On the use of relevant models and analyses for the structural mast design of America’s Cup racing yachts (AC75)

Thanks to their excellent mechanical performance characteristics, continuous carbon fibre composite materials are widely used in the construction of racing yacht masts. For the past 30–40 years, masts have been designed using methods that were mostly developed through trial and error. As part of this process, beam models are used to define the mast tube, balancing efficiency and computation time. As sail shape design is driven by mast bend, it is essential that these methods produce increasingly accurate results. Due to the development of hydrofoils, significant variation in sail shape is anticipated, given the increased boat speeds and wind ranges. In the case of America’s Cup 75-foot boats, mast bend controls sail shape, meaning greater accuracy is required when creating finite element models (geometry, mesh, loads, analysis, etc.). This study aims to establish a methodology for quantifying the impact of model selection and its parameters on design safety margins. Key design parameters are analysed to determine the most suitable methodology for accurately designing a highly bent mast tube. The study shows that conventional design methods, which use beam models for mast structural design only, are not fit for designing high-performance yachts. • First comprehensive study of mast design for latest America’s Cup racing yachts. • Finite Element Analyses comparing different modelling strategies (1D vs 2D). • Significant limitations are found in the classical 1D beam model. • Accurate prediction of the mast bend is key to determining its performance. • Durability of the mast depends on the ability to withstand load variability.