Signal Tower — Canalough

Situated adjacent to c. 100m N of Black Ball Head (OD c. 85m). Located on a small flat rocky outcrop with moderately sloping ground adjacent to the S that gives way after a short distance at the steep sea cliffs that forms the coastline. The surrounding area consists of unenclosed rough pasture with a small number of disused fields, defined by irregular earthen banks, located adjacent to the NW. The adjacent stations in the signal tower\station chain are found at Dursey Island (CO126-005----), located c. 11.63kms to the W, and to the W side of Bere Island (CO128-013----), located c. to the 10.7kms to the E\ENE, now largely collapsed. The signal tower\station at Black Ball Head is located c. 750m SSW of a megalithic structure (CO127-052----) located adjacent to the coastline at Blackball Harbour. An early-nineteenth-century (c. 1804-5) two-storey over partial raised basement square-plan signal tower\station (ext. dims. c. 5.85m N-S x c. 5.85m E-W; int. dims c. 4.22m N-S x c. 4.28m E-W), built with roughly coursed rubble stone masonry. The walls of the signal tower face, N, E, S, and W. The signal tower is well-preserved and survives to its full height (H c. 11.5m). Sections of lime render surviving to the exterior with surviving patches of slate-cladding evident to much of the tower at the upper levels, which indicates that this tower was originally weatherclad. The N elevation bulges at the centre externally to house an internal chimney flue. There is a square-headed doorway to the centre of the S elevation at first floor level, which retains a cut stone sill\threshold to the base. This doorway would have been originally been accessed via a retractable ladder. The doorway is protected by a rectangular rubble stone machicolation supported by three squared rubble stone corbels. There are pairs of square-headed window openings to the E and W elevations at ground and first floor levels. Most of the cut stone sills have now been removed. A door opening has been formed at ground floor level to the N elevation. Bartizans are located on the NE and NW corners; these are built with brick and each is supported by three squared rubble stone corbels. Much of the cut stone coping survives over the parapet walls. A freestanding single-storey rectangular-plan rubble stone structure (ext. dims. c. 5m E-W x c. 3.5m N-S) is located adjacent to the N elevation of the signal tower\station. This structure formerly had a mono-pitched roof, now removed\collapsed. Cultivation ridges are evident in the landscape adjacent to the tower\station. The signal tower is set at the NE corner of an irregular sub-rectangular enclosure (ext. dims c. 40m NE-SE x c. 15m SE-NW) with a triangular protrusion to the NE corners. Enclosure defined by rubble stone walls that are collapsed in places. The E end of the enclosure deviates from the usual rectangular pattern found at signal tower\station sites in order to avoid a rock outcrop. Kerrigan established that the signal mast had been erected and the signal tower completed by 1805 (Kerrigan 1995, 278). The Ordnance Survey first ed. six-inch map, surveyed 1841-2, shows the signal tower\station set in the triangular protrusion with a small freestanding structure located adjacent to the N, and a larger freestanding rectangular-plan structure in the SE corner of the enclosure. The Ordnance Survey third ed. six-inch map, surveyed 1897-1904, indicates that the structure to the SE of the enclosure had been removed by this time but the small square building N of the signal tower is still indicated. The signal tower was part of a system of over 80 signal stations constructed by the British Board of Ordnance in the first decade of the nineteenth century to warn of the approach of a French invasion fleet. Signalling between sites was accomplished using a naval signal post. The system formed a continuous chain from Dublin Bay running clockwise all the way around the coast to Malin Head in County Donegal. It was abandoned by the mid-1810s when the threat of a French invasion diminished (Kerrigan 1995, 157-66). Compiled by: Stuart Rathbone Uploaded on: 15/09/22