They are friends, enemies, training partners and rivals - and a mirror image of the Emirates Team New Zealand America's Cup yacht in more ways than one.
Italian syndicate Luna Rossa launched their giant AC72 catamaran on Friday, revealing it to be covered in a striking, chrome-like mirror finish - a glistening spearhead of the Italians' US$90 million campaign, about half of which is supplied by Italian fashion house Prada.
Yesterday they began trialling the monster speedster, versions of which have caused other Cup syndicates (Oracle, Artemis) problems.
Oracle flipped their 72-footer over a week ago. Artemis were due to get their big cat back in the water after damaging the enormous wingsail - but returned to the yard when they heard cracking or popping noises.
The only cracking noise heard at the Viaduct was the magnum of champagne swung vigorously by Miuccia Prada to 'christen' the Luna Rossa catamaran.
She is a fashion designer and granddaughter of Prada founder Mario Prada and the inspiration behind the Miu Miu fashion label - and if she swings a Prada handbag at you like she swung the champagne ... duck.
She is married to Prada CEO Patrizio Bertelli the Luna Rossa syndicate boss and the 'marriage' with Emirates Team NZ is clearly just as successful.
Not only are the two syndicates the only America's Cup forces to have a boat in the water, the shared ETNZ design is travelling better than other versions of the AC72 template.
ETNZ and Luna Rossa have a symbiotic relationship. Team NZ could not afford to build a second boat unless they shared their design and technology with the Italians. The Italians will build only one boat but will assemble two of the wingsails. They could not have made the Cup deadlines after a late entry without the Kiwis' help.
That made for an America's Cup oddity at the Viaduct - Team NZ and Luna Rossa team members mixing happily. The Cup has been far more synonymous in recent years for bitter enmities, defections, dirty tricks and legal actions.
The New Zealand-Italian rapport will end when they face off in the Louis Vuitton Cup in San Francisco from July-September. The winner will take on holders Oracle for the America's Cup.
As Bertelli said: "The objective is for us both to get to the Louis Vuitton Cup finals and then we will beat each other up on the water. We have two virtually identical boats that can be mutually beneficial. We can compare boats and improve boats better that way than in isolation. It is going to be very interesting."
The chrome-style overlay will cost the Italians a bit in weight - it adds about 15kg - but both teams will be looking to gather data and refine gear and techniques by sailing against each other, probably from about mid-November.
Team NZ may have an edge with their second boat which will be designed to incorporate all the perceived benefits of the first boat plus some design and technology gains engineered in the building of the second AC72 - the yacht that will be raced in San Francisco. The Italians will race the Mk I version launched on Friday.
Team NZ theoretically have an edge on the water too. They have a 10-0 record against Luna Rossa in America's Cups although, as team boss Grant Dalton said earlier: "No one should think that is going to stay the same way forever."
The AC72s have already shown themselves to be devilishly tricky craft and which sail on the edge. Capsizing and breakages could be a big part of this Cup.