Signal tower

The National Monuments Service's description

Situated on top of the ridge that runs NE-SW down the length of Great Blasket\An Blascaod Mór (c. 233m OD). The coastline is located approximately 350m to the NW and 420m to the S. Located on a very narrow level area on top of the ridgeline with steep slopes to the NW and SE. The surrounding area consists of unenclosed rough pasture. The adjacent tower\stations in the signal tower chain are found at Bray Head, Valentia Island (KE087-107----), located c. 24.5kms to the SSE, and at Sybil Head (KE042-190----), located c. 10.4kms to the NNE. The site of the signal tower on Great Blasket\An Blascaod Mór is located c. 3.4kms NE of a group of seven circular corbelled drystone huts (KE051-008---- to KE051-008006-) located to the SW end of Great Blasket\An Blascaod Mór, and c. 1.25kms SW of a holy well (KE051-004----), known as Tobernacruha\Tober na Croise, which is located adjacent to the coastline to the NE end of the island.

The remains of an early nineteenth-century (c. 1804-5) originally two-storey square-plan signal tower (approx. ext. dims. 5.85m NE-SW x 5.85m NW-SE) built with roughly coursed rubble stone masonry. The walls of the signal tower face, N, E, S, and W. The signal tower is now badly collapsed and only small sections of the ground floor level are now upstanding. These limited upstanding sections are surrounded by a large spread of rubble. Kerrigan established that the signal mast had been erected and the signal tower completed by 1806 (Kerrigan 1995, 278).

Traces of a sub-rectangular enclosure (ext. dims. c. 50m E-W x c. 20m N-S) are visible with an expanded rounded end to the W of the signal tower and a narrow rectangular-plan section to the E. The enclosure now survives as grassed-over banks and sections of collapsed rubble stone walling. What appears to be the mount for a signal mast is visible to the W of the signal tower. The stone mount is set in the base of a wide circular hollow demarked by a ring of flat stones. The mount is a neatly carved square stone block with a central slot. An upright stone is mounted in the slot, but it is not clear how long this has been in place.

The Ordnance Survey first ed. six-inch map, surveyed 1841-2, shows the tower set in the middle of an irregular sub-rectangular enclosure with a slightly rounded W end. The Ordnance Survey third ed. six-inch map, surveyed 1914-5, shows a more regular enclosure that is almost rectangular in plan and lacks any rounded element at the W, suggesting that the current form of the enclosure may be relatively recent. ‘Eire Sign 38’ is located to the W of the signal station, although the associated lookout post (L.O.P. 38) is located on the mainland at Dunmore Head.

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

Images by: Dr James Bonsall

Uploaded on: 27/07/22

Images:
KE051-017----.01 View from W
KE051-017----.02 Probable signal mount to W
KE051-017----.03 Detail of probable signal mount to W

References

Kerrigan P.M. 1995 Castles and fortifications in Ireland 1485-1945. Cork. The Collins Press.

Rathbone, S. 2020. ‘The Construction, Survival and use of Signal Defensible Guard Houses in Connacht and Ulster’; unpublished PhD Thesis, Institute of Technology, Sligo