America's Cup challengers 'running scared' as Team New Zealand ponder lending boat to Stars & Stripes

America's Cup challengers are running scared, according to one veteran commentator, after Newshub revealed Team New Zealand could hand over their first boat to another syndicate. 

If allowed, struggling Stars & Stripes could become the fourth challenger. 

And the off-water manoeuvring is all unfolding, as the first foreign hopeful hits the water in Auckland.

American Magic looked right at home on the Waitemata - it's AC-75 foiling and flying in a light breeze. 

But another US team have put a controversial spanner in the works. Stars & Stripes have gone to the independent America's Cup arbitration panel to seek permission to use a boat built in another country.

Currently, that's not allowed under the rules.

Most likely, Te Aihe - Team New Zealand's first boat - will fit that bill and Sail World editor Richard Gladwell believes an extra boat in the challenger series benefits all parties. 

"If you look at what's best for the Cup, it's certainly good for that," Gladwell tells Newshub.

"The other guys might just have to get over themselves -  these guys [Stars & Stripes] have read the rules a bit better than the others."  

The event desperately needs another challenger - alongside American Magic,  there's only Italy's Luna Rossa and Ineos Team UK - but the move has reportedly angered them all.

"This is a challenger absolutely betraying the other three challengers," veteran America's Cup sailor Tom Ehman says.

But Gladwell calls that narrative sour grapes, as the off-water politics heats up.

"The challengers will dress it up and say it's a huge advantage for Team New Zealand, and they're just putting their own fox in the challenger hen house."  

"They're scared of these guys coming out in a Team New Zealand hand-me-down and they might beat us in the Cup."

The America's Cup is well and truly on.