America's Cup: Covergate - Teams take aim at American Magic's cockpit fairings
by Richard Gladwell 15 Aug 2024 15:37 BST
American Magic - AC75 - Day 22 - June 18, 2024 - Barcelona © Ugo Fonolla / America's Cup
The latest Rule Enquiry requesting an interpretation of the rules governing Surface Finishes is clearly aimed at the US Challenger, American Magic.
The question uses the AC75 Class Rules governing the characteristics of surface finishes as a rules missile, aimed at US team, and questions the legality of the honeycomb fairing covers used on the four recumbent cyclor cockpits on the US Challenger.
Looking back at the AC37 Joint Recon Team images, the covers were first spotted on May 27 while American Magic was dockside at the US team base. However, on looking for subsequent sailing shots to see if the fairings/covers were in place while the team was training, there is nothing definitive until the last day of the Joint Recon program on June 22.
Since June 23, when the teams could undertake their own reconnaissance in Barcelona, the team spies have had the opportunity to shoot photos, which could be blown up, allowing the fairings to be examined more closely. That is what Sail-World did to get a close up image of the honeycomb structure. That image is as shown above. Anyone with access to the Recon system could have done as we have.
The image used to illustrate the Rule Enquiry was taken by the Recon team, who had special access to the American Magic base and were assigned a set shooting point. The other five America's Cup teams did not have this level of insight.
Plenty of photos were taken of American Magic by the Recon teams since the fairings first appeared on May 27 and until the shutdown of the Recon program three weeks later on June 22 - so the US team's covers were not new to spies from other teams.
The latest Rule Enquiry under the guise of "Rule Enquiry #242 - Cockpit Fairings" was lodged a few days ago on August 12, 2024, about 50 days after the Recon Teams first highlight the development. This Rule Enquiry is very late-timed - with just a few days remaining before the start of the third Preliminary Event, and the start of the Challenger Round Robins.
The implication is that the teams have known about it for 10 weeks, and didn't raise the issue at the first opportunity, if other teams had questions as to its legality. To be generous, maybe they only thought of it recently - who knows?
It was an oblique question of the Rules Committee, rather than a direct protest, apparently to test the legality of the fairings on American Magic.
"We are considering a meshed fairing for our crew cockpits but are concerned that they are not permitted by the AC75 Class Rules," says the opening line of the Enquiry.
Since the filing of the Enquiry, and independent submission on it by all teams, five have opined that the covers were prohibited.
The opening line on the sixth read: "As this Rule Enquiry is clearly directed at a feature of American Magic's AC75 Class Yacht, we will explain the components in question."
There is little doubt that American Magic didn't lodge the Enquiry, given their apparent defence/explanation of it.
However, that is not a definitive answer either, teams do get rule interpretations as a form of insurance. Back in the 1983 America's Cup, when Australia II's wings on their keel were subject to a long-running rules attack, the British Victory '83 team produced an earlier ruling from the then International Yacht Racing Union saying that the wings were not illegal and that the Australians winged keel had been measured properly.
Maybe American Magic had picked up a rumour that a challenge to the legality of the covers was imminent once they had sailed a race - and the prudent move was to raise the issue beforehand with the Rules Committee?
Co-incidentally the Rule Enquiry emerged after the teams participated in several official Practice sessions in August, when the usual rules were suspended for two boats being prohibited from sailing for more than 20secs on the same heading, and rounding marks within 30 seconds of each other. Although no official results were published, one could suspect that American Magic showed a nice turn of speed.
The likely explanation is that the Enquiry is disruptive in its real intent and timing. The fairings/covers have been a known issue for two and a half months and yet the Rule Enquiry has been lodged just a week before the start of America's Cup hostilities. The America's Cup AC75s first lined up against each other during several official practice sessions earlier this month, and American Magic may have displayed a significant speed edge, prompting the Enquiry to the Rules Committee.
A "No" from the Measurement Committee would make life difficult for American Magic, as the covers would have to be modified or removed, which would be very disruptive so close to the start of a major regatta.
American Magic was the first team to trial cyclors on its modified AC75, which sailed in the 2021 America's Cup in Auckland.
After that exercise, American Magic opted for the use of recumbent cyclors, acknowledging that their use was less ergonomically efficient (by about 10%); however, their lower profile meant that the aft section of the hull/decks was more aerodynamically efficient, and was, therefore a gain.
The aerodynamic gain made by the use of recumbent cyclors became apparent in the recent Practice Racing, when the slim lines of American Magic were contrasted with the pot-bellied hull shapes of the other teams who opted to use upright cyclors and paid the price with a higher sheerline.
However in doing so, they assumed an outlier's position in design of their AC75 - and Cup history tells you that design outliers are always vulnerable to this sort of Rules Enquiry.
The subsection of the Rule being questioned deals with the boundary layer and prohibits any "devices and finishes whose primary purpose is altering the structure of the boundary layer".
The question is whether the patterning on the fairings affects/alters the boundary layer of air passing over the deck and cockpit fairings/covers. The Rule includes a formula to help determine the thickness of the boundary layer. Ultimately, this will probably resolve the issue.
In its explanation of the fairings, the team says they are there to "restrict bulk vertical airflow down into the cockpits, as would be apparent to any aerodynamicist." The cyclor cockpits on American Magic have much bigger deck openings than those on the other five AC75s - who use cyclors working in a more efficient upright position.
Of course, if the Rules Committee ruled against the honeycomb fairings/covers, then an alternate would have to be put in place, or American Magic would have to sail with open cockpits. And, of course, the ghost team that lodged the Rule Enquiry, so they could do the same, wouldn't be able to fit covers/fairing on their cockpits either.
American Magic is an extreme boat in the AC75 fleet, and has the most unusual cockpit layout of the six challengers. The four sailing crew members are well forward across the boat, and the cyclors are pulled forward behind them. This positioning moves the crew weight forward in the AC75, and the crew are closer to the pivot point for the foil arms.
The five other teams have conventional upright cyclors, with two sailing crew and two cyclors in line fore and aft on each side of the AC75. Their crew weight is further aft.
It is bit far-fetched to suggest that a team would seriously consider changing its layout to mimic the American Magic layout at this stage of the regatta - lending credence to the likelihood that this rules question is intended to be disruptive in the best traditions and gamesmanship of the America's Cup.
We've seen many such ploys in the past - fibreglass 12 Metres in Fremantle; the use of the Kiwi bowsprit in the 1992 Louis Vuitton Cup; the progressive lowering of the Kiwi's hula in the 2003 America's Cup; the multi-measurement certificates of Liberty in the 1983 America's Cup; the legality of foiling in the 2013 America's Cup - and many more.
The Rules Committee has yet to produce a draft Decision, however the teams have already given their views - which are mostly a thumbs-down.
The problem with the Enquiry from American magic's perspective is that they have to take it seriously, and respond. Even if they win the point 100%, it can still be very distracting for the team and it management in particular - right when they are about to enter a critical phase of the America's Cup cycle.
The other issue is that win or lose, the history of these sort of measurement issues is that they don't go away - and one decision from the Rules Committee often just leads to the initiation of another Enquiry. Getting a partial win, at this stage of the campaign is as bad as a loss, if 11th hour changes have to be made.
Even at this stage, and without a draft decision from the Rules Committee (which indicates the direction of travel of the final ruling), American Magic would have to be planning now the design construction changes they need to effect changes required by a partial or completely adverse decision. All this is a distraction for key team members, including management, designers and builders - when their focus should 100% be on the teams performance in the Louis Vuitton Cup, which starts in less than two weeks.
The "easy" way out is to just remove the offending part, but in American Magic's situation the use of recumbent cyclors is a vital part of their boat design, as it has created several design opportunities that the US team designers have been able to exploit - such as reduced topside height, less aero resistance and drag.
Sailing coverless with such large deck openings is not an ideal situation due to the airflow disruption around the deck and sails. Plus the big openings permit more water to get below, from spray or a nosedive.
Cockpit boxes?
In an earlier Rules Enquiry, a team questioned whether carrying a large box in the cockpit was permitted. The box is not bonded to the hull/cockpit.
The Enquiry reads:
"It is proposed to fit a box, of dimensions yet to be defined, as shown in Figure 2. This box shall not be bonded to the hull, but it could be attached to the hull to prevent movement while sailing. The box can be removed from the yacht when not sailing. Once the box is removed the yacht is back to the configuration as shown in Figure 1. The box would be weighed as part of the Platform."
Given the design teams' obsession with reducing all forms of drag, wanting to plonk a large box in the cockpit, with its potential to disrupt airflows, is a very unusual design initiative to implement at this late stage of an America's Cup campaign.
It is not clear how the box works with a deck-sweeping mainsail foot. It must be assumed that the box is not the shape shown in the diagram, and one will be used which is a lot more sympathetic to airflows around the mainsail foot and will provide a better endplate on the rig.
In its draft ruling, the Measurement Committee has said the "box" is not part of the hull but is part of the "platform" and, therefore, will need to be included when calculating boat weight.
What happens next on the fairings/covers is anyone's guess.
The cockpit box question has largely been resolved - but it will be intriguing to see how the ruling is used.