Author: Eng. Giancarlo Belloni
These days, as Italians, we watch the 37th edition of the America’s Cup with a hint of disappointment. The races are between Taihoro – Team New Zealand, which has held the cup since 2021 (defender), and Britannia – Team UK, which became the official challenger after defeating our Luna Rossa in the Louis Vuitton Cup final in Barcelona. On the other hand, we are extremely proud of Luna Rossa’s victory in the first women’s America’s Cup.
Even those who don’t usually follow sailing will have noticed how different these boats are from the usual ones we might see during a seaside or lake outing. Without a doubt, one of the most significant differences is the presence of foils—movable appendages on each side of the hull that can be submerged or retracted from the water, allowing the boat to literally fly. Going into a bit more technical detail, once a certain speed is reached, the foils generate a hydrodynamic lift that raises the boat above the water, significantly reducing drag. For these high-performance boats, this means reaching speeds up to four times the wind speed. According to an interesting detail in the protocol, the foil movement and control systems were created by the defender for all teams, while the movable arms supporting the foils were supplied by Luna Rossa. However, each team had free rein to design the foils themselves.
The use of foils is not new in itself, having gained some notoriety since the mid-20th century, especially with fast ferries known as hydrofoils. Regarding the America’s Cup specifically, foils made their debut in the 34th edition (2013), when the competition involved rigid-wing catamarans. The same type of boat, with a reduction in size and costs, was adopted in the following 2017 edition. The catamaran’s structure allowed a relatively simple application of the foil concept, where each hull supported its own movable foil, which overall was almost hidden from the untrained eye.
With the return to monohulls in the 36th edition of the cup (2021), foils became much more prominent, uniquely characterizing the boats (AC75) even to the general public. In fact, even when the boat is stationary, you don’t need to be a specialist to notice the two movable arms that end in T-shaped appendages.
It’s worth remembering that in 2020, with the upcoming races approaching, the cup’s organization likely faced some challenges when a Brazilian naval engineer named Manoel Francisco Cortes Chaves revealed his rights to the monohull solution with two lateral movable foils. This solution is the subject of the international patent application PCT WO 2017/083947, based on an earlier Brazilian patent application from 2015, from which Chaves duly derived a New Zealand national patent, thus consolidating his rights in the Hauraki Gulf, off the coast of Auckland, the designated venue for the races.
Image from Chaves’ patent
How the dispute between Chaves and the America’s Cup ended is unknown, as there is no information available online. What we can imagine is that the competition’s organization somehow managed to resolve the situation, as in the current edition, the boats have retained and developed the same solution as before. As for Chaves, there is no further news, except that he gave up protecting his invention in the United States, abandoning the related patent application. This abandonment could suggest that Chaves was discouraged to the point of giving up defending his rights. However, we prefer to think that, on the contrary, Chaves reached an agreement so advantageous that he considered himself fully satisfied, making the U.S. patent unnecessary!