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.