gris-Nez in 1941. In the spring of 1942 these locations were identified as a Festungsbereich (FB) or Fortress Area. In 1943 this term was dropped and replaced with Verteidigungsbereich. The formation of the Verteidigungsbereich led to the designation of Festung or Fortress for the former FBs that included several major ports with U-boat or S-boat bases. Not every major port was designated as a VB or Fortress, however; Ostend in Belgium, for instance, is a notable exception.

Thus in 1943 and 1944 sections of the coast of France, the Low Countries, Denmark and Norway were identified as

1. Festung or Fortress;

2. VB or Defence Area; or

3. Freie Küste (literally ‘Free Coast’) – the area not covered by a Festung or VB, but which may have included StP or StP Gr.

Norway, Denmark and the German Bight had no officially designated Festung, but a few historians claim that some VBs were really Fortresses. Denmark included four VB (Frederikshavn, Hansted, Aalborg and Esbjerg). In Mur de L’Atlantique en Norvège, J.B. Wahl lists at least eighteen Festung in Norway, but none is comparable to those in France and the Netherlands.70 The Netherlands included one VB (Den Helder) and two Festung (Ijmuiden and Hoek van Holland). The mouth of the Schelde, including Walchern Island, was included in a KVA (see below). The remainder of the Dutch coast consisted of sections defended by StPs and sometimes StP Groups. A port that was not a Fortress or VB was usually protected by a StP Group.

In France and Belgium OB West divided the entire coastline into Küstenverteidigungsabschnitt (KVA) or Coastal Defence Sectors, which might include any of the above types of sections in the sector and facilitated command and control problems. Initially, in 1941 the FBs were created mainly around ports. Most of the construction involved naval positions. The FBs were still under the command of a naval officer in 1942. The designation changed to VB in 1943 when most of the Regelbauten construction was for army positions. Prior to this, the army had relied mainly on field fortifications built by the regimental troops of a division. Usually, a VB included one of a division’s regiments and its colonel was the designated commander of the VB. The FBs that had been designated as Festung created a special command problem because the Kriegsmarine had divided the coastline into sections commanded by Seekommandant (Seeko). This naval commander, usually an admiral or captain, was in command of all naval land forces, including the naval coastal batteries. The harbour commanders were subordinate to him. The Seekommandant’s port commanders, usually naval captains, often outranked the army Fortress commanders, the latter often having the rank of colonel. Most Fortress commands included naval units and naval ground units, and the special detachments assigned to the fortress by the army and the Luftwaffe. In some cases an army division was assigned to a fortress, putting its general in command. This often happened shortly before and after the Allied invasion of Normandy. A KVA was supposed to be defended by any army division that included troops to hold the various fortifications, augmented by troops from the higher Corps and Army commands. The artillery batteries, which did not belong to an army division, and the coastal artillery units came under Corps command. Hitler decreed that after the enemy landed on the beaches, the naval coastal batteries came under army command.

OB West created twenty-one KVAs in France and three in the Low Countries. Letter designations from A through to J (the letter I was not used) were used in the Fifteenth Army command that included all of Normandy in 1942. The Seventh Army command (Brittany to the Spanish border) began its designations with A at St Malo in Brittany and ended them with F on the Spanish border. In May 1942, after reorganization, First Army took over a section of the Atlantic coast, including the corps of the Seventh Army stationed in KVA D through to KVA F. Seventh Army retained command in Brittany and took over Lower Normandy (Fifteenth Army’s KVA H through to KVA J), including a corps from Fifteenth Army assigned to that region. Some KVA were subdivided when a second or even third division took over part of its coastal defence after 1942. The Fifteenth Army’s KVA A in Belgium was divided into KVA A3 and A2. KVA A1 in the Netherlands included the mouth of the Schelde. Thus, there was one division in each of the three parts of KVA A. KVA D and E in Fifteenth Army command, KVA J and C in Seventh Army command, and KVA E in First Army area were divided into 1 and 2 each. These were not subdivisions but new KVAs. This was done to avoid having to re-letter the entire system.