Where do we go from here… The treatment of the front of the twin-skin sail is pretty uncontroversial, attaching to the back of a structural spar, but batten configurations and controls will take more working out, as will the critical connection down the leech. And then there are the mechanics at the head of the sail itself. In parallel with aggressive experimentation into soft wings (next issue) taking place in Europe, some very exciting development awaits…
Work on the details of the rule began in
earnest once the concept of a foiling mono- hull had been agreed between the Defender and Challenger of Record. Publication last November of the video animation of this extraordinary craft, with the look of a nautical praying mantis, elevated sailors’ eyebrows around the world and the sugges- tion it should have been released on 1 April elicits another chortle from Bernasconi. But such is the sophistication of the simulators now the designers know that what might look like a cartoon fantasy will fly. ‘We gained a huge amount of confi-
dence that what the simulator was show- ing was borne out in reality on the water with the AC50. And as we made changes to the simulator model we saw the same changes on the real boat – so we’ve gained a lot of confidence that the simulator is by and large a good representation of the physics of sailing,’ says the former McLaren designer, who looks to Formula 1 for an analogy on Peter Burling persuad- ing him to have a go at flying the real thing after the AC50 skipper had watched him at work on the simulator. ‘He might have been a bit kind in saying
that,’ says Bernasconi with a laugh. ‘Stick anyone in a Formula 1 car and they can press the accelerator and get to the end of the straight – probably struggle a bit more in slowing down and going around corners! ‘I actually find the simulator easier to
drive than the real thing. I think that’s probably just being a bit daunted by the possible consequences on the water… (more laughter). I’ve had enough complete wipeouts on the simulator to know what I’m capable of!’ Bernasconi confirmed suggestions that
the AC75 should reach similar speeds to an AC50 downwind but be quicker upwind, with the extra weight of the bigger boat giving it more righting moment. But for the sailors it will be quite a handful. ‘Using the simulator we’ve been sailing
the AC75 concept for quite a few months and so we’ve learnt about the characteris- tics; it’s a difficult boat to sail, for sure. We see that as a good thing. We want it to be
as much of a sailing competition as a pure design competition – and it’s an exciting boat to sail. But, yeah, we’re pretty confi- dent from all the simulation work we’ve done that it’s going to be pretty cool.’ Development of the simulator was
borne out of financial necessity in the last campaign because the team hadn’t the budget to build more boats. Now new challengers are being encouraged to adopt a similar philosophy in their research and development to keep down costs. Other money-saving measures include
many one-design elements and strict limits on the number of other major components that can be built, from hulls and masts to sails and foils. Bernasconi: ‘The foil arms are pretty
massive composite components – if that was something that was left open teams would inevitably build more of them because you want to optimise them as you learn and you probably take bigger risks because you want to be optimised to the nth degree. That means they are more likely to break. But in the end they are out of the water most of the time so in terms of the performance differential you will get between a good one and a bad one relative to the amount of money you would be spending, it’s not a very good equation. That’s the reason we wanted to make the foil arms one-design.’ A further advantage of one-design parts
is that it should reduce the number of loopholes that plague the rulemakers. ‘The very first rule we wrote was the rudder rule because in a way it’s sort of simple,’ explains Bernasconi. ‘But even with that you start thinking about the ways people will try to get around that rule and have rudders that deflect in strange ways.’ In trying to make the AC75 rule bullet-
proof each section has been peer reviewed by all sides. But there are limitations. ‘I mean I think the wording in the rule is so technical now that it’s quite difficult to get people from outside yacht design to read it and see where the loopholes might be,’ says Bernasconi. ‘Any one section of the rule originally
written by one person gets checked by other people. And then, whether it was Luna Rossa or ourselves writing that, the other side would read that part of it and come back with more comments. Then in the last few weeks other challenging teams have had a draft and been able to come back with comments of their own. So there are quite a few stages of checks and balances. But it is very complex and so almost inevitably there will be some holes we haven’t spotted.’ Too complex? A deterrent to new
teams? ‘We probably would end up with more entries if we went for a very conven- tional displacement boat that would be easier for teams to get into. But we didn’t feel it was right for the Cup and you’ve got to strike a balance between doing a boat that’s at the forefront of sailing technology and providing inspiration to drive the sport forward – versus just something that will purely get the most entries.’ Safety has been another driving force
for the rulemakers, with the focus on keep- ing the sailors away from flying foils: ‘It’s something we’ve thought pretty hard about and there are quite a few rules in there that are safety-driven – maybe some that are more obvious that others. ‘For instance, there’s a rule on mini-
mum transom width and the rule on maxi- mum rudder elevator width, so the hori- zontal at the bottom of the rudder can’t be more than 3m wide and the transom has to be 4m wide. So that is effectively saying that if you fall off the boat you’ve got half a metre clearance on either side before hitting the elevator. ‘I think on any high-performance boat
the biggest risk is hitting something – a sailor coming off the boat or hitting some- thing on the boat – so whenever the sailors are forward of the foils they need to be clipped on with a maximum tether length of 2m, so they couldn’t fall over the side and hit the foil on the way down.’ So with the rule now sorted the Cup
defenders are turning their minds to find- ing innovative ways to beat it by following the same philosophy that earned them the right to write it, as Bernasconi explains: ‘I guess what we back ourselves on is that we have got a very strong team of designers and engineers and we’ve developed good tools over the years – so although it’s maybe surprising to go away from the class of boats we won in, in a way we see our strength as designing when there is innovation to be made. So by having a very new class we are confident that we can do a good job of it.’
SEAHORSE 39
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