AUCKLAND (Reuters) — The next America’s Cup regatta will be sailed in Auckland in 2021 in 75-foot monohull yachts but only if New Zealand’s largest city can build the infrastructure needed to stage the regatta, holders Team New Zealand said yesterday.

They took international sport’s oldest trophy off Oracle Team USA with a stunning 7-1 victory in Bermuda’s Great Sound in June in a regatta raced in high-powered foiling catamarans.

TNZ chief executive Grant Dalton released the protocol, or rules, for the 36th America’s Cup at the Royal New Zealand Yacht Squadron yesterday.

They had been written in consultation with the official Challengers, Italian syndicate Luna Rosa.

Dalton said the date was yet to be confirmed and they had not signed a host city agreement as Auckland still had no infrastructure for the America’s Cup base and they needed to start construction by the middle of 2018 for a 2021 regatta.

“The intention is to hold the Cup in 2021,” Dalton said at a media conference. “At this stage no infrastructure exists to hold it by that date. We [New Zealand] have just come out of an election but there has been some planning going on. Infrastructure needs to be started by mid-2018.”

Dalton added that if Auckland was unable to complete preparations in time, the regatta would be moved to Italy, but it was not a warning shot to the government. “We need to give certainties to teams,” he said.

Dalton, who had already signalled his desire for a nationality clause, said each crew of ten to 12 sailors must be contain at least 20 per cent from the challenging country.

The rest of the team must have established residency criteria, which Dalton said was determined by being resident in the country for 380 days between September 1 2018 and September 1 2020.

“The most significant America’s Cup in my time was when Australia 2 beat Liberty in Newport, Rhode Island in 1983,” Dalton added. “It was country versus country.

“Countries need to be encouraged to grow their own talent.”

The specifications for the new boats would be released on November 30.

Dalton added that each syndicate could build two boats and there would be pre-regattas in 2019 and 2020. Contrary to what he told Italian media two weeks ago, he said there was still the possibility for “cyclors” to be used.

TNZ used “cyclors”, grinders who sat on upright bike stations and used their legs rather than arms to generate the hydraulic power needed to sail the foiling catamarans, in their successful challenge.

Last week he was quoted as telling La Stampa that “grinders will return”, indicating the cyclors would not feature, but said yesterday that the rules did not preclude them.