A Method for Computing the Equilibrium Heading of Turret-Moored Platforms With Validation Using Real Data

Abstract Technological innovations facilitated the exploration of oil fields in progressively deeper waters regions, a transition that shifted towards the implementation of FPSOs as the installation of long-distance pipelines become economically unattractive. Yet, these vessels bring an additional trade-off regarding their mooring systems: either they are spread-moored based – leading to higher stresses on the mooring system and being more sensitive to harsh environments – or they are turret-moored based – diminishing the aforementioned factors by allowing a free rotation around the turret, possibly impacting offloading and cargo transfer operations. This paper focuses on the latter system, presenting a novel approach to compute the equilibrium heading for a turret-moored vessel based on more general open-access environmental databases. To validate these results, real heading measurements obtained from an FSO unit operating offshore Brazil were used. Some detailed analyses are shown and discussed, highlighting key factors that evince the method’s strengths and limitations. Through these findings, the authors hope to provide a basis for improved operational planning and safety in turret-moored platform operations.