Bomvrij militair object, 1e Polderweg bij 4

English translation

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Description

Cluster 28. Group Shelters Type P.

NEW HOLLAND WATERLINE

Introduction

Four earthed GROUP SHELTERS TYPE P as examples of defensive components added to the Fort aan de Klop. Concrete group shelters formed an answer to the arrival of heavy projectiles and high-explosive grenades. The latter have a highly explosive bursting charge and caused a rain of metal splinters, which could cause many casualties. According to the weight of the grenade and the protection against it, there has existed since 1928 a classification into resistance or protection classes, formed by two numbers, e.g. W 12-15. The first indicates that the covering is sufficient for impacts of projectiles up to that calibre (in cm); the second that protection also exists against one or at most a few impacts up to this higher calibre. The earliest types of shelters offered only protection against grenade splinters and were called 'splinter-proof'. The Group Shelters Type P were built in the years 1939-1940 in multiple locations in the Netherlands according to a more or less uniform or standard design. The total number of built examples is approximately 700, of which around 570 in the New Holland Waterline; the majority (approximately 400) of these still exist. The building programme of the Group Shelters Type P was not completed at the outbreak of the Second World War and a number of examples have visibly remained unfinished. Type P (also called 'the pyramid' because of its distinctive shape) is presumably the most well-known type of concrete defensive structure in the Netherlands. The type stemmed from the so-called VIS 77 (Regulation for Setting Up Positions no. 77), from 1928, and had among other things the purpose of forming part of the defence of a number of improved and new accesses, including in particular (motorway) roads and (electrified) railways. The Group Shelter Type P usually came into being in the immediate vicinity of already existing or contemporaneously realised casemates, gun positions, fortifications or group nests. They were also built on forts. Because the group nests and other (earthwork) fortifications were later almost everywhere levelled or demolished, the concrete shelters nowadays sometimes lie partly below ground level. The rectangular entrance lay then partly below terrain surface. The entirely closed front side of the Group Shelters Type P was intended to be covered by earthworks, which could form part of a glacis for protection of a group nest or a covered way. These earthworks are now mostly no longer present or can only be recognised with difficulty, but in particular on forts or in terrain otherwise characterised by relief, there sometimes still exists covering. There exist various variants of Type P, both in terms of dimensions and protection class as in execution and detailing. Thus there are examples built in the protection classes W 15-21 and W 21-28 with dimensions varying from approximately 5.50 x 7.20 x 4.70 m to 6.50 x 8.20 x 4.90 m (w x d x h). Many examples of Type P were built in inundatable areas, in a number of cases a visibly applied pile foundation, while often a retaining wall and occasionally a trough with stairs for preventing inundation water has been incorporated in the then elevated, square entrance and in yet others a concrete foundation plate projecting all around (visibly) is present.

Description

GROUP SHELTERS TYPE P are single-storey, usually in reinforced, approximately 100 to 180 cm thick cast concrete executed, grenade-proof, military shelters, which could provide shelter for 10-12 men of infantry / artillery. The Group Shelters Type P were built on a rectangular floor plan. The visible height above ground level varies. The two blind side walls and the rear wall are executed vertically up to approximately 3 m height. Above this, these walls turn inward at an angle of approximately 45 degrees, then continue into a flat covering. On the right in the rear wall is an (later either filled in or not) entrance opening at locally varying height above ground level. The entirely vertical, closed front wall reflects the angles of 45 degrees and thus ends as a 'truncated pointed gable'. In a number of cases, iron hooks or brackets were cast into the wall(s) which could serve to attach camouflage material. A characteristic component on top of the Type P shelter is the conical, concrete 'outlet', which was intended for use of a periscope. These periscopes were in practice, however, never installed. The interior of the Group Shelters Type P consists of a short corridor (usually with a concrete retaining wall or balustrade and usually a few descending steps) and from there a 'sluice' directed to the left which was to be lockable by a (consisting of multiple parts) heavy, steel door with bolts. Via a second, comparable door, a rear, virtually square room could be reached to the right, the actual shelter. The entrance could be covered from this room by a loophole. The steel doors were, however, rarely or never installed and the entrances were later often filled in. The ceilings located at approximately two metres above floor level are flat and rectangular. In a number of cases interior components still exist, such as (remains of) wooden benches or a support for the firearm for covering the entrance.

The complex Fort aan de Klop encompasses a total of four Group Shelters Type P: three located to the north of the tower in the heart of the work and one to the east thereof at the entrance of the fort. The shelters are partly covered with earth.

Valuation

The GROUP SHELTERS TYPE P at Fort aan de Klop are of general interest because of:

* Cultural-historical values as part of the New Holland Waterline as designed by C.R.T. Kraijenhoff and in its initial form from 1815 by him, Jan Blanken and major-engineer Willem Offerhaus and thereafter by others during approximately 125 years was strengthened and improved.

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

These are components from the period 1939-1940. These components are examples of reinforced concrete group shelters.

* Ensemble value and situational values as part of the New Holland Waterline. Also because of the functional and physical cohesion with the other components of the complex.

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

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