Atlantic wall - A remarkable feat of engineering

Inspired by Berns thread earlier, I thought I'd type up a few points about the Atlantic wall from a book I've been reading: D-Day. Dawn of heroes by Nigel Cawthorne.

The Atlantic wall was the name given to the line of coastal fortifications built by the Germans that stretched from the tip of Norway to Spain. The idea was to make any seaborne operation of mainland Europe impossible.

The origins of the wall began with Operation Sealion to assist in the control of channel approaches. Hitler ordered the Navy to install batteries of long range guns in the Pas De Calais that were capable of bombarding the English coast in the area of the proposed landing sites. By the end of August 1940, the Navy had 30 batteries in place and the Army had 42.

However, due to the failure of Operation Sealion, any further plans were shelved until 29th September 1942 when Hitler called for a conference to discuss defences in the west. Plans were called for 15,000 strong points to be manned by 300,000 troops along a stretch of concrete wall running from the Arctic circle to the Pyranees. The plans were agreed on the 14th December 1942 and construction began 4 days later.

Originally, under Fuhrer directive number 40, the German Army, Navy and Air force were ordered to collaborate in the building but after the raid on St Nazaire in March 1942, construction became a matter of urgency so the Todt organization was also brought in. As a result, there were seven hundred different standard designs that went into the construction of the wall.

At the peak of construction in May 1943, Half a million men were using 769,000 cubic meters of concrete each month with 13,134,500 cubic meters in total. Although the original fortifications were built by the Navy and the field defences were built by the armys construction battalion, after the Todt organisation was brought in, most of the building was done by slaves whose welfare was not of much concern to anyone.

Where possible, fortifications were embedded in rock, otherwise massive concrete foundations were constructed. At first, high quality concrete was brought in from Germany, but when Allied bombing began causing transportation problems, ordinary Portland cement was used, along with local sand and aggregates. Although all fortification work was supposed to comply with the German standard DIN 1164 - and pamphlets explaining this were printed up in numerous languages - using local materials left the construction wide open to sabotage. Forced labourers put too much sand in the mix, or even sugar, leaving the concrete much weaker than specification.

The planners soon realised that it was not possible to defend every sections of the coast equally, so the idea of strategic coastal defences were proposed. There were to be four types of coastal defences built.

The smallest was the Resistance nest designed to defend against local attacks of armour and infantry. Manned by one or two squads, it was laid out around at least on anti-tank gun. These were flanked by machine gun nests and mortars which were sited slightly forward, usually on the forward side of a dune, to give a wide field of fire. Zigzagged communication trenches would run to the rear of the sand dunes and there would be air-raid shelters within the trench system. Rifle trenches would be dug along the crest of dunes to cover all approaches and dead ground, and the whole area would be surrounded by entaglements of barbed wire and fields of anti-personnel and anti-tank mines.

The Strongpoint was the most common type of defence. These had a group of smaller positions in a diffuse grouping around a core of heavier weapons, such as artillary or anti-aircraft guns. Batteries would be mounted under concrete casemates. But where the emplacements were in the open, they would be surrounded by bunkers housing the command posts, supply depots and crew's quarters. The heavy weapons would be ringed by machine guns, anti-tank guns and light anti-aircraft guns, spread out to make them less vulnerable to air attack, but still contained within a defensible perimeter. A strong point would be manned by at least platoon, often backed by a local reserve.

Larger groupings, defending the principle ports and estuaries, were known as Defence sectors. These had local reserves for immediate support and could call up the main mobile reserve. There were fifteen of these between Holland and the Spanish border.

Between each of these defences were Intermediate positions which were manned by small detachments. There were not intended to be defensive positions, rather outposts used to maintain continuous surveillance of the coasts. Then in the last months before the invasion Hitler added huge fortresses at the defence sectors where he thought the Allies were more likely to strike.

By the time of the invasion, 12,247 of the planned 15,000 fortifications had been completed along with 943 on the Mediterranean coast.
Half a million beach obstacles had been deployed along with six and a half million mines.


Cheers,
marcus

 

He who defends everything defends nothing.

Frederick II

 

I am guilty of saying this before, but having shares in the European concrete companies must have been a good little earner.

I just wonder what was the total tonnage of concrete poured during the war years!

Regards
Tom

 

I feel sorry for the slave labour that had to build it, i wonder if they sabotaged the materials as they built it?.

 

Apparantly so Bern. I know I would

as above
using local materials left the construction wide open to sabotage. Forced labourers put too much sand in the mix, or even sugar, leaving the concrete much weaker than specification.

 

Hitler declared that "I am the Greatest Fortress" builder of all time"..... (not).

 

Apparantly so Bern. I know I would

as above

That will teach me to skip through it!

 

Hitler declared that "I am the Greatest Fortress" builder of all time"..... (not).

Agreed.

Other than the 26 km of actual landing areas in Normandy, the remainder was little more than a monument to futility.

 

Atlantic wall, Maginot line, Siegfried line - all A remarkable feat of engineering
And a complete waste of time and effort.

By the way there’s nothing low quality or inferior regarding the British invented ‘ordinary Portland’ cement.

And the German specification of cement was invented and developed by William Aspdin of Northfleet, Kent.
He latter moved there to Germany to show them how to do it back in 1853.

Of course the cement/concrete produced in other parts of the world may not have been so good a German stuff because they did not read the manual and follow the instructions.

Singe (I. Eng Civils, MCIHT)

 

I feel sorry for the slave labour that had to build it, i wonder if they sabotaged the materials as they built it?.

A museum in the northwestern part of Jutland, Denmark, where the atlantic wall is located in Denmark actually describes how the locals who were forced to help build the bunkers indeed mixed too much sand in the concrete to make it more unstable. That is when they had the chance, and they weren't being watched by the wehrmacht.

However everytime I go to explore the atlantic wall in this country it always strikes me just how solid these structures are after all these years though. It does take some solid ingenurity to make these emplacements standing after almost 70 years. Especially with the costal erosion rates around the west coast.

 

George Forty's 'Fortress Europe - Hitler's Atlantic Wall' - well worth a shufti.
Lots of good stuff on construction, occupation, and breaching of the wall. Well illustrated with plans & photographs, and scattered with Forty's usual anecdotal notes from people who were there at different times.
It's one of my favourite WW2 books in the 'slightly unusual technical' category, and sits well with Neil Short's 'Tank Turret Fortifications' as a rough guide to the European fortifications and their construction.

Adam, thanks for the heads up. Just ordered Forty's book