A range of technical innovations are frequently cited as the reason for driving, the AC75 fleet’s impressive performance.
Southern Spars has played a leading role since entering the America’s Cup fold in 1995, with the supply of Team New Zealand’s innovative high-performance carbon mast that took them to a historic victory. Southern Spars’ sister company, Future Fibres, is also increasingly central to the trajectory of composite innovation in the Cup.
AC75 class rules specify several key one-design aspects of mast design and construction in addition to the geometry and materials of the fittings, mast rotation restriction to 45°, and the height of the mast rotation ball relative to the waterline.
Through controlling the 45° mast rotation, each team has at their disposal a mechanism to access enhanced power and performance. All AC37 participants have selected North Sails Helix structured luff technology, which has redefined what a sail can deliver.
With a mast designed to react to the conditions by rotating to the exact degree needed to exploit every breath of wind, you could almost say that the masts on AC75s have become part of the sail, or the other way around.
Another way masts influence sail shape is mast bend. This is where teams can differentiate their masts to influence performance. While the D-spar minimum laminate and core details are specified under AC37 class rules, teams are free to add more laminate if they choose to. There is scope to increase the overall stiffness of the mast, or to alter the deflection response—optimising it to suit the desired degree of mast bend that the team’s sail designers are calling for.
While the rigging for AC37 is a fully one-design, identical ‘supplied’ component from Future Fibres, some significant changes have been made to the rigging packages since the 36th America’s Cup. One talking point is the elimination of the backstay. Mast bend, which would conventionally be influenced by backstay control, is now almost solely manged by sail controls. Cap shrouds have been enlarged and jib locks upgraded from 5t to 8t for this edition of the cup. Future Fibres rigging packages are equipped with integrated fibre optic load monitoring, for performance analysis and to keep an eye on loading limits.
Luff tracks, batten stiffness, batten locations, halyard locks and mainsail controls all sit within the remit of team designers. It remains to be seen which technical factors will rise to the surface during the 37th America’s Cup, but it is
a safe bet that ripple effects from technological choices and innovations will be felt around the wider sailing landscape in the coming years.
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