German Shelters, Dugouts and Bunkers in the Ypres Salient
The number of concrete bunkers built by the Germans in the Salient was staggering. Their intense building programme from late 1916 to mid-1917 saw 1,773 in the northern area, 500 in the central area, 118 in the southern area, and 385 in what was known as the Wytschaete Salient. In the area between the Ypres-Roulers Railway and Bixschoete there were 757 concrete bunkers in the first two front lines, and a further 245 in the third line. There were 633 bunkers in the Albrecht Stellung and 123 in the Wilhelm Stellung. When we add in those located in the Flandern I and II Stellung, we are looking at a figure of 9,000 bunkers.
Bunker types
Many bunkers were built to combine various functions and that function changed as the military situation developed. German bunker types included:
Troop shelters built to provide secure shelter during artillery bombardments. The accommodation bunker at St Julian is a good example of this type. It was built in 1916 for troops holding the Albrecht Stellung and it had four rooms that accommodated up to one hundred men.
The interior rooms were lined with sheets of corrugated iron (elephant tin)
The bunker was known to the British at Hackney Villa and was used as a troop shelter by the British after it was captured in August 1917. It took a direct hit from German artillery in the same month and flares being stored in a room ignited causing a fire and evacuation of the bunker. The bunker we see today is half the size of the original with much of it removed post WWII.
Reinforced machine gun emplacements, these were built in significant numbers in the Flandern I and II Stellung. An example stands behind the 34th Division Memorial at Langemarck. This bunker formed part of the Wilhelm Stellung and was built using poured concrete on a wattle-work framework. The uneven surface is a result of this.
The exposed iron work visible on the corner is old railway line and this use was never conceived in any construction manuals. This bunker was not built to any design style and was built in some haste, and this is evident from its uneven construction and the different layers of concrete. The bunker was captured by the 29th Division in October 1917. It was used as an HQ bunker by elements of the 34th Divisional artillery and engineers. There is absolutely no truth to the story that the brother of TE Lawrence, Robert, commanded an advance dressing station here in September 1918. There were no British troops in this area at that time.
Two other bunkers of the original Flandern I Stellung are at Tyne Cot Cemetery. These belonged to a concentrated line of similar bunkers in this area. The Germans built a second line of bunkers behind; one is located under the Cross of Sacrifice, and two others are buried beneath the pavilions at both ends of the Memorials to the Missing at the back of the cemetery.
The 34th Battalion, Australian Imperial Force, had reached this point before being stopped and it was 23-year Captain Clarence Smith Jefferies who led the attack on the bunker that now forms the base of the Cross of Sacrifice, capturing four machine guns and thirty-five prisoners. The bunker at the base of the Cross of Sacrifice was used as an Advanced Dressing Station after its capture.
With ten other ranks, he then attacked the bunker in the south-east corner of the cemetery where he was killed and is now buried. He was awarded a posthumous Victoria Cross and his grave is next to the bunker at grave XL.E.1. Sergeant Lewis McGee, 40th Battalion (Tasmania),10th Australian Brigade, 3rd Australian Division, was involved in the attack on the bunkers in the south-east corner and he won a VC in this action. He was killed on 12 October 1917 and is also buried in the cemetery at grave XX.D.1.
Medical bunkers, a considerable number were built in the Salient between 1916 to 1917 and they usually had three or four chambers. Cryer Farm is a good example of this type of bunker
Storage bunkers for the safe storage of ammunition and other stores. A good example can be found on Nonnebossenstraat.
Artillery bunkers these became obsolete with the development of flash spotting and sound ranging. There is an example of one which was part of the Oostaverne Line and is on Gapaardstraat. It shows evidence of having received multiple strikes from British shells. This bunker caused the 45th Battalion Australian Infantry so much trouble during the second stage of the attack on the Oosttaverne Line. In attacking this Captain Young and other Australians were killed. After it's capture the immediate area was named 'The Better 'Ole'.
This bunker, built inside the original farmhouse that stood here and incorporated the brick walls, is located on Delporte Farm and was a control post for the battery which held up the Australian and prevented them from moving down the Blauwepoortbeek valley. the Germans abandoned it when they retired from the Oosttaverne Line.
Anti-tank bunker, these were built near important roads or railroads and normally housed a Russian Putilov 76.2mm gun, many of which had been captured on the Russian front. A good example of this type of bunker is Cheddar Villa with the firing slit covering Buffs Road.
This bunker was being used as an aid post by the 1/4 Battalion Oxfordshire and Buckinghamshire Light Infantry. During the night of the 7/8 August 1917 a German shell landed inside the door, it was facing the German lines, and exploded killing or wounding the occupants.
Minenwerfer bunkers were built below ground for concealment and housed the crew and the ammunition
Observation bunkers were built to observe the British lines and as the Germans usually held the high ground, they constructed their bunkers close to the ground and these still had good observation
Command posts were not that different from troop shelters and had one chamber were the company commander lived. Others had more than one chamber and had rooms for communications, commander’s aide, and large window openings to let in natural light for the meeting and planning rooms. A good example of this type of bunker can be found at Zandvoorde which was built in 1916 by the Armierungstruppen and has six rooms. This bunker was used in 1917 and was the battle HQ for the Zandvoorde Division.
The builders of the bunker also left their mark by creating a plaque which is on the outside near the southern entrance it reads Erbaut 3. Komp. Arm. Btl. 27 1916
Another example of a command bunker is located in what was Cambrai Reserve Trench line.
Also Scott Post in Polygon Wood. Post war, Post war, this bunker was filled with ammunition collected within the wood which was then detonated in an attempt to destroy the bunker. Only the back wall buckled.
Communication bunkers housed telephone, telegraph light signalling, pigeons, and messenger dogs. A light signal post had large openings in the wall facing the German rear area. The Ziegler bunker near Boesinghe is the best example of this type of bunker.
Cookhouse bunkers, as the name suggests, were built to provide facilities to cook the food for the troops.
The Germans built concrete shelters to protect the entrances and shafts to their underground mining systems. An example of this type is the Dietrich counter mine located in the Bois de Wytschaete (name of the wood from British trench maps)
From the autumn of 1917 the Germans decided to standardise their bunker type, and these could be used for any function including all the above. The Einheitsunterstand (unit shelter) bunker consisted of two chambers, two entrances at the rear and on either side were stairs that allowed the bunker to be used as a parapet. The roof sloped to the front and had an opening for a trench periscope for observation. As with the command bunkers, they had an opening at the rear for communication and electrical cables. They could accommodate twenty men or more including command personnel.
Early type of Shelters
The early German shelters were mainly constructed of a roof made of tree trunks or wooden beams and with a layer of roofing felt placed on top. Like the British, they also added a buster layer or used concrete and again like the British shelters, they were prone to flooding. The walls of these shelters were made of logs to support the weight of the roof and it was not uncommon for a near miss to bring the structure crashing down on the men sheltering inside. The Germans also used corrugated iron in their shelter construction however, it took German industry time to produce enough to keep up with the demand of the military this, despite the use of this material being described in the German military manual of 1893.
From 1915, the Germans began to use armoured concrete blocks to build shelters. There is a good example of these shelters in the preserved Bayernwald (Bavarian Wood) or Bois Quarante on British trench maps near Wytschaete.
There are four shelters in the trench system that were built using trench blocks. The space within each is limited to maintain the strength of the shelter.
Concrete Blocks in construction
The Germans began using ferro concrete in 1915 to build blockhouses and machine gun posts in the Ypres sector. From autumn 1915 there was a growing controversy in Britain over how the Germans were acquiring their cement and aggregate. This led to a diplomatic fall out with the Netherlands, as the Germans were acquiring their supplies from there and shipping it via the canal network to Germany. During 1916 the German consumption increased six-fold and this further increased tension between the British and the Dutch governments.
Ferro concrete was used in the construction to ensure that the shelters were blast proof. These ferro concrete blocks could be used in stretcher bonds using cement and iron rods through the holes which held the bricks together. Examples of this type of shelter were found during archaeological digs at Fortin 17, now the industrial site at Boesinghe, in the early 1990s. One can be viewed on the golf course now in the grounds of the old White Chateau at St Eloi/Hollebeke.
The Germans manufactured the blocks on an industrial scale at sites in Wervick, Roeselare, and Koeklare and were assisted in this by Belgian workers under the watchful eye of German military engineers. The finished blocks were transported to the front line via a narrow-gauge railway network.
By the autumn of 1917 the Germans had ceased to use concrete blocks in their bunker construction as it was found that they were not as strong as first thought. The British also discovered this as most of the damaged and destroyed bunkers they found were those built with concrete blocks.
Another, post war, use of the blocks was in the construction of farmyard walls, hardcore in roads or incorporated into driveways. The metal rods were sold as scrap.
Poured concrete in construction
The early use of concrete also had its limitations, although it was in widespread use to build fortifications. Initially, the front-line units lacked the knowledge of how to use reinforced concrete.
Poured concrete was made using a concrete mixer with a layer poured into the framework and a further layer poured on when the first layer had dried. It took several weeks for the concrete to harden. The construction of these types of bunkers were mostly built in the second defence areas and back to the rear areas. The building process was a phased process that involved the use of several specialised teams.
A team would excavate the site, this involved the use of civilian or prisoner of war labour under German supervision. The Germans employed many Russian POWs in the construction work. As this was going on another team was creating a mesh framework using iron rods. On the completion of the foundations a team began pouring the concrete to create the floor and as this was going on an iron work squad began connecting the iron rods to the mesh where the walls were to be built. Wood workers then arrived to begin building the framework for the concrete to be poured into. This wooden framework was normally left in place as it provided insulation and usually had a layer of roofing felt attached to keep moisture out of the room. It also allowed a nail or screw to be driven into the wood to support telephone or electricity cables or for shelves or cabinets to be fixed to the wall for the storage of personal possessions or materials. The wooden framework also acted as protection against pieces of concrete that came off when the bunker was struck by a shell. As wood became scarce the Germans turned to elephant iron to make rooms within their concrete bunkers. For the roof construction, I-beams and boards were put into position and the first layer of concrete had to be dry before the other layers were added. The site was then back filled with earth and earth added to the roof, to hide it from enemy observation, with the bunker further reinforced with layers on the side facing the enemy. Early bunker constructions were also reinforced with an extra layer of concrete blocks.
Reuse of captured bunkers by the Allies
The Allies made use of captured German bunkers however, as the entrance was on the wrong side, facing the German lines, they created a new entrance on their side and reinforced the old entrance with a layer of ferro-concrete. The Ziegler bunker is a good example of a reversed bunker.
In his memoir ‘Another World 1897 – 1917’ Anthony Eden wrote about a captured German bunker his battalion headquarters occupied, just after the Battle of Messines, in June 1917: ‘It was so well sited and stoutly built that the several days of bombardment before the Messines attack had not effectively damaged it. The interior was divided into a larger area, about three-quarters of the length, where the faithful signallers and orderlies were established, and a smaller cell beyond for the C.O., myself and our immediate staff. As the enemy know the exact location of this pill-box and shelled it constantly, we understood only too well how vulnerable that narrow corridor was to any chance or well-aimed shell.’
His words were rather prophetic. His battalion was in the middle of a relief by another battalion: ‘One by one the messages came in from the companies that relief was complete and, with the last message, Jarvis and I were on our feet to leave when there was a resounding explosion which shook and swayed the pill-box and blew out all lights.’ A German 5.9 shell had come through the gap in the corridor and burst in the doorway of the larger room when it was crowded by the various battalion personnel in the midst of the relief. He wrote: ‘I cannot remember how long it took us to disentangle the dead from the dying, or how many hours we spent getting the wounded away to our first-aid post. Gradually the runners and signallers who had been out on duty came back and helped, but our eventual return to our support line was carried out in a daze.’
Location of the Bunker and the Drainage
The location of the bunker within the landscape was important. The bunker was built on the slope of a hill, never on the crest, as this made it difficult to spot from ground level and the bunker was not as visible against the background. This was the same principle used in trench construction, in that the parados was made higher than the parapet in order that the soldier looking over the parapet was not visible against the background. The height of a bunker above ground was like that of a parapet and most of the fortifications stood about a metre above ground which was similar in height to the breastworks of trenches.
Drainage was also important. A dry construction site was important for building a strong concrete bunker. To help them identify suitable sites for their bunkers the Germans, from late 1916, employed geologists to help them find the ideal locations for their bunkers. They were first employed during the building of the Flandern Stellung. They investigated every bunker building pit and through soil surveys gave advice on whether to pit could be deepened without hitting the ground water beneath and if so, advised on moving the site or digging drainage ditches. Most of the bunker floors were not much more that one metre below the surface which was the same depth as the trench floor which allowed the trench drainage system to help remove the excess water from the bunker. This was achieved by adding a gutter to the bunker which was connected to the trench drainage or if no trench was nearby then to a lower waterway nearby.
A good example of the drainage system can be found in the command bunker at Zandvoorde. This has a roof that protrudes from the back, and this prevents rainwater from running down the back of the wall with the water gathered in a gutter in a concrete gulley running behind the bunker and diverted away.
Another method used for keeping the bunker dry was to use a sump at the lowest point in the bunker and the water was drained via a pipe.
Shelter construction from 1918
With the increasing weight of artillery fire from 1917 onwards, which was destroying many of the existing shelters, and this artillery fire was adding to the difficulties in constructing new shelters by making it difficult in getting construction material to the front line, the Germans rethought their system. They began to develop new types of shelters that were easy to build and could be hidden in the moonscape battlefield. They took the form of hiding them within a shell hole and were constructed of corrugated iron, the elephant iron as described in the British system, metal plates, timber, duckboard, and branches. These shelters could accommodate three men lying down and took four to six hours to build.
The Germans had intended, after the Third Battle of Ypres had drawn to a close at the end of November 1917, to build new defensive positions of trench lines and bunkers in the Salient. However, after their Spring offensive and the Battle of the Lys, which brought them to the very gates of Ypres, these defensive lines would have had to have been built from scratch and they did not progress with the plan. In the main they lacked the manpower due to their offensives and the onset of the Spanish flu pandemic. In addition, the Russian POW labour they relied on had been repatriated following the Russian withdrawal from the war and the Treaty of Brest-Litovsk of March 1918. They also lacked the construction material and the transport to move it, the transport infrastructure having been destroyed. With the Allied Final Offensive of September 1918, the German army in the Salient collapsed and by the Armistice in November 1918 the Allies were 50 miles beyond the Salient.