British challengers INEOS Team UK unveiled their second generation America's Cup yacht in Auckland on Saturday, just 24 hours after fellow challengers American Magic launched their second boat and almost capsized it.
The British AC75 foiling monohull, named 'Britannia', had one significant difference from their first generation boat, with the addition of a bustle keel.
The bustle is supposed to help reduce the resistance from waves and is designed to help lift the boat out of the water and then reduce air resistance when it is foiling.
"It looks like a rocket, let's hope it sails like one too," skipper Ben Ainslie told reporters at the launch.
"We have got to push the boundaries and I think with this boat we have pushed it pretty ... hard.
"I don't think we have left much on the table and the whole team share that philosophy, that we have got to go for it if we are going to win this thing."
Britannia's launch follows that of American Magic's 'Patriot' on Friday, but the New York Yacht Club syndicate had some issues in their first trials on Auckland's Hauraki Gulf.
Video footage emerged on Saturday of the yacht almost capsizing as it attempted a gybe in about 20 knots before it slammed back into the water and came to an almost sudden stop.
"We had a great nosedive, and that was exciting," said skipper Terry Hutchinson. "It was nothing that we haven't seen or done on our other boats."
Italian syndicate Luna Rossa are due to launch their second generation yacht on Tuesday, with the teams having just two months of further trials before a regatta that also involves holders Team New Zealand in December.
The challenger series then runs from Jan. 15 to Feb. 22 next year before the America's Cup match against Team New Zealand begins on March 6.
(Reporting by Greg Stutchbury; Editing by Sonya Hepinstall)
