Western HVDC Link: Update on mattressing and cable laying, 19th June 2015

Mariners are advised that concrete mattresses have now been installed at cable crossings along parts of the Western HVDC Link cable route in the Irish Sea, and work on cable installation is due to resume on or around 23rd June 2015.  Further detail on the concrete mattressing and cable laying work is provided below.

Concrete mattressing campaign

Mariners are advised that concrete mattresses have now been installed at 8 locations along the cable route.  These mattresses have been installed to protect existing submarine cables and pipelines.  A notice to mariners about the installation of these mattresses was issued in May and can be downloaded here.

The central locations of each of the cable crossings are given below.

  • Scotland – N. Ireland 2 cable: 54° 56.083’N 005° 32.823’W
  • Moyle Interconnector North cable: 54° 55.779’N 005° 32.545’W
  • Scotland – N. Ireland Pipeline: 54° 54.913’N  005° 31.714’W
  • LANIS 3 cable: 54° 53.814’N  005° 30.664’W
  • Scotland – N. Ireland 1 cable: 54° 41.405’N  005° 18.647’W
  • Manx – N. Ireland cable: 54° 16.299’N  005° 10.394’W
  • ESAT2 Cable: 53° 42.492’N  003° 48.646’W
  • PL1030 Pipeline: 53° 31.491’N  003° 34.852’W
  • PL1032/1033 Pipeline: 53° 31.490’N  003° 34.840’W

(Note: all positions referenced to WGS84 datum).

 At each location several mattresses have been installed, each measuring 3m x 6m.  A full list giving the as laid location of all of the concrete mattresses has been made available for mariners operating in the vicinity of the cable crossings and can be downloaded here.

Deep Water Cable Installation

The first deep water cable installation campaign is due to start on or around the 24th June 2015.  This work will commence approximately 37km from the Wirral end of the cable and continue towards the Isle of Man for about 120km.  A notice to mariners about this work can be downloaded here and is summarised below.

Installation work will be carried out by the cable laying vessel Giulio Verne, accompanied by the vessel Go Pegasus.  The Go Pegasus will follow the Giulio Verne at a distance of approximately 500m, and will tow a cable burial plough, providing for simultaneous burial.

Two separate cables are due to be installed, and will be laid approximately 30m apart from one another.  Each cable will be laid separately.  The cables will each be simultaneously buried along their entire length, except where the cables cross existing cables or pipelines.  At these crossings, guard vessels shall monitor the cable until appropriate post-lay protection (with concrete mattresses or rock placement) can be installed.  The cable crossing locations are:-

  • Hibernia Cable: 53°45.058’N  003° 48.853’W
  • Sirius South Cable: 53° 43.574’N  003°48.733’W
  • ESAT2 Cable: 53° 42.492’N  003° 48.646’W
  • PL1030 Pipeline: 53° 31.491’N  003° 34.852’W
  • PL1032/1033 Pipeline: 53° 31.490’N  003° 34.840’W

(Note: all positions referenced to WGS84 datum).

Prior to cable laying, the vessel Go Pegasus will conduct a pre-lay survey and conduct a Pre-Lay Grapnel Run along the cable routes.  This is due to commence on or around the 23rd June 2015.

Giulio Verne will also recover one of the two cable installed as part of the shallow water cable installation last year and make a joint between this cable and the one aboard the vessel.

Please note that installation dates are approximate and could be affected by project progress and weather conditions.

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:-

Vessels will be monitoring VHF Channel 16 throughout the operation.

The vessels involved in this work will be restricted in their 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.

Notices to Mariners

The Notices to Mariners currently issued for this project are:-

  • Deep Water Cable Installation – this is being carried out by the vessel Giulio Verne, starting in June 2015.  The Notice to Mariners can be downloaded here.
  • Concrete mattressing – along the cable route concrete mattresses are being used at all crosssings of existing cables and pipelines.  A notice to mariners about the mattressing campaign can be downloaded here.

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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