SCORCH JIP - Feedback from field recovered mooring wire ropes
Journal
Proceedings of the Annual Offshore Technology Conference
Journal Volume
3
Pages
2115-2142
Date Issued
2014
Author(s)
Rosen, J., Potts, A., Fontaine, E., Ma, K.-T., Chaplin, R., Storesund, W.
Abstract
Abstract Forensic investigations performed as part of the SCORCH JIP on wire ropes that were recovered from FPU mooring systems from Indonesia and Thailand are described. These wire ropes were used in tropical seawater for operating periods ranging from 9 to 14 years before being replaced for various reasons, including corrosion and fatigue concerns. The observed degradation mechanisms within the wire ropes are summarised and the severity of degradation is assessed in view of the external conditions (load duty, direct environment – sea water or mud), sustained by the rope and the rope construction (6-strand and 8-strand). Residual break tests were performed on 7 of the recovered wire rope samples. Mooring design codes pertaining to the corrosion endurance of steel wire ropes are reviewed with respect to recommendations for galvanic coating thickness and lubricant/blocking compound. The results for the recovered wire ropes from tropical waters are compared with reported zinc dissolution rates from cold North Sea waters.
SDGs
Type
conference paper