Robotic Inspection of Mooring Chains in Air and Water (RIMCAW)

Failure of mooring chains that secure floating structures in off-shore production of oil and gas results in oil leaks due to the rupture of flexible pipes that bring product to the surface. The clean-up costs of environmental pollution run into hundreds of millions of pounds. It is therefore important to inspect the mooring chain links to assess the extent of corrosion, fatigue cracking and developing weld faults before they result in failure of a chain. It is very expensive to remove a chain weighing many tons and bring it to shore to inspect it. Savings can be made by perfoming non-destructive testing (NDT) of a chain in-situ while it is in operation. The heavy chains generate large dynamic forces so that inspection using divers is extremely hazardous. The project aims to develop a small, compact mobile robot that can climb on mooring chains both underwater and in air to scan chain links with advanced ultrasound sensors. The robotic NDT system will provide a tool to assess the condition of mooring chains to enable asset managers to make decisions on repair and remaining lifetime of a chain. It will reduce inspection costs by speeding up coverage of a mooring chain and remove the need for diver inspection which costs £40,000 per floating structure and puts their lives at risk.