The 23 m (75 ft) monohulls feature wing-like sailing hydrofoils mounted under the hull, a soft wingsail,[1] and no keel.

[2] Following the 2017 America's Cup, winners Royal New Zealand Yacht Squadron accepted a notice of challenge from Circolo della Vela Sicilia stipulating a monohull would be used in 2021.

Conceptual graphics of a monohull with soft sails and topside canting hydrofoils were released on 21 November 2017, and the first draft of the class rule was published by the defender and the challenger of record on 29 March 2018.

[3] The return to monohulls with soft sails after three America's Cups on multihulls with wingsails is reminiscent of earlier America's Cup classes and seaworthy traditions, but the rule included hydrofoils to attract high performance crews and large TV audiences.

[32] Team New Zealand apparently ignored correspondence from Chaves' patent attorneys for over two years before simply dismissing the allegations.