Design and Demonstration of a Nylon Semi-Taut Mooring System for a 225-kW Floating Wind Turbine off the Coast of Maine

Abstract This paper discusses the design and performance evaluation of a quarter-scale semi-taut nylon mooring system created specifically for the University of Maine's 225-kW VolturnUS+ prototype, which is planned to be deployed off the coast of Castine, Maine, in Spring 2025. The test site was strategically chosen due to the high likelihood of experiencing multiple full-scale equivalent 50-year storms during winter. As such, this paper aims to present data that illustrates the system's performance under ultimate and fatigue limit state conditions. Notably, this marks the first deployment of a floating offshore wind turbine equipped with a nylon mooring system in the United States. The insights gained and data collected from this initiative will be instrumental in assessing the viability of nylon for mooring applications in floating offshore wind turbines, particularly in shallow to moderate water depths. Furthermore, this project is intended to function as a real-world testing platform for innovative floating offshore wind technologies, which are essential for launching the first round of commercial floating offshore wind farms in the United States.