A vessel contractor required James Fisher’s controlled flow excavation (CFE) technology and specialist personnel to expose mooring chains and piles in Singaporean waters, supporting asset integrity inspection and reburial.   

Customer challenge 

Our customer required excavation and exposure of mooring chains and piles in shallow offshore conditions to enable safe ROV and diver access. Strict trench depths of 0.5m per excavation pattern were consistently required to protect against over-excavation, and complicated by strong currents. 

Solution for our customer

The T4000 CFE system deployed by James Fisher was highly effective, with consistent mass flow even in demanding subsea conditions. Following two trial configurations to establish the most effective vessel speed and operating pressure, excavation activity exposed the mooring chain to a depth of 1.5-2.0m. 

Our impact to our customer

• Enabled controlled de-burial, recovery, and installation of replacement mooring chain   
• Demonstrated precise trench depth control   
• Fast exposure of critical subsea structures for further inspection   
• Safe, stable operations in strong currents and fluctuating tidal ranges   
• Reduced risk of unplanned downtime during inspection