America’s Cup, la nuova classe spiegata da Tom Schnakenberg
AlinghiAmerica's CupVela 2 Marzo 2009 Zerogradinord 0
AMERICA’S CUP, THE HOT SEAT
[singlepic=1870,170,250,,left][Source Alinghi and Seahorse] At right: In his element: the task of co-ordinating a rule for the America’s Cup fell to the free-thinking and enormously experienced Tom Schnackenberg. Team Origin designer and Cup veteran Andy Claughton found the experience ‘rather more enjoyable and less self-indulgent’ than some previous America’s Cup rule fests!
SH: Can you describe the process of designing AC33…
TS: We have had a very active 10 weeks! The process was similar to that of the AC90, and we deliberately used many of the clauses already developed for AC90 12 months ago. Because of our previous experience, this time it seemed familiar and it ran smoothly, in spite of the interruption caused by the holidays. The boat was originally proposed with overhangs, and girth restrictions (a sort of mini J-Class), but as different designers got into the act, it quickly evolved into a boat defined only by length overall, weight, maximum beam and draft – this will allow a very simple measurement process for the hull. Also, every change seemed to make the boat go faster!
SH: Can you describe the most important parameters…
TS: We are looking at a relatively light boat, 17.5 tonnes, which is 26m (85ft) long with a maximum beam of 4.8m. The draft is deep at 5m and because of that – even though the boat is light – it has a similar amount of power to the boats that we are used to which weighed 24 tonnes. It is lighter and longer in the water so more slippery at speed; it is easier for the boats to go fast than the V5s which dig a big hole.
The AC33s will tend to ‘scoot’ when they get a puff. Sailing upwind the biggest difference people will see is probably a bigger variety in styles of sailing among the boats. You can change the AC33’s mode more easily than you could with a heavier boat, so sailors can ease sails and go a bit faster if they choose or can squeeze everything in and sail higher and slower with almost the same net performance. Generally, the boat will be more exciting for both the sailors and the spectators.
SH: Crew number and maximum crew weight…
TS: The crew weight is slightly higher than in the past, 16 people averaging just less than 94kg, so a total of 1,500kg of crew. There is a subtle difference – it’s not spelt out in the rule, but has been discussed in the group – in that we want the crew to be checkweighed from time to time, typically at the end of a race. This means it will be the actual weight of the people as they sailed the yachts – they may be a little dehydrated but only to the tune of 0.5 or 1 litre of fluids – so we won’t be seeing a crew losing 5kg per person for the weigh-in, then rehydrating and racing heavy. So we have increased the weight a little, but the actual weight of the people won’t go up because of the method. It should be a lot healthier!
SH: And the major differences compared to a V5 boat?
TS: Well, when you look at the V5 boats, they are really narrow, so that’s the biggest difference people will see; the V5s have big overhangs and the AC33 doesn’t have that. The rig heights are almost the same and the sailplans will look similar – if you look closely you will see that these boats don’t have overlapping jibs any more, but the overall profile of the sails is very similar to the V5’s. The boats will be a bit wider and will probably sail a little more upright than the old boats when I think the extra length will become obvious; the V5s had a waterline length of only just over 20m and we are talking about a boat of nearly 26m.
SH: And some idea of the performance parameters…
TS: I don’t know them as well as the designers, but upwind they will go a bit faster than the V5 boats. Perhaps not in light winds – in 6kt the V5 will be just as good as these boats – but through the range up to about 13-14kt I think this boat will be a tiny bit better. This will be partly because the AC33 will be happier to go fast through the water. As the breeze goes up these boats will become slightly more difficult to sail because they are wider, especially at the stern. We don’t think they will heel over as much as the V5 boats – V5s love to heel, you see them sailing around with 30° of heel most of the time, whereas most ocean-racing boats sail upwind at just over 25°. These new boats will be somewhere around the 25° mark, I think.
Downwind they are quite different. There is no spinnaker pole for one thing; because the boat is lighter and has got unlimited spinnakers it will tend to sail fast. It will be a lot more like the TP52. The V5 tended to sail at certain angles to the wind, and as the wind increased they would bring the pole back flying bigger and bigger sails and go downwind quite deep. Then at some point at around 20kt a V5 would benefit from hotting up again. This AC33 boat will be in that sort of mode in all wind speeds; it’ll lean over more downwind, 10-12° of heel, and the passing will tend to be more often overtaking to windward rather than by soaking.
SH: Will the AC33 favour a different type of sailor?
TS: I think they’ll be similar to what we have now. The loads will be a bit higher upwind – but not much. The jib will be a bit easier to handle. The fact that the boat doesn’t want to heel over so much will probably mean that the mainsail trimmer, the traveller trimmer and the grinders who work with them will be busier keeping the boat just nicely on its feet; the jib sheet loads are the same or slightly higher. So upwind it will be almost the same; downwind there is more going on – you’re pressed over, you’re sailing heeled.
Through the gybes there will be a bit more distance from where the clew sits on one side to where it’s going to be on the other side, so we will have to spin a lot of sheet through each turn. The gybes will be important as the boats decelerate quite quickly when you turn, and then pick up the speed again quickly. The timing of the gybes will be key in terms of passing. It might sometimes be a case of chasing the boat into the corner and then beating it on the gybe rather than just going fast. I think they will be exciting to watch.
SH: How long will it take to design and build a competitive boat?
TS: Well, that’s tricky – it’s a case of ‘how long is a piece of string…’
The longer you have the more you learn and so to design a competitive boat you just have to have the same amount of time as the other guy. That’s a feature that we have put into the competition regulations. We believe that the boat can be designed in a few months and that we can start building it at the end of the summer, launch it at the beginning of spring and race it in 2010. Everybody will have the same amount of time to build a competitive boat.
SH: Early launch – advantage or disadvantage?
TS: What is proposed in the competition regulations is to pick as a group, among all the competitors, what we think is a reasonable and sensible timeframe starting with the earliest date to launch (probably early 2010). You can launch it later if you like, but we will start the practice racing soon afterwards and we will set a date when all boats can only be sailed in Valencia, to bring all competitors to the venue. And there is only just enough time because we will be racing the actual event in late April or early May…
SH: Are there ‘no-sail’ periods planned?
TS: No, it is not necessary between the earliest launch date and the event dates in 2010. There are so-called practice races, as we signalled for the AC90, and these are the only days when you are allowed to race with another boat from another team. These will be officially organised practice races that don’t count for anything but provide an opportunity for people to race. It’ll be a case of a team simply saying ‘our boat is available, we’re keen’ and AC Management will organise a schedule, giving even opportunity to all the boats that are ready to race.
SH: When do you expect the first boats to be launched?
TS: I think the teams will meet those dates, it’s logical for the Europeans. There is always some tension between the design and sailing teams on the launch date. The sailors want to get on with it and get their hands on the boat – they can make the boat faster the longer they spend on it. The design team say, ‘Patience, we’re working very hard, if you can wait another couple of weeks we can give you a faster boat…’
SH: What percentage of the boat can be altered post-launch?
TS: There will be a generous limit, enough to make a bow change, for instance. And we are discussing a rule that says that changes that are made with bog or even timber and foam with fibreglass over the top of the hull laminate – so non-structural – don’t actually count. So you can try things out without it counting – you would have to tell the technical director first, he’d take a look at the drawings and it would count as zero. If you like the change you can manufacture a new piece of hull, cut the boat and change it. The idea is that a change with fairing materials is a cheap change, and easily reversible, so why penalise teams for it?
SH: And what restrictions are there above the deck?
TS: They are pretty simple this time. We have signalled in the rules that rigs and sails are a candidate for loosening in future versions, but right now it is very similar to the V5.0 regulations except that we have allowed composite rigging instead of steel, so that would save a lot of the weight and is in keeping with other areas of yachting. Apart from that difference the rules on the mast are much the same; they require the rigging to be round so we don’t get into a space race in streamlining rigging, that’s the same.
In terms of quantities, we propose to limit the number of masts and appendages. Sail packages will be more limited than ever before. We propose to register every single sail that can be used and we are not distinguishing between practice sails and race sails. These numbers were discussed by the various sail designers in the teams; they will allow a logical sail development programme.
Another change relates to sail material. If there were no limits on spinnaker material everybody would feel compelled to make most of their sails from Cuben Fiber or similar. The compromise proposed by the group is to allow one of these sails on the boat in a race, but it has to have a mid-girth smaller than 63 per cent of the foot length. If the mid-girth is greater than 63 per cent then the spinnaker must be made of woven nylon or polyester – as in the last Cup. It is a compromise because as you shift from that 63 per cent Cuben sail to an 85 per cent polyester sail there will be a drop-off in actual sail performance.
SH: And dates for pre-regattas and challenger selection series?
TS: We are deciding a schedule to fit the pre-regattas around existing events, we don’t want to clash. The first pre-regatta will be in July, the second in October. The 2010 schedule is still being agreed; it can be adjusted and come forward in time as required. Tentatively the challenger selection series will begin late April/early May with the Match in July.
SH: Are the pre-regattas compulsory?
TS: Work in progress. But we have agreed that race results will not be carried forward. Most teams want to compete in 2009 but there may not be enough V5 boats available this year, so we may have to consider boat sharing or chartering. We’ll be discussing this among the competitors at the next meeting in March and will test the consensus.
ROLF VROLIJK ALINGHI PRINCIPAL DESIGNER
[singlepic=1871,170,250,,left]SH: What has been the input of both the challengers and the Defender?
RV: All entered challengers were invited to participate in the development of this new class rule and initially there wasn’t any fixed idea on which route we would go. The only idea we had was Tom [Schnackenberg] proposed to use the AC90 as a base so we didn’t have to start from zero. We would have to write the rule but keeping the parameters open. The first meetings were only about discussing the different options and seeing if there was any direction and any consensus. Of course we gave some guidelines in the beginning, and in the end the boat didn’t come out exactly where we would like to see it.
SH: What can we expect from the new class?
RV: For the sailors a new class means starting from zero, which is very challenging. On the other hand, we are talking about the same number of crew we have on the existing boats so the major part of the manoeuvring will be very similar. But the two main differences from the V5 boats are that the new boat will not have any overlapping headsails and will have an unlimited spinnaker area and no spinnaker pole so a fixed bowsprit, so this will be a big learning curve for the crews.
SH: Could you compare it to any existing class?
RV: The AC33 is a box rule like the AC90. It was clear that everybody wanted a box rule and not just a rule with a formula where you could trade off sail areas and displacement and length. One of the reasons was that we had a short time to develop the boat so the more we leave open and the less we make it complicated, with this kind of formulation, the better probably and the closer the boats could end up. There was a clear indication from all the challengers that this is what they wanted.
SH: Many of the designers involved say that the AC33 will be exciting both to sail and to watch…
RV: It will be a very impressive boat because it will not look like other racing yachts. It will have a very long, slender hull with a very high-aspect ratio rig, comparable to the old J-Class yachts that raced all those years ago. What’s very different compared to the V5.0 is that V5s had long overhangs. These boats will be sailing on their full waterline length, which could be up to 26m, which is really long for this kind of displacement. The speeds will be a lot higher downwind – up to 2kt in VMG – which means many more opportunities for passing lanes.
SH: And also less expensive than the V5.0s or the AC90s…
RV: It’s cheaper than the AC90 because that was the biggest and fastest monohull you could build under the Deed of Gift. This boat is in the same direction: it’s also a box rule, the length overall is 85ft but it’s a lot lighter with less sail area. The features that are decisive on cost, particularly stability, will be similar to the V5’s. I wouldn’t say that the cost will be a lot lower than the existing boats, but for sure it won’t be more expensive. You have slightly more hull area but on the other hand there’s less ballast, plus no overlapping sails, which is cheaper for the sail package. It’s the whole package that will be the same or even slightly less expensive than the V5s.
SH: Is there potential for evolution as with the ACC?
RV: I don’t think there’s any difference. What’s interesting is to see if the class also develops outside the America’s Cup, because this would really give the boats a nice life.
SH: And the chances of smaller teams with the new class…
RV: We sat around the table with all the challengers and asked them what they really wanted, and there wasn’t any team that wanted to have the V5 boats again! They were all in favour of this new class, because they see a much bigger chance to be competitive. The development time will be so short for 2010 that teams will have to start building immediately after the summer, so this means that the big teams won’t have a lot more time to develop their boat, there won’t be two-boat testing. My guess is that this is probably the best chance ever for a small team to be competitive.
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