With the recent publishing of the newly proposed protocol, it was announced that the next Americas Cup would be sailed using the IACC Rule as before, but that there exists the potential for some changes within the rule. The new versions will most likely be labeled Version 5.0. The question that many are asking is, just what might those changes be, if any? This of course leads to speculation and there is no shortage of opinions. By looking at the defender and challenger of this most recent Cup, as well as looking back at previous designs, we can begin to form some general ideas as to what essentially worked, what did not work, as well as what might be improved upon. This has lead to what I see as areas for potential changes in the IACC rule.

One area that most designers as well as sailors agree upon is that to date the IACC Rule has done a reasonable job of producing designs, and with 82 boats built under the current rule in what could be seen as a relative short period it is hard to disagree. So, a good question that many might be asking is, if it is not broke, then why fix it? It is partially due to this somewhat rapid development that has led designers to move down the path of the current trend we see in ACC designs. That being essentially, a long, narrow, maximum displacement or near maximum displacement for a given length, and a maximum sail area or near maximum sail area for that given length and displacement. It is this trend that has pushed designers to what is often referred to as the upper corner of the IACC Rule.

The first generation of AC designs took on a definite trend with boats being of medium weight and wide flair above the waterline. The exception to this trend was NZL 20 with a measured length of just a little over 21.5 meters and a displacement of just a little over 20,000 kg. By 1995 designers had progressed through the learning curve at a fairly rapid rate, with the winning design NZL 32 already pushing the maximum displacement corner of the rule at 25,000 kg and a measured length of just under 22.4 meters. The 1995 generation of AC designs all had slimed down in beam as well to an average of 4.25 meters. The length penalty becomes quite steep as boats reach a measured length of 22.2 meters. With the 1995 generation of designs in some cases coming in close to 22.4 meters in measured length and already hitting the maximum displacement of 25,000 kg. One had to wonder in designers had begun to hit the wall of the IACC Rule.

In 2000 many AC teams put of lot of their focus into keel / bulb, rudder and rig development, but Team New Zealand came out on top again with their combination of a progressive hull shape with the now famous knuckle bow and the millenium rig, proving that the wall had yet to be reached. With length (L) in the IACC Rule formula being a combination of the length of the hull at 200 millimeters above the waterline and girths measured at the ends of that length anything over 21.2 meters a penalty is applied. However overhangs in simple term are essentially freebies and so the designers of NZL 60 pushed the design envelop even further with regard to hull shape by creating more effective waterline length in an attempt to gain more speed.

The positive side to all this is that as more and more designs end up in this upper corner. The result was closer relative performance values between a larger number of boats, thus creating more exciting and closer racing. At the same time this still allowed latitude in design. There is no better evidence of this in the most recent Cup between Alinghi and Team New Zealand. Although the two boats were of different design philosophy. The relative performance between the two boats was very equal at times.

On the negative side, as the performance values become closer and closer between boats so does the trend to push certain aspects of the IACC Rule to its limits. Stretching any design to its limits can yield a higher than normal error factor. Performance, stability and even structural integrity all can be pushed to unpredictable areas of the unknown. This can produce less than optimal designs that to some extent can have a less than positive effect on the credibility of the rule. Again we can use our most recent benchmarks in SUI 64 and NZL 82 as examples. It could be said that SUI 64 in general terms is an extension and improvement of NZL 60 from 2000. No doubt having the core of the sailing brain trust from that winning 2000 team on Alinghi played some role in the development in their designs. As for NZL 82, with the departure of almost 1/3 of their team from 2000, it was evident that a departure of sorts also took place in the philosophy of their development of the two latest boats. Already a lot has been written and discussed as to what caused the 5 - 0 loss to Alinghi and so it is not necessary to beat a dead horse on this issue, but to some extent taking that departure in design philosophy was a contributing factor. So, lets go back to the original question as to what changes if any will take place in the IACC Rule for the next Americas Cup?

During a Blue Ribbon panel discussions on the future of the IACC Rule last fall. Several top AC designers agreed that lowering the maximum displacement value within the rule could have a positive effect on a boats ability to sail in a wider range of conditions. Thus reducing the criticism of the current trend in AC designs of having a narrow range of performance, and give a little more breathing room in the rule itself. What a lot of people may not know is that the Americas Cup Class Rule does have a wide range for displacement written into the rule, with 16,000 kg. the minimum and 25,000 kg. being the maximum. However with this variable in displacement comes trade offs in length and sail area. Since hull speed is proportional to waterline length in displacement mode and the IACC Rule in simple terms allows more length and sail area for a higher displacement. One can see why designers are tempted to go for long, lean, heavy boats. As waterline length is increased, beam overall and beam on the waterline are decreased. There are trade offs here as well in the reduction of wetted surface of the hull form, but not without some loss in overall stability which can have a negative effect on performance. The IACC Rule does have a maximum Beam overall of 5.55 meters, but does not have a minimum, There fore we can see why designer are tempted to reduce beam in relationship to increase length The current generation of Americas Cup boats have an average Beam overall of 4.00 meters with Beam on the waterline in some cases less than 3.00 meters. A question that has come to the attention of some designers is just how narrow can an AC boat go before we reach reasonable limits?

The issue of stability has come into focus as to one of the problems that may have occurred with NZL 82. By trying to maximize the length on the waterline through the use of the hula. They were left with the tedious task of having to balance hull form in proportion to beam and keel and bulb configuration. Maybe a bit too tedious of a task for the principal designers of NZL 81 and 82 for whom I personally have the greatest respect for. Looking outside the box so to speak takes time to research and time equals money. Something that might have also played a role with Team New Zealand.

By lowering the maximum displacement factor within the rule, designers would be encouraged to produce boats that could be seen as being better proportioned with regard to length, beam and sail area. One would essentially end up with a somewhat shorter length on the waterline which could encourage a higher beam overall and beam on the waterline and somewhat smaller sail area. The stability factor would improve on a global scale and thus produce boats that could sail in a wider wind range without sacrifice to performance. Oracle BMW did adopt a similar design philosophy and proved it to be successful under a fairly wide range of conditions. A lot does depend on the location of the next Cup. Since no decision will be made until December of this year, there is the potential that not enough time will exist to fully develop and study a new maximum displacement limit. However, if the cup is to be held in a location that has more consistent wind, which could reach current maximum limits on a regular basis, one can bet that designers will be looking at lighter displacement as a key element for the next generation of AC designs, despite the trade offs in length and sail area.

One area that will no doubt see some change is the definition of appendages currently under Rule # 19 - 20.2 and rules related to hollows Rule # 16, 16.1 A - E. It is within these rules that the loopholes for the now famous hula are found. Again a lot has been discussed as to its legality and probably will continue, but it is important to note that no matter what one's opinion may be, it comes down to the definition of what an appendage is and interpretation of those definitions. The hula is likely to be a one time shot and more than likely we will see a re - wording of the rules in these areas that will prohibit any type of appendage of this nature again. By many accounts the hula did not perform as originally expected and that the time and effort in assuring it did not touch the hull was one of the many factors related to Team New Zealand's poor performance. Nothing beats time on the water.

Getting away from hull development for the moment, there still exist under the current rule a fair amount of latitude for development in rig, keel / bulb configurations as well as sail development. Some designers feel that it is in these areas that some of the most innovative work is yet to come. Looking at Alinghi, Oracle BMW and Team New Zealand, we saw three different approaches with regard to rudder, keel / bulb configurations. We may be reaching certain limits with regard to hull shapes, but there is no shortage of ideas as to what is seen as optimal below and above the hull form itself.

Although the next Americas Cup is 3 - 4 years away, with the announcement of a series of regattas leading up to the event starting as early as later this summer. Teams will be gearing up with already existing designs and looking to improvements right away. As stated before research takes time and time equals money. It will be important of teams to obtain financial resources early on and spend as much time on the water as they can as this has proven to be a formula for success. The Americas Cup has entered a new era and a new format has been proposed. Although I believe that we will see some change within the IACC Rule itself, I believe they will be minor in order to preserve the credibility of the class and the event itself. While I personally see the new protocol as a breath of fresh air, a major overhaul of the IACC Rule could discourage teams for participating. My opinions are supported by the new protocol, which stipulated that design information can be sold on the open market through October of 2004. This is a win - win situation for designers and AC teams alike. It is this part of the new protocol that gives me the impression that the changes are meant to encouraging more teams to take part. This will have the effect to improve the image and structure of the event itself.

It is important for the Americas Cup to continue to evolve both in format and in design. The time is right for that format to change and in time the opportunity will be right for the IACC Rule to change as well, but keeping the basic parameters of the current IACC Rule in tact for the moment will have a positive effect on the event for the future.

Russ Lenarz

03/09/2003