ILV Granuaile was chartered by the Geological Survey of Ireland (GSI), on behalf of the Department of Communications, Marine & Natural Resourses (DCMNR), to conduct a seismic survey at the Rockall and Hatton Banks in July of 2004. The seismic survey was part of the National Seabed Survey which has been ongoing for 4 years. The charter was for 27 days from mobilisation to demobilisation at Dublin Port.

The seismic survey equipment employed for data acquisition was a 1200 metre hydrophone on its own motorised cable reel, with air guns attached. An array of high powered computers and monitors was installed on the bridge for monitoring the 95 channel hydrophone, processing the acquired data, and position monitoring.

A party of eight people from the charterers was with us for the duration of the charter: the Party Chief supervising the survey and representing the charterers on board, a geologist conducting quality assurance of the acquired data, two on-line surveyors processing the acquired data, three technicians from the company which rented the hydrophone and air gun to the charterers, and one cetation (whale and dolphin) officer to conduct a wildlife study of the survey area.

At 1800 hours on 30 June, with the equipment loaded and tested, we departed from Dublin Port in strong westerly winds on passage to the survey area. The forecast was for the winds to decrease to light at our destination. The trip to the deployment area was uneventful, the strong winds and heavy swell giving the surveyors an opportunity to find their sea-legs and come to terms with what conditions on board could be like for the following 27 days.

The Irish Lights crew was also beginning to realise exactly what to expect for the next 27 days. When out of telephone range mobile phones were switched off and questions such as ‘will we get Coronation Street out there’ and ‘Liverpool are playing Arsenal next Saturday—will we see it’ were asked. The soap and footie fans were clearly anxious. Fortunately, satellite TV ensured that all the soaps and football could be followed.

After four days steaming we arrived at the deployment site in good weather conditions, the hydrophone and air gun were deployed, and the survey commenced. Our task was to run some 22 survey lines of an average length of 150 nautical miles. Our instructions from the charterers were that the maximum speed was to be 5 knots and that we were not to survey in weather conditions where winds were above force 5. These limitations were set as the expensive hydrophone could become damaged if it were subjected to excessive strain.

The weather was ideal for the first week, with light winds and low swells. Due to our location there were 19½ hours of daylight, with full darkness occurring from midnight to 0430 hours. The surveyors reported that data acquisition was excellent and all was going well. Daily situation reports were transmitted by Satcom C to the office in Lower Pembroke street, and Irish Lights was monitoring our position with Purple Finder, a satellite based vessel monitoring system.

During the long calm days the cetation officer, Mick Mackey, an Austrailian working at University College Cork, set himself up on the monkey island with a camping seat and binoculars. He was astounded by the amount of sea life that he observed in that period. Pilot whales, sperm whales, a pod of killer whales, sun fish, cormorants, and arctic terns. Six hundred pilot whales were observed during the course of the survey. Our crew became quite competent in observing and distinguishing the gender and age of pilot whales, thanks to the observation books which Mick left on the bridge, and would report comprehensive sightings to him after his meal breaks.

We observed a lot of fishing activities taking place and several Russian and Spanish long line fishing boats were encountered during the survey. We also observed several commercial vessels transiting the area, and with AIS installations we were able to identify their names, destination, number of persons on board etc.

After the initial week the weather took a turn for the worse and long periods of good settled weather did not return. Atlantic lows were passing frequently causing us to lie hove to for up to four days at times. The remainder of the survey was carried out between the lows. However, even with this weather, 90% of the survey was completed and weather downtime limitations were not exceeded. The surveyors were pleased with all data acquired.

During the final day on location the wind was westerly force 8 and a decision was made to return to Dublin. An initial course was set for Inishtrahull Sound and we proceeded with following winds and seas.

The Channels* set in on the second day of our return passage. Some 100 nautical miles from the Donegal Coast I heard a lot of activity on the Monkey Island. I went to investigate and found members of the survey team and our crew huddled into corners holding their mobile phones to the sky hoping to get a signal. There was a general air of excitement about the ship that I have not witnessed since I was deep sea and homeward bound. The Irish Coast Guard radio operators at Malin Head added to that homeward bound feeling with their enthusiastic welcome home as we passed their station.

On our return to Dublin demobilisation took place. The ship berthed at Sir John Rogerson’s Quay and we prepared to resume Irish Lights operations. A modest reception on board was hosted by Irish Lights, attended by the charterers and interested parties who were attending workshops relating to the National Seabed Survey in Dublin that day. Our Chief Executive, Mel Boyd, made a speech, followed by speeches from the primary charterers.

The charterers concluded that the survey had been well executed and valuable data had been acquired for the National Seabed Survey. They said that Granuaile was an excellent platform for this type of work because of her well appointed deck, her equipment, accommodation, and the professionalism of her crew.

From my own perspective I was more then satisfied with the performance of the ship, her equipment, and especially the crew who demonstrated, as usual, a high degree of professionalism, friendliness, and courtesy to the surveyors.



* The term channels is a jolly jack term, still used today, to describe the exitement felt by British sailors of the Royal Navy when their ship entered the English Channel after years of being away. Arrival in the Channel meant the voyage was over and the ship would soon be arriving at a home port meaning leave for her crew. Irish and British sailors still use this term near the end of a trip to describe the anticipation of going home on leave.



Captain Dermot Gray is Master of ILV Granuaile.