Evaluating Offshore Rope Fibers: Impact on Mooring Systems Integrity and Performance

Abstract

Objectives/scope Polymeric Fiber Ropes have been used extensively for Permanent Offshore Deep-Water Mooring systems. High strength polyester ropes have been used for FPSO mooring with proven performance of more than 20 years. Fiber rope have no corrosion issues and superior performance in fatigue. There is also a need to evaluate the applicability of fiber ropes instead of steel chains and/or steel ropes used on top and mudline segments. Long-term performance and integrity with the benefit of a lower Total Cost of Ownership (TCO) can be expected. The OTC 24025 paper addresses integrity issues on permanent mooring systems. Authors concluded that a great majority of premature failures/damages are associated with steel components such as chain, wire ropes and connectors, and not with fiber rope segments. It is also necessary to assess long-term performance and environmental resistance of synthetic rope regarding its use in top side, mudline, as well as shallow water mooring for the growing business of Marine Renewable Energy and Offshore Wind Farms (FOWT). It is also important to study the lifetime assessment of polyester mooring ropes. FPSO operators are also considering life extension of existent mooring systems installed over 10-15 years ago evaluating the impact of creep, hydrolysis and other environmental issues such as UV and marine life growth.