Evaluating Mooring Line Test Procedures through the Application of a Round Robin Test Approach

Faryal Khalid,Peter Halswell,Philipp R Thies,Peter Davies,Nicolas Lacotte,Lars Johanning

doi:10.3390/jmse8060436

Abstract

Innovation in materials and test protocols, as well as physical and numerical investigations, is required to address the technical challenges arising due to the novel application of components from conventional industries to the marine renewable energy (MRE) industry. Synthetic fibre ropes, widely used for offshore station-keeping, have potential application in the MRE industry to reduce peak mooring line loads. This paper presents the results of a physical characterisation study of a novel hybrid polyester-polyolefin rope for MRE mooring applications through a round robin testing (RRT) approach at two test facilities. The RRT was performed using standard guidelines for offshore mooring lines and the results are verified through the numerical modelling of the rope tensile behaviour. The physical testing provides quantifiable margins for the strength and stiffness properties of the hybrid rope, increases confidence in the test protocols and assesses facility-specific influences on test outcomes. The results indicate that the adopted guidance is suitable for rope testing in mooring applications and there is good agreement between stiffness characterisation at both facilities. Additionally, the numerical model provides a satisfactory prediction of the rope tensile behaviour and it can be used for further parametric studies.

Highlights

Emerging technologies, such as marine renewable energy (MRE), readily adopt components and standard guidance from conventional industries for a novel application
To de-risk industrial innovation in MRE, the experience from conventional industrial application must be combined with the knowledge of the application area
Synthetic fibre ropes were proposed for deep-water moorings of floating offshore oil and gas platforms by Del Vecchio nearly 30 years ago [1], and are widely accepted [2,3]

Summary

Introduction

Emerging technologies, such as marine renewable energy (MRE), readily adopt components and standard guidance from conventional industries for a novel application. To de-risk industrial innovation in MRE, the experience from conventional industrial application must be combined with the knowledge of the application area. This can be done through an integrated approach involving comprehensive numerical modelling, and a dedicated component physical testing programme, as well as field demonstrations. The low linear density of polyester fibre ropes compared to steel wire and chain has made them the preferred choice beyond 1500 m depth. Fibre ropes could offer significant advantages for MRE applications through peak load reduction [5], but a thorough technology assessment must be conducted to quantify risks and uncertainties

Methods

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Discussion

Conclusion