For British fans there’s a real sense of optimism building down at the Port Vell in Barcelona with INEOS Britannia launching their new AC75 for the first time and getting the initial tow-test period and sail-fitting procedure underway on a very long day for the sailors and support team. In the water by 10.15am with the mast up and a swarm of technicians and sailors working diligently through the systems checks, INEOS Britannia was a hive of delighted activity throughout the morning, with a sense of anticipation that could almost be bottled.

For the first time we saw both the foils and stepped-rudder arrangement and with so much speculation shoreside on what innovations this highly technical team, supported by the brilliance of Mercedes Applied Science, have brought through, the recon camera lenses were clicking.

What we saw was a progressive, logical design of the foils, back-slung off a beautifully sculpted bulb and similar in form to Alinghi Red Bull Racing. The detailing is where the percentages are found, and flow tails were dotted all over the span with the obligatory camera mounted to capture every piece of flow data imaginable and Pitot tubes protruding forward - measurement is everything.

The rudder itself was a departure from the norm and featured two steps leading to a slender bottom section from which the back slung, slightly W-shaped foil was attached.

A marvel of design sculpture and engineering, this is an area that the team appear to be highly invested in with perhaps angular rake adjustments achievable. On the tow test, it was noticeable just how forward the rudder angle was raked - interesting.

One highly notable and potentially significant nuance of INEOS Britannia today was the crew set-up with the helms sitting in the forward pods and the trimmers sitting right at the back of the boat in the aft pods. The two-man cyclor team either side were today seated in the middle two pods and in the aft cyclor pod HMI (Human Machine Interface) systems could be seen. Has INEOS Britannia gone rather radical here and concentrated weight forward and thrown a spanner in the accepted works where most teams run the trimmer in the most forward position. We will have to wait and see whether this was a commissioning set-up and whether it stays but INEOS Britannia are certainly not afraid to buck convention.

With the yacht in the water, it was very quickly all business. On deck we got a first glimpse of the mainsheet system that the recon team recorded as being: “black outer tube with sheave and yoke at the end removed from interior actuator. Multiple ropes threaded into tube, before connecting back to main actuator.”

Dock-out was into the mid-afternoon at 3.25pm and almost immediately the team were into the tow-test, coaxing the boat onto foils at speeds estimated in the 18-22 knot range. The team ran out for approximately two miles and then stopped to put technicians below for what appeared to be a small issue that required the boat to slow-tow back to harbour. Once back, the sails were loaded and a long period of sail fitting got underway with the double-skinned M1-1 mainsail fitted first and then the team took their time launching and setting the jibs going through the J1-1, then J2-1 and finally the J3-1. Dock-in was at 8pm with the light fading in Barcelona – long day, very productive and plenty of smiles all round. The British will now be looking to take the programme forward at pace with a decent sailing block now planned. The first sail is a tantalising prospect now.

Joining INEOS Britannia out in Barcelona on a stunningly flat day was Alinghi Red Bull Racing who have been getting used to the new, and very radical design, AC75 with plenty for the sailors to learn on a daily basis. A really solid training day ensued with the dead southerly breeze in the 7-11 knot region that allowed the team to rifle through the pre-sets, gain the data and push through the technique with a real sense that big gains are being made on an almost daily basis.

In the flat water and light airs, ‘BoatOne’ certainly looked potent with recon estimates of speeds through the 40-knot barrier, that were not confirmed by the team who tend to keep a very tight lid on performance numbers. The bow-down tendency of the boat was not on display today with the sailors able to keep her pretty much dead-level on pitch with Maxime Bachelin, portside helm, addressing the issue rather interestingly saying: “It's more a factor of the waves, like sitting on flat water it's very steady. The boat is not moving that much and it's making the team confident that on the flat water we are in a good shape and as well very happy about the boat how it’s behaving on the flat water.”

Another observation from recon was the team pushing hard VMG angles downwind, perhaps really trying to get to the VPP numbers. Again, Maxime didn’t confirm this saying only: “It was just to try a different angle for the foil and to see the behaviour of the foil and step by step to see how it was on the flat water.”

Summing up the day, Maxime added: “Today we spent more than four hours on the water, and it was a big step forward for the team to train on the flat water. We could confirm some good settings onboard, and it makes a lot of confidence for the team.” No sailing now planned until Tuesday next week for the Swiss and a full report on the day's action is available below.

Out in Cagliari, Luna Rossa Prada Pirelli pushed their beautifully balanced AC75 into some punchy wave states with perfect Spring-like conditions and a breeze that was magical at 9-14 knots. Andrea Tesei more than summed it up as he described the day to the recon team saying: “It was a really good day, we had a bit of waves, we’ve had the mistral the past days so the sea-state was pretty flat, so tested the boat in some waves in a range that was around 9 to 14 knots. We shifted two headsails and had a try on both and yeah first part was mostly checking systems and still commissioning a bit of the boat that we are doing day by day, and the latter part of the day was a bit more concentrated on racing, no physical marks but a bit of, let's say, racing practice for the boys on the bikes."

Asked to compare the feeling of the new AC75 to the bespoke LEQ12 that the team did all their training on, Andrea who has been a key Flight Controller throughout this campaign said: “For sure the LEQ12 was a bit of a ‘beast on steroids’ this boat’s a bit more of a big ship, the movements are less nervous, she's a bit more locked in, a bit easier on some aspects.”

Still running with the legacy anhedral foils that make downwind sailing in waves, particularly difficult, Andrea gave his commentary saying: “Sure, the anhedral is hard to sail in these conditions especially in waves, it is a bit less forgiving. Anyhow it was the first day in waves for the big boat so we need to find the groove and find the correct way to sail the boat and the easiest way as well, you cannot always replicate targets in a wavy state, so you need to be able to work around your set-up to make it a bit easier and ease into it.”

Luna Rossa Prada Pirelli have the weekend blocked-out to continue sailing if they wish to and the conditions remain as perfect as they were on the Bay of Angels today. The Louis Vuitton 37th America’s Cup is really starting to crank into gear now. We’re at the start of the business end of the regatta and it’s all very real. (Magnus Wheatley)