SubseaPartner was contracted by Odfjell Technology to execute a manned underwater operation campaign on the West Bollsta rig. The work was performed using a Light Dive Craft (LDC) with a shore-based dive system, operating at depths of 5–10 meters. All dives were planned as no-decompression dives using NITROX, in accordance with Norwegian diving treatment tables.

Key Activities:

• Opening and cleaning of four seachests located at port and starboard, forward and aft inside the pontoons.
• Plugging and unplugging of various overboard valves:
  • 4 × 300 mm ballast overboard valves
  • 1 × 35 mm valve
  • 2 × 125 mm fire water valves
• A change in method was implemented during the operation, switching from water injection to low-pressure air to improve cleaning efficiency.

Safety & Compliance: Operations were conducted in line with applicable regulations and project-specific execution plans, with a strong focus on safety and risk management.