Maersk NanHai6 Engineering & Construction Support

The Scope

Maersk Drilling contracted Cube Offshore to carry out a detailed integrity analysis of the NH6 burnerboom integrated hull supports and certify them in accordance with DNV Drilling Plant.  Additional burnerboom davit supports were installed to reduce support fatigue damage when in the stowed position alongside the hull.  In addition to this, a number of structural modifications & additions were made to the rig’s infrastructure including mooring chain hang-off points, gantry beams, access stairs and modifications to the forward BOP carrier for the Santos Fletcher Finucane project.

The Outcome

Cube Offshore conducted an offshore site survey onboard the NH6 followed by a detailed structural analysis of the burnerboom and hull supports.  This analysis indicated code non-compliance in the hull supports due to a progressive historical increase in burnerboom weight (additional equipment, loading, modifications, additional pipework, etc).  Cube Offshore proposed and implemented a weight reduction program for the burnerboom (removal of redundant pipework) and a strengthening program for the hull supports.  Cube engaged DNV at an early stage to ensure Class compliance of all works which adopted Australian Standard steel and hull welding procedures.


Burnerboom hull supports (Port & Stb.) – strengthened.

Burnerboom hull support – strengthening detail.

Cube hotworkers fitting up and welding out the strengthened hull attachment detail.

Completed structural strengthening joint in the burnerboom hull supports