Fatigue of mooring chain in air and water -- Results and analysis

The paper will present the results of the joint industry study into the fatigue resistance of large diameter anchor chain, and discuss the interpretation of the results. The study represents the largest body of well documented corrosion fatigue tests on a variety of different chain grades and sizes. The analysis of the results uses all the available fatigue data, including the life of tested but un-failed links, to determine suitable fatigue curves for mooring lines of different lengths. Many of the findings were to be expected, based on past data, but there were some surprises with respect to chain grade. Fracture surface examination indicate that the fatigue cracks had propagated across a large percentage of the section prior to final fracture. Post test inspection of un-failed links indicate that many cracks had initiated prior to failure.