America’s Cup showcases composites-intensive AC40 foiling yacht designs

One-piece 3Di sails from North Sails GmbH (Hamburg, Germany), carbon fiber rigs from Southern Spars (Auckland, New Zealand), and Future Fibres’ (Valencia, Spain) multistrand composite rigging push the boundaries of AC40 sailing performance for the upcoming Youth America’s Cup and Puig Women’s America’s Cup.

The AC40, introduced as a new class in 2021 by event organizers, is a multi-use foiling monohull that all the confirmed teams will use for sailing and testing purposes. The one-design yacht from bow to stern is said to eliminate the technical recon that surrounds the Louis Vuitton America’s Cup, bringing the focus sharply onto the teams and their personnel. While the Youth America’s Cup crews include Olympians and world champions across various classes, the Puig Women’s America’s Cup showcases some of the most prolific names in world sailing, including the likes of Hannah Mills — claimed to be one of the most successful female Olympians of all time.

Essentially, the AC40 is meant to represent the next stage in the evolution of foiling innovation. The smaller sibling of the AC75, each AC40 is fitted with various composite solutions.

According to its website, North Sails’ sail structure is “composed of multiple hair-thin spread filament plies applied in precise, high-resolution vectors (length and direction) to optimize strength-to-weight ratios and compressive loads.” 3Di sails are 70% fiber and 30% resin; they have a streamlined shape to deliver less draft and more drive, and maintain a “zero Mylar construction … enduring shape retention and withstand[ing] harsh weather.”

Future Fibres, a company that specializes in providing composite rigging solutions, merged with Southern Spars’ Composite Rigging business in 2014. The range of products offered by Future Fibres includes static rigging, running rigging and furling cables, all made from composites. Future Fibres, is the design rigging supplier for both the AC75 and the AC40. Each AC40 is equipped with ECthree — the premier rigging product for yachts in the 30- to 65-foot range.

As foiling yachts evolve, Southern Spars plays its own part, even bringing lessons from America’s Cup innovation to landmark maxi and superyacht projects in recent years, such as Mills 60 Flying Nikka and Baltic 111 Raven.

The AC40 has plenty in common with its larger counterpart, the AC75. With respect to its rig package, the AC40 also features a D-shaped Southern Spars mast, which rotates up to 45° to harness the performance power of its twin skin North Sails mainsail. Both feature T-shaped foils that lift the yacht out of the water, reducing drag and enabling higher speeds. Both feature advanced control systems.

There are some key differences, however. The most obvious of these is that the AC40 is scaled down, with a 12-meter hull and 18-meter mast. Reduced size and displacement make the AC40 lighter and more responsive, making it well-adapted for fleet racing, which forms the bulk of both the Youth and Women’s America’s Cups.

Onboard an AC40 there is a crew of four individuals — comprised of two helms and two sail trimmers — rather than the 11 crew members on an AC75. With the absence of cyclers, human power is replaced by battery power for running the hydraulics, which play a key role in operating the foils, sails and other systems.

It will be no surprise if crew members in the Youth America’s Cup go onto compete for the Auld Mug in coming years. There is, however, no precedent for the Women’s Puig America’s Cup. Historically dominated by male sailors, with women having participated only occasionally, 2024 marks the first standalone women’s event in the 173-year history of the America’s Cup. Southern Spars and its partners are proud to contribute to this significant milestone.