Western HVDC Link: Deep Water Cable Post Lay Installation Burial Works, 23rd November 2016

[Update – the information in this notice has been superseded by more recent notices.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 that the vessel Normand Pacific is due to commence Post Lay Installation Burial Works along part of the Western HVDC Link cable route, starting in December 2016.  This update provides a brief summary of the detail included in the  Notice to Mariners describing this work, which can be downloaded here.

Information is also provided below on the location of rock protection areas on the completed sections of the cable route to the south of the Isle of Man, and on the location of exposed cable areas that are presently awaiting burial or protection in the North Channel – Firth of Clyde area.  The Notice to Mariners providing information on these locations can be downloaded here.

Post Lay Installation Burial Works

Post Lay Installation Burial Works (PLIB) are due to be carried out by the Normand Pacific using a jetting tool.  This will be used to bury sections of exposed cable.  These have been identified in earlier Notices to Mariners and are also listed in the NtM about these works.  Areas where jetting is not possible (such as service crossings) will be protected at a later stage in the project.

These works will be carried out along the completed sections of the cable route in the North Channel and the Firth of Clyde (Campaigns 3 & 6),  These are illustrated and listed in the NtM about these works.  The work is due to commence in December 2016 and to be completed in January 2017.

The notice to mariners describing this work can be downloaded here.

Vessel details

Details of the vessels involved in these operations, along with their present location can be found on MarineTraffic.com via the links below:-

The vessel will be monitoring VHF Channel 16 throughout the operation.

The vessel involved in this work will be restricted in its ability to manoeuvre and other vessels are reminded to navigate with caution in their vicinity and pay strict attention to instructions issued to them by navigation authorities.

Rock Protection and Exposed cable locations

A notice has been issued to provide an update on the location of rock protection areas along parts of the route where construction work has been completed, and also the location of exposed cable sections along parts of the cable route where installation work is on-going.  This notice is summarised below and can be downloaded here.

Rock Protection Areas

Mariners are advised that the rock placement works of Campaign 1 and Campaign 2 to the south of the Isle of Man have been completed.  Guard vessels are no longer stationed in this area as the cable has now been protected by burial and rock placement.

Mariners are advised to take note of the location of the rock protection on the cable route.  The height of the rock protection within the areas indicated is approximately 0.8m, and the rock berm has been designed to have a 1:3 gradient.  The rock berms may therefore extend approximately 3m either side of the cable.

The locations of the rock protection areas are listed in Table 1 of the Notice to Mariners, which can be downloaded here.

Exposed Cable Locations

There are several sections of exposed cable along the cable route including the planned cable crossing locations previously communicated through notice to mariners. 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 22nd November 2016) has been compiled.  This list is included as Table 2 in the notice to mariners that can be downloaded here.

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 these exposed sections are shown in Table 2 of the Notice to Mariners which 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).

Notices to Mariners

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

  • Post Lay Installation Burial Works  – this is the notice described above.  It was issued on 22nd November 2016 and provides information about the cable burial work for Campaigns 3 & 6 of the cable route which will be carried out between December 2016 and January 2017.  The notice can be downloaded here.
  • Rock Protection Areas and Exposed cable locations, Irish Sea – this notice is also described above.  It provides an update on the locations of rock protection areas and exposed cable locations which are awaiting protection as of the 22nd November 2016.  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.

If you have any queries about the Western Link project, please contact Jim Andrews, Fisheries Liaison Officer by e-mail or by phone on +44(0)7908-225865.

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

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