AC75 wind measurement system is not perfect, but the same system worked very well in Bermuda
Just over a week ago, in case you’d missed it, the first of what was to have been three America’s Cup World Series was decided in the final race.
On the second leg of the six-leg race, a deficit of 800 metres was turned into a 300-metre lead and winning margin.
The following day, the Xmas Cup ran out of wind just before the finish line. Britannia II was physically only a few metres astern of the race leader, Te Rehutai – but in reality, was 5,500 metres adrift – or two legs behind.
Surprisingly the sail that could have made a difference, the Code Zero, remained firmly in the sail lock on the teams’ chase boats.
What was learned from the two series?
Firstly, all teams have a weak spot in winds at the lighter end of the range, which is not 6.5kts during the race – but only for a five minute measurement period before the race start.
The AC75 wind measurement system is not perfect, but the same system worked very well in Bermuda. Its only weak spot was demonstrated in one of the last Practice Races, where Emirates Team New Zealand and Luna Rossa Prada Pirelli were due to race. In the five minute period between minutes nine and four of the countdown, the wind did not trigger the lower limit of the rolling average of 6.5kts, and the start proceeded.
Within the final four minutes, the wind became significantly lighter. Neither the Italian nor the Kiwi boats could foil, and in the end, both struggled to make it to the start line before the race was blown up, several minutes after the starting signal.
During the third and final day of the ACWS, we saw several instances of AC75’s sailing at speeds of close to 30kts, but making 0kts VMG (speed toward the next mark).
It was similar to what we saw on Bermuda, where the AC50’s could make a windward mark on occasions, but when the time came to turn downwind, the sailing physics didn’t work out. All they could do was sail back and forth hoping for a slight increase in pressure, which would be sufficient for them to point in the direction of the leeward mark, and maybe gain a race-winning edge over their opponent.
Then Regatta Director Iain Murray likened the situation to cutting a piece of wood with a blunt saw.
In the whole of the Bermuda regatta, light winds only precluded racing on two days out of 17, and caused another race to be abandoned and restarted, after a time limit expired.
On several occasions the course was set up for a sea breeze, only to have the westerly check-in around 4.00 pm – confounding the forecasters – and making racing feasible on Course C but not on Course A.
For various reasons, the British Challenger, INEOS Team UK failed to fire – due to a combination of breakdowns and poor light weather performance. From the outset, they came under siege from the world’s mainstream and sailing media – most of whom have never seen an AC75 sailing, but seem to have answers aplenty.
There is a sense of déjà vu about the Brit’s situation. Forty years ago Jack Knights wrote ahead of the America’s Cup Challenger Final in 1980: “In most previous challenges the British didn’t know what had hit them until they were being congratulated for going down like gentlemen. This time they understood the magnitude of their task within a week of arriving in Newport. Once you diagnose the problem, you are halfway to a remedy.”
Whether INEOS Team UK have diagnosed their problem will be revealed in two and a half
British helmsman, skipper and team principal, Ben Ainslie has certainly put a brave face on the team’s issues. The best possible spin on the situation is that Britannia II has some significant issues in lighter winds, but is competitive, all systems working as they should, in the moderate to fresh.
Maybe the Brit’s problem could be as simple as a poor wing choice when they declared their configuration five days ahead of the start of racing. For the Prada Cup, the AC75’s configuration needs only be declared two days in advance of racing.
The rule’s intention is for the teams to use wings that are “all-purpose” – able to operate across the range of conditions and not be targeted for an expected windstrength, based on a long-range weather forecast.
Looking back over Sail-World’s image files, several wing shapes have been trialled by INEOS Team UK, including ones that look to be more conventional.
Of course, while there is a limitation of six wings per boat, that doesn’t mean three pairs, and each AC75 can also have up to 20 wing flaps. Add into that mix the allocation for the first boat (another six wings and 20 wing flaps) – and Ainslie’s team should have plenty of data and options.
Getting additional horsepower out of the rig is another option for INEOS, and indeed all teams. While hull surgery may be an obvious option, other team designers say the hull is just an endplate between the rig and the water – quite a different proposition from displacement yacht design.
While American Magic finished ahead of Luna Rossa, the US team has been sailing in Auckland since July – more than any team, other than the Defender. The position could easily be reversed, once the Italians get in some more sailing miles – which they have been doing since the conclusion of the ACWS.
Emirates Team New Zealand topped the leaderboard for the ACWS, despite being the last boat to launch. The Kiwis had been in the water for less than four weeks, compared to the almost eight of the other three – who launched within five days of each other between October 16-20. ETNZ splashed on November 19.
There is a limit as to what can be read into a three-day series. Fortunately, each day was quite different – Speed being the determinant on Day 1, Match racing on Day 2, and lighter air Flight control prowess on Day 3. The regatta management got a good workout over the three-day series and the five days of practice racing. Herding the spectator fleet is a work in progress.
All teams claim they have plenty of developments to put aboard, and no doubt are looking to put the polish on their crew-work, match racing skills and systems reliability during the five weeks of racing in the Prada Cup.
Quite how Emirates Team New Zealand approaches the next two and a half months will be followed with real interest by kiwi fans.
Overarching the intrigue on both the Defender and Challenger sides of the equation is COVID-19. The cancellation of the 2020 Rolex Sydney Hobart Race should be a salutary lesson to all involved in the 36th America’s Cup regattas.