Dredging for Subsea 7 in the North Sea

Scope of works:

Subsea 7 required dredging to remove rock dump, sandy trench backfill and natural seabed beneath an existing 8” ID flexible pipeline. Suitable clearance was also required to allow the operation of a diamond wire saw to then cut out manageable sections of the pipeline for recovery.

Scope of supply:

  • 2 x diamond wire spreads
  • 2 x dredge spreads (6" and 10")
  • Shared hydraulic power unit (HPU) and control/reeler
  • Experienced technicans

The 6" and 10" dredgers were well received by the divers with regards to performance and manoeuvrability although it was noted that the addition of a swivel head on the tiger tail would allow for better handling. Following the client feedback, a new swivel head was designed and built within two weeks of this information being received.

PDF icon.png Download 'Dredging for Subsea 7' case study.