| Summary : Old Blockhouse, as it is known, was built between 1548 and 1552 as a raised gun platform with adjoining living quarters. In 1652, it was referred to as 'Dover Fort' in a Parliamentary Survey of Scilly. The blockhouse is situated on a low headland at the south-east edge of Old Grimsby Harbour, on the east coast of Tresco. It commands a field of fire to the north-west, across the harbour and to the north-east between Tresco and Tean. The blockhouse forms part of a series of fortifications built on Scilly between 1548 and 1554 in response to threats from the French. A second blockhouse, now known as Cromwell's Castle, was built on the other side of the island (see Monument Number 303385). In 1651, during the Civil War, the blockhouse was used by Royalists to mount heavy gunfire on Parliamentary forces attacking the adjacent stretch of Tresco's north-eastern coastline. It is recorded as still in use in 1750. The blockhouse consists of a gun platform of four unequal sides, which is paved with hard standing on the north-west and north-east sides for artillery. The platform is defined by a parapet, one metre thick, with splayed openings for guns, known as embrasures. The blockhouse was built of randomly coursed granite walling with more regular quoins. A storage chamber, probably for ammunition or gun powder, is built against the south-east wall. The blockhouse was defended from landward attack by a single semi-circular rampart around the western and southern crest of the headland's summit. It is visible as an earthen bank up to 10 metres wide and 0.5 metres high externally. Coastal erosion along the headland east of the blockhouse has revealed mortared walling within deep deposits of blown sand. These are thought to represent lines of seaward defence for the blockhouse. It is now in the care of English Heritage. |
More information : (SV 89721546) Block house (NR) (1)
A small blockhouse existed in 1554, probably on this site and the basis for the present 'Old Blockhouse' used in the Civil War.
It now consists of a rectangular stone paved platform approached by stone steps from west and originally had a parapet with embrasures at west end of north and south side. Traces of an earth bank of uncertain date defended it from landward attack.
In the Parliamentary Survey of 1652 it is called 'Dover Fort'.
Meagre living quarters were provided with originally a lean-to structure in the south west corner. Later a room was added to the south west corner with access to the platform. (2)
The Blockhouse. Late 16th or early 17th century. Grade 2. (3)
In 1796 it was 28ft long, 22ft wide and had two stone platforms on top, secured by a parapet. (4)
The blockhouse is as described above.
Surveyed at 1:2500 on PFD. (5)
Listed 1992. (6)
Antiquity Model. (7)
Scheduled. Old Blockhouse, as it is known, was built between 1548 and 1552 as a raised gun platform with adjoining living quarters. In 1652, it was referred to as 'Dover Fort' in a Parliamentary Survey of Scilly. The blockhouse is situated on a low headland at the south east edge of Old Grimsby Harbour, on the east coast of Tresco. It commands a field of fire to the north west, across the harbour and to the north east between Tresco and Tean. The blockhouse forms part of a series of fortifications built on Scilly between 1548 and 1554 in response to threats from the French. A second blockhouse, now known as Cromwell's Castle, was built on the other side of the island (see associated monument record). In 1651, during the Civil War, the blockhouse was used by Royalists to mount heavy gunfire on Parliamentary forces attacking the adjacent stretch of Tresco's north eastern coastline. It is recorded as still in use in 1750. The blockhouse consists of a gun platform of four unequal sides, which is paved with hard standing on the north west and north east sides for artillery. The platform is defined by a parapet, one metre thick, with splayed openings for guns known as embrasures. The blockhouse was built of randomly coursed granite walling with more regular quoins. A storage chamber, probably for ammunition or gun powder, is built against the south east wall. The blockhouse was defended from landward attack by a single semi-circular rampart around the western and southern crest of the headland's summit. It is visible as an earthen bank up to 10 metres wide and 2 metres high externally. Coastal erosion along the headland east of the blockhouse has revealed mortared walling within deep deposits of blown sand. These are thought to represent lines of seaward defence for the blockhouse. (8)
A brief history and description. (9)
A discussion of the order of construction of the defences on Tresco, including the Blockhouse, is presented in this publication, along with several illustrations. (10)
The slight earthwork bank, less than 0.5m high, around the Blockhouse is not as smooth and neat as depicted on the AM (SV 81 NE 29) but the general impression is correct. (11)
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