FPSO Case Study

Chain Winch Maintenance

Critical asset maintenance for safe operations


A North Sea Operator came to MDL for assistance in the inspection of an HPU and two chain winches on their FPSO. This was done in advance of chain lifting operations - part of the planned replacement of three mooring chains. The preparation phase was split into three sections, starting with the inspection of the client’s HPU and followed by two offshore phases to overhaul the winches.

MDL Solution

The HPU’s hydraulic oil tank was only half filled so MDL cleaned and refilled it. Additionally, MDL recertified the HPU to safely operate in explosive environments. During pump testing, it appeared that the HPU’s pumps were operating close to maximum capacity, so a reliable backup motor was added to the system. Two MDL supervisors and technicians inspected and tested the starboard chain winches onboard the FPSO. They installed a new motor and performed brake-stall tests on both winches.


By adding an extra motor to the pump setup, addressing the leaking valve on one of the winches and conducting brake-stall tests, One Team MDL created a robust safety net for the upcoming operations while keeping POB requirements to a minimum. Thanks to MDL's 20+ year winch expertise, the maintenance works were completed in time for the critical chain winch operations to proceed without disruptions, backed up with a Report of Thorough Examination (RoTE) for the asset owner's records and peace of mind.

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