Western HVDC Link: Update on Exposed cable locations in Irish Sea, North Channel, Firth of Clyde – May 2017

[Update – the information in this notice has been superseded by more recent notices.  The notice remains as part of the historical record of notices issued for this project.  Please refer to the most recent notice for an up-to-date record of the notices presently in place for this project.  This can be accessed via the project description page here.]

Mariners are advised of an update to the locations of exposed areas of cable on the Western HVDC Link cable route following recent cable laying and protection activities.  The location of the areas of exposed cable is given in a Notice to Mariners that can be downloaded here and which is summarised below.

Exposed cable locations

There are several sections of exposed cable along the cable route at locations where cable burial or protection has not been possible and at some remaining planned cable crossing locations.  These sections are currently being monitored by Guard Vessels which have been deployed locally.

To assist all mariners, a consolidated list of exposed cable locations  (as of 9th May 2017) has been compiled.  This list is included in the notice to mariners that can be downloaded here.  A brief update on the status of different parts of the route is provided below.

Firth of Clyde (Campaigns 4a & 4b)

Cable laying work has been completed along most of this route (from Ardneil Bay to the west of Ailsa Craig).  The only exposed areas remaining are close to the landfall, at three planned service crossings and at the end of the cables, where burial work will be carried out after jointing work has been completed.  The location of the exposed areas in the Firth of Clyde is given in Table 1 of the notice to mariners which can be downloaded here.

North Channel & Firth of Clyde (Campaigns 3 & 6)

Campaigns 3 & 6 run through the North Channel and into the southern part of the Firth of Clyde.  On these sections of the route there are still some small exposed areas of cable associated with localised hard seabed conditions.  A review is being carried out to reduce the requirement for protection by rocks along this part of the cable route.  The locations of the exposed areas is detailed in Table 2 of the notice to mariners that can be downloaded here.

Irish Sea (Campaign 5a)

A length of cable has been surface laid between KP233 (approximately 18.5km south-west of the Calf of Man) to KP176 (approximately 16km east of Millen Bay, NI).  The southern end of this cable has been jointed to the cable laid during Campaign 2 at KP233.

The cable is currently being buried by post-lay jetting along the route by the vessel Normand Pacific.  The location of this cable is detailed in Table 3 of the notice to mariners that can be downloaded here.

Guard vessels

Guard vessels have been stationed along the cable route during installation and burial to ensure the safety of marine users.  They will remain in position until cable protection  operations are completed to advise mariners of the location of exposed cable.

In areas where the cable crosses other cables and pipelines that are in service, the guard vessels will remain on station until cable protection has been completed in these locations (either through concrete mattressing or rock placement).

Vessels are requested to pass at a safe speed and distance and fishing vessels are advised to remain a safe distance (approximately 1.5 nautical miles) from the areas identified. Guard Vessels have been deployed at each location to aid in monitoring the exposed areas and advise of safe distances locally.

The locations of Guard Vessel areas and exposed sections are shown in Tables 1, 2 & 3 of the Notice to Mariners which can be downloaded here.

Notices to Mariners

The Notices to Mariners that are presently in place for this project are:-

  • Exposed cable locations: Update, Irish Sea North Channel, Firth of Clyde – this is the notice described above.  It was issued on 9th May 2017 and provides an update on exposed cable locations in these areas.  The notice can be downloaded here.
  • Western HVDC Link: Cable Installation Campaigns 4b (Firth of Clyde) and 5a (Irish Sea) – this notice was issued on 9th May 2017 and provides an update on proposed cable installation work in the Firth of Clyde and the Irish Sea.  It can be downloaded here.
  • Debris – this notice was issued on the 15th March 2017.  It informs mariners of the location of some debris that was found during the Pre Lay Grapnel Run along the cable route to the south of the Isle of Man.  The notice can be downloaded here.
  • Concrete mattressing – along the cable route concrete mattresses have been laid at crossings of existing cables and pipelines.  A notice to mariners about the mattressing campaign conducted in 2015 can be downloaded here.

Earlier notices are all rescinded.

Posted in Fishery Liaison, Western High Voltage DC Link, Western Link Undersea Cable

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