Fortress Europe- European Fortifications Of World War II

by J E Kaufmann

  LOCATION

  The Germans gave these fortifications the name of Benes Line, but the Czechs referred to them as their own Maginot Line. Since heavy fortifications covered only a small stretch of this position, in the present work the term "Benes Line" will refer to the whole defensive system of Czechoslovakia, while the term "Czech Maginot Line" will refer to the defenses between Ostrava and Nachod.' To the west of Nachod lighter defensive works ran along the border, formed a semicircle around Pilzen, and continued eastward along the border to Bratislava.

  The mountains running east from the Elbe River near Dresden, Germany, to Ostrava, commonly known as the Sudeten Mountains, consist of various ranges that include, from west to east, the Luzicke Hory, Jizerkske Hory, Krkonose, Orlicke Hory, and Nizky Jesenik. The heaviest Czech fortifications were built on both sides of the Orlicke Hory that extend from the vicinity of Nachod to Kraliky. Some of the major positions were built from west of Nachod to the vicinity of Trutnov. The large defensive works actually began in the Krkonose, or Giant Mountains, known to the Germans as the Riesengebirge. A second, higher range of the Krkonose that began near Trutnov reached elevations of up to 1,600 meters along the German Silesian border, creating a formidable obstacle that required fewer defenses. There were few fortifications in the Nizky Jesenik range that rose to an altitude of about 700 meters to the east of the Krkonose. The more rugged Hruby Jesenik that ran north and parallel to the Nizky Jesenik, and reached elevations up to 1,400 meters, were lightly fortified. More heavily fortified works began where the Hruby Jesenik range ended, to the west of Opava, and continued to the vicinity of Ostrava, covering the Oder Gap.

  There were only scattered light defenses in the western part of the Sudeten, in the Jizerkske Hory and Luzicke Hory. However, more continuous lines of light fortifications covered all the mountain passes to the west of the Elbe, where the Krusne Hory or Ore Mountains (Erzgebirge in Germany) formed much of the border, particularly at the Bohemian Gate, a gorge created by the Elbe River where it enters Germany.

  The western border with Germany, equally mountainous, was lightly fortified because the Cesky Les, or Bohemian Forest, created another formidable barrier. These lighter fortifications occupied the east side of a river valley that ran along part of the southwest border and the higher sections of the Bohemian Forest. The Sumava range formed part of the southwestern border with Germany and part of the Austrian border. Although not as high as the highest point in the Krkonose, the Sumava had larger expanses of territory at elevations above 1,500 meters. The Eisentein Pass, one of the few access points to the region, was easily defended.

  A continuous line of light fortifications began at the point where the mountain barrier opened on the border with Austria, to the southwest of Brno on the Moravian border, and extended to Bratislava. Almost half of the southern Moravian border with Austria, known as the Moravian Gateway, was covered by heavier fortifications. However, there were no large forts like those found on the northern border. At Bratislava, in Slovakia, some heavy fortifications were built.

  The southern border of Slovakia and Ruthenia opened into Hungarian territory, and was crossed by the primary trade routes that lead back to Hungary or west toward Moravia. Between Bratislava and Kosice this was mostly covered by light fortifications that defended the economic heart of Slovakia, which was vulnerable from the south. Scattered light defenses also covered some sectors near Uzhorod because this part of Ruthenia was also exposed to Hungary. On the other hand, the northern sections of Slovakia and Ruthenia were well protected from Poland by the great barrier of the Carpathian Mountains.

  The economic heart of the country, which lay between Pilzen and Prague, was protected by a first line of light defenses that ran from north to south, to the west of Pilzen, and a second, similar line to the west of Prague. A pair of light defensive lines were planned to cover the hilly terrain of western Moravia in the Moravian Heights. A final line was to be built from a point west of Ostrava, through the foothills of the Carpathians, to the Austrian border in eastern Moravia. The terrain of the western half of Czechoslovakia was ideal for successive fortified lines and allowed the army to operate on interior lines.

  HISTORY

  The Little Entente offered the Czechs no security against German aggression in the 1930s, a fact that became apparent at the end of the 1920s, when the French army appeared to take a purely defensive posture. Foreign Minister Benes had already alerted his fellow Czechs that they must act, but his warnings went unheeded until Hitler's war machine began to expand. By the time the Czechs took action, time was running out. Since their attempt to improve their relations with Poland, Hungary, and Austria met little success, they turned towards the Soviet Union in early 1935. However, this association proved to be just as problematical as the one with France because there was no direct land link between Czechoslovakia and the Soviet Union. Thus, realizing that they were virtually isolated, the Czechs finally decided to fortify their borders.

  Thus in 1934, the Czechs sent a military mission to study the first completed sections of the Maginot Line. The French, on the other hand, sent General Belhague, one of the designers of the Maginot Line, to assist the Czechs with the construction of their heavy defenses. Other French military advisers soon followed. As a result of this technical support, the Czech forts and heavy casemates show a strong French influence.

  General Ludvik Krejci, the Czech chief of staff, prepared a ten-year plan that set the completion date of the fortifications for 1946. In the 1930s, General Jan Syrovy, his superior and the equivalent of commander-in-chief of the army, received the credit for conceiving the Czech Maginot Line. The planning stage took most of 1935 and the first work began in 1936, at the time the Germans reoccupied the Rhineland. Unlike the French, who focussed on fortifications, the Czechs also strove to modernize their air and tank forces, expending their resources to acquire adequate numbers of aircraft and tanks.

  As they began the construction of the fortification, the Czechs established a better security system than the Belgians or the French because they refrained from using foreign construction companies or laborers from Germany. Their greatest security problem was the Sudeten Germans, who inhabited the regions where most of the fortifications were to go up.

  Because time was critical, the Czech military leaders decided that the heaviest fortifications would be built from Trutnov to Ostrava to prevent a German army in Silesia from splitting the country in two. Successive defense lines from the western border to the foothills of the Carpathians would allow continued resistance if the enemy breached the outer defenses. The heavy defense line of the north, and the smaller one in the south, on the Moravian Gateway, would secure the flanks.

  In 1936 the Type 36 light bunker was designed and it soon occupied the most forward defense line. This type of bunker was small, rather weak, and gave frontal fire but it was economical and easy to build. However, it could serve no more important purpose than the French avant-poste. The larger Type 37 light bunkers followed, occupying the main defensive line. In most cases Type 37 bunkers formed one or two lines behind the line of heavy casemates.

  The real Czech "Maginot Line," stretching from Trutnov to Ostrava, included a series of Maginot-like forts. Unfortunately, none were finished by the fall of 1938, although several were near completion, awaiting only their artillery weapons and turrets that had not yet been delivered from the factories. Work on other forts, which the Czech called "tvrz" or fortress had barely begun.' Thus the line was far from being fully operational.

  Fort Dobrosov illustrates the trials and tribulations the Czechs had to face during the construction of their fortifications. The position was surveyed in April 1937 and building began in September 1937. Its estimated completion date was the fall of 1940. The construction proceeded smoothly and the labor force was increased from almost 500 to about 1,000 workers one year later. However, by the time of the 1938 Munich Conference, only three blocks of the original plan, which called for an entrance block and six
combat blocks, neared completion. Two of these blocks were infantry blocks and the third was an artillery casemate that had no cannons yet. The subterranean galleries that should have spanned 1,750 meters and included additional underground facilities, were only roughly hewn and only partially completed. During the Munich Crisis only one infantry block was occupied by a garrison of twenty-five men. At that time five other forts begun earlier were still a year from completion. The Czech army, nonetheless, readied them for combat, despite the absence of artillery.

  The annexation of Austria to Germany in March 1938 spurred the Czechs to build large defensive works in the south. These were not actually tvrzi, but rather medium and heavy individual casemate positions for infantry and artillery. Again, not all were completed by the fall of 1938. The final defense lines that were to stretch across Moravia from north to south never passed the planning stage by 1938. Yet, despite their small number, the completed Czech fortifications were an asset to be reckoned with since they had the advantage of easily defended terrain and the support of a relatively modern army.

  The protection of the Czech borders was entrusted to Border Infantry Regiments and Border Defense Battalions in 1935. At the end of 1936, special higher commands were created to lead these troops. Late in 1936, when the Czechs maintained an army of merely 100,000 men, the government approved the creation of forty-two fortress battalions with a combined strength almost equal to the standing army's.

  Eight Border Sector Commands, each of division strength, were deployed on the Bohemian and Moravian frontier and four on the Slovakian border. Each command included a fortress regiment and several border-defense battalions. Similar sized commands, known as Defensive Groups, manned the interior defenses, including those of Prague and Pilzen. These specialized formations were considered elite units like the Czech artillery and tank troops and the French fortress troops. Neither ethnic Germans nor political extremists were allowed to serve in these units.

  The line of heavy fortifications in the region of Zamberk was occupied by two army corps: the II Corps and the IV Corps. The IV Corps covered all the positions between Zamberk and Ostrava and fell under the command of the Second Army. The II Corps guarded the area extending west, past Trutnov, and was under the First Army. Instead of using Fortified Sectors like the French, the Czechs established Engineer Group Commands or ZSVs that were subdivided into the equivalent of sub-sectors. Thus ZSV III comprised eight sub-sectors.

  SECTOR (AND PREFIX) IV Corps Border Defense Command 37 ZSV I I Moravaska Ostrava (MO) Border Defense Command 36 ZSV IV Opava (OP) ZSV I Stare Mesto (STM) II Corps Border Defense Command 35 ZSV III Kraliky (K) ZSV X Rokytnice (R) ZSV V Nachod (N) Border Defense Command 34 ZSV VI Trutnov (T) TVRZI Orel, Smolkov Sibenice, Vrch, Orlik Kronfelzov Hurka, Bouda, Adam Bartosovice, Hanicka Skutina, Dobrosov Jirova Hora, Poustka, Babi

  DESCRIPTION

  There is no denying a strong French influence on the Czech school of fortification. Indeed, many of the Czech structures are strongly reminiscent of the French "New Front" fortifications, especially the smaller ouvrages and the single mixed-entrance blocks.

  First of all, the organization of the fortified fronts was strikingly similar to the Maginot Line's. Thus the heavy Czech fortifications that began west of Trutnov and ended near Ostrava spanned a distance of almost 200 km and included fifteen artillery tvrzi. This defensive line was obviously similar in length to the Maginot Line and had a similar number of artillery tvrzi only slightly smaller. In addition, as in the Maginot Line, the Czech artillery tvrzi were supported by interval casemates, heavy bunkers the Czechs called forts, which were quite similar to the French. However, a few of these interval casemates were more heavily armed than their French equivalents and were used as a substitute for the French petits ouvrages.

  Most of the tvrzi were located in the II Corps area, which included the Orlicke Hory and the Krkonose, where several forts were built on both sides of the ranges. The forts in this area, clustered about 5 to 10 km apart, close enough to support each other as adequately as the French Maginot ouvrages. In addition, the forts of the Krkonose were positioned close enough to the border for their artillery to cover the approaches on the enemy side.

  On the other hand, in the IV Corps area-between Zamberk and Ostravamost of the tvrzi were more than 10 km apart, which did not allow for adequate mutual protection. Furthermore, few of the artillery pieces were able to reach the other side of the border.

  The design of the Czech tvrzi also owed much to the French school even though there were significant differences between the two schools. For instance, the average Czech tvrz included six combat blocks instead of seven, had a single entrance block instead of two, and accommodated a garrison of about 525 men instead of 625 men. However, like the French, the Czechs designed three types of combat blocks for infantry, artillery, or observation. As in the Maginot Line, the tvrzi included one or more cloches per block, no more than one turret per block, and three guns per artillery casemate. However, the Czechs departed from the French model when they substituted the French 75-mm weapons with their own longer-range 100-mm guns mounted in twin gun turrets and three 105-mm howitzers in gun casemates.3 In addition, the Czechs designed a special non-retracting turret for 120mm mortars to take the place of the French 81-mm mortars. The machine gun turret was non-retracting, but, like the mortar turret, it had a low profile to reduce its vulnerability. Furthermore, having apparently learned from the French experience, the Czechs used a modified and improved cloche. They also used light weapons of Czech manufacture, similar to the French, in their casemates.

  The Czech tvrzi from east to west were as follows:

  NOTES: AO=Artillery Observation, Obs=Observation and/or GFM cloches, Cas=Casemate, Tur=Turret, / = combination, Inf=Infantry, Iso=isolated positions, MG=Machine Gun, 120=1 20-mm Mortar, 105=1 00-mm Howitzer, 100=100-mm Gun.

  The design of each of the above tvrzi included a single entrance block that was several hundred meters behind the combat blocks. Some casemate combat blocks had entrances similar to those of the French, which may only have been intended for exits.

  The largest tvrz planned was Babi, the last on the western end of the line of heavy fortifications. Babi was designed with two 100-mm gun turret blocks and two 120-mm mortar turret blocks instead of the regulation one per fort and two 105-mm casemate blocks instead of the standard two. With ten combat and one entrance blocks, it was intended to be by far the largest of the Czech tvrzi. To the east of Babi, the neighboring forts of Poustka and Jirova Hora were the next largest with eight and nine combat blocks respectively. They had the same amount of artillery, except for the fact that Poustka/Jirova Hora had one less 100-mm gun turret block.

  Reluctant to depend on any other country, the Czechs decided to themselves produce all the key components of their tvrzi such as weapons and armored parts. This decision caused delays because some of the artillery pieces had to be designed and tested before they could be produced in larger numbers. As a result, the 100mm weapons were not ready for production until 1938.

  The casemates were to be armed with 100-mm howitzers. Since the Czech turrets and armored cloches were not identical to the French, they had to be perfected and tested before they could enter the production lines. The cloches were the first major armored elements to be manufactured and installed. There were various types of cloches: observation cloches, light weapons cloches, and heavy machine gun cloches. The first cloches were installed in various tvrzf in 1938.

  The Czechs needed more time to produce their artillery turrets but they ran out of it when the Munich Crisis took place. As it is, only the blueprints for artillery turrets remain. These turrets were to be powered electrically, requiring only a few seconds to move into the correct firing position. However, they could also be operated manually, but in this case their movement would require over a minute and a half. The steel walls and roofs were 175-mm to 450-mm thick for all turret types. The mortar turret was the most unusual because only its heavy roof was exp
osed to the surface and its pair of breech loaded mortars were mounted on a circular rotating piece in the middle of the roof.

  The Czech classification system included six types of concrete protection. The first two types, identified by the Arabic Numerals 1 and 2, were found mainly in interval positions, the last four, identified by Roman Numerals I through IV, were used on heavier works. The Roman Numeral series was similar to the French, its heaviest type-Type IV-being 3.5 meters of reinforced concrete and designed to resist 420-mm rounds. The main difference between the French and the Czech concrete lay in the method of mixing and pouring. The Czech method apparently yielded a greater resistance than the French, but less than the German.

  The Czech artillery casemate was quite similar to the French, and, as in the Maginot Line, each was modified to suit the terrain. Its armament consisted of three howitzers with a 45 degree field of fire each, a light machine gun position that covered the fosse, and, usually, two cloches. Adjacent to each gun room was an M3 magazine. An emergency exit, located either on the upper or lower level, opened into the fosse and was defended by an interior blockhouse position. The subterranean gallery was accessed by two lifts and a stairway. The lower level included a rest area, called "ready room" by the Germans, storage rooms, filters, and a WC. At the lower level, under the gun positions, there were gas-proof chambers for expended shell casings that were conveyed there through a funnel behind the guns. The artillery casemates were served by approximately eighty-five men.

  The Czech artillery turret block was also similar to the French. Below the turret and its forward armor were two levels. Here too the spent shell casings were ejected into a funnel and slid down a toboggan to a shell room in the subterranean gallery. The upper level included a munitions magazine, an M-3, and a control room. Below was the counterweight, filter room, and rest area. A stairway and lift gave access to the subterranean gallery. The artillery turret block required a garrison of about sixty men.