21 March 2017
LR’s Dr Rebecca Sykes presented at the floating wind conference FOWT 2017 in Marseilles on the Technology Qualification of Nylon Mooring Line for a Floating Wind Turbine.
The cost drivers of electrical cables, the interest in developing maritime space with water depths which exceed that which fixed offshore wind is currently commercially viable and areas where the geotechnical conditions suit neither monopiles nor jackets, is starting to create a market for floating wind. In shallower water depths (<100m) the wave motion can becomes increasingly elliptical leading to increased surge loads and displacements. In these environments, expensive and heavy conventional chain-based mooring systems are not as effective, nor does it provide sufficient compliance to avoid snatch loading. Chain moorings also add weight to the floater which is an area in which cost savings are currently being sought.
Nylon based mooring system can provide an attractive solution in some deployment sites. Lloyd’s Register was part of a JIP set up to make advances in qualifying nylon via a rope testing programme so that it can be deployed safely and certified for permanent moorings. The JIP has developed new modelling methodologies for nylon rope and reported on physical tests results. The presentation given in FOWT describes the qualification approach followed by LR in the JIP. Rebecca Sykes, Technology Innovation Leader and Positional Moorings Principal Specialist, Arnaud Guillet, were engaged in many interesting discussions with floating wind technology developers and rope manufacturers following the presentation, showing that the topic is certainly of keen interest as more small scale demonstration farms go from early planning to concept stage.