Siem Clears Caithness-Moray Subsea Route

Siem Offshore’s Anchor Handling Tug Supply Vessel (AHTS) Siem Ruby has cleared rocks and boulders along the proposed subsea cable route for the 1.2GW Caithness-Moray transmission project in Scotland.

This is the first in a series of major offshore activities throughout 2017 that will allow the installation of two high voltage direct current (HVDC) cables that will be capable of carrying renewable electricity between Caithness and Moray, according to Scottish & Southern Electricity Networks (SSEN).

Siem Ruby used a specialist subsea boulder clearance plough to clear the route along the seabed.

The same vessel will subsequently be used to create a trench to lay the cables within it. The cables will then be installed from a purpose-built cable laying vessel in two campaigns – the first from Noss to the midpoint of the cable route and the second from Portgordon to the end of the previously laid cable.

Following the installation of the cables the plough will be brought back and reconfigured to backfill the trench using the seabed material previously excavated during the trenching operation.

The GBP 1.1 billion Caithness-Moray project is on schedule for completion in 2018.