Scantling assessment of large yacht rigs using carbon-fiber and aluminum masts

Weight saving is crucial in naval architecture to reduce costs and improve performances. In sailing ships design, rig's scantling is important also for ship stability, as rig's weight generates heeling actions on the vessel, due to heeled navigation. Therefore, rig's weight saving remarkably reduces ship's heeling, allowing to increase the wind exposed area, consequently improving the sailing performances. However, because of the complexity of the structure and uncertainties in loading conditions, the structural scantling of a rig implies the adoption of high safety factors. Furthermore, the increasing trend to use composite materials represents an additional source of complexity due to their anisotropic non-homogeneous nature and uncertainties on material properties, and generally implies even larger safety factors, besides implying high construction costs. The present work shows a comparison between an existing 76 m carbon mast and an aluminium alloy one. Suitable FEM models of both rigs were built up and used to assess the structural system strength according to applicable class rules. The cross-section stiffness of the aluminium mast was optimized in order to make masts’ performances comparable. The optimized aluminium mast, of comparable weight of the carbon one, results to be more cost-effective for such range of sailing vessels.