Kazemat (B10), tussen Rijnauwen en Vechten Vechten (Bunnik 26)

English translation

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Description

Cluster 41.

Introduction

SHELTERS TYPE 1918/I are reinforced concrete, shellproof personnel shelters, which usually formed part of linear, deconcentrated defensive works. Most specimens within the complex 'Intermediate Position Rijnauwen-Vechten' now lie north of the motorway A 12, a smaller number south of it. Shelters Type 1918/I and Type 1918/II were built according to more or less uniform or standard design in 1918 at multiple locations in West Netherlands. Both types occur within the Stelling van Amsterdam (amongst others at Spaarndam) and at various locations in the Nieuwe Hollandse Waterlinie (amongst others at Naarden, in the area between the Fort bij Rijnauwen and the Fort bij Vechten (= the Houtense Vlakte) and at Fort Everdingen. Depending on the period of origin - and thus the expected impact force of projectiles - the term 'bombproof buildings' was used, when they were deemed to be able to withstand a predetermined number of impacts from heavy calibre. At the beginning of the 20th century a standard was developed for this, which is linked to the diameter of high-explosive projectiles, expressed in resistance classes. Thus there is a resistance class W 12-15: capable of withstanding prolonged bombardment with high-explosive grenades of 12 cm and occasional hits from 15 cm. The total number of specimens of Types 1918/I and 1918/II built in the Nieuwe Hollandse Waterlinie amounts to approximately 225; the majority (circa 165) of these still exist. The greatest concentration of shelters Type 1918/I and 1918/II is now still found on the Houtense Vlakte, where 147 were realised. The shelter Type 1918/I (ca. 125 units) usually came about at the front of double trench systems. The shelter Type 1918/II (ca. 100 units) was mostly built along the rear trench. Because the trenches and other earthworks were later largely levelled everywhere, the concrete shelters nowadays usually lie partly below ground level. The front face, which was always completely closed in earlier times, was usually entirely covered by earthworks that formed part of a glacis for the protection of the trench or of a covered way. These earthworks are now usually no longer present or only recognisable with difficulty. In a number of cases the earthing on the front face or the flank was deliberately (partly) removed in the years 1936-1938 or not re-applied in order to convert the 20-year-old shelters Type 1918/I and 1918/II into machine-gun casemates. Dozens of such converted specimens are present in the Nieuwe Hollandse Waterlinie. Of Types 1918/I and 1918/II there exist variants, which can be identified amongst others in the inclination angle of the throat side and by differently executed access openings.

Description

SHELTERS TYPE 1918/I are single-storey, usually executed in approximately 1.00 m thick reinforced cast concrete, shellproof, military shelters, which could provide shelter for 8 infantrymen / artillery personnel, at protection class W 15-21. The linear relationship that characterised the shelters during their operation is still clearly observable in the field. The shelters 1918/I were built on a rectangular ground plan, with dimensions of approximately 5.00 x 5.50 x 3.70 m, (w x d x h), of which the base is rarely or never visible. The visible height above ground level varies, but within this cluster at the highest point amounts to 1.50 to 2.50 m. Both blind side walls and the closed front face are executed vertically, in order to transition with a sharp angle into the roof surface sloping slightly backwards. This roof surface descends after a blunt angle at an inclination of approximately 45° towards the often not, or only partly visible, low, vertical (underground) wall on the throat side. A variant of Type 1918/I has a less steep slope here. In a number of cases iron hooks were cast into the walls which could serve to attach camouflage material. The shelters Type 1918/I were constructed as monolithic concrete works and were only accessible via one access opening, on the trench side - the throat side. These eccentric, right-positioned openings in the wall are surrounded by a thickened concrete frame, which is positioned in the same plane as the rear, slanting roof surface. Variations occur in these frames, amongst others with a reinforcement at the top. The low-positioned openings were later usually closed by means of masonry or concrete, but specimens stuffed with rubble also occur. In a few cases the shelters are still open or have been reopened. (Remains of) doors or shutters have not been found and are in any case extremely rare; however, iron hooks still remain in the ceilings near the openings, in which iron shutters could be hung. In a number of cases in the years 1936-1938 an extra wall opening was made on the front face, diagonally or to the side to serve as a firing port for a machine gun. Thus the function changed from shelter to that of machine-gun casemate. The interior of the shelters Type 1918/I consists of a rectangular space, positioned approximately half below ground level, which is accessible in a crouching position via a concrete staircase of a few steps located in a corner. The ceilings, positioned just over two metres above floor level, approximately 1.00 m thick, curve slightly at the front face.

Valuation

The SHELTERS TYPE 1918/I of the Intermediate Position Rijnauwen-Vechten are of general importance because of:

* Cultural-historical values, as components of the Nieuwe Hollandse Waterlinie as designed by C.R.T. Kraijenhoff and initially realised from 1815 by him, Jan Blanken and major-engineer Willem Offerhaus and subsequently by others over approximately 125 years strengthened and improved.

* Military-historical values as part of a continuous military defensive line between the former Zuiderzee and the Biesbosch. This consisted mainly of a coherent system of inundation fields and associated inundation facilities and fields of fire. This system was supplemented with various types of built or constructed (defensive) works from different periods which served to or contributed to the closure of non-inundatable terrain or other accesses.

* Architectural-historical values, in particular as an expression of military-strategic building, which is based on: a. the system of inundation and access defence (19th and 20th centuries), b. the race with the increasingly powerful offensive means (20th century), c. the system of 'living' field fortification in depth (20th century)

These are components from the period 1914-1918. These components are examples of reinforced concrete shelters, now without earth covering.

* Ensemble value and situational values as components of the Nieuwe Hollandse Waterlinie. Also because of the functional and physical coherence with the other components of the complex and in particular in the linear positioning, which is a reminder of the associated trench systems.

* The components are representative (characteristic) because they are clearly recognisable as part of a deconcentrated defence line added to the existing fortification system.

* The components are reasonably well preserved and can still be clearly recognised as built elements in the field.