A time to smile

Alinghi 5 was launched on Lake Geneva by the world's biggest helicopter on 9 July; the culmination of over a year's work. Central to the design and ongoing development are - among the 27 other team members on the design team - Grant Simmer, design team co-ordinator; Rolf Vrolijk, chief designer; and Dirk Kramers, chief engineer...

SH: How did the general defence strategy evolve in terms of ordering and approach?

Grant Simmer: This Cup has been a very stop-start affair. To start with we tried to organise a multi-challenger event with all the entered teams, we began with the AC90 class and anecdotally had the event not been stopped by BMW Oracle then the semi- finals would be underway right now.

When we lost the first BOR lawsuit in November 2007 we started working on a multihull. We decided to do it in-house; we employed Nigel Irens and Benoît Cabaret as consultants to work with us and help us conceive the boat, but the conceptual design was primarily led by Rolf Vrolijk and Dirk Kramers together with Michael Richelsen's team doing the analysis.

Then, of course, we won the appeal, so stopped designing the multihull and went back to trying to organise a multi-challenger regatta - this time working on the AC33 design rule with the challengers. Finally Oracle took us back to court and won the last appeal, so we stopped working on the AC33 and started working on the multihull again.

In terms of the original concept of the boat, that happened back at the beginning of 2008 and since then it has primarily been a question of detailed design and making it happen. There has also been a huge amount of work on the structural and systems design on the boat while the overall development is ongoing.

SH: Once the build plan was formulated, how long did each major element require in terms of development, design, engineering and build?

Rolf Vrolijk: The conceptualisation - length, beam, hull shape, fore and aft mast position - continued up until the end of February 2008 and the construction started in May. The design and develop- ment of this boat is ongoing, though; this is a first step in the development process towards the 33rd America's Cup.

Dirk Kramers: We spent approximately three months on the concept design (length/beam/weight/tri/cat). At that time we were facing a possible race in October 2008, so the brief for the boat that we had to build was for something that could be constructed very quickly. Something very simple, because with that kind of time- frame we were way behind on the learning curve. Then there was a period in the summer when we tried different schemes on the 41-footer Le Black. So we did our development, experimentation and VPP validation throughout the summer of 2008, the results of which were then transferred into the refinements of the concept.

SH: And given Alinghi's proven success with full-scale remodel- ling, how much scope is there for significant redesign?

RV: The real decisions on further development, optimisation or changes will come after we have collected information on the concept itself. Besides, we are waiting for BOR to declare which boat they are going to use and also our final venue decision. We have a lot of boatbuilding resources available so it gives us the ability to modify relatively quickly. We would obviously want to keep sailing and would build parts and patch them in as quickly as possible; the non-sailing time would be minimal - we used to do that with the Version 5.0s and would do that with this boat as well.

DK: The multihull benefits enormously from the sailing and tuning process; much more so than monohulls, so sailing time is really important for us. This was very evident in the 1988 Cup where the speed advances over the summer were huge on the Stars & Stripes cat. The learning process doesn't stop when you launch the boat; it is just the beginning of the next stage.

SH: Assuming they push the Custom House Registry to the limit, what is your best guess about the boat that BMWO will finally measure in?

GS: We have no idea, but when they challenged they entered with a unique vessel that happens to be named USAand is 90ft length on load waterline, 90ft beam at load waterline and 90ft extreme beam... and we know their final boat must be of these dimensions.

SH: How useful are the best computer models now for assessing multihull performance?

DK: We have made huge strides on that; Michael Richelsen and Dan Bernasconi have been working feverishly to come up with a completely new VPP and CFD program for multihulls. They have spent a lot of time and hard work on the project and hopefully we will see the fruit of their labours.

GS: Another thing we did with the 41-footer was validate the codes using measurements we made using this boat - as Dirk says, we have come a long way!

SH: Surely - as a spin-off from an eventual DoG Match - this experience has pushed multihull CFD and VPP development forward compared to the lower-budget Orma-type campaigns?

RV: This is such a unique boat and such a unique event that the work that has been done on the development of the tools and the concept is really tailored; it is very difficult to compare it to anything else, particularly in the world of offshore sailing. It is actually more comparable to what has been happening on the lake here in Switzerland where there is a lot of development of multihulls, foils, sails, even flying concepts.

Having said that, the fundamental tools have improved a lot; this boat is the product of using those tools but for a very specific goal - they can also be used for other concepts. There will be trickle- through to the wider industry from every area; foils, rigging, systems on the boat, sails and much more.

SH: Given the high loads of a big-beam design even in low winds, how much relative structural weight can be pared away compared to, say, building an all-round design?

GS: Very little, because once you are flying a hull on a multihull you're at maximum righting moment. If you are designing a boat to leap off waves in the Southern Ocean obviously it is a differ- ent criterion from the potential venues for this match. But in terms of righting moment, it is as high in this boat as in any other boat of this size.

DK: The static loads are fairly straightforward; it's the dynamics that you have to use some higher factors for in offshore sailing. Even while sailing in a straight line, in relatively flat water there are dynamics involved, so developing the load cases for the analysis is quite tricky. To protect ourselves against these relatively poorly understood dynamic load cases we implemented quite an extensive loads- monitoring program led by Daniele Costantini and Luc Dubois. Many loads will be monitored in real time while sailing.

SH: In which case, is the real gain that only a certain (large) rig envelope needs exploring...

GS: Obviously the rig size for different venues is an important decision and we have seen that BOR have done a lot in that area, they have got three rig sizes so far for their two boats...

SH: Can you guess the weight of the BMWO boat?

DK: We can guess but that is about it. Anyway, even to guess the weight you need to know what the structural decisions are that they have taken and even if we knew which boat they were going to use, it would be hard to get the accurate weight.

SH: How much actual measured vertical flex is expected in these boats corner to corner within the target sailing envelope?

DK: More than we would like! We have tried to make it as rigid as possible, but there are some compromises that you have to make on the rigidity to enable the sails to sheet properly, for example; it is an area of constant trade-offs. The dynamics of the sail plan and the rigidity come with dynamic loads that get larger so it's a tricky road to navigate.

SH: Has the Alinghi boat prompted notable component development, particularly of advances with carbon rigging and sail/foil management?

DK: Yes, very much. During this boat's construction process we ended up working with a lot of Swiss sub-contractors who have done a terrific job for us. We also developed many components in-house. Our very small engineering staff of Kurt Jordan, Aaron Perry, Kirst Feddersen and Brett Ellis have been flat out producing designs for all aspects of the boat since January 2008.

SH: Though obviously not cheap, it seems that this DoG project may actually work out a great deal less expensive than a classical monohull defence. Is it perhaps sensible that we now actively consider a more open era of America's Cup matches?

GS: The boat that we built is approximately five times more costly than a Version 5.0 and we have done most of the work in- house. I suspect that BOR have spent a lot more than us, from what we have heard; probably twice as much as we have to get here, but then they have been sailing a lot longer and they have built two boats, so...

If you want to contain costs you have to have cost-curbing measures like the ones we proposed for a multi-challenger 33rd America's Cup on monohulls. Otherwise, the sky is the limit; with a completely open design space you really could spend anything you want.

DK: Cost-curbing is really the only way to keep us under control and to determine where we go. We have very definite budget limits for both money and time, although the time budget seems to change with every legal move. The more time you have, the more money you will spend. (That was the cost-curbing principle for the original AC90/2009 plan – one boat/short timeframe equals less cost.)

GS: The example of America3is a good one – their design philosophy in 1992 was to look under every stone and that is a pretty expensive design philosophy.

SH: Finally, what are the immediate plans for the boat?

All: Sailing, sailing, sailing, learning, learning, learning.

After all the arguments: with a compression strut in place of the mast to maintain structural rigidity, the most eagerly anticipated new raceboat for many years breaks cover in typically spectacular fashion. When the spar arrived - in similar style - for stepping a few days later even the ringleaders (opposite:Simmer, Butterworth, Vrolijk and Ernesto Bertarelli) could not conceal the schoolboy excitement...