When the Luftwaffe failed to defeat the RAF in September 1940, Operation Seelöwe, the planned invasion of Britain, was postponed and eventually cancelled altogether. That left Britain isolated but still fighting. Hitler always intended to attack the Soviet Union and launched Operation Barbarossa in July 1941. Then, in a fit of bravado, he declared war on the USA following the Japanese attack on Pearl Harbor on 7 December 1941. Hitler had succeeded in ensuring that an invasion in the west could be launched from an undefeated Britain allied with a powerful America while still fighting the inexhaustible Soviets in the east. He needed a bulwark in the west so that he could focus on the Soviets
At Hitler’s instigation, plans were set in motion in early 1942 to construct an impregnable wall in the west. This was to extend from the Arctic Circle down the coast of Norway to Denmark, The Netherlands, Belgium and round France all the way to Spain, some 2,800 miles of coastline. There was no consensus among the Nazi hierarchy about where an invasion might fall. Hitler favoured the shortest route across the Channel, Kent to the Pas-de-Calais, but von Rundstedt and Rommel did not share his views and looked to areas of coastline more favourable to an amphibious assault, such as Normandy. Hitler insisted that the ports along the French coast be made into fortresses. Irrespective of where the Allies landed, he believed they would need at least one port with harbour facilities to allow an invasion to succeed.
These conflicting views and the absence of a strategic master plan for the Atlantikwall meant that its construction was piecemeal and some stretches of coastline were left virtually undefended. Rommel tried to rectify the situation from early 1944 with beach obstacles and anti-glider obstacles in fields but the Atlantikwall was incomplete by the time of D-Day, 6 June 1944. The ports were well defended on the landward sides by complexes of strongpoints with artillery, machine-guns, mines and barbed wire. Gun batteries were placed along the coast to engage ships. The strongest of these were casemated in thick ferroconcrete.
Steel-reinforced concrete is very resistant to shells and bombs. Fifteen-inch salvos fired by warships and 1000lb bombs dropped from aircraft all proved to be ineffective against reinforced concrete even under direct hits. However, the occupants of the bunkers suffered greatly under the concussion of the ordnance. On D-Day, the preparatory bombardment from the warships effectively suppressed the ability of many German defenders to fight back except on Omaha beach but here the defenders ran out of ammunition and were eventually overrun by determined assaults.
At Hitler’s instigation, plans were set in motion in early 1942 to construct an impregnable wall in the west. This was to extend from the Arctic Circle down the coast of Norway to Denmark, The Netherlands, Belgium and round France all the way to Spain, some 2,800 miles of coastline. There was no consensus among the Nazi hierarchy about where an invasion might fall. Hitler favoured the shortest route across the Channel, Kent to the Pas-de-Calais, but von Rundstedt and Rommel did not share his views and looked to areas of coastline more favourable to an amphibious assault, such as Normandy. Hitler insisted that the ports along the French coast be made into fortresses. Irrespective of where the Allies landed, he believed they would need at least one port with harbour facilities to allow an invasion to succeed.
These conflicting views and the absence of a strategic master plan for the Atlantikwall meant that its construction was piecemeal and some stretches of coastline were left virtually undefended. Rommel tried to rectify the situation from early 1944 with beach obstacles and anti-glider obstacles in fields but the Atlantikwall was incomplete by the time of D-Day, 6 June 1944. The ports were well defended on the landward sides by complexes of strongpoints with artillery, machine-guns, mines and barbed wire. Gun batteries were placed along the coast to engage ships. The strongest of these were casemated in thick ferroconcrete.
Steel-reinforced concrete is very resistant to shells and bombs. Fifteen-inch salvos fired by warships and 1000lb bombs dropped from aircraft all proved to be ineffective against reinforced concrete even under direct hits. However, the occupants of the bunkers suffered greatly under the concussion of the ordnance. On D-Day, the preparatory bombardment from the warships effectively suppressed the ability of many German defenders to fight back except on Omaha beach but here the defenders ran out of ammunition and were eventually overrun by determined assaults.
Building the Atlantic Wall. Note the concrete in the chute in the foreground and the steel reinforcement in the background
The problem for the majority of Germans manning the strongpoints and batteries in Normandy was their utter isolation on D-Day. They were cut off from reinforcement and resupply by the bombardment from the ships and aircraft so could only hold out as long as their ammunition lasted. This was sometimes expended in less than a day. The fortified ports were well supplied and capable of holding out for months. Boulogne put up a fierce resistance and did not surrender until late September 1944 (the time of Operation Market Garden in The Netherlands). Dunkirk did not surrender until the end of the war in May 1945, nor did Lorient, Saint Nazaire and La Rochelle along the Atlantic coast.
The Americans took Saint Malo and Brest by direct assault and paid dearly. They discovered that infantrymen had to sneak up on each bunker to squirt flamethrowers, push pole charges, toss hand grenades and fire rifle grenades through embrasures. Typically, a bunker with a steel machine-gun turret took eight infantrymen armed with two flamethrowers, a bazooka and two Browning Automatic Rifles to subdue it. Tanks, tank destroyers and artillery had to fire rounds into embrasures at point blank range to knock out bunkers. In the Gironde, Thunderbolts bombed the bunkers, fired rockets at them and smothered them in napalm.
The Americans took Saint Malo and Brest by direct assault and paid dearly. They discovered that infantrymen had to sneak up on each bunker to squirt flamethrowers, push pole charges, toss hand grenades and fire rifle grenades through embrasures. Typically, a bunker with a steel machine-gun turret took eight infantrymen armed with two flamethrowers, a bazooka and two Browning Automatic Rifles to subdue it. Tanks, tank destroyers and artillery had to fire rounds into embrasures at point blank range to knock out bunkers. In the Gironde, Thunderbolts bombed the bunkers, fired rockets at them and smothered them in napalm.
An American M18 Hellcat tank destroyer during the fighting in Brest
Fortifications at Saint Malo after the fighting was over. Note the American flag on the bunker on the right
Sometimes, it took the courage of one man to knock out a bunker. At Cherbourg, Corporal John Kelly of the US 314th Infantry Regiment used a 15lb charge on a 10ft pole to try to knock out a bunker in a strongpoint that had been repeatedly shelled and bombed. He attacked the bunker three times with three pole charges and ended up throwing grenades through the embrasure. He won the Congressional Medal of Honor. When K Company of the same regiment was held up by an 88mm and machine-guns, Lieutenant Carlos Ogden took an M1 fitted with grenade launcher and approached the bunkers under heavy fire. Although wounded, he reached the 88 and destroyed it with a rifle grenade. He was wounded again but destroyed two machine-guns with hand grenades. He, too, won the Congressional Medal of Honour.
Attempts to disable the casemated guns at Fort Roule at Cherbourg proved frustrating. The Fort was a tough nut to crack because it could only be approached along a ridge well covered by defensive fire. It was shelled by warships and by artillery as well as bombed and strafed by P-47s of the US Ninth Air Force. The 314th Infantry Regiment eventually captured it on 25 June. They lowered charges down ventilation shafts and on ropes over the side of the cliff on which they had been built, detonating the charges via a trigger. Anti-tank guns fired into the embrasures and a demolition team attacked down the tunnels inside the cliffs armed with bazookas and pole charges. It took a day to capture the casemates. They can still be reached through the tunnels. One of the buildings in the fort has been turned into the Musée de Guerre et de la Libération.
Attempts to disable the casemated guns at Fort Roule at Cherbourg proved frustrating. The Fort was a tough nut to crack because it could only be approached along a ridge well covered by defensive fire. It was shelled by warships and by artillery as well as bombed and strafed by P-47s of the US Ninth Air Force. The 314th Infantry Regiment eventually captured it on 25 June. They lowered charges down ventilation shafts and on ropes over the side of the cliff on which they had been built, detonating the charges via a trigger. Anti-tank guns fired into the embrasures and a demolition team attacked down the tunnels inside the cliffs armed with bazookas and pole charges. It took a day to capture the casemates. They can still be reached through the tunnels. One of the buildings in the fort has been turned into the Musée de Guerre et de la Libération.
Gun casemate at Cherbourg after the fighting. Note the battle damage
The British had foreseen difficulties when it came to dealing with bunkers and had come ashore on D-Day with a range of specialised equipment, known as Hobart’s Funnies (after Major-General Percy Hobart commander of the British 79th Armoured Division). These included the AVRE (Armoured Vehicle Royal Engineers) and the Crocodile, both based on the Churchill tank. An AVRE could be fitted with a range of devices including a petard mortar that fired a bunker-busting 18kg bomb 140 metres, while the Crocodile was a flamethrower tank with a range of 110 metres. These were very effective against bunkers, trenches and gun emplacements.
Because ferroconcrete is so resistant to explosives, the fortifications of the Atlantikwall proved to be very difficult to destroy in combat and, indeed, after the war. Some structures still exist more or less intact. Many of those in Normandy and around Brest, Saint Malo and Lorient bear the scars of war. Some of the big channel gun casemates still exist. Most prominent of all the survivors are the structures on the Normandy battlefield. The Atlantikwall did not prevent an invasion but it certainly made life very hard for many Allied troops.
Because ferroconcrete is so resistant to explosives, the fortifications of the Atlantikwall proved to be very difficult to destroy in combat and, indeed, after the war. Some structures still exist more or less intact. Many of those in Normandy and around Brest, Saint Malo and Lorient bear the scars of war. Some of the big channel gun casemates still exist. Most prominent of all the survivors are the structures on the Normandy battlefield. The Atlantikwall did not prevent an invasion but it certainly made life very hard for many Allied troops.
One of the casemates of a cross-Channel gun near Boulogne. Note the anti-rocket chains intended to detonate rockets fired by Typhoons before they could enter the opening