Fibre ropes for Station-keeping : Engineering properties and qualification procedures

Fibre ropes are today increasingly used for the station-keeping system of permanent Floating Production Units and drilling units. Following a development period, and eight years after the first installations of FPU's in Brazil, this technology has reached a stage of maturity where it will soon be addressed in International Standards (the station-keeping standard and a rope standard). This happened as the result of accumulated knowledge, through a number of R& D studies over the world on the engineering properties of the ropes, and of growing practical experience in the Industry (for both Users and Manufacturers), from which product qualification and Certification procedures were developed. The present paper reviews these two aspects that are indeed closely interrelated : • engineering properties of the rope as a line component, required for the design of a station-keeping system, • qualification and acceptance procedures of the product, ensuring that the purchased rope has the expected properties. This review addresses the most important parameters such as rope breaking strength, endurance under cyclic loading (T-T fatigue), durability, and load-elongation properties. The review highlights the achievements as incorporated in the International Standards and in the latest Classification Guidelines, and identifies areas where further progress is still desirable.