Thursday, 1 November 2012

KRY12_03 / GEO12_02 - Inishbofin, Inishturk & Killary Harbour

In July and August 2012, the RV Keary and RV Geo spent several weeks mapping the seabed around Inishbofin, Inishturk and Killary Harbour. The vessels were based in Inishbofin harbour for the duration of the survey.

Initially, two specific sites were mapped for BIM (Bord Iascaigh Mhara) who are investigating the potential of deep-water aquaculture sites in the area. In addition, a larger area around the islands was mapped to provide bathymetric data for oceanographic current modelling to be carried out by the Marine Institute, along with extending INFOMAR coverage into the area around the islands.

The survey data revealed very interesting underwater topography, containing extensive rocky outcrop, fault lines and sedimentary features.

Below are images of the survey coverage and the vessels at work. Note that the colour scales may vary between the survey coverage images - the red and blue ends of the spectrum represent shallower and deeper water, respectively.

Survey coverage by RV Keary and RV Geo around Inishbofin and Inishturk. The RV Geo carried out the shallower water mapping along the coastlines. Data in this image is still in the process of being finalised and contains some errors.

The "Stags" rocks off the NW coast of Inishbofin.

A view of Inishturk's rugged coastline from the RV Geo.

RV Keary.

A backscatter map of the seabed around Inishbofin and Inishturk, merged with a shaded relief map. Backscatter maps are produced from the strength of the sound waves returning to the multibeam sonar, having reflected off the seafloor - this provides information on seafloor hardness, which is then represented in greyscale here (darker shades represent harder seabed). The grey polygon in the centre and eastern part of the map represents the extent of seabed previously mapped by the RV Celtic Explorer.

Folded rock strata on Inishturk's coastline. The onshore geology on both islands is complex and ancient - the seabed mapping carried out during the survey should help to extend the understanding of it into the offshore environment.

RV Keary transiting from Inishbofin to Cleggan.

RV Keary tied up alongside Inishbofin's ferry, the Island Discovery, in Inishbofin harbour.

Structural geology of Inishturk, with seabed coverage by RV Keary and RV Geo around the island. Onshore, faults are shown in black and the synclinal axes of folded strata are shown in red. The fault marked with the red arrow appears to extend offshore in a south-easterly direction as a discontinuity in the seabed rock outcrop.

Along with successfully acquiring bathymetric data, the INFOMAR vessels completed inshore mapping around Inishbofin and Inishturk - the data will be freely available in several formats on the INFOMAR website in the future.

Wednesday, 24 October 2012

KRY12_02 Bunmahon

Between the 13th and 18th June 2012, the RV Keary carried out seabed mapping off the coast of Bunmahon, Co. Waterford. This survey was conducted in support of the INTERREG funded Atlanterra Project, which has designated the Bunmahon area as a Geo-park. Learn more about Atlanterra at

During the survey work the Keary was based in the port of Dunmore East, from which the vessel could transit to the survey area. Existing bathymetric data lay to the south, having been collected by the RV Celtic Voyager in 2007, and it was ensured that the RV Keary's coverage overlapped with that to provide quality control on the data.

Two uncharted shoals were mapped during the course of the survey, with this information then delivered to the UK Hydrographic Office (UKHO) in the form of H-notes. The UKHO will then issue a Notice to Mariners, alerting them to these hazards and will include the shoals in New Editions of charts.

Examples of the data collected are below:

Seabed data collected off Bunmahon shown as shaded relief

Backscatter image of the seabed off Bunmahon. The RV Keary uses a multibeam sonar to map the seabed - when the sound waves it produces reflect back off the seabed, the strength of the return provides information on the hardness of the seafloor material. This greyscale map was produced using that data. Note also that this image shows the data collected by the Celtic Voyager to the south.

Shoal discovered during survey operations - originally charted at 14m depth (LAT) but now found to be at 7.5m depth (LAT). The top half of the image shows it in plan view, while the lower half is a profile view. LAT = Lowest Astronomical Tide.

Tuesday, 19 June 2012

INIS-Hydro - 2012 Progress

The 2012 survey season began with the RV Keary and RV Geo vessels making a return to Dundalk Bay, to continue mapping as part of the INISHydro Project. Both vessels have been re-mobilised and kitted out with survey instrumentation after wintering in Dublin.

The Geo, a 7.5m RIB operated by the Geological Survey of Ireland, underwent some significant re-fitting - this took the form of an extension to the aft part of the cabin, allowing for a larger work area for the surveyor's station and an equipment rack for the dry end of the survey instrumentation. A generator was also fitted in the Geo's engine bay, which removed the previous reliance on batteries to power the survey gear. These additions have greatly increased the RV Geo's capabilities as a survey craft.

RV Keary arriving into Port Oriel at sunset. Both vessels operated from this harbour, which is situated south of Dundalk Bay

INIS-hydro is a 3 year INTERREG IVA Programme with the Maritime and Coastguard Agency (MCA) in the UK as lead partners. The project brings together 7 partners to conduct hydrographic surveys in Ireland, Northern Ireland and Scotland. The partners are the MCA, Geological Survey of Ireland (GSI), Marine Institute (MI), the Agri-Food and Biosciences Institute (AFBI), the Scotish Association of Marine Science (SAMS), the Northern Lighthouse Board (NLB) and the United Kingdom Hydrographic Office (UKHO).

Areas of seabed to be mapped during the INISHydro project

The surveys will be undertaken in Dundalk Bay, Carlingford Lough, Dundrum Bay, the Firth of Lorn and South West of Islay by several different vessels drawing on expertise from the various partners. The bathymetric data will deliver 3D baseline maps using multibeam echosounder technology which will be freely distributed. The project also plans to harmonise hydrographic survey specifications and synchronisation for future surveys.

INISHydro partner organisations

These surveys comply with the partners obligations under the Safety of Life at Sea conventions and will be augmented with auxiliary scientific data collected in conjunction with the bathymetric data. Details of the project can be found on the website at

The project is essential as the current nautical charts for these areas were produced largely in the 19th century and whilst they were an enormous achievement for the surveyors of their day, these charts are not as reliable as their terrestrial counterparts and warrant updating. The territories to be mapped in the INISHydro project encompass important navigation channels, areas of environmental interest and potential sites for marine renewable energy. INISHydro also involves a very significant level of cooperation, bringing together so many partner organisations.

RV Keary and RV Geo in Port Oriel. Note the cabin extension on the Geo, which was added prior to this survey season

INISHydro mapping in 2012 commenced in April, with the arrival of RV Keary and RV Geo in Port Oriel. The vessels worked in partnership, with the Keary focusing on the approaches to Dundalk Harbour and the Geo carrying out survey operations around Dunany Point and the southern, shallow portion of Dundalk Bay.

Strong winds resulted in a rough sea state at times

Due to the exposed nature of Dundalk Bay, operations were sometimes hampered by regular strong, easterly winds. However, in spite of this the vessels significantly extended the bathymetric coverage that was gained last year (bathymetry is the water depth). The Keary mapped out a large wedge-shaped area of seabed that includes an interesting channel-like feature - this feature was also noted in last year's INISHydro blog entry.

RV Keary 2012 bathymetric coverage (does not include RV Geo coverage)

The Geo extended last year's shallow water coverage into an area of shoals around the headland of Dunany Point at the southern extent of Dundalk Bay, along with merging with RV Keary coverage to the east.

RV Geo coverage to date, merging with Keary coverage in the east. Note that the colour scale is different from the previous image - similar colours between the images do not represent the same depth

Mini ROV (Remotely-Operated Vehicle), a valuable tool for inspecting the Keary's propellors