Since the first beacons using open fires on the ground (often operated by wreckers to lure ships onto the rocks) there has been a continual evolution in the technology used in the provision of marine aids to navigation. This evolution has seen the development of lights from wood and coal open fires, through candles, lamps fuelled by animal fat, whale oil, paraffin oil, coal gas, carbide gas, bottled acetylene and propane gas, to electric filament lamp lights, electric discharge lamps, and light emitting diodes (LEDs). Sound signals have evolved from bells and explosive charge systems, through pneumatic sirens and horns, to electric horn systems.

The development of electricity also heralded the electronic age and radio aids to navigation including radio beacons and radio direction finding systems, racons (radar transponder beacons), satellite navigation, and differential GPS. This evolution continues today.

Lights and fog signals
With the completion of the electrification of gas lights, all our lights now use electric lamps of one type or another. However, many of these consume a lot of electrical energy. More energy efficient lamps are now available, leading to reduced power system requirements and cost savings. The increasing use of electronic aids and GPS reduces the need for long range lights. Large 1 kW metal arc lamps in first order lens systems are being replaced with single, or clusters of, low power lamps in the traditional lens, while reducing the range of the light to meet present needs. At offshore stations this can allow conversion from diesel generator power to solar power. At headland stations mains fail generator sets can be replaced with battery back-up systems.
At the other end of the scale there is often a need to increase the range of short range lights such as those on buoys. Modern sources such as tungsten halogen lamps and light emitting diodes (LEDs) make this possible with economical power sources.
Similarly, the need for high- power fog signals has diminished over the years, with many fog signals discontinued and others reduced in power. The mighty pneumatic systems, like Bull Rock, Baily, and Inishtrahull, have given way to electric horns with a range of two nautical miles.
 

Kilcredaune Lighthouse
The refurbishment of Kilcredaune Lighthouse was completed at the end of March 2005. The existing optic, a 5th order rotating catadioptric lens with two symmetrical panels, was retained, and the rotation motors replaced with a pair of Bodine brushless dc motors. The new 12 Volt 5 Amp cc8 etched evvelope lamps give a range of 15 miles, and are fitted in an Automatic Power apcl 10 lampchanger.
The existing standby diesel generating set, which started automatically in the event of mains failure, was removed. A new duplicated battery and charger arrangement was installed, comprising two sealed 330 Ampere-hour (Ah) batteries which will run the station systems for four days if the utility mains supply fails.
A Datac 932 monitoring system was installed to monitor the aid to navigation and pass information to the Telemetry Monitoring Centre at Dun Laoghaire by phone line.

St John's Point Donegal Lighthouse
St John's Point Donegal stands at the south-west tip of the long tongue of land after which it is named, and marks the peninsula and the many submerged rocks and shoal waters between it and the Bullockmore Buoy. The light has a 14 nautical mile range.
The station has undergone a major refurbishment to provide reliable operation for the next 20 years. The existing catadioptric cylindrical refractor lens was retained and the three 100 Watt lamps were replaced with an energy efficient cluster of four 35 Watt IRC halogen lamps. Two emergency lanterns with range of six nautical miles were installed. The station is powered from utility mains. The mains-fail generator set was retained to provide backup power for helicopter re-fuelling and the Attendant's dwelling.
The aid to navigation is powered from a duplicated battery system of 260 Ah capacity and chargers providing 4 days' reserve in the event of long term mains failure. The old Datac 900 series remote telemetery unit which monitored Rathlin O'Birne Lighthouse was replaced with a Datac 932 monitoring system. The Attendant's and workmen's houses were fully refurbished.

Cashla Bay Lighthouse
Cashla Bay lighthouse, often referred to as the 'cube on a tube' because of the shape of the construction, provides a 24 hour directional light to guide vessels entering Rossaveel Harbour. A new Vega pel6 precision directional light, fitted with a 250 Watt M36 tungsten halogen lamp, was put into operation on 18 July 2005, providing increased daytime ranges of three nautical miles (white sector) and two nautical miles (red and green), with night time ranges remaining at eight nautical miles (white) and six nautical miles (red and green). The station is powered from utility mains and the back-up battery was replaced with duplicated back-up batteries and chargers.

Old Head of Kinsale
A re-equip of the station at Old Head of Kinsale is in progress. A new energy efficient optic comprising two 150 Watt cdmt lamps in the existing biform first order lens was commissioned on 9 October 2005, with a reduction in range from 25 to 20 nautical miles. A new Pharos Marine SA850/4A fog signal also became operational with a reduction in range from four to two nautical miles.
The mains-fail generator set was replaced with a duplicated battery and charger providing 4 days' reserve. The surplus 12 kW generator will be used in Dun Laoghaire to provide mains-fail back-up during the rebuilding project. Nothing is wasted!

Blackrock Sligo lighthouse
The year 2005 has seen a major refurbishment of Blackrock Sligo. A new light comprising a 12 Volt, 35 Watt hp lamp mounted on an APCL 5 flasher lampchanger in an ML300 lantern was exhibited on 1 August to provide a light with a nominal range of 10 nautical miles.
The installation phase of this project was conducted in co-operation with ILV Granuaile, which remained on station and supported the technical team from Dun Laoghaire from 31 July to 14 August.
The installation team, under the management of the project manager, Brian Cogan, was accommodated on board Granuaile and were assisted by the crew under command of Captain Dermot Gray in all phases of the work. The new batteries and other equipment were lifted by helicopter from Granuaile to the rock. The team spirit of professionalism, determination, and co-operation by all should serve as a model for similar operations.
In April 2005 repairs to the landing and the gabion breakwater were completed. The work included removal of a large number of boulders that had been washed into the dock, replacement of three gabions displaced by winter gales, and the addition of five additional gabions at the tower end of the gabion wall, to replace the last remnants of the old masonry wall which was washed away.
In October 2005 a concrete apron was constructed around the base of the tower to protect against undermining. The work was necessary following storm damage to the existing apron earlier in the year. Forty-eight skip loads of ready mixed concrete were underslung by helicopter from Sligo Airport to the lighthouse for this work.

Ballycotton Lighthouse Since electrification in 1978 Ballycotton has been powered from triple diesel generator sets, with one generator running and two in reserve. This necessitated periodic visits from ILV Granuaile to refuel the station, as well as regular maintenance of the generators and fuel system. In July 2004 the esb laid an underwater mains electricity cable from the shore to Ballycotton Lighthouse, and the three generator sets were replaced with a 10 kW mains fail generator on 16 April 2005. The batteries and chargers were upgraded.
It was found that there was water within the structure of the tower walls. Drains have been installed in the walls while the source of water ingress is being investigated.
The existing light and 4 nautical mile fog signal were retained. This project is designed to provide reliable operation of the station for the next 10 years.

Electronic Aids to Navigation
Evolution is also evident in electronic aids to navigation.
DGPS The General Lighthouse Authorities' differential Global Positioning System (DGPS) was installed in 1998, using the radiobeacon transmitters to broadcast the DGPS corrections. The computers and communications routers of the system at Dun Laoghaire, Mizen Head, Loop Head and Tory Island were replaced by Trimble Navigation Ltd in early 2005 and updated to meet today's needs in a joint project with Trinity House and the Northern Lighthouse Board. The wire T transmitter antenna at Loop Head was replaced with a larger antenna and new 30 metre high masts in order to improve the performance of the antenna in bad weather. With the development of satellite navigation, the services to be provided in the next generation of DGPS are being examined by the GLAs and IALA.
Racons The future of racons is also under consideration. Following proposals in the International Telecommunications Union regarding reducing the bandwidth of S-band radars, the new generation of radars may not trigger existing S-band racons. Work is on-going in this area.

Automatic identification systems (AIS) Under the International Convention for the Safety of Life at Sea (SOLAS) all vessels greater than 300 tonnes engaged on international voyages must be fitted with AIS since the end of 2004. While the scope of AIS covers a wide range of applications, including ship to ship and ship to vessel traffic services, the focus of aids to navigation providers including Irish Lights is the use of AIS as an aid to navigation. AIS allows for a range of functions and Irish Lights has been involved in developing and trialling these over the last two years.
AIS trials in Dublin Bay using transponders on Kish, Baily, ILV Granuaile, and regular trading cargo vessels continue. A project financed by the (UK) Department for Transport investigating the use of AIS safety-related text messaging to warn shipping of traffic separation schemes and Marine Environmentally High Risk Areas in the North Channel has been completed in conjunction with the General Lighthouse Authorities' R&D Department. An EU Interreg IIIA financed project is being set up to assess AIS performance through the provision of AIS capability for the most critical floating aids in the Interreg IIIA area which covers the north and north-east coasts of Ireland. Six AIS base stations have been installed, at Fanad Head, Rathlin West, Ferris Point, Blackhead Antrim, South Rock Lightfloat, and St John's Point. Datac monitoring was deployed on five buoys, Limeburner, Foyle, South Hunter, Strangford, and Hellyhunter. The Belfast Fairway buoy will be fitted with an Akari AIS transponder.
Using the information from the Datac monitoring the base stations will transmit AIS information about the location and status of the five monitored buoys, thereby providing synthetic AIS capability for these buoys. This is designed to develop understanding and capability in deploying AIS aids to navigation and increase safety and cost effectiveness in our waters.
Loran-C The 2001 Volpe report in the USA drew attention to the vulnerability of GPS. Since then many organisations, including IALA and the Royal Institute of Navigation, have raised concerns over 'sole means' navigation. It is widely felt that a terrestrial based radionavigation system should be provided to back-up and compliment GPS. This view is reflected in the GLA marine aids to navigation strategy document 2020 The Vision.
In May 2005 the transmitter originally intended for Loophead was installed at the Rugby standard timing signal station in England, as part of a GLA R&D trial financed by the Department for Transport to assess the four main performance parameters of accuracy, integrity, availability, and continuity. The transmitter feeds into a new T antenna strung from existing tower masts. In September 2005, the Rugby station was integrated into the Lessay Loran-C chain. A static measurement campaign is being organised by the R&D department to evaluate the trial signals. Irish Lights is assisting by installing a Reelektronika Loradd receiver at Blacksod.
The Northwest European Loran-C System (nels) agreement terminated on 31 December 2005. France will continue to operate transmitters at Lessay and Soustons and the Control Centre at Brest, and will also finance the continued operation of Ejde. In December 2005 Norway announced that it would continue the operation of the four Norwegian stations until the end of 2006.

Kish Lighthouse rock armouring T

The Kish Lighthouse is unusual in that it has no foundation in the traditional sense. The structure is a concrete caisson that simply sits on the sea bed. Erosion close to the tower could easily, and quickly, undermine the lighthouse and cause it to tilt. To prevent such erosion a 15m wide layer of rock armour was placed around the structure at the time of construction. The integrity of this armouring is crucial to the long-term stability of the Kish tower.
Although the rock used is sufficiently large to ensure that it will not be moved by tidal and storm action it does, however, appear to sink slowly into the seabed. Erosion of the seabed beyond, but close to, the rock armouring could also cause loss of the rock armour. Surveys are therefore undertaken regularly to ensure that the rock armour is intact and to monitor changes in the sea bed nearby so that preventative action can be taken before irreparable damage is done.
It has been necessary on two occasions (most recently in 1992) to top up the armouring to ensure that it remains high enough above the underside of the caisson to prevent erosion of the sand from underneath the tower. It was also necessary to place small stone in the area beyond the rock armour in 1982 both to fill depressions that had formed and to increase the resistance to erosion in the future.
ILV Granuaile undertook a survey on 8 and 9 April 2005. Seán Cullen, Hydrographer of the Irish National Seabed Survey, Geological Survey of Ireland, was present as an advisor and also processed the data acquired during the survey. Jim Pickett, Civil Engineering Operations Manager, analysed this data and, happily, confirmed that the sea bed and rock armouring are stable.
In a separate project the Commissioners of Irish Lights, Dublin City Council, the Marine Institute, and contractors are co-operating on the installation of a tide gauge at Kish Lighthouse in connection with the Dublin Flood Defence Monitoring network. The system is also part of a national tide programme and will provide data to Met Éireann. The data from the tide gauge will be used for monitoring, research, and flood warning.

Structures
Evolution has an impact on structures as well as on aid to navigation systems. Following the automation of headland lighthouses, the Keepers' dwellings at many of them are being used for alternative heritage or holiday home purposes. At offshore stations the need for ventilation rather than heating has become apparent. Combined solar-diesel heaters are being used to condition dwellings and ensure they are habitable when needed.
The dwellings at Bull Rock and Eagle Island were upgraded to maintain living conditions while renovation of the storey-and-a-half house at Rathlin East was completed in October. The hand of time was evident in the footbridge at Mizen Head, when advanced internal corrosion necessitated the closure of the bridge in May 2005. A temporary scaffolding system over the bridge was opened in June 2005 to restore access to the light and buildings, pending development of a long term solution.
In August 2005 IALA arranged a seminar in Gothenburg to consider a balanced approach to lighthouse preservation through realistic, practical, and workable solutions to the restoration and preservation of different structures. A paper detailing Irish Lights' experience was presented by Dr Patricia Warke of Queen's University, Belfast, who described a case study on interior granite weathering in the offshore lighthouses of Eeragh, Slyne Head, and Eagle Island.
During 2005 it was found that the external rendering on the tower at Broadhaven was in very poor condition and had de-bonded over at least a third of the tower. This necessitated removal of the external render from the tower and its replacement with a lime based render which would be consistent with the original construction. This was completed in July 2005.

Major floating aids to navigation
A mini refit of the Kittiwake Lightfloat on the South Rock station was carried out on station by a combined Dun Laoghaire and Granuaile team. In addition to essential maintenance an AIS base station was fitted, thereby increasing the aids to navigation capability of the ship.
During the refurbishment of large automatic navigation buoy (Lanby) B in Dun Laoghaire, the remote control and monitoring system was upgraded by fitting a Datac 900 remote telemetry unit with 932 processor and replacing the radio link to Wicklow Head with a GSM telephone connection directly to the Monitoring Centre in Dun Laoghaire.
Vessel position monitoring was upgraded by fitting a Datac 922 remote telemetry unit GPS monitor. The remote telemetry units were linked so that each can reset the other, providing additional redundancy. Refurbished Lanby B was placed on the Codling station in November 2005 and Lanby C was recovered to Dun Laoghaire.
Evolution is also evident in the provision of major floating aids. Refits are carried out either on station or as short term projects in drydock, using a superbuoy as temporary aid on station. There is therefore no need for a spare lightfloat, enabling the sale of the Lightfloat Skua in May 2005.
Replacement of steel daymarks on buoys with standardised aluminium daymarks also involves discontinuation of sound signals on buoys; 2005 saw the withdrawal of sound signals on Skulmartin, Limeburner, South Hunter, Barrels, and South Long buoys.

Work in progress
The busy schedule of maintenance, refurbishment, and replacement of obsolete systems continues. Site works on the rebuilding project at Dun Laoghaire are set to commence in January 2006. The conversion of Rockabill from diesel generator power to photovoltaic power is in progress, taking account of the fact that Rockabill is a protected structure and a Special Protection Area under the Birds Directive, under which the island is designated as a Refuge for Fauna and a European Site.
The replacement of the Coninbeg Lightfloat with a superbuoy and adjacent fixed structure is at the planning stage, while equipment is being purchased for a major upgrade of equipment at Chaine Tower.
Refurbishment projects are in progress at Ballinacourty, Eeragh, Fastnet Rock, and Dunmore East. Storm damage repairs, routine and breakdown maintenance, painting, and building operations continue to be carried out to ensure that the Commissioners not only meet IALA availability targets but also ensure that our structures, buildings, and heritage are maintained in a cost effective and efficient manner.

The five year programme to convert buoys to standard aluminium daymarks and upgrade the solar power systems and lanterns is nearing completion.
My thanks and congratulations to all the Engineering Team for a splendid job.