Exploring Kent's Past

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Monument details

Summary

In 1917, the Admiralty requisitioned the land beside Yantlet Creek which was developed from 1920 by the War Office as a firing point, comprising buildings, structures, a new road laid over an existing track, an internal railway and wharf. The road and buildings were arranged on a north-west to south-east axis, with the dock and firing point set at right angles on a south-west to north-east alignment with Shoeburyness. It was known as both the Grain Island Firing Point and the Yantlet Battery. The principal function of the firing point was to measure the velocity of shells fired from the gun emplacement.

Monument Types

• FIRING RANGE (Modern - 1920 AD to 1955 AD?)

Full description

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Unpublished information supplied by English Heritage describes the site thus:

"The early history of the Hoo Penninsula and the Isle of Grain is summarised in Research
Report Series no. 39-2013, an archaeological desk-based assessment of the site (Edgeworth,
2013), and will not be reproduced here.

The history of the firing point and trials battery at Yantlet Creek is connected to the general
history of artillery trials and practice firing in England which, up until the 1840s, principally took
place in Plumstead Marshes in Woolwich or Sandwich in Kent. In 1849, the Board of
Ordnance bought land at Shoeburyness in Essex, some 5 miles to the north-east of the Isle of
Grain across the Thames Estuary, where a permanent garrison was established by 1854. In
1905 Shoeburyness became known as the Experimental Branch going on to play an important
role in artillery design, testing and development throughout the C20.

In 1917, the Admiralty requisitioned the land beside Yantlet Creek which was developed from
1920 by the War Office as a firing point, comprising buildings, structures, a new road laid over
an existing track, an internal railway and wharf. The road and buildings were arranged on a
north-west to south-east axis, with the dock and firing point set at right angles on a south-west
to north-east alignment with Shoeburyness. It was known as both the Grain Island Firing Point
and the Yantlet Battery, its layout and structural details of the buildings recorded on a drawing
of 1924 from the National Archive (TNA WO 78/512912).

Historic photographs show the operation of the site. The principal function of the firing point
was to measure the velocity of shells fired from the gun emplacement through two velocity
screens hung from two pairs of masts positioned approximately 70m apart; the inner masts
were 33.5m (110ft) high, the outer 64m (210ft). Mostly naval guns were tested; the exact
position of the velocity screens was calculated beforehand according to the planned angle of
fire. The screens were moved into position along a network of wires suspended from the
masts and the results were measured in the velocity room building, which is no longer
standing.

Heavy guns and munitions were transported to a dock constructed on the north side of Yantlet
Creek, immediately to the rear of the gun emplacement. The guns were transported to the site
from Woolwich Arsenal and Shoeburyness on the barge ‘Gog’, towed by the steamship
Katherine II. A travelling crane or gantry lifted the guns off the barge and transported them
onto the gun emplacement. A railway branch line to the firing point was constructed at the
same time as the battery, an extension of the South Eastern and Chatham Railway, Hundred
of Hoo branch line of 1865. Close to the dock, the line split into two with one branch serving
the battery, running underneath the masts and screens, and the other serving the wharf; the
railway line seems to have ceased operation in the 1940s. Shells from the barge were also
mounted on railway carriages and taken to a railway firing point to the south-east of the site.
The structures at the railway firing point are only partially revealed, and are likely to have been
truncated; thus they do not form part of this assessment.

Edgeworth describes the site at Yantlet as essentially an ‘out’ battery of the Shoeburyness
establishment. Staff travelled between the two sites by barge or rail when long range gun trials
took place, and personnel from Shoeburyness were involved in observation and measurement
of the trajectory of munitions fired from Yantlet onto the south-east Essex coast.
The firing point was used throughout the interwar period and Second World War, ceasing
operation in the 1950s. Thereafter the velocity screen masts, screens and gantry were
removed and a number of domestic and operational buildings were either demolished or
altered. The site is retained as a demolition site, with portacabins located on the concrete platform of the gun emplacement, and destruction of munitions taking
place on Lees Marsh to the north. An access road and flood bank have been constructed to the south of the gun emplacement, partially overlying the concrete bases of those structures and separating the gun
emplacement from the dock. The land is tenanted for grazing by Yantlet Farm.

The following buildings remain: the former forge, workshop and powerhouse are in use as agricultural
buildings: the former married quarters and police houses are in private ownership, altered and continue to be used as dwellings; the former guard house of the 1930s remains and appears to retain its use. All the other operational and domestic buildings have been demolished, including those directly associated with the velocity testing.

Details:

PRINCIPAL ELEMENTS
The area of assessment has comprised the core of the firing point; it does not take in outlying structures such as the railway firing point to the south-east and structures on the foreshore to the north. The structures assessed included the remains of the dock and wharf, gun emplacement and the structure supporting the pairs of masts. The workshop, forge and former powerhouse were also considered.

DESCRIPTION
GANTRY PATH, SOCK AND WHARF: the concrete bases for the gantry path, a linear bridge-like frame
which moved along a set of tracks, remains with a sunken concrete platform in between. Each base is
approximately 190m long and 3m wide, and the bases are approximately 10m apart, with the single rail for running the gantry running along the inside of both bases. A standard gauge railway, part of the battery’s rail infrastructure, ran along the south-east base but no longer survives. However, the tracks for an internal tramway remain set into the north-west base; it is likely that wagons to move explosives and machinery used the tramway. At the south-west end of the gantry path is the dock measuring 32m x 10m created on the north side of the creek, in part framed by the bases for the gantry which would have moved over the barge to remove munitions and guns. From the south-east end of the southernmost concrete base, an ‘L’-shaped timber post and beam wharf structure 3.5m wide carries on for 26m to meet the creek’s bank, before turning south-easterly along the bank for approximately 40m, broadening out to 6m wide to form a wharf. A branch of the railway which came directly to the wharf no longer survives.

GUN EMPLACEMENT: at the north-east end of the gantry path is a raised concrete platform for the gun
emplacement measuring 14m x 10m. As with the dock, the gantry would have travelled over the
emplacement lifting the heavy guns in and out of position. Steps lead up to the platform from the north-west.

MASTS AND ANCHOR POINTS: the velocity masts and screens no longer remain. They were positioned
perpendicular to the line of the gantry path, 35m and 109m away from its north-east end. The bases survive and comprise raised rectangular concrete foundation blocks approached by a flight of steps to the south-west, each pair linked by a concrete strip with rails set into them, perhaps for running the screens along. The bases have metal pins and bolts at each corner of a rectangular scar, where presumably the metal corner posts of each mast were attached. On top of the north-west bases are smaller circular plinths, concrete with external metal banding and a central metal spike for attaching an unknown piece of equipment, perhaps also relating to the screens. The masts were secured by tethering each to three anchor points radiating outwards in an arc. The points comprise a concrete base with metal spools; the Heritage Protection Department survey identified ten such bases, but these are not mapped.

BUILDINGS
The following buildings are shown on the plan of the site dating 1924:

POWERHOUSE
Exterior: the powerhouse is a single storey building fronting onto the access road. It is constructed of shaped concrete blocks and has a catslide roof with asbestos tiling laid in a diamond pattern, with cresting to the ridge and to two projecting, gabled ventilation louvres. The central bays project, flanked by plainly detailed verandas, and there is a central timber double door leading to the engine and generating rooms. Four doors of red-painted timber under concrete lintels have the names and functions of the rooms painted in yellow lettering, reading from left to right, Battery Room, Generating Room, Engine Room and Rectifier Room. Most of the window openings are blocked, but the surviving ones have multi-light metal casements.
Interior: there was no interior inspection in February 2015. However, the Heritage Protection Department survey previously recorded tiled floors with raised concrete platforms, but there is no machinery apparent.

WORKSHOP
Exterior: the double-height and single storey workshop is constructed from shaped concrete blocks and has a tiled, gabled roof with three lights in the apex at each gable end. It lies to the north-west of the powerhouse, parallel to but set back from the access road. The main vehicular access at the south-east gable end has a half-timber door, probably of a later date. Standard gauge rails enter the workshop through this entrance, the terminus of a short branch line off the Yantlet line branch which served the battery. A pedestrian entrance lies at the north-east end of the façade. At the lower level of the front, rear and north-west elevations, large window openings with concrete lintels and cills are now blocked and the fenestration removed.
Interior: the rails run along the rear of the building to the north-west gable. There is no machinery present, but next to the rails is a raised brick and concrete platform which may have supported machinery. The metal roof trusses have raking shores; the underside of the roof has timber plank cladding and timber battens.

FORGE
Exterior: immediately to the north-west of the workshop lies a single storey forge with a hipped roof, clad with metal sheeting, surmounted by a raised ventilation louvre with a gablet. Constructed of shaped concrete brick, the forge has a timber stable door to the front and is lit by large, multi-light metal casements, one to each elevation.
Interior: the forge has a timber roof structure. The freestanding metal forge itself remains, the flue leading up to the louvre. The manufacturers named on the front of it are ‘Alldays and Onions Ld, Makers, Birmingham, England’."

Mentioned in Isle of Grain Historic Area Assessment conducted by English Heritage in 2014. "Another notable military establishment on Grain was a gunnery firing station, set up on the northern marshes by the Admiralty in 1917 for the testing of naval ordinance". In 1923 a jetty was built on the Yantlet along with other facilities. "Guns, transported from Woolwich Arsenal by barge and railway, were regularly fired across the marshes until the 1950s, despite the complaints on the local population". The remains include "a brage dock, remains of a jetty and the concrete base for a gantry crane, built c. 1917 for the loading and unloading of guns". Mention is made of a surviving conctrete and brick pillbox, but the it has not been possible to identify the exact location (3).

English Heritage, 2013, Grain Island Firing Point, Yantlet Creek, Isle of Grain, Medway. Archaeological Desk-Based Assessment (Bibliographic reference). SKE31445.

historic england, 2015, Grain Island firing point, Yantlet Creek, Isle of Grain, Medway, Kent (Unpublished document). SKE31389.

<3> English Heritage, 2014, Isle of Grain, Hoo Peninsula, Kent: Historic area assessment (Monograph). SKE29397.

Sources and further reading

Related records