Marine Notice 3D Ocean Bottom Cables (OBC) Seismic Survey over the Corrib Gas Field, West Coast of Ireland.

Monday, 16 April 2012

Notice to all Shipowners, Fishing Vessel Owners, Agents, Shipmasters, Skippers, Fishermen, Yachtsmen and Seafarers

The Department of Transport, Tourism and Sport has been advised that Shell E & P Ireland Limited is scheduled to carry out a 3D seismic survey off the west coast of Ireland, over the Corrib Field.  The coordinates of the overall survey area are highlighted in the table below and there is also a map attached for reference.

The planned start date of the survey is 1st June 2012 and, weather permitting, the survey should be completed around the middle of September 2012.

The seismic acquisition will comprise a two-boat operation; the “M/V OCEAN PEARL” (Call sign: LAGD6) will lay the Ocean Bottom Cables on the seafloor and will collect all data records, whilst the “M/V MALENE OSTERVOLD” (Call sign: LCIU3) will serve as the source vessel.  In addition to the seismic vessels, a third vessel will act as a Guard Vessel. 

Seismic acquisition will occur over a set of six active 12km long solid Ocean Bottom Cables laid 400m apart on the sea bed at a depth of 350m by the “M/V OCEAN PEARL”. At the end of each cable is a 1km lead-in section which is attached to a standalone buoy at surface. These buoys contain a power pack as well as a recording system. Each buoy contains a radio-link with the cable-laying vessel for remote control of the buoy and for data quality control. Each buoy has a GPS receiver, so its location is well known to both seismic vessels. One by one these cables are ‘rolled along’ i.e. picked up from the northern edge of the active spread, and redeployed at the southern edge.

The “M/V MALENE OSTERVOLD” will be towing two seismic sources, and operating around the set of six active 12km long cables.

The overall survey area as shown in the map below is divided into three work areas or Contact Zones (A, B and C). A Contact Zone is defined by a 10 kilometre radius circle. The coordinates of the centre point of each zone are listed on the map. Radio Navigation Warnings will be given out daily by the Irish Coast Guard, giving the coordinates of the centre point of the working area / Contact Zone for that day.

All vessels will be listening on VHF CH 16 throughout the project.

All vessels, particularly those engaged in fishing, are requested to give the “M/V OCEAN PEARL”, and the “M/V MALENE OSTERVOLD” a wide berth and keep a sharp lookout in the relevant areas.



Latitude (WGS84)

Longitude (WGS84)













All mariners are reminded of their responsibilities under the International Collision Regulations and are reminded of Marine Notice No. 17 of 2007, which gives general advice in relation to the activities of vessels engaged in survey work for hydrographic, seismic, fishing research and underwater operations

The International Regulations for Prevention of Collisions at Sea are implemented in Irish law by the Collision Regulations (Ships and Water Craft on the Water) Order, 1984 (S.I. No. 29 of 1984) as amended by the Collision Regulations (Ships and Water Craft on the Water) (Amendment) Orders, 1990 (S.I. No. 36 of 1990), 1993 (S.I. No. 287 of 1993) and 2005 (S.I. No. 47 of 2005).  These Statutory Instruments are available from the Government Publications Sales Office, Molesworth Street, Dublin 2, Tel: (01) 6476834, or from the website:

Director General,

Maritime Safety Directorate,

Department of Transport, Tourism and Sport,

Leeson Lane, Dublin 2, Ireland.


For any technical assistance in relation to this Marine Notice, please contact: The Marine Survey Office, Leeson Lane, Dublin 2, tel: +353-(0)1-678 3400.  

For general enquiries, please contact the Maritime Safety Policy Division, tel: +353-(0)1-678 3418.

Written enquiries concerning Marine Notices should be addressed to:

Maritime Safety Directorate, Department of Transport, Tourism and Sport, Leeson Lane, Dublin 2, Ireland.

email: [email protected] or visit us at:

Last Updated ( Monday, 16 April 2012 )