Fortress Europe- European Fortifications Of World War II

by J E Kaufmann

  The Allies rushed to the Dyle Line, believing the main German thrust was coming across the Albert Canal. Other forts of the PFL I were soon engaged. The Belgian forces in the Ardennes were ordered to withdraw quickly, abandoning the region to the main German spearhead.

  On May 10 the Germans engaged other positions of the PFL I, Fort AubinNeufchateau opened fire against them, but by the evening of that day the fort was surrounded. German heavy artillery pounded the fort on May 11 and their numerous infantry assaults were driven back. The Luftwaffe joined the heavy artillery in the bombardment and finally breached the fort's defenses by May 15. On May 20 another German infantry attack was beaten back with the help of Battice, but the fort was badly damaged. After another major assault on May 21, the fort surrendered having expended most of its ammunition.

  During the first days of the invasion the Germans brought up 355-mm and 305-mm weapons to bombard the PFL I. On May 13, 305-mm mortars fired almost 200 shells on Fort Battice, causing no significant damage. General Fedor von Bock, commander of Army Group B, unhappy with the waste of lives on both sides after the fierce battle for Aubin-Neufchateau, on May 20-21, demanded both Battice and Tancremont to surrender. Both forts had held out for about a week and a half with out hope of support or relief as the Belgian army withdrew from the Albert Canal Line. Battice surrendered on May 22, the day after Aubin-Neufchateau but Tancremont continued to hold out. Little more could have been expected from them, and although some of the tactical decisions might appear to be a repeat of 1914, these forts were better built and performed much better than their predecessors.

  The Germans simply bypassed Tancremont. It did not surrender until May 29, one day after the Belgian army was ordered to lay down its arms. For the other forts, those of the PFL II the story was different because the lines of communication through Liege had to be opened.

  The forts of the PFL II had been in action since the first day. Some tried to support Eben Emael. Belgian army units had withdrawn from Liege by May 12 leaving the forts isolated. General von Bock stated that two of the forts of Liege had fallen by May 14, but all the Meuse bridges were down. His main concern was to open the road and he preferred to avoid tangling with the forts if possible. To von Bock the whole PFL position represented a threat to his line of communications far behind the front lines. On May 15, dive bombers attacked Fort Flemalle, and damaged its 120-mm mortar turret and breached the counterscarp. The garrison surrendered the next day. On May 18 the same engineer battalion that spearheaded the relief force for the paratroopers on Eben Emael assaulted Fort Barchon. A Czech 420-mm howitzer bombarded the fort. The engineers breached Barchon and, with demolitions and flame throwers supported by 88-mm anti-aircraft guns, they eliminated most of the fort's turrets and machine gun positions. Barchon surrendered the same day as did the nearby forts of Pontisse and Fleron. Bock claimed the latter gave up without a fight, and on May 19 he visited Fort Pontisse where he found its heavy armored turrets overturned as a result of Stuka attacks. Only the air vent, disguised as a water tower, outside of Barchon continued to resist. Fort Evegnee succumbed the next day. The forts south of Liege remained, with Tancremont, isolated.

  The Belgians withdrew from the Albert Canal Line and frontier defenses as the Allies took up positions on the Dyle Line. The position was not strong and in the south the Germans found it easy to breach undefended sections of the Element C anti-tank obstacles. In other places the gates themselves offered the assault engineers protection from the defenders small arms fire.

  As the main German thrust through the Ardennes gained momentum and crossed the Meuse by May 14, German troops engaged the defenses of Namur. By May 16 Allied troops were disengaging from the Dyle Line and by May 18 the Belgian army was taking up positions on the Dender River as the PFN was left to its own devices. By May 22 most of the PFNs forts had fallen, and on that morning 88mm anti-aircraft guns supported the attack on Fort Maizeret. These weapons helped eliminate most of the fort's turrets and cloches. Assault troops crossed the moat and forced the garrison to surrender.

  The Belgian army fell back upon the Ghent Bridgehead on May 19. On May 17 the key fort of Lierre on the PFA was taken by a coup de main. Antwerp was abandoned by May 18. By May 26 the Ghent Bridgehead had fallen and the army was clinging to defenses along the Lys River. Surrender soon followed. Except for the PFL I and the Albert Canal, most of Belgiums defensive positions proved of no significant value. Building so many other defensive positions, failing to commit a reasonable force to defend southern Belgium, and insisting on a policy of strict neutrality until the last moment, assured the collapse of Belgium.

  Top Right: One of the largest canal casemates on the outer bank of Antwerp's AT ditch (which ran north from the Albert Canal to the Schelde). Many of the 22 restored forts and redoubts were on the ditch. These two-level casemates fired to the flanks and their sluices controlled the water level. (Kaufmann)

  Bottom Right: Ft. Eben Emael. Fortin 01. 60-mm AT gun, 3 MGs, and 3 searchlights. Observation cloche can be seen above. (Wes Micket)

  Above: Rolling Gate. Designed to be used locked together in line or singly as AT obstacles. They were also used in the Atlantic Wall. (Kaufmann Collection)

  Left: Ft. Barchon. Air intake. Ft. Barchon was one of the old restored forts of PFL-2 which received a new concrete air intake located beyond the fort's perimeter. The defensive weapons embrasures can be seen on the block which is designed to appear as a water tower. (Kaufmann)

  Cloche for Hvy MG. Note: Periscope position can be seen behind MG position.

  Plans of Battice, Eben Emael, Aubin-Neufchateau, Trancremont: B=Block, C=Coffre, BM=Mortar Block, BE=Entrance Block, J,O,P,W=Air Intakes (P&W also entrances)

  Chapter 4

  NETHERLANDS

  BACKGROUND

  On September 18, 1939, LTC Robert Brown, American Military Attache to Brussels, reported that in the event of war between the Germany and Britain, "Holland will be invaded." In addition, he stated, "It must not be excluded that the Great National Redoubt of the Netherlands will be attacked from the rear." The war was not a month old when even a foreign observer could see that the situation in the Netherlands was precarious.

  Born out of a religious revolution during the Reformation, the Netherlands had had an unusual history compared to most European nations. Their fortified cities, which relied upon their remarkable water defenses, had foiled the invading Spanish Army during the Eighty Years War that ended in 1648. The new nation became one of northern Europe's first republics and one of the leading sea powers of the seventeenth century. Thanks to windmill-powered pumps used in the construction and maintenance of polders, the country grew in size by reclaiming land from the sea. However, the low-lying land could quickly be returned to the sea to deter invaders. The last major European conflicts in which the Netherlands participated were the wars of the Napoleonic Era. The defeat of Napoleon and the restoration of the Netherlands' independence transformed this former republic into a monarchy, and left the former Austrian Netherlands, or Belgium, under its aegis. However, this territorial expansion lasted only until the Belgian Revolution of 1830, the last European campaign in which the Dutch Army would be involved until 1940.

  As Europe prepared for a new war in the aftermath of the Franco-Prussian War of 1870-71, the Netherlands made some effort to modernize their antiquated fortifications. Previously they had relied on individual positions that could be used for creating water barriers. However, with the exception of the Old Waterline, no actual continuous fortified line existed in the Netherlands before the mid-nineteenth century. The Old Waterline was a hastily improvised position set up in the 1670s to stop the invading French army with inundations. It ran west of Utrecht and was designed only to defend the province of Holland.

  In the nineteenth century the New Water Line, to the east of Utrecht, was created as the main line of defense. It ran from the Zuider Zee to the banks of the Maas and Rhine Rivers where a bridgehead was created. This line relied heavily on mass
ive inundations. Its heaviest fortifications had to be placed on the high ground near Utrecht that took more time to flood. The modernization of this position began between 1866 and 1871.

  Meanwhile, Prussia created the Second Reich, establishing a major power on a large part of the Dutch border. The Netherlands responded by erecting several new forts, one of the largest of which was Fort Rijnauwen, built between 1868 and 1879.

  In the 1880s, the Netherlands adopted the fortress rings already prevalent in France, Belgium, Germany, and Austria-Hungary. While the New Water Line became the main line of Fortress Holland, the key city of Amsterdam received a protective ring beginning in 1883 with the construction of Fort Abcoude. This ring eventually became the National Redoubt. Once more, inundations played a key role in the new defense by creating a barrier several kilometers wide. Numerous other forts, most of which sat on artificial high ground, filled out the line, occupying key points near roads and along canals among the numerous polders.

  While the new forts were built, many older forts were modernized. East of the fortified town of Gorkum, on the end of the New Water Line on the Waal (Rhine) River, the new fort of Vuren built in the 1840s was refurbished in the 1880s. South of the Waal, the old bridgehead with its medieval works continued in service, and its defenses were supplemented with sluices at Woudrichem and Bakkerskil. Fort Bakkerskil, built earlier in the century at the Papsluis (a key sluice in the area) was renovated in the 1880s. The bridgehead position from the old defenses was advanced to higher ground southeast of Woudrichem and was strengthened with the addition of Fort Giessen in 1880. This fort had large, earth covered, brick barracks and twelve guns that stood high on its walls. In addition to these and other forts, the Dutch also built small supporting gun battery positions.

  Near the north end of the New Water Line, the old fortress of Naarden was modernized in the 1880s and became part of the World War I era defenses. Not far from Naarden the second line of defense began at the fortress of Muiden, near the mouth of the Vecht River. During the middle of the nineteenth century, a coastal battery was set up at Muiden and later it received a bombproof tower, one of nine built in the forts of the New Water Line by 1860. By the 1870s these towers became virtually obsolete and had to be given earth cover to meet the demands of the ever changing war technology'. Muiden protected several of the most important sluices for flooding the northern part of the water line.

  The Dutch completed a total of 42 forts in the Amsterdam Position at the end of the nineteenth century. They adopted the Belgian method of using non-reinforced concrete in their construction. Each fort included two retracting 57-mm gun turrets and a casemate mounting two 110-mrn guns that covered each flank. Large caliber guns occupied separate battery positions behind the defensive line. At the end of the century sluices for flooding the land in front of the line were completed. It took half a day to fully inundate this area.

  Coast defenses included a number of forts, complete with moats. The French built Fort Prins Frederik and Fort Sabina Henrica near Willemstad during the Napoleonic Wars. The Dutch modernized them in 1860 and the 1880s, by adding eight 240-mm Krupp guns to Fort Sabina Henrica and five to Fort Frederik. Not far from these forts in 1883, Willemstad, on the Holland Deep, received two four-gun batteries of 240-mm coast defense guns and new shelters. The Willemstad Position, created in 1860, encompassed Fort Sabina Henrica and the small position of Fort Hell. In 1874 the Willemstad Position was modernized and enlarged to form the Holland Deep Position.

  New weapons rendered many of these fortifications obsolete after World War 1. However, the Netherlands remained firmly convinced that they could maintain their neutrality, secure behind their water defenses.

  MAJOR FORTIFICATIONS

  The Grebbe Line and Fortress Holland

  The Frontier Lines

  LOCATION

  1. The Grebbe Line and Fortress Holland

  The Grebbe Line and Fortress Holland constituted the core of the Dutch defensive system. The Grebbe Line, which kept Amsterdam beyond the range of modern artillery, passed through the highest part of the country where the elevation rose up to 30 meters, and the Grebbe Berg constituted the highest point of the Netherlands. The Grebbe Line relied on water barriers that passed through the area for its defense, and was in part protected by some woodland areas. As in the rest of the country, the land was mostly level and devoted to agriculture.

  Fortress Holland's New Water Line paralleled one of the country's major canals and stretched from the Zuider Zee to the Lek and Waal Rivers, both channels of the Rhine. The country behind the New Water Line was low and included much of the country's polder lands from the Holland Deep to Walden Sea. Over 20% of the region's level land was below sea level with only the road embankments and scattered trees rising above it.

  The New Water Line joined the South Front that stretched along the Waal River to the North Sea. Along the South Front much of the land had been reclaimed from the sea, and guns placed on top of the old forts had a commanding field of fire over the level terrain.

  The West Front, which covered the coastline up to the Den Helder Position, included large areas of sand dunes similar to parts of the Belgian coast. All the major Dutch ports were inside Fortress Holland: Amsterdam on the Zuider Zee and Rotterdam on the Lek River. Den Helder, Ijmuiden, and Hoek van Holland on the coast included some facilities for naval vessels. They occupied part of the same coast line from which the Spanish Armada had been unable to pick up troops in 1588, because lighters were needed in the shallows.

  The Den Helder Position, which defended the northern sectors, was sometimes considered part of Fortress Holland. On the other hand, the fortress ring of Amsterdam, occupying many positions in the polder lands, formed part of the Northern Front.

  Finally, the country's only new heavy fortifications stood at two points on the Great Dike, barring the entrance to Fortress Holland from that quarter.

  2. The Frontier Lines

  Border defenses were established in places where natural obstacles existed already, otherwise they turned inward to find such features. The F and Q Lines covered the open northern quarter of the country and used the few watercourses present. The Ijssel Line followed the river of the same name which flowed up to 40 km behind the border at most points. It connected to the Maas Line which ran along the Maas River, south to the Belgian border. Sometimes these two lines are referred to as the Maas-Ijssel Line or Ijssel-Maas Line. Fort Pannerden was located near the point where the lines joined. Further south of the Maas Line, the city of Maastricht, with its defenses, incorporated the Juliana Canal to form a major obstacle.

  The Peel-Raam Line, a few kilometers behind the Maas Line, paralleled a major canal and passed through the Peel Marshes. The land in this region was also relatively level and unobstructed, the marshland constituting one of its few natural barriers.

  Finally, the isolated positions of Bath and Zendijk on the neck of South Beveland were separated by polders that could turn the peninsula back into an island if nec- essary.z South Beveland was more important in helping the Belgians than the Dutch because it covered the mouth of the Schelde River, which led to Antwerp.

  HISTORY

  The Dutch, feeling secure in their neutrality for a few years after the Great War, did not plan new fortifications or work on them until the 1930s. The only exception was the northern part of Fortress Holland where the Great Dike (Afsluitdijk) was being built. The States-General approved the damming and draining of large sections of the Zuider Zee in 1918, planning to drain the Northeastern Section by 1941. The dike, which sealed the Zuider Zee in 1932, was wide enough to carry a roadway and offer a new approach into Fortress Holland. Thus the country's two newest forts went up on either end of the dike early in the 1930s.

  The New Water Line, which formed the old East Front of Fortress Holland, was too close to the major population centers of the country to adequately defend the area from long range artillery. Thus it was time to create a new defensive position, the Grebbe Line, 2
5 km in front of the New Water Line. The original Grebbe Line, which had been used since the eighteenth century, consisted of a series of canals and dams that could inundate the area, and of earthen redoubts that defended the key positions. It was abandoned as a major defensive line after the Napoleonic Era. In 1935 the army commander became interested in extending the East Front defenses forward to the old Grebbe Line. When war became imminent in 1939, General Willem Roell, commander-in-chief, called for its activation, turning it into the main position by early 1940. Construction on most of the line's defensive works, including an anti-tank ditch, began in 1939. By the spring of 1940, the inundation mechanisms were completed.

  Between 1929 and 1938, Fortress Holland received thirty new heavy bunkers, and the Maas and Ijssel river lines forty after 1936. The largest of these bunkers, known as river casemates, had two to four levels and mounted an anti-tank gun and machine guns. However, no more than two stories rose above ground level facing the enemy. At first thirty large bunkers were built, but after 1938, smaller, more economical three-man bunkers, over 2,000 of which were built throughout the Netherlands, became more common.

  The New Water Line of the East Front got the most attention prior to 1936 where some of the heaviest fortifications were built at Fort Kijkuit in 1935. The South Front, based on the great river barriers, required few improvements. It received anti-tank and machine gun bunkers between 1936 and 1937 to protect the bridgehead at Moerdijk.

  The main part of the North Front, which consisted of the Amsterdam Ring or Amsterdam Position, did not receive significant improvements since most work was done near the Great Dike.