How the double-skinned mainsail works

When the concept for the AC75 was unveiled, this boat to be sailed in the 2021 America’s Cup illustrated a bold and modern vision for high performance fully foiling monohull racing yachts. While the doubters from that November 2017 reveal have eaten crow, another question lingered.

Is this the future of yachting?

This boat was so “out there” that if this was the future, the sport was in trouble. More complexity. More limitations. And definitely more expense.

Among the other-worldly features was the double-skinned mainsail, a design that had traits of the solid wing without the logistical challenges. Brilliant, but please lord, this cannot trickle down to recreational sailing. One modern mainsail was costly enough, but to double it? Yikes!

While the AC75’s side foils have emerged beyond the America’s Cup bubble, the unique mainsail scheme has stayed put. As a result, it remains one of the defining technologies of the modern America’s Cup that is least understood. This report attempts to reveal its secrets: click here.

Defender New Zealand and Challenger of Record from Great Britain confirmed the Protocol for the 38th America’s Cup on August 12, 2025. The close of the initial entry period was October 31, 2025, with late entries considered up to March 31, 2026.

The AC75 has a helm and trimmer on each side of the boat along with a fifth crew position and a sixth passenger position.

38th America’s Cup: https://www.americascup.com/

38th America’s Cup entrants:
• Emirates Team New Zealand (NZL) – Defender
• Athena Racing (GBR) – Challenger of Record
• Luna Rossa (ITA) – Challenger
• Tudor Team Alinghi (SUI) – Challenger
• La Roche-Posay Racing Team (FRA) – Challenger
• American Racing Challenger Team USA (USA) – Challenger
• Team Australia (AUS) – Challenger

After the 2024 event, Barcelona, Spain declined hosting another edition, with the venue moved to Naples, Italy. Challenger racing is May 22 to July 4 before the 38th Match on July 10-19. Full details.

Preliminary Regattas:*
May 22-24, 2026 – Cagliari, Italy
September 24-27 – Naples, Italy

* The Protocol noted how there would be as many Preliminary Regattas as possible, with the intent to have three during 2026 and one possibly in early 2027, and a final event at the Match Venue immediately prior to the challenger series. Only two have been thus far revealed.

Source: AC media