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Early 20th century gun battery 150m north of St Mawes Castle

A Scheduled Monument in St. Just-in-Roseland, Cornwall

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Coordinates

Latitude: 50.1569 / 50°9'24"N

Longitude: -5.0239 / 5°1'26"W

OS Eastings: 184099.201884

OS Northings: 32913.593723

OS Grid: SW840329

Mapcode National: GBR ZH.G9JQ

Mapcode Global: FRA 08CL.W0G

Entry Name: Early 20th century gun battery 150m north of St Mawes Castle

Scheduled Date: 9 October 1981

Last Amended: 10 July 1996

Source: Historic England

Source ID: 1013808

English Heritage Legacy ID: 15421

County: Cornwall

Civil Parish: St. Just-in-Roseland

Built-Up Area: St Mawes

Traditional County: Cornwall

Lieutenancy Area (Ceremonial County): Cornwall

Church of England Parish: St Just-in-Roseland

Church of England Diocese: Truro

Details

The monument, which falls into three separate areas, includes an early 20th
century gun battery at St Mawes, situated on the upper slope of a broad
headland flanking the east side of the Carrick Roads, the mouth of the River
Fal, on the south coast of Cornwall. This monument is contained within a wider
area in the care of the Secretary of State. The gun battery was built between
1900 and 1904. It contains four gun emplacements protected by an earthen
rampart and served by an underground magazine whose access-well is cut into a
levelled stance behind the rampart. Two observation posts, for minefield
control and position finding, are located within the monument to the north
west of the gun emplacements and the battery caretaker's house and access
route are situated south east of the emplacements. On the hillslope below the
battery are two sockets which held sighting posts for use in seeding mines
along submarine minefield alignments laid across the Carrick Roads.
The battery's earthen rampart extends over 70m north west-south east, rising
steeply from the hill's upper slope and topped by a narrow level platform in
front of the gun emplacements. The emplacements themselves each comprise a
raised concrete platform into whose forward sector is set the circular steel
gun-mounting with projecting securement studs around its periphery, called a
hold fast. A short flight of steps rises up one side of the platform and in
its rear face are two rectangular recesses called expense lockers, which
stored ammunition for the gun's immediate use and which are closed by paired
hinged steel doors, most of which survive in place. The forward edge of each
gun platform is protected by a broad raised concrete apron set into the rear
of the rampart and whose upper surface is chamfered outwards at a shallow
angle. The rear face of an apron on the north eastern of the central
emplacements has two metal loops supporting a vertical post, called an anti-
strafing post, which acted as a stop to prevent the gun traversing too far
east and firing on the artillery castle by accident. The north western three
emplacements are spaced 7m apart, each pair linked by a low concrete catwalk
behind a vertical rampart-facing wall into which are set two more ammunition
storage recesses. The south eastern gun emplacement is 12m from the others and
separated from them by a turfed rear scarp of the rampart.

Behind the gun emplacements is an area, c.7m wide, levelled into the hillside
and backed by a steep scarp containing a further small storage recess near the
centre. Within the levelled area and behind the south eastern two emplacements
is the access well to the underground magazine.

The magazine's access well measures c.12m long by 2.5m wide, with concrete-
faced sides descending vertically c.4m to the concrete floor. Its upper edge
retains its original tubular railings, while above opposite corners along the
south west side project curved tubular stanchions called davits, which were
fitted with pulleys at their tips and which could swivel on their mountings.
The davits were used for lowering ammunition supplies into the magazine. A
steel flight of steps giving access to the floor have not survived.

From the floor of the well, an arched doorway in the south west side contains
a double-door opening to the brick-built interior of the magazine proper. From
this door, access was gained to the shell store and, with the addition of a
further two emplacements to the 1900 battery in 1902-4 the magazine
arrangements were altered to store more cartridges. The cartridge store was
originally entered through another door from the lightwell (now blocked)
directly into a shifting lobby. The north west wall of the lobby was
demolished to enlarge the cartridge store and a new door created through to
gain access from the shell store to the cartridge stores. The shell store
retains its original racking and an arched window to the right of the door has
its original grille. On the north east side of the access well, a doorway
gives access to brick-built war shelter accommodation for the battery's
detachment of troops. The doorway is flanked by two windows to its left and
one to its right, all with concrete lintels and sills. The right-hand window
retains its original grille; the other windows show no fittings for mounting
such a grille. A lamp room with a door and window also extends from the north
west end of the access well. On each long side, two ventilator pipes emerge
from the upper walling and rise vertically, some showing parts of their
internal fans in their upper end.

Close to the north west of the battery are two small observation posts, 8m
apart north west-south east and largely concealed in a slight rampart whose
forward edge is set back slightly from that of the battery. Both have concrete
walls and are reached by a flight of steps descending to the rear of a semi-
ovoid chamber, c.2.5m wide. The south eastern post served as a minefield
control cell for the submarine minefield in the Carrick Roads; it has
galvanised corrugated steel sheeting as its rear `wall' and a thick steel
sheet forming its roof, beneath which is a narrow horizontal observation slit
in the wall's front curve. The slit has been blocked by concrete but retains
its wooden frame on the inner face, and a little way below this, granite
slabs, called corbels, project inwards from the sides to support the position-
finding table and its sighting equipment. The north western post was a
position-finding cell for the battery and is more strongly built, with a
concrete rear wall and a concrete roof on which is bolted a tubular steel
pipe. The forward end of this post is angular rather than curved and has
remnants of iron sheeting lining its observation slit. Beneath the slit, the
now missing position finding table and sighting gear was supported on a corbel
projecting in from the front wall and on two free standing concrete plinths
behind the slit. The rear wall of this post retains its wooden door frame.
The access route into the battery is along a partly-metalled terrace extending
25m east from the levelled area behind the gun emplacements and linking with
the public road running down the slope. To the south of the terraced access
route is a subrectangular levelled stance, 20m wide by up to 25m long,
containing the accommodation for the battery's caretaker, together with a
separate brick-built privy.

The hillslope below the battery contains two small sockets set on two of the
alignments of mines in the post-1896 submarine minefield laid across the
Carrick Roads and operated from the control cell next to the battery. The
sockets held sighting posts inserted when mines were being seeded on the
alignments. These sockets are situated 80m apart on a WNW-ESE axis; each
survives with a concrete casing, 0.5m square in plan, with its level upper
surface set almost flush with ground level. Within the casing is a cast iron
lining, 4cm thick, around the socket, 16.5cm in diameter. The WNW socket
remains open to a depth of 0.58m; the ESE socket is infilled with soil.
Their original covers have not survived in situ but one is preserved in the
contemporary engine room beside the Henrician artillery castle.

The construction, use and wider context of this battery are documented by a
range of contemporary sources. From the 1890s, the defences at St Mawes,
Falmouth and St Anthony's Head, were administered as a single defended port to
protect the anchorage in the Carrick Roads and the port of Falmouth against
enemy cruisers and, especially, the new fast motor torpedo boats. The initial
defences in this phase at St Mawes involved, by 1898, mounting two 6 pounder
quick-firing (QF) guns on an earlier battery near the shoreline, below the
Henrician castle to the south of this monument. These were designed to
complement the submarine minefield laid out across the Carrick Roads by c.1896
but those guns were soon found to be inadequate for their purpose and in June
1900, authorisation was made to build the first part of the battery in this
monument, deploying the more powerful 12 pounder QF guns, mounted at a higher
elevation giving a greater range. In this initial construction, completed by
July 1901, the battery consisted of the two south eastern gun emplacements and
the underground magazine behind them. The battery was substantially enlarged
and its complement of guns doubled in a second phase of construction, between
March 1903 and November 1904, when the two north western gun emplacements were
added, together with their connecting catwalks. This phase also included the
building of the two small observation posts to the north west of the battery,
the caretaker's house to the south east and, beyond this monument, a
searchlight station on the coast and an engine room to power it, situated
north west of the Henrician castle.

Following a further review in 1905, the Owen Report, the defences of Falmouth
were considerably scaled down. This resulted in an order to reduce the
strength of this battery in 1906, followed by its closure in 1910. During
World War II, the St Mawes headland was fortified from 1941 by a battery
on the coastal margin south west of this monument, together with a minefield
control post on the hillslope to the west. Although the battery in this
monument was not re-armed, a range hut, now demolished, was built on the
levelled area north west of the earlier magazine's access well.

The dwelling house which was formerly the battery caretaker's house, all
modern fences, gates, garden furniture and sheds, the overhead electricity
supply cables and their posts and fittings, and the roadsign with its post and
pit are excluded from the scheduling but the ground beneath them is included.

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

Source: Historic England

Reasons for Scheduling

The distinctive form of coastal defence batteries developed at the end of the
19th century differed fundamentally from earlier batteries and provided the
first application of design principles that characterised such defences until
the abolition of coastal artillery in 1956.

Their design and location reflects major developments in armament technology,
the nature of the perceived threat and defensive policy. Until the 1890s,
heavy carriage-mounted guns recoiled up an inclined plane, and the gun's
movement across a horizontal plane was provided by mounting the incline on
rails. The gun crew had to keep well back from the gun during firing and
return to the gun to re-load it from the muzzle before returning it to its
firing position, slowing the rate of fire. By 1885, an effective breech-
loading system improved the speed of re-loading, but the major advances came
later with the development of guns whose recoil was absorbed by hydraulics and
compressed air. Hydraulics were also deployed for ammunition supply from
magazines. Lighter steel gun barrels and improved propellants allowed greater
muzzle velocities and increased range without requiring the guns to have an
enormous size and weight, while brass cartridge cases enabled more rapid re-
loading.

By the end of the 19th century these developments allowed batteries to mount
light, powerful guns fixed on a central pivot, enormously improving the guns'
manoeuvrability and accuracy, and enabling rapid fire with the gun crew
remaining close around the gun, protected from bullets and shrapnel by a
gun-mounted shield. The new batteries reflecting this advance had fixed
guns on steel mountings set in concrete emplacements, slightly sunken behind a
concrete apron and protected from artillery fire by an earthen rampart. They
were served by brick-vaulted magazines built deep underground, linked to small
ammunition stores called expense magazines at the emplacements by
hydraulically-operated shell and cartridge hoists. The underground magazines
had an access well behind the emplacements.

The stimulus for implementing these major improvements in coastal batteries
from the 1890s arose from a shift in British defence policy away from large
land defences around major towns and military centres to counter threats from
an invading army and towards coastal defences to counter the threat to naval
and commercial ports and anchorages from the new generations of more
manoeuvrable enemy cruisers and particularly from fast motor torpedo boats.
The resulting new design of batteries were initially deployed along strategic
points of the south coast and around major coastal centres elsewhere, when
France was perceived as the main potential enemy. During the 1900s, the
emphasis shifted to increasing the fortification of the east coast as Germany
became viewed as the chief threat. This occasioned the scaling down and
closure of some south coast batteries, a trend confirmed by the Owen Report of
1905 which substantially downgraded the extent of the perceived threat to many
anchorages and therefore the strength of batteries needed to protect them.
This produced the pattern of coastal defences prevailing at the start of the
First World War and marks the end of this distinctive phase of policy and
design in the nation's overall defences.

This battery at St Mawes shows well the new design features which were used
during this short-lived but important phase of coastal defence and it remains
little modified by later activity. Its replacement of the slightly earlier and
inadequate 6 pounder battery near the shoreline emphasises the formative stage
that it represents in the deployment of the new armament. Its inter-dependence
with the submarine minefield is emphasised by the intact survival of the
minefield's control cell and the sighting post sockets. The well documented
history of this battery's construction, armament and decline during the first
decade of the 20th century closely reflects the known shifts in national
policy through that period. Its proximity to the Henrician castle and the
successive gun batteries on the headland from the 17th century onwards
demonstrates well the developing nature of gun batteries and the armament and
strategic methods they represent throughout the post-medieval period. This is
set in its wider context by the monument's association with the surviving and
complementary defences at Pendennis and, for later periods, St Anthony's Head.

Source: Historic England

Sources

Books and journals
Dorman, J, The Later Defences of Falmouth 1895-1956, (1993)
Heggie, A V, Lane, M, Delta Graphics, , St Anthony Battery
Morley, B, The Castles of Pendennis and St Mawes, (1988)
Stevenson, I V, Some West Country Defences, (1989), 11-26
Tosh, D, St Mawes Castle A Brief Guide, (1993)
Other
by letter, 18/3/1995, Information from Dick Linzey, EH Architecture & Survey Branch,
DoE/HBMC, AM Terrier and GAM mapping for CO 278: St Mawes Castle, (1984)
Linzey, R, Pendennis Castle. Obs & Hist Notes to accompany condition survey, 1995, EH report, February 1995
Title: 1:10000 Ordnance Survey Map: SW 83 SW
Source Date:
Author:
Publisher:
Surveyor:

Source: Historic England

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