Loss of Integrity on Mooring Lines – Causes and Consequences

Abstract

In the history of offshore industry, position keeping has been an essential part for allowing operations to be performed, and production to be maintained. This is often done by connecting mooring lines between the vessel and placed anchors on the seabed. Although the history of the mooring line goes back several decades, or even centuries if considering ships, the technology is far from optimal even today. Failures does happen at what can be considered a regular basis in this context. Looking at reports from these occurrences, this thesis will elaborate on what happened, why they happened and what to be learned from what happened. Furthermore, they will be compared to each other to check if they have some sort of similar causes, alas trending failures. These trends will be discussed and evaluated, and given some personal suggestions for improvements if possible or if reasonable to improve. A risk elaboration on the loss of integrity of one or more mooring lines is also an important aspect of this thesis, as it gives an understanding of how serious an event a failure of this kind can be. In this section, simple risk methods will be illustrated like a bow-tie diagram showing preventative measures that can be used for loss of integrity of a mooring system.