AC34 Day 3 and a big day in store with the breeze forecast to be nudging the upper limits, starting at 18 knots and building to 20 then 22 knots by the second race. The strong flood tide will keep the water flat and raise the effective wind limits to 24.9 kts in race 1 and 24.5 in race 2.

So with just a few hours to go until the third day of racing there’s plenty of tension here, but what has been the chatter around the docks during the 24hr lay day? Much of it has focused on how fast teams are still learning and how accurate the sailing is becoming.

Nailing the start at speed and on time in an AC72 doing 40 knots is a good example.

To put it into context imagine trying to hit green at the traffic lights in your car at speed. First set yourself up 300m out then stamp on the gas to accelerate to 50mph. Then, without touching the accelerator pedal or brakes for the next 14 seconds hold your nerve to hit the line exactly as the lights go green. Not just before and certainly not after, but spot on when the lights switch.

Clearly I’m not going to advocate trying it, but I’m pretty sure I couldn’t do it anyway. But that is the level that these teams are now operating at. And thanks to the superb TV footage and the incredible skills of the teams, we’re expecting them to nail it every time.

Yet behind these impressive skills lies a learning curve that’s steeper than it’s ever been during an America’s Cup.

As we’ve witnessed in the four races so far, the heat of battle is pushing these teams harder than they could ever replicate in training. They are also learning new tricks at high speed on the hoof.

“Learning as you go? You’re not kidding!” said one of the Oracle team members just after Sunday’s spectacular fourth race.

“Just two weeks ago we reckoned we could only execute a perfect foil to foil gybe 50 percent of the time – two weeks ago. Today we had to do two in a row with no margin for error, under real pressure as we headed into the finish with the Kiwis on our tail. I’m telling you, that’s how fast we’re all having to learn.”

I had a further opportunity to chat to some of the sailors at the recent Andrew Simpson Sailing Foundation charity dinner, (a superb fund raising auction for a very worthy cause in honour of the late Olympic sailor and Artemis team member, make sure you take a look www.andrewsimpsonsailing.org). Here the view was the same with all referring to the near vertical learning curve.

They were also all talking about foiling, not just what it’s like on a Cup boat but which Moth they had just bought. Get them started on this topic and you’ll need to have cleared your diary for the next few hours.

Again, there’s a real, sense of excitement at what is happening in the sport right now. Particularly interesting given that these are hardened professional sailors in an event that is better known for the long term and financially demanding quest for miniature gains in speed and the ‘too cool for school’ manner of its sailors who have to grind out the same training routines day after day.

Having spent a good deal of this year talking to teams and crews about the boats and how they were going to tame them, there is a new buzz among the sailors. Where previously teams talked of boats that were simply too powerful and dangerous in certain conditions, now the mood is changing. Sure, they all treat these boats with huge respect, but as they learn more with each day they gain confidence in the boat and themselves.

“There is no going back now,” said Jimmy Spithill the other day.

Even those that are no longer in the game are looking ahead. Behind the scenes Luna Rossa is said to be preparing for the next Cup already, irrespective of who wins this match while others are already starting to pull together potential commercial partners.

So although ardent fans will be hoping for another victory for their team, what many here in San Fran would like to see is a day where both teams win a race apiece. The dream ticket for the Cup going forwards is to have further evidence that the bold vision can deliver after all.

Racing starts at 1315 Local (2115 BST)