This section deals with the principal types of concrete antitank
obstacles erected by the Germans in the coastal defense zones of
France, Belgium, and The Netherlands.
The Germans make a practice of constructing concrete antitank walls
in all coastal areas where a strong defense is planned. Walls of this
type are used to block streets and roads in coastal towns, at the
approaches to strategic points, and on the outskirts of towns, generally. Often
the Germans prepare a continuous obstacle along the entire sea front of a town
by constructing concrete walls in line with the front elevation of existing
buildings. First, rough timber shuttering is erected along the site proposed
for a new wall, and then the concrete is poured. Light steel reinforcement
is sometimes used, but often there is no reinforcement at all. Often metal
hooks project from the top of a wall, to serve as anchors for barbed wire.
To improve the effectiveness of a concrete antitank wall, the Germans often
dig a ditch in front of the obstacle or prepare a tank trap in the form of a
pit covered with planks and gravel, or garnished netting.
In areas where there are quarries which can supply large quantities of stone, road
blocks are often constructed of the native stone, instead of concrete.
b. Continuous Walls
When a continuous wall is erected along the sea front of a coastal
town, a minimum thickness of 6 feet is the general rule. It is reported
that the average thickness is from 8 to 11 feet. The height of such a
wall is usually from 6 to 8 1/2 feet.
c. V-shaped Walls
The Germans frequently erect V-shaped walls across the roads or tracks
leading inland (through defiles between cliffs and dunes) from beaches. The
point of a V-shaped wall is always toward the sea. These walls are especially
common in open coastal stretches between towns. The dimensions of walls of this
type are similar to the dimensions of continuous walls. It must be expected
that the apex of the V will contain gun emplacements, or that the entire V
will have been built to serve as a pillbox.
d. Walls with Gaps
When the Germans build a concrete wall with a gap, the gap is usually
wide enough to allow only one vehicle to pass through at a time. The gap
can be closed by means of girders, rails, or gates fitted into sockets
imbedded in the wall.
It has been reported that in certain European coastal areas the Germans
use an interesting type of staggered double road block. These obstacles
consist essentially of a pair of walls or barricades, sited one behind
the other, but projecting from opposite sides of a road. Each wall projects
across 1/2 or 2/3 of the width of the road. These walls, which are never
less than 6 feet thick, may be of masonry or concrete, or may simply
consist of log barricades filled with earth or sand. The horizontal
and vertical logs are about 1 foot in diameter. The vertical logs are
driven deep into the ground, and additional resistance is provided by
diagonal bracing. Obviously, such obstacles are intended to slow down
advancing vehicles, and thereby render them much more susceptible to
2. OTHER CONCRETE OBSTACLES
a. Dragons' Teeth
Concrete obstacles known as "dragons' teeth" are used by the Germans to block
streets, exits from quays, and well-defined beach exits where the level
of the beach is approximately the same as that of the roads leading
inland. A typical arrangement consists of four to eight staggered rows
of tapered dragons' teeth, with 6 to 8 feet between the teeth in each row
and 6 to 8 feet between rows. Often the bases of the teeth are connected
by concrete beams, in lines parallel with the road; this is a means of
reinforcing the obstacles against possible overturning. The total height
of these obstacles may be from 3 to 6 feet.
b. Plain Blocks
Plain concrete blocks are used in the same way as dragons' teeth, but
are also found in defiles between sand dunes, which might afford an
entrance inland for vehicles even though no well-defined road exists. These
blocks are arranged in from one to three rows, and are not always
staggered. In dune country they are also found on forward slopes, near
the crests. The blocks may be rectangular (3 feet wide on each side and
4 feet high) or cylindrical (3 to 4 feet in diameter and 4 feet high).
3. RAILS EMBEDDED IN CONCRETE
In coastal towns the Germans often use straight or curved steel rails
embedded in concrete to block ramps, promenades, streets, and all other
exits leading from beaches. Sometimes three or four lengths of straight
rail are combined to form a skeleton pyramid, with their bases embedded
in concrete and the tops bolted together. Rail-and-concrete obstacles are
generally from 3 1/2 to 4 1/2 feet high.