Reasons for Designation
Blockhouses are small strongly-built defensive structures, built from the late
14th to mid 17th centuries and designed to house guns and protect the gunners
and ammunition from attack, often while being located in a forward or exposed
position. Blockhouses vary considerably in form, construction and ground plan
but were typically sited as forward defences to cover anchorages, harbours,
other defences and their approaches. They include a single free-standing
structure, usually built of stone, incorporating a gun platform. The gun
platform may be situated in a tower or a bastion. Accommodation for the
gunners or look-out troops was of limited extent if provided at all.
Twenty-seven blockhouses with surviving remains are recorded nationally,
providing information on the developing fortification methods and military
strategies during the later medieval and early post-medieval periods.
The blockhouse at St Catherine's Castle survives well. Despite minor
modifications, the original built structure remains almost intact and retains
clear evidence for its former internal layout and fittings, together with its
manner of armament. Its reinforcement by the adjacent bastioned curtain wall
is unusual. The historical context in which the blockhouse was built is
well-documented and the monument's design is of special interest, being an
immediate precursor to the building of Henry VIII's principal coastal
fortifications. The depiction of the blockhouse as half-built on the 1540 map
provides unusual confirmation for its date of construction and emphasises its
role as part of a group of fortifications along the coast. Its proximity to
the surviving earlier blockhouses across the Fowey estuary and the successive
alterations arising from its re-armament as a gun battery during the Crimean
War and World War II demonstrate well the developments in military
architecture, technology and defensive tactics since the medieval period. At
each stage the monument functioned as an integral part of a wider defensive
network, underlining the continued importance of this monument in the nation's
defence.
Details
The monument includes an early 16th century blockhouse and bastioned curtain
wall on the tip of a rocky headland, St Catherine's Point, at the entrance to
the River Fowey estuary on the south coast of Cornwall. The curtilage of the
blockhouse, as defined by its curtain wall, was refurbished in 1855 to form a
gun battery during the Crimean War. After serving as a practice battery in the
later 19th century, it was again modified and re-armed in 1940 as an
emplacement in a more extensive World War II gun battery occupying St
Catherine's Point. The blockhouse, curtain wall and later battery are Listed
Grade II* and are in the care of the Secretary of State.
The blockhouse was built between 1538 and 1540 during the reign of Henry VIII
to strengthen the defences of the Fowey estuary as a preliminary response to
heightened threats of attack from France and Spain in the immediate aftermath
of the Reformation in England. It survives with a small blockhouse building on
the tip of the headland's ridge. A north east - south west curtain wall
extends down both slopes from the rear of the blockhouse and incorporates a
small subrectangular bastion beside the blockhouse. The curtain wall
terminates at precipitous cliffs at each end, cutting off a near semicircular
area of c.500 sq m above the cliffs at the end of the headland.
The blockhouse building has a D-shaped plan and is situated on the highest
point within the curtain wall, allowing its curved wall an uninterrupted
prospect up the estuary to the north east, and extending round, across the
estuary mouth to the east, to face southern aspects out to sea. It was built
on a prepared platform levelled into the rock, giving its straight north west
wall a rock-cut face to first floor level. The blockhouse is built of slaty
rubble laid to course. Its walls, up to 1.35m thick, rise through two floors
and define an internal area measuring 5m north east - south west, along the
straight rear wall, by up to 4.4m north west - south east, from the rear wall
to the apex of the curve.
The ground floor entrance faces north east and has a pointed arch framed in
white freestone, chamfered along its outer edges and measuring 1.98m high by
0.89m wide. Three almost semicircular gun ports pierce the base of the ground
floor wall, facing north east, ESE and SSE. The north east and ESE ports are
1.2m wide and 0.9m high on the outer face while the SSE port was larger, 1.6m
wide and 0.93m high, and is now blocked. The gun ports have short outer splays
and long barrel-vaulted inner splays: each inner splay and its vault is
unique, ranging from 1m wide to 2.55m wide on the inner face, reflecting
ad hoc solutions to supporting the wall above. A tall narrow fireplace was
provided in the south west wall, rising to a chimney in the wall thickness.
The rock-cut north west wall on the ground floor contains a recessed wall slot
for a small guard chamber immediately within the entrance. This chamber
extended 2.15m back from the entrance and was 1.75m wide, shown by wall
footings visible in the earth floor on the opposite side of the entrance;
joist slots in the rock face show its ceiling was 2.27m high. Higher joist
slots, in the masonry above the rock-cut face, are for the first floor at 2.9m
above the present ground floor surface; its floor slot is visible across the
masonry of the south west wall.
The first floor has five narrow windows with semicircular heads: two face
north east, two SSW and one faces ESE. The north east window above the
entrance is largely blocked, with a later brick-arched oven built into the
lower blocking and itself now blocked. Behind the windows are long inner
splays, much higher than the outer window apertures, with barrel-vaults
truncated by flat lintel slabs inserted in a later rebuild and their bases
0.5m-0.8m above the upper floor level. The enlarged vaults behind these
windows would enable their use as lookout and small-arms positions. To the
right of the first floor ESE window, and also facing ESE, is a larger gun
port, similar to those on the ground floor, with a deep barrel-vaulted inner
splay and its base at the upper floor level. Another gun port, now filled by
several phases of blocking and wall rebuild, is visible in the first floor
masonry of the north west wall, above the rock-cut face. That gun port has a
landward line of fire along the adjoining spine of the headland. In the west
corner, a winder stair ascends from the first floor to a former parapet walk
and was lit by two narrow slit windows, both now blocked.
Beyond the blockhouse, a short length of curtain wall, 2m-2.5m high, extends
south west from beside the blockhouse's west corner to the cliff edge, its
upper edge stepped as it descends the slope. The bulk of the curtain wall
crosses the much longer steep slope north east from the blockhouse. Adjoining
the blockhouse itself, this wall defines a small sub-rectangular bastion
projecting north west from the wall-line of the curtain and the blockhouse
rear. The bastion has straight sides and a curved outer wall, 0.75m thick,
pierced by two small inwardly-splayed musketry slits. The bastion is up to
5.75m north east - south west by 3.2m north west - south east internally.
Within its south west wall, an exposed steep rock face has a narrow cut shelf
and several hollows, denoting former staging erected beside the rear of the
blockhouse.
From the bastion, the curtain wall descends north east in a straight line to
the cliff edge. This wall, up to 3m high and 0.8m wide, also has a stepped
upper edge and is pierced by ten more musketry slits. A broad gateway through
the curtain wall is located close to the cliff edge and measures 2.16m wide
and 2.5m high, spanned by two flat granite lintel slabs. Its sides are faced
by neat granite quoins which end slightly short of the lintel, suggesting the
lintel slabs have been raised after original construction.
Within the curtilage defined by the curtain wall and the cliff edge, later
modifications mask or remove other features pertaining to the 16th century
blockhouse. East of the blockhouse, a platform was levelled into the rock at
the tip of the headland, 8m below the level of the blockhouse. The platform
now supports features of the 19th-20th century reuse. However, walling shown
at this location on an early 18th century engraving indicates that the
platform itself has a much earlier origin. The musketry slits in the curtain
wall show that the original route from the entrance to the blockhouse followed
the inner face of that wall. Its lower slope course has been removed by the
rock-cut insertion of a 19th century magazine beside the entrance, also
blocking the lower four musketry slits in the curtain wall.
Contemporary records give the building of this blockhouse as in the charge of
Thomas Treffry, a prominent landowner of Fowey, who went on to supervise the
building of Pendennis and St Mawes Castles on the River Fal estuary from 1540
in the main phase of Henry VIII's strengthening of the nation's coastal
defences. This blockhouse replaced two much earlier blockhouses a short
distance up the estuary on opposite banks at Fowey and Polruan, both of which
still survive. An extant map of the south west English coastline drawn in
summer 1540 depicts the blockhouse in this monument as `half-made' and those
earlier blockhouses as `decayed'. By 1684, the burgesses of Fowey reported the
blockhouse in this monument also as decayed, but a report on the town's
defences in 1786 indicates that it housed six cannon. In 1815, after the
Napoleonic Wars, all of the gun batteries covering the entrance to the estuary
were abandoned.
Major refurbishment of St Catherine's Castle was undertaken in 1855, during
the Crimean War. A battery for two guns was built on the seaward edge of the
lower levelled platform, below and east of the blockhouse, and a magazine was
built into the rock beside the curtain wall entrance.
The battery's two adjacent emplacements are accommodated behind a continuous
built parapet of mortared rubble capped by iron-cramped granite coping,
bevelled to the outer side. The parapet is 1.53m wide and rises to 1.46m high
along its inner edge. Within the part-circular recesses at the rear of the
parapet, each emplacement has two concentric iron gun carriage rails, called
racers, set in granite beds. The outer and inner racers measure 5.56m and
2.08m in diameter respectively along their midlines. Within the inner racer,
granite paving surrounds the central iron pivot post, 0.38m high and 0.19m
diameter, from which the pivot pin rises a further 0.12m.
The magazine was cut into the rock along the 5m of inner face of the 16th
century curtain wall beside the gateway. It has a flat roof and extends 3.75m
from the curtain wall, faced to the north east by an uncoursed rubble wall, 4m
high, alongside the gateway. The original route along the curtain wall to the
blockhouse at the upper level was replaced by steps cut into the rock forming
the south east side of the magazine.
This phase of refurbishment was commemorated by a series of square granite
plaques marked `WD 1855' affixed to the outer face of the curtain walls and
bastion, and to the inner face of the south west length of curtain wall.
Documentary sources record that in 1887, the Crimean War battery was armed by
two 64-pounder rifled muzzle-loading (RML) guns, manned by Artillery
Volunteers, and retained as a practice battery. This type of gun was obsolete
by the end of the 19th century and the battery was abandoned.
During World War II, from June 1940, St Catherine's Point became a gun battery
and observation post, the various structures of which extended from this
monument to the higher ground to the west. Within this monument, the
south western of the two Crimean War gun emplacements became the site for one
of the two guns which were this battery's initial armament. The 19th century
RML gun mounting was removed and the emplacement was filled with concrete to
the top of the 1855 rampart to serve as a solid foundation for mounting the
gun, a 4.7-inch naval gun. A large concrete protective shelter was built
around the gun and a concrete pill box, with a lower roof, was built alongside
it. The Crimean War magazine beside the gateway was reused for its original
purpose, as an ammunition store, while the 16th century blockhouse was used as
the firing point for a controlled minefield laid across the mouth of the Fowey
estuary. Other structures in the World War II battery were situated on higher
ground from 50m west of this monument, where another 4.7-inch naval gun
was mounted. After the war, the guns were dismantled in October 1945; in
succeeding years the concrete shelter and gun foundation in and around the
19th century gun emplacement, together with the pillbox, were broken up and
removed but the rock-cut recesses that accommodated them remain along the
north west and south west faces of the lower platform. These faces bear slots,
grooves and plug holes where the roofs, joists and walling of those structures
were keyed in to the adjacent bedrock.
All English Heritage notices, fixtures and fittings, power supply cables,
drains and the harbour light 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.
