Rotten Island Lighthouse (Irish: ''Teach Solais An tOileán Bréan)'' is a harbour light to light the passage from St. John's Point to inner channel and past the rocks to the anchorage within

Killybegs Killybegs () is a town in County Donegal, Ireland. It is the largest fishing port in the country and on the island of Ireland. It is located on the south coast of the county, north of Donegal Bay, near Donegal Town. Its Irish name ''Na Cealla ...

Harbour,

Donegal Bay Donegal Bay (''Bá Dhún na nGall'' in Irish) is an inlet (or bay) in the northwest of Ireland. Three counties – Donegal to the north and west, Leitrim and Sligo to the south – have shorelines on the bay, which is bounded on the w ...

Ireland Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...

. It is operated by the

Commissioners of Irish Lights The Commissioners of Irish Lights ( ga, Coimisinéirí Soilse na hÉireann), often shortened to Irish Lights or CIL, is the body that serves as the general lighthouse authority for Northern Ireland and the Republic of Ireland and their adjacen ...

History

The Inspecting Commander of the

Coastguard A coast guard or coastguard is a maritime security organization of a particular country. The term embraces wide range of responsibilities in different countries, from being a heavily armed military force with customs and security duties to ...

wrote to the Ballast Board on 21 April 1832 recommending that a light be placed on Drumanoo Point.

George Halpin George Halpin (Sr.) (1779? – 8 July 1854), was a prominent civil engineer and lighthouse builder, responsible for the construction of much of the Port of Dublin, several of Dublin's bridges, and a number of lighthouses; he is considered the f ...

, Inspector to the Ballast Board, agreed that a light was necessary but he recommended

Rotten Island Rotten Island ( ga, An tOileán Bréan) is a small island close to the entrance of Killybegs Harbour, an inlet of Donegal Bay, in County Donegal, Ireland. Features Rotten Island lighthouse was established in 1838 and is still operational. It ...

instead. The Ballast Board then approved a light in 1833 and Statutory Sanction was obtained from

Trinity House "Three In One" , formation = , founding_location = Deptford, London, England , status = Royal Charter corporation and registered charity , purpose = Maintenance of lighthouses, buoys and beacons , he ...

Design and construction

The lighthouse and keepers' houses were designed by George Halpin and the works were carried out by the Board's workers under his inspection. The conical tower of cut granite was painted white. The original light was a fixed white

catoptric Catoptrics (from grc-gre, κατοπτρικός ''katoptrikós'', "specular", from grc-gre, κάτοπτρον ''katoptron'' "mirror") deals with the phenomena of reflected light and image-forming optical systems using mirrors. A catoptric ...

third order lens pointed to land 66 feet above high water and visible in clear weather for 12 miles. It was first exhibited on 1 September 1838 before completion. The cost at the end of 1839 amounted to £8,697.19s.4d. On 15 September 1836 three men drowned while returning from work on the rock as their boat capsized.

Changes

In 1910 the fixed light was changed to a fifth order

dioptric Dioptrics is the branch of optics dealing with refraction, similarly the branch dealing with mirrors is known as catoptrics. Dioptrics is the study of the refraction of light, especially by lenses. Telescopes that create their image with an objec ...

lens, flashing with a character of one flash every three seconds. This new light was introduced on 13 December 1910. The station was automated on 7 January 1959 and the dioptric lens with its revolving machine and vaporised paraffin incandescent burner were replaced by a new fourth order cylindric refractor lens. Its mantle light source used dissolved acetylene from a battery of cylinders giving a

candlepower Candlepower (abbreviated as cp or CP) is a unit of measurement for luminous intensity. It expresses levels of light intensity relative to the light emitted by a candle of specific size and constituents. The historical candlepower is equal to 0.981 ...

of 2,600 white light and 500 in the red sector. This appeared to be worse than the old light and mariners using the harbour complained about the new lens. The light was converted to

electric Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by ...

on 1 February 1963 which increased the candlepower to 13,000 white and 2,600 in the red sector of the light. The character though remained the same, one flash every three seconds. If the

electricity supply Mains electricity or utility power, power grid, domestic power, and wall power, or in some parts of Canada as hydro, is a general-purpose alternating-current (AC) electric power supply. It is the form of electrical power that is delivered to h ...

fails, an automatic changeover to batteries comes into operation and an acetylene standby can be fitted if the battery standby fails. The character was changed to one flash every four seconds on 1 February 1965.

References

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External links

Commissioners of Irish Lights
{{Authority control Lighthouses completed in 1838 Lighthouses in the Republic of Ireland Lighthouses on the National Inventory of Architectural Heritage

History

Design and construction

Changes

See also

References

External links