In situ winch replacement needs an ACE of space
One of the most difficult problems to overcome in installing a bespoke 200 ton SWL replacement anchor mooring winch onto the FPSO Anasuria was simply getting it to fit into the existing space.
The
Anasuria
was the very first purpose built floating, production, storage and offloading (FPSO) vessel to be constructed for Shell UK Exploration and Production in the UK and is located 60 miles off Aberdeen in the North Sea.
Being an FPSO, the vessel has a turret system which anchors the vessel to the seabed via chains and anchors.
The
vessel then rotates around the turret, inside which the anchor handling winch is located.
ACE winches were contracted to design and manufacture a winch for tensioning the anchor chains and due to the constraints of the installation a complete logistics and ‘cradle to grave’ approach had to be undertaken.
Basic design problems were that the existing space on the vessel was very small for such a large pull capacity winch. A detailed design study utilising ACE standard drive concept gearboxes was carried out to achieve the duty in such a confined space.
The
se drive units are based around the Hagglunds Compact high torque low speed DNV approved motor and brake.
Due to the logistical and physical positioning constraints, the winch had to be designed, manufactured and fully function tested then stripped down into eight boxes for shipping to the vessel. Size of parts for assembly was very important as there was no crane facility for assembly of the winch into the turret. All winch components were moved from deck to location through narrow corridors using chain blocks.
Tidal conditions played a crucial role in ensuring the turret was in a safe loading position for transferring of the winch parts. Precise load control was also paramount with high equipment classification FPSO standards.
James Gregg, technical director of ACE Winches, project managed the complete design, manufacture, installation and commissioning, which included many technical and logistical problems, with reliability always critical. Speaking about the unique project Mr Gregg said,
‘This was a specialist piece of work for Shell and had a number of technical and logistical challenges that ACE were able to competently meet.’ He added that this project demonstrated the company’s ability to provide an integrated solution from design to installation ‘no matter how challenging the requirements.’
ACE has successfully complied with all Shell and DNV standards and the winch was fully certified by DNV.
