Aberdeen-based Ecosse Subsea Systems used its Scar1 trenching tool on a seabed clearance project for the Total operated Laggan-Tormore project West of Shetland. The system was deployed to remove up to 1000 boulders that were stalling cablelaying and umbilical installation work. The Scar1 cut a 10m-wide swathe over a 67km route, displacing boulders up to 2m in diameter and removing soil to leave a flat seabed for pipelaying. Typical seabed clearance involves a ‘boulder grab’ device, which displaces rocks one by one and leaves operators reluctant to tackle boulders larger than 0.5m in diameter.
Originally developed as a subsea plough, the Scar system was redesigned and fabricated to meet Total’s requirements and mobilised within a 10-day window.
The plough worked at depths of 640m, believed to be a record for this type of equipment, and at optimum performance was clearing up to 1000m of seabed per hour.
According to Ecosse Subsea Systems managing director Mike Wilson, the Scar system ‘is extremely robust, easily mobilised, can work in the harshest environments and in depths up to 3000m.’
Subscribe
