Wednesday, 13 October 2010

KRY10_03 Clifden and Mannin Bay

On completion of the survey portion of work in Kinsale, the RV Keary made the transit to Clifden Bay to begin mapping in Clifden Bay, Mannin Bay and the seabed outside the bays, north of Slyne Head to Cruagh Island. The inner most and shallowest areas of the bays had been surveyed using LiDAR earlier in the year. Click here for more information on that LiDAR survey.

Overview image of multibeam sonar data of all coverage achieved in Clifden and Mannin Bays. LiDAR coverage is represented by the hatched area.

Initially the survey was concentrated in the deeper water areas, seaward of the bays. It was in this area, NE of the Barret Shoals that a steep outcrop of rock rising to a chart depth of 12.2 metres in surrounding water depths of 30 to 40 metres was mapped for the first time. This significant shoal was surveyed in detail and a H102 note was prepared for the United Kingdom Hydrographic Office (UKHO) so that this shoal location can be quickly updated in the charts as a possible danger to navigation.

Datasets showing the previously uncharted shoal mapped during INFOMAR survey KRY10_03, NE of the Barret Shoals.

Multibeam sonar data showing three charted shoals mapped west of Clifden Bay during INFOMAR survey KRY10_03. The data shows that water depths are shallower (shown as red and orange colours) over these rock outcrops than the surrounding seabed (shown as green and blue colours) and can present a danger to navigation.

Entrance to Clifden Bay with the beacon on Errislanan marking the southern entrance of the bay. In the background are the Twelve Pins mountains of Connemara. The ruins of Clifden castle can also be seen in the centre of the photograph. The RV Keary anchored in Clifden Bay during the survey of Clifden and Mannin Bay.

All INFOMAR data is available for free download here.

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