Details

The monument includes an early 19th century redoubt or circular fortification,
set within a dry moat and outer glacis (sloping bank); additional World War II
fortifications, including gun emplacements and observation posts survive, as
do structures associated with the later 20th century use of the redoubt as a
military training facility. It is situated at the head of the shingle beach on
the western edge of the Hythe Ranges.
The redoubt was constructed between 1804 and 1812, to support a defensive
chain of 21 martello towers, guarding the coastline of Romney Marsh between
Hythe in Kent and Rye in Sussex. It was specifically designed to help protect
the Marshland sluices which emptied into the sea at Dymchurch, then the
administrative centre for the Marsh.
The circular redoubt is brick built, with granite and sandstone dressings, and
was constructed on two levels. It measures up to around 68m in diameter
externally, and stands to a height of about 12m. The sloping roof of the
parapet wall, designed to deflect cannon shot, protrudes above the lip of the
brick retaining wall of the moat, which encircles the redoubt at a distance of
around 9m and was intended to protect it from bombardment and ground assault.
Beyond the moat, an earthen bank, or glacis, was constructed against the outer
face of the retaining wall, sloping away from the lip of the moat for a
distance of up to 60m. This has been partly disturbed in places by past modern
activities, including the construction of an access road to the north, and the
concrete sea defences to the south.
The first floor entrance to the north west is approached by a footbridge
which originally spanned the moat on a series of stilt-like legs, and was
capable of being collapsed in time of attack. This has been replaced by a
steel bridge. The entrance passage leads directly onto the open gun platform,
which is located at roof level behind the encircling parapet wall and
overlooks the circular, central parade ground below. The gun platform was
designed to accommodate ten 24-pounder cannons, with firing ranges of around
1.5km, mounted on wooden traversing carriages and positioned behind
granite-dressed embrasures. Each emplacement was served by an expense
magazine, in the form of an arched recess, which supported a firing step
above, set into the adjacent merlons. Many original features of the gun
platform are now concealed beneath asphalt and an array of superimposed
structures added during World War II, including gun emplacements, observation
posts and associated magazines and shelters. Modern radar scanning equipment
is also installed, and in use, in the south eastern World War II gun
emplacement.
A double, external stone staircase, situated behind the entrance, leads down
from the gun platform to the parade ground. A more direct link between the gun
platform and the casemates below, was provided by three internal stone
staircases, set within the thickness of the outer wall of the redoubt. The 24
vaulted, barrack casemates were arranged around the central parade ground and
are interlinked, together with smaller, intervening chambers by a central
walkway. They provided accommodation for up to 350 men and officers, as well
as stores for ammunition and supplies. The water supply was held in rainwater
collection cisterns, installed beneath the floors. The outer wall of each
casemate is pierced by a small fan-light, and the inner wall opens directly
onto the central parade ground. The casemates retain many of their original
features, including hearths and ventilation shafts, and are largely unaffected
by later alterations, although brick partitions were added to the casemates
during the 20th century.
More significant modifications were made to the outer wall of the parade
ground during the later 20th century, to accommodate a military training
facility. A mock street scene, constructed mostly of concrete panels, was
attached to the surrounding structure by means of a steel frame, and
associated structures include six breeze-block firing points and a control
tower, built over the north western portion of the gun platform.
A number of features are excluded from the scheduling, these are; the radar
equipment and associated wiring installed in the south eastern gun
emplacement, all modern fixtures and fittings, including components of the
modern electricity and telephone systems, all modern materials and equipment
stored within the redoubt and materials used to seal doors and windows, the
surface of the modern access track, all modern fencing and the concrete
surface on the south eastern edge of the glacis; the ground beneath, and/or
the structures to which these features are attached is however included.

MAP EXTRACT
The site of the monument is shown on the attached map extract.

Source: Historic England

Reasons for Scheduling

Three redoubts, or large coastal artillery forts, were built between 1804 and
1812, at Harwich, Dymchurch and Eastbourne, to provide garrisons of up to 350
men to supplement the contemporary martello towers, built as a systematic
chain of defence along the coast between East Sussex and Suffolk. The redoubts
are circular, brick built structures up to around 68m in diameter, and stand
to a height of around 12m. They comprise 24 casemates (bomb proof vaulted
chambers), built around a central, circular parade ground. These provided
accommodation for the officers and men, as well as stores and a cook house.
Above the casemates was an open gun platform with emplacements for ten 24-
pounder cannons, each with its own adjacent expense magazine, which held shot
and charges for immediate use.
The redoubts were enclosed by dry moats, with an encircling glacis slope,
designed to protect the fort in time of attack. However, the defensive
strength of the martello tower system, and its associated redoubts, was never
tested before the end of the Napoleonic War, soon after which the concept of
the martello tower was rendered obsolete by developments in heavy artillery.
Some of these fortifications continued in use into the 20th century as
observation posts or gun emplacements during the two World Wars.

Despite extensive additions, particularly during the 20th century, the
Dymchurch Redoubt survives well and displays a diversity of original
components. Furthermore, when viewed as part of a wider defence network along
this part of the coastline, the monument provides a significant insight into
the strategic integration of the martello tower system in the defence of
Britain during the 19th century.

Source: Historic England

Sources

Books and journals
Campbell, R H, The Grand Redoubt - Draft Option Study, (1997)
The Conservation Practice, , South Coast Martello Towers - a report of survey, (1996)

Source: Historic England