Heavy fortifications

When talking about heavy fortifications it usually means infantry casemates and artillery groups with their entrance blocks, retractable turrets and artillery casemates. Their construction parts were unified, but used with respect to local needs. Typical casemate had at least one armoured dome (small casemates hidden in the woods had usually only one dome as well as bigger one-sided casemates). The biggest casemates were built definitely as parts of the artillery groups, e.g. artillery casemates were almost 50 metres long and were built up of more than five thousands cubic metres of reinforced concrete. Domes or cupolas intended for installation on roofs of the biggest casemates weighed about 56 tons.

As Czechoslovak fortifications were based on side (flanking) firing, they were designed to be used in lines. These lines were organized as separate sectors (comprising usually 30 to 50 casemates). You can see which sectors were built at finding the line section of this site. Sectors were further divided into subsectors (about 10 casemates) construction of which was contracted with civil engineering companies and realised under construction supervision of army specialist. They were built pretty quickly, companies were often forced to build a sector in no more than 250 days (with exception made for artillery groups, where a deal was usually about two years, because artillery groups had also underground system of passages and munition halls). Reason for construction of artillery groups was to strengthen a line of infantry casemates and supply them with their artillery in case of enemy attacks. Because firing range of artillery howitzers used in artillery groups was twelve kilometres, they were built about every fifteen to twenty kilometres of defence line. In 1938, five artillery groups were finished (but not equipped with howitzers, which were not planned to be installed until 1939) and ten others were under construction (all of them at the northern border).

Infantry casemates were mostly built with two floors (upper was a combat floor with firing rooms and munition stores whilst bottom floor was intended for bedrooms, washroom, engine and gas filters). As is mentioned above, they were based on flanking firings, so main embrasures were faced to the sides (with few exceptions of some wery rare unique casemates designed for a front firing). On the roof you domes and cupolas were placed. They differ in purpose. While cupolas were intended for heavy machinegun firings, domes were primarily designed for observation and only secondary for close defence firings of light machineguns.