Team New Zealand’s preparation for their America’s Cup defense had a slight backward step on Friday when an object in the Waitematā Harbour caused a capsize during a training run.

However, it was a brief setback before the team’s two boats, AC40-3 and their training boat LEQ12, flew along at near 50 knots flexing their muscles to their America’s Cup rivals.

While the recon boat looking at an issue with LEQ12, the AC40 was sailing downwind about a mile to leeward and struck a UFO (unidentified floating object) and capsized.

Team New Zealand capsize on the Waitemata Harbour after hitting a UFO (unidentified floating object). Photo / America's Cup

It was righted and sailed the rest of the session, the America’s Cup website reported.

The two AC40s then got into racing mode and nudged the 50-knot barrier as the training boat kept up with the pace.

Nathan Outteridge, Pete Burling, Liv Mackay, Leo Takahashi, Sam Meech, Marcus Hansen, Josh Junior and Blair Tuke were all on board the two vessels.

“Two windward/leeward runs in close proximity, then the boats blasted off together to the Motukorea Channel between Rangitoto and St Heliers and set on a broad reach down to Bean Rock where the recon RIB just couldn’t keep up, even at 46 knots,” the America’s Cup website said.

“As the two hardened up for the ‘work’ home it was here that the LEQ12 showed its pace and by Rangitoto Wharf, Pete Burling and Nathan Outteridge called for the windward board to be dropped to allow the one-design AC40 to catch up. Encouraging for the design team who have made some pretty big changes to the LEQ12 both visible with the foils and unseen below decks.”

“When many would have called it a day and tripped into the weekend, the Kiwis went for it and put on a performance that in many ways, changes sailing, and its perception, perhaps forevermore. This was high performance at a level unseen before in 40-foot grand prix foiling race boats and utterly mesmerising to watch,” the report continued.