Last month we mentioned a revealing Twitter comment from Oracle’s bowman Brad Webb who said the American boat had flown through to leeward of the red Artemis boat. Where Oracle was hydrofoiling, the Swedish boat was doing that conventional thing that boats do - of floating on the water. But as Webb, pointed out, merely floating is soooo last century. “They might be rethinking no-fly strategy,” tweeted Webb, a harsh but fair observation of Artemis.

The lesson has not been lost on the Swedish team, who have now put their boat back in the shed for some drastic plastic surgery. Even then, when it re-emerges it won’t be a fully foiling beast but will move the team closer to the direction already being pursued by the other three teams. According to team boss Paul Cayard, their second boat - the one they’ll race in anger - is also being reconfigured from a ‘skimmer’ to a fully-foiling catamaran.

So it appears the design dilemma between floating or foiling has well and truly been put to bed. Even on the short courses of the forthcoming America’s Cup, the higher peak speeds of hydrofoiling are now deemed to outweigh the downside of greater drag at low speeds, when there isn’t enough wind to lift the hulls above the waves.

The AC72 was predicted to attain speeds up to 40 knots, and the Kiwis are already achieving that, and then some, during their training and racing sessions against their Italian friends on Luna Rossa. During one downwind leg on the Hauraki Gulf near Auckland, the Emirates Team New Zealand boat averaged over 39 knots on a leg that included three gybes. So the pure straight-line speed must be well in excess of 40 knots. No wonder Artemis has been rethinking its no-fly strategy.

While the wing rigs are one of the most eye-catching and awe-inspiring aspects of these wonder boats, the design of the underwater surfaces is becoming established as the chief battleground for the design teams. Artemis, and Oracle too, are converting AC45s to foiling boats while they wait for their second and final AC72s to be launched. The tactics at foiling speeds become radically different to those used in more conventional boats, as Artemis helmsman Nathan Outteridge knows very well from his exploits on the International Moth, an 11-foot carbon-fibre foiling dinghy in which he has won the World Championship. When you’re foiling you’re sailing twice, three-times, sometimes even four times the speed of the actual wind. How can a sailing boat actually travel multiples faster than its power source - the wind? It takes some getting your head around the concept. So the teams need all the foiling practice they can get, whatever the size of vessel.

The AC45 has been a great precursor to the main event, but apart from a final America’s Cup World Series event in Naples in April, that’s about it for the fast 45-footer. Except that a bunch of national youth teams have been trialling for a spot in the Red Bull Youth America’s Cup, which nicely fills the gap in early September between the end of the Louis Vuitton Cup and the America’s Cup proper. The only risk is that the spectacle of 10 identical AC45s flying around in close proximity might eclipse the America’s Cup itself, with two potentially mismatched 72-footers separated by minutes on the race course. It will be thrilling to see two AC72s flying above the surface at 40 knots, but will we get the thrill of a close contest? It’s hard to imagine, although I hope my scepticism is proven wrong.