01 May

FPSO Thruster Change-out, Air Diving and ROV work

N-Sea Offshore Limited was contracted to provide air diving intervention on three FPSO’s as well as ROV inspection services in line with annual class inspection requirements.


Diving intervention was carried out from the Daughter Craft ‘Edradour’ which was launched and recovered from the Mothership ‘Siem N-Sea’. In addition to the Daughter Craft the ships FRC was utilised as a support craft to mooring operations and for personnel transfers.

Scopes included FSO STL and mooring inspection, subsea assets inspection, gas export clamp installation, hull and mooring inspections, plug and blanking plate installation, ICCP anode blanking plate install – diving, spring buoy repairs.



  • Works at multiple client assets, with long transit distances and changing schedule requirements due to changes in operational priorities and weather opportunities at more exposed assets
  • Changes to engineering requirements and management of variations



  • We assembled dedicated offshore project teams who all had past experience of working for N-Sea on the systems and assets assigned to the project with all of the divers and supervisors having previous experience on campaigns with this client.
  • Detailed onshore planning and project documentation from project teams.
  • Developed close contractor / client working relationships with onshore and offshore interfaces having previous working relationships.
  • Realising the rising costs faced by operators in the North Sea we had to ensure that our tender submission reflected these needs without compromising on safety.
  • Adaptable vessel scheduling to accommodate client’s offshore operational windows.
  • Flexibility in management of offshore resources, i.e..
  • Effective management of SOW in terms of accommodating ROV scopes during periods of diving down time to maximize efficiency.
  • Effective management of engineering changes and associated VOs.



  • Zero accident / incident.
  • Class inspection scopes all completed to client satisfaction.
  • Planned Light construction works completed on time despite challenges faced due to client procurement and engineering info supply issues. N-Sea MOC commended for achieving this and the benefits brought to the project.


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