Upgrading to Version 5

GBR Challenge's Derek Clark gives his views about the proposed changes to the America's Cup Class rule

The day after the America's Cup venue announcement in Geneva, the challengers were whisked off to Valencia to see the venue and take part in a meeting were the proposed changes to the America's Cup Class rule, to be known as Version 5, were revealed.

Version 5 has been conjured up by a combination of Alinghi, Oracle and Ken MacAlpine, America's Cup Management's Technical Director and are expected to be finalised once the challengers have returned their comments upon it later this month.

There have been many rumours flying around about what the new boat might look like. Among these have been the possibilities of a canting keel, maybe an arrangement like the Reichel-Pugh sponsored CBTF system, a dramatic lightening of the boats and a general 'turboing'. What has in fact transpired is a very minor development of the ACC rule that should provide a fraction more horsepower downwind.

"The whole design space within the rule has compressed - when you see it on a graph you have to use your glasses to see it!" says Derek Clark, GBR Challenge's head of design who attended the meeting in Valencia. "Some of our guys describe it having become a restricted rule with some fuzzy edges."

With the exception of Oracle, all the ACC boats in Auckland were in one area of the box as defined by the rule and version five effectively discards the 'unused' areas of the box. "Essentially where they have gone is to reflect where all the boats were and said ‘look guys, don’t worry about these other boats, why don’t you push yourself into this area’." says Clark.

One of the best examples is displacement. Version 5 sees this reduced by one tonne, down to 24 tonnes max from 25 tonnes. Before the boats could have displaced anywhere between 16 and 25 tonnes. This time Clark believes that there is a range of around just 300kg - between 23.7 and 24 tonnes - before you start being penalised.

Lightening the boat has been compensated by a marginal increase in maximum draft. "By coming a tonne lighter you have less righting moment so to balance that they have gone down 100mm in draft, which should give us the same righting moment," explains Clark. "They have also taken away the draft penalty part of the rule which Oracle played quite well last time."

During the last Cup Oracle is believed to have had a deeper draft than the other challengers and despite having to take a hit on sail area as a consequence this seemed to benefit her performance upwind.

Similarly maximum beam has been reduced from 5.5 to 4.4m. While this seems a more dramatic change, only the first generation ACC boats were anywhere near maximum beam and Clark maintains that most in Auckland were less than 4m.

Under the ACC rule the length of the boat is a function of the girth of the boat at various girth stations along the hull and the distance between those girth stations. "The tendency has been to be pretty much minimum girth forward and not much different aft," says Clark. "So the length between girth measurement has been pretty similar between the boats and again that is reflected in how the rule is going to work now. There are harsh controls very early on in the design space - much earlier than there was before."

Downwind sail area has been moderately enlarged: "We have a multiplier of the spinnaker size, which is based on measured sail area," says Clark. "It was 1.5x that and now it is going to 1.6x that. So bigger kites and a slightly longer spinnaker pole - it was 1.35x on J and now is 1.4x on J. So not huge changes there."

The amount of variation in measured sail area (the combined area of the foretriangle and mainsail) is another area that has been considerably tightened. "Last time the big difference was between Oracle and the rest of us. The rest of us probably had sail areas between 310 and 322sqm, whereas Oracle was probably another 15 under that in their most extreme performance profile when they had maximum draft. Now we are going to have even closer sail areas than that. We are thinking plus or minus a couple of square metres - around 320-321sqm."



More mid-girth restrictions have been introduced for headsails. Under the previous rule there was only one at 60%. Now two more have been proposed at quarter and three quarter heights.

While hulas have thankfully been banned, the new rule doesn't look like it will prohibit 'batwings' (see photo above). "The batwing offers you the ability to sheet a sail very hard and to define the twist at certain points," explains Clark. "It is almost like having a solid sail." The batwings have been developed so that they change position to work for different twist angles, for headsails with different amounts of overlap and girth - a significant area of development.

"I was disappointed to see the batwings still there to be honest," continues Clark. "It is like adjustable wings in race cars - it is interesting, but I am not sure it has a lot of application outside of our particular thing. Maybe if you want to power up the boats up in light airs, then allow more overlap on the jib and a more normal roach for example. That is easy to do. At the moment we are allowed to be 3m (of overlap on genoas) aft of the mast, maybe you could have come back 4m?"

Also to be allowed under the new version of the rule are inflatable battens in the overlapping headsails. "This is something we worked a little bit on with Kookaburra, where we were trying different methods of supporting sails," says Clark. Why inflatable? "Because if you have a batten that is working hard and doing its job and a genoa that is overlapped as much as we are in the pre-start that is going to be flogging itself against the shrouds and mast." Hence a solid batten would rapidly destroy itself.

Exactly how these inflatable battens will be constructed remains to be seen. On Kookaburra Clark says they used high pressure tubing wrapped in a sock of Kevlar. It is likely that the end result will be semi-rigid ie with two halves made in carbon that will have an inflatable bag between them to make them rigid.

Rig-wise Clark says there has been a slight lowering of the all-up weight of the mast "an allowance in the construction of the rig to allow better materials and slightly better process".

Clark's biggest objection to Version 5 is that the crew has been increased from 16 to 17 plus a non-participating observer. Hence the '17th man' will become the '18th man'. One theory about this is that it will allow Larry Ellison back into the Oracle afterguard. "I don’t understand why there is an extra person on board. We were surprised about that. I’d asked for less. When we first put the rule together in 1988-9, we had a look at what a 12m needed which was only 11, and we put couple of extras on it. So we were at 13-14 crew. When you watch the boats being sailed now with 16 it is plenty. In fact you get the feeling there tends to be one too many.

"I think for the excitement value of sailing these boats is that they should be undermanned, not overmanned," continues Clark. "The 12 metre with 11 on board, people were flat out and that was one of the great things about the sailing on the boat - you were never in a position where you didn’t have a physical role."

Previously alongside the helmsman the afterguard would include a navigator and a tactician. Now there can also be a strategists and a pit runner, who takes the load off the tactician to wind up the runners.

Clark fears that the extra crew will have a major cost implication: "Ross Blackman [CEO of Team New Zealand] said that over the period of a campaign, because the quality of that person would have to be quite high - he might be a specialist in meteorology or something like that - he could be an expensive person. Ross estimated over the three year life of a campaign, taking into account all the associated costs that come with having an extra person, he thought an extra $1 million wasn’t unreasonable. A high quality person will get maybe 150-200,000$ per year - three years of that plus their costs... Even if it were a standard crew it would still be significant, so it seems to be not along the lines of reducing cost." And then of course you need one on each boat...

Generally there seems to have been little attempt to curb costs with the new rule. "There is the closure of the rule and the limiting the amount where we can go looking at the different boats, but I’m not sure that would reduce the amount of time we would spend in the tank," says Clark. "I think it is likely we would just spend more time looking at the detail. Certainly last time we did have a look at boats outside of the 25 tonne range but probably no more than 15% of our time in the tank. Now we don't have to look at any of that part. So yes there will be some savings, but if you save money in one place you will tend to spend it on another project somewhere else, whereas people are a direct cost, especially on the race boat."

Generally Clark seems reasonably happy with the modifications. A dramatic lightening of the displacement - it is believed that one proposal was for the boats to shed 5-6 tonnes - would not necessary make for better match racing he maintains.

"The best match racing is when the boats go the same VMG upwind as down. If you can imagine sailing a catamaran where you can go twice as fast downwind as you can upwind, as you round the weather mark it would be kind of like a Formula One car which burns away from the corner and has already got a start on you. Then as the boat goes faster and faster downwind, the apparent wind comes further forward so the trailing boat has to gain even more distance to get on the wind of that boat - they would never be able to get forward enough on the other boat to get into his apparent wind. So the more equal the upwind and downwind speeds are of the two boats the better the match racing. They have increased the downwind speed to increase the opportunity of passing - it is a view, but it is not a view I would share. If you look at the game theory behind it, I am not certain that is actually what happens."



One advantage of the modest changes is that there won't be a marked difference in their loadings and thus existing boats won't require huge structural modification. The pre-regatta program announced by ACM seeing the boats racing in Version 4 mode in 2004 and Version 5 in 2005, so it is unlikely that many boats will be converted prior to September 2004.

"I think one of the things which would be interesting, is rather than force us to be version five boats for 2005, if they wanted to reduce costs and limit the effective gains that the big teams have got would have been to wait until 2006 before you can have a version 5 boat," says Clark. Alternatively why not let version four and five boats sail together? He feels that there would be little difference between the boats particularly in the upper wind range and it would allow some of the newer teams to play.

The biggest area of 'discussion' in Valencia was over how much existing boats can be modified. Modifications in the America's Cup Class are strictly monitored and almost everything must pass the measurer. The new Protocol issued in Auckland in March specified that modifications of up 85% could be made to up to two of a team's existing boats. "It was put in there to give us all the ability to make major changes to our hulls to enable us to catch up to where Oracle and Alinghi were," says Clark. "Now they are pulling that back to being more like 30-35%. So there was a bit of discussion about that to say the least..." In comparison newly built boats can be modified by 50% in the course of an AC cycle, the same as last time.

The objections have been bolstered by the fact that most of allowed modifications made to the boats would be taken up in simply making them comply with Version 5 of the rule. "It is an even bigger problem for Team New Zealand because they would need something like a 60% hull change to convert from a hula to a standard boat, let alone a Version 5 boat," says Clark. "So clearly that the amount that was discussed means that they couldn’t do that with those boats. So a special dispensation? That would be unfair on everyone else. So I can’t see it staying at the lower figure."

Clark says that reduction in the amount of modification was put in to limit the further development of the more developed teams like Alinghi and Oracle. "They felt 'we are a big syndicate we could afford to do four new hulls'. But if we don’t get the opportunity to catch up then all you do is maintain the status quo as you move to Version 5. So it would just be favouring the fast boats from last time."

Despite the tightening of the rule Clark believes there is little chance of the America's Cup Class becoming the world's most expensive one design. "Last time everyone was about 25 tonnes and look at how different the boats looked." In fact the difference between version four and five boats will be so slight that they will hardly be apparent on the boat, let alone off it. Which begs the question, considering the huge cost implication for the campaigns - why amend the rule at all if the changes are going to be so slight?