ABERDEEN, UK —Rotech Subsea has completed a four-month cable de-burial and reburial campaign at the Saint-Nazaire wind farm offshore France’s Atlantic coast.
The company deployed its controlled flow excavation equipment spread for the program on omega joints and cable ends at the site off the Guérande peninsula.
The RS2 tool operated in heavy/dense sands at a depth of 20 m to 30 m, de-burying 650 m of cable, including two joint areas and four cut points in a single pass. With backfill occurring quickly at the site, repeat passes on the four specified cut points allowed divers to sling the cable for cutting operations.
Following remedial works, the cable was buried to 1.5-2 m DOL in one pass, aside from two small remedial sections. The tool’s maximum outlet pressure of 60 kPa and maximum jet flow of 4,000 l/s allowed it to cope with the soil conditions as it progressed at a rate of 1 to 2 m/min.
Tugger winches on the support vessel controlled the tool’s orientation while it remained suspended above the seabed/cable as the vessel traveled along the cable route. Trench depth for the de-burial and burial operations was monitored in real time using a tool-mounted sonar imager.
09.21.2022
