THE America’s Cup has never seen anything like this.

When Team New Zealand’s 50-foot catamaran speeds around Bermuda’s Great Sound, four of the six crewmen are hunched over, furiously pedalling away.

That’s right, mate, pedalling.

When the red-and-black cat tacks or gybes, the “cyclors” unclip from their cycling pedestals in one hull, join the choreographed dash across the trampoline netting stretched across the boat and clip into the cycling pedestals in the other hull, and continue pedalling away.

One of the cyclors, 28-year-old Simon van Velthooven, has an Olympic bronze medal in track cycling.

He might soon be an America’s Cup champion if the Kiwis’ astoundingly fast design package, of which the cycling system is just one component, whisks them to victory against two-time defending champion Oracle Team USA.

The Kiwis replaced grinders and their arm power with the cyclors. Their pedalling powers the hydraulic systems used to trim the wingsail and raise and lower the daggerboards, or retractable centerboards, that are tipped with hydrofoils.

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Cyclors for Emirates Team New Zealand pedal Josh Junior makes his way across the boat. Source: AP

When the cats reach a certain speed, they rise up on the leeward daggerboard and rudders, with the hulls completely out of the water. Daggerboards on both hulls are in the water for a few moments during tacks and gybes.

The actual sailing is done by helmsman Peter Burling, 26, an Olympic gold and silver medallist; skipper Glenn Ashby, 39, an Olympic silver medallist and multihull whiz who controls the wingsail with an Xbox-like device; and Blair Tuke, 27, Burling’s Olympic teammate who has a dual role of cyclor and foil trimmer.

This is the first time cyclists have powered a boat in the America’s Cup match. A Swedish team tried a cycling system in an unsuccessful challenge in 1977.

“If you have half a brain and you know that your legs are stronger than your arms, why wouldn’t you give it a go?” van Velthooven said.

Team New Zealand won the first four races against Oracle Team USA last weekend and leads 3-0.

It started with a negative point because Oracle Team USA, owned by billionaire Larry Ellison, won the qualifiers. Racing resumes on Saturday (Sunday morning AEST).

The underfunded but always crafty Kiwis, the hard-luck losers in the 2013 America’s Cup, began secretly working on the cycling system three years ago in Auckland. When their test boat was launched in February, there was surprise and scepticism from outsiders.

Team New Zealand helmsman Peter Burling. Source: AP

Oracle, of course, had team members watching from a spy boat.

“I think they said, ‘Ah, we heard rumours that you’ve been testing but we never thought you’d actually bloody do it,’ ” van Velthooven said.

“It was good to keep it 100 per cent secret until the boat rolled out.”

Other than the bike seats that can be seen in the cockpits, little is known of the system. And the Kiwis aren’t real chatty about it.

“It doesn’t look like a bike at all. Just imagine a set of cranks and that’s about it, really,” van Velthooven said.

Does it have a chain?

“No comment. Not yet,” he said.

He does let on that the cyclors wear mountain bike shoes and use mountain bike pedals.

“It’s purely high performance and it does its job well and it’s been designed well and it’s been designed really light,” van Velthooven said.

Van Velthooven, 28, said he learned to sail while growing up but veered into cycling. He won the bronze medal in keirin at the 2012 Olympics. When he didn’t make the world championship team for track cycling in 2015, Team New Zealand called and asked him to test their cycling system.

Emirates Team New Zealand sails during a training session in Bermuda. Source: AP

“It was a big hurdle when they actually put the test bikes in the race boat,” he said. “They had mocked it up in the shed. It looked funny then to us. We were either going to be the laughing-stock or the best power source the Cup has seen. It’s worked out well.”

Van Velthooven’s spot is in front. On days when there are multiple races, he swaps out with Joe Sullivan, an Olympic rowing champion.

“Position one is more of a mercenary. We just go as hard as we can and let the other guys not pedal as hard so they’re dialled in for all the races,” van Velthooven said.

Van Velthooven calls the cyclor system “a 10th of 10 different things that are all working at the same time to give a package that’s 100 per cent awesome.

Blair and Glenn have almost unlimited hydraulic fluid to play with when racing gets heated. It’s just awesome that it’s all worked out, all the ideas that the designers had and then for the machinists and boat builders to build it, and then to go out there on the water and actually see it working as we dreamed it, is a pretty awesome thing to deliver for the boys.”

The America’s Cup resumes on Sunday morning (3am AEST) and is broadcast live on Fox Sports Australia.