As the Round Robins progress and Barcelona impresses, the AC75 mast and rigging systems are showcasing exceptional speed and performance. While many point to innovations like the return of the cyclors, advanced foil designs, and cutting-edge control systems, the role of high-performance rigging and composite masts is equally critical. Since the introduction of composite materials in the America’s Cup, mast design and rigging technology have significantly shaped the on-water outcomes.
Southern Spars, a leader in carbon masts, has been pivotal since 1995, helping Team New Zealand to victory with their innovative designs. Their sister company, Future Fibres, continues to drive rigging innovation, playing a central role in the advancement of AC75 rigging systems.
Class Rules
The AC75 class rules outline strict specifications for mast design, including shape, size, and material composition. For example, the mast must adhere to a D-section shape and specific carbon fiber parameters such as fiber modulus, areal weight, and resin content. Additional rules govern mast fittings and shroud geometry, limiting mast rotation to 45 degrees and defining the mast’s height relative to the waterline.
Mast Rotation
By controlling the mast rotation, teams can unlock enhanced performance. All participants in AC37 have chosen North Sails for their sail design, particularly leveraging the Helix structured luff technology. This technology optimizes sail shape and performance by managing load distribution, taking advantage of every breath of wind. With mast rotation precisely aligned to conditions, the AC75 masts function almost as extensions of the sails themselves, blurring the line between mast and sail.
Thickness & Stiffness
Another crucial aspect of AC75 mast design is mast stiffness and bend control. The class rules set minimum laminate and core details, but teams can add additional layers to modify the mast’s stiffness and deflection response. This allows teams to fine-tune the mast bend to suit their specific sail performance goals, balancing weight and stiffness for optimal results.
No Backstay
One major change in the AC75 rigging system is the removal of the backstay, which traditionally influences mast bend. Now, sail controls alone manage mast shape, increasing the loads on the shrouds. To compensate, Future Fibres has enlarged the cap shrouds and upgraded jib locks for this edition of the Cup. Additionally, integrated fibre optic load monitoring helps teams track performance and manage safety limits in real-time.
Looking Ahead
The America’s Cup continues to push the boundaries of mast and rigging technology, with innovations in luff tracks, batten stiffness, and mainsail controls expected to shape the future of sailing. As Mark Hauser, General Manager of Southern Spars, noted, “Our close partnerships with elite teams drive innovation, which will influence the broader sailing industry for years to come.”
