AC75

The AC75 (America's Cup 75) is a racing yacht used in the 2021 America's Cup match and planned to be used for the 37th America's Cup and 38th America's Cup matches. The monohulls featured 
wing-like sailing hydrofoils mounted under the hull, a soft wingsail, and no keel.
The rule.
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. 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.
Under the protocol, each competing club could build two yachts, but two-boat testing was excluded except during the "PRADA Christmas Cup" on 17–20 December 2020, and for the defenders during the "PRADA Cup" 15 January – 22 February 2021. To reduce design and testing costs of the class unique class features, the rule specified foil controlling systems all manufactured by defender team and foil arms all manufactured by the Challenger of Record's builder Persico Marine.
List of AC75 yachts.
The visible differences between designs have been commented by most of the yachtbuilding community and the specialized press as each of the boats were launched.
Speeds.
Potential speed of was claimed based on computer simulations.
Notable high speeds actually recorded in racing were:
Patent claim.
In October 2020 patent infringement was claimed in New Zealand regarding the canting foil system used in the boats that have been produced. Team New Zealand said it had already rejected the claim because its system did not infringe any patent.