Polruan Blockhouse


Heritage Category: Scheduled Monument

List Entry Number: 1019056

Date first listed: 30-Nov-1959

Date of most recent amendment: 14-Mar-2000


Ordnance survey map of Polruan Blockhouse
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The building or site itself may lie within the boundary of more than one authority.

District: Cornwall (Unitary Authority)

Parish: Lanteglos

National Grid Reference: SX 12336 51085


Legacy Record - This information may be included in the List Entry Details.

Reasons for Designation

A chain tower is a small structure built beside a river or harbour to house the mechanism for raising and lowering a defensive chain to prevent the passage of ships in times of danger. They were built on the east, south and south west coasts of England on the important maritime approaches, such as those of Portsmouth, Plymouth and Dartmouth. The approach and towns in the Thames estuary were also chained. There were only 14 examples recorded nationally, and of these only five are known to have extant remains. The chain was normally laid across the river bed from bank to bank and raised when necessary. One or both ends of the chain would have a tower or building to house the lifting mechanism, and the other end would have a simpler means of attaching the end of the chain. Chain towers were usually strong, stone structures, capable of being defended, sometimes with dry moats or ditches to the landward side, and with accommodation for short term use by operators of the chain and a defensive garrison. There was a great variety in design. The earliest completed example is at Fowey, Cornwall, built after a raid on the town in 1457; a later example is at Gillingham, Kent, in 1667; most were constructed in the late 16th century.

The Polruan chain tower known as Polruan Blockhouse is one of only five known to exist in England. It and the chain tower on the opposite bank of the River Fowey are the earliest chain towers to have been constructed. The Polruan chain tower is also one of the most complete examples of a chain tower, being little altered since its construction. It became obsolete in the 1520s when St Catherine's Castle was built at Fowey, although it was reused briefly during the Civil War.


Legacy Record - This information may be included in the List Entry Details.


The monument includes a chain tower known as Polruan Blockhouse on the south coast of mid-Cornwall. The chain tower survives as a two storied rectangular building constructed on a low rocky promontory which juts out into the River Fowey, and is located opposite another chain tower known as Fowey Blockhouse (SM 31864). The structure is roofless and is orientated north west-south east. It is constructed of the local slate stone with moulded granite surrounds to some windows, gun ports and the main entrance. The tower is approached via a footpath through Polruan, and is entered through the main doorway, with a round arched, moulded granite surround at ground floor level in the south east wall. To the north east of the entrance is a rectangular slit or gun port, with three similar gun ports above the entrance. Built into the thickness of the wall, they appear as wide rectangular openings on the interior narrowing to slits on the exterior. Just above the ground floor gun port on the interior is a small square hole or recess in the wall, known as a putlog hole. On the southern corner at the top of the walls one crenellation survives. In the eastern corner on the interior is a doorway with iron hinges for a door, and the first few steps of a spiral staircase, with a doorway giving access to the first floor. In the southern corner is a rounded recess which probably held a spiral staircase from the first floor to the roof. On the ground floor of the north east wall is another gun port and two putlog holes. The north east ground floor wall appears thicker along this side, forming a wide ledge at first floor level, and there are two further gun ports on the first floor. This wall looks out towards the river mouth. The north west wall faces the opposite bank of the river towards Fowey Blockhouse. This wall contains a rectangular entrance with steps down to the rocky promontory, to give access at ground level to the river, and a gun port to the north with a rectangular recess or large putlog hole above. Again this wall is wider, forming a narrow ledge at first floor level, with two further gun ports with granite surrounds. The western gun port is in the shape of an inverted keyhole. The south west wall faces upriver and contains a fireplace at ground floor level, with a gun port (probably later) inserted into its back wall, and a fireplace with chimney on the first floor. To the east of the ground floor fireplace is a window with granite mullion and on the first floor is another similar window to the west of the upper fireplace. The upper fireplace had a large slate mantel. The ledges formed by the two thicker walls may have been to support floorboards, or to strengthen those walls most likely to come under attack. The windows and fireplaces are in the wall looking upriver, from which direction attack was least likely. The tower is a Listed Building Grade II*. Both this chain tower and the one on the opposite side of the river were probably built in response to a raid on the town of Fowey by the French in 1457. Leland, travelling in the 16th century, states that the towers were built during the reign of Edward IV (1461-1483). Polruan Blockhouse was equipped for use with guns, the inverted keyhole gun port in the upper north east wall, and the timbers set into the sills of the three first floor gun ports above the south east entrance for the mounting of small guns, support a mid- to late 15th century date. The two chain towers were designed to have a chain laid across the river between them which could be raised to prevent enemy shipping reaching the town of Fowey. Leland also records that after hostilities with the French ceased, the men of Fowey continued to raid French shipping and as a punishment had their ships confiscated by the men of Dartmouth and the chain between the two towers removed. In 1776 two links of a large chain were dredged up from the Fowey estuary, which were believed to be part of the chain across the river. Advances in artillery made the tower obsolete and it was superseded by St Catherine's Castle in the 1520s, on the opposite side of the river. The tower is illustrated on a map of around 1540. Marked `decayed', it is shown as a two storied building with crenellations and possibly a wall extending out along the rocky promontory. An engraving of 1786 also shows a crenellated wall extending along the promontory though an earlier engraving of 1734 does not. Possibly this wall, of which there is no trace today, protected access to one end of the chain across the harbour mouth. This tower was reused during the Civil War. In 1644 the Parliamentarians were being forced to retreat down the Fowey peninsula and were hoping to escape from Fowey by ship, however the Royalists seized and held Polruan Blockhouse, so giving them control over shipping entering or leaving Fowey. The later gun port inserted into the ground floor fireplace in the north east wall may have been made at this time. The lifebelt and its box on the exterior of the north west wall, the two information plaques above the south east entrance, the cable along the wall to the south of this entrance and the concrete surface of the footpath to the south east entrance are excluded from the scheduling, although the ground beneath all these features is included.

MAP EXTRACT The site of the monument is shown on the attached map extract. It includes a 2 metre boundary around the archaeological features, considered to be essential for the monument's support and preservation.


The contents of this record have been generated from a legacy data system.

Legacy System number: 31863

Legacy System: RSM


Books and journals
Chandler, J, John Lelands Itinerary: Travels in Tudor England, (1993)
Keast, J, The Story of Fowey, (1987)
Keast, J, The Story of Fowey, (1987)
Keast, J, The Story of Fowey, (1987)
Keast, J, The Story of Fowey, (1987)
Saunders, A D, Fortress Britain, (1989)
Saunders, A D, Fortress Britain, (1989)
Brown, S, 'Devon Archaeological Society Proceedings, Berry Pomeroy Castle' in Berry Pomeroy Castle, , Vol. No 54, (1996)
Parnell, G, 'Devon Archaeological Society Proceedings, Berry Pomeroy Castle' in The Gunports at Berry Pomeroy Castle, , Vol. No.54, (1996)
Consulted January 1999, Cornwall SMR entry for PRN No. 26851,
Title: 1:25000 Ordnance Survey Map; SX 05/15; St Austell and Fowey Source Date: 1980 Author: Publisher: Surveyor:

End of official listing