New dome for Inishtrahull Lighthouse
Brian Kelly
Inishtrahull, located approximately 10 kilometres north east of Malin Head, is home to the most northerly Irish lighthouse. The original lighthouse built on the eastern end of the island was established in 1813 largely due to the increase in the number of British Navy ships using Lough Foyle. In 1958 a new lighthouse was established on the western end of the island at which stage the old lighthouse was taken out of service. Both the new lighthouse and the ruins of the old one can be found on the island today. The station was automated and the last of the lighthouse keepers left the station on the 30 April 1987.
The lighthouse was solarised in 2000 and, as part of that project, the station also underwent a major re-equip and replacement of some time expired equipment. 2010 saw the undertaking of a 10-year intervention project designed to attend to any items requiring attention since the solarisation. The solar and diesel engine start batteries, Racon and fog detector were all listed for replacement as part of the project though arguably the biggest part, and certainly the bit which required the most planning, was the replacement of the existing lighthouse dome with its integrated fog signal diaphone. It was decided that the best solution was to replace it with a new Glass Reinforced Plastic (GRP) dome. As it had been a long time since we had fitted a GRP dome this added an additional level of complexity to the project.
It was decided that the project would be tackled in two phases: the replacement of the dome was the first priority as it needed a run of good weather to complete the task. Once the new dome had been fitted phase two, which included all of the inside work, would start. As this phase of the work wasn't dependent on good weather it could be completed as we headed into the autumn and winter months.
A Notice to Mariners was required for Phase one of the project as it required the main light to be extinguished and the use of temporary lights. This had the effect of reducing the range of the light to 10 nautical miles. Notice to Mariners No. 7 (2010) was published on 26 April 2010.
Drawings for the new dome were prepared by the Drawing Office team and a number of suitable companies were invited to Tender for its manufacture and supply. Following an extensive selection process the contract was awarded to Frank Casey Glassfibre in Kildare.
On 29 June 2010 the main light was extinguished and the temporary lights were switched on. The scaffolding around the dome was erected by the coast team and that allowed a team of technicians to start dismantling the old dome. Due to its size and weight it had to be cut up into small sections using gas burners before being lowered to the ground. The replacement dome was underslung from Malin Head on 19 July using the contract helicopter.
A new stainless steel wall plate was secured to the lantern onto which the new dome would be attached. Both sections of the new dome were then raised to the top of the tower, sealed and bolted together. The dome was now ready to be secured to the lantern. Plenty more sealant was used and the new dome was bolted on to the new wall plate. A new stainless steel ventilator, new lightning protection and down pipes were fitted to the dome.
While all of this work was going on the plans for the delivery of the materials required for Phase two to the station were being finalised. The ship was used as the base from which to fly the materials to the station, significantly reducing helicopter flying time and costs. Granuaile took delivery of the new batteries and other necessary equipment in Dun Laoghaire before travelling north to Inishtrahull.
The plan was to fly the batteries to the station on 14 September; however, nobody told the weatherman of our plans! The weather changed bringing strong winds which made helicopter operations impossible. The following days saw heavy seas which made it impossible to lift the equipment off the deck of the ship. Thankfully after five days it all fell into place. On 19 September the batteries and chargers were air lifted to the station and all of the old sections of the diaphone were flown on to the ship for return to Dun Laoghaire. On 5 October all of the old batteries were taken ashore to Malin Head where a recycling contractor collected them free of charge and brought them off for recycling.
This project is due to be completed later this year within budget. All projects require lots of planning, and this was no different. Having Granuaile and the helicopter in the same area on a specific day as well as having the contractor on site to meet the helicopter took some juggling. A big thank you must go to everybody who was involved in the project. There are too many to mention by name but you all know who you are. From the Drawing Office Technicians who designed the dome and the scaffold to the Coast Team who built the scaffold, the crew of Granuaile, both helicopter pilots, our Lighthouse Technicians, Support Operatives and Attendants - all deserve great credit for the manner in which they seamlessly worked together in a highly professional and efficient manner.