On the foils again

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(Source:Sailrocket) Hi all,

I’m happy to say that the new foil design is currently in transition from the drawing board to reality.

It has been a long, frustrating but necessary path to this point.

We have had to go back to school on this one.

There has been a big shift in understanding from the last blog to where we are now. Some things just didn’t fit into the high speed sailing forensics puzzle and we refused to neglect them. We had been constantly told how thin foils were the only way to go… and yet our big, ‘fat’, Mk1 foil had repeatedly hit over 50 knots. When we applied the theories and associated numbers that sent us down the path to superthin foils to the old Mk1 foil it showed that we would be very optimistic to even achieve 40 knots. It was obvious that something was wrong and that other options were open to us that needed to be explored. We withdrew from the outside world of expertise and chose to resolve the problem in house using our own small core design team. The fact is that you need to understand these problems very well yourself so that you can be in a position when dealing with outside expertise to ask A/ the right questions and B/ know the difference between bullshit and brilliance. I think it has taken us this long to achieve that status… and to be fair… we are yet to prove it. It has taken a long time but then this is an extremely complex problem of physics (as everyone keeps reminding us) and at the end of the day I’ll be strapping myself into the final exam paper submission.

So, where are we? Well for starters the new foil is going to be a lot smaller than the original foils.


They are also going to be made out of carbon composite instead of the steel option we were previously looking at. The reasons for this are many and varied. A lot has to do with our own particular operating requirements i.e. in a perfect, flat, high speed world we could use much smaller foils still but the reality is we are punching through high frequency chop even on the brilliant Walvis Bay speed-strip and these ideally small foils would not cope. In the end we have had to pick a span/depth compromise that we felt comfortable with. I am glad that we did those brutal foil modifications in that last sesssion last year. Chopping 15cm chunks of the foil one after the other gave us some great insights into how forgiving VESTAS Sailrocket 2 can actually be. The fact that she got up and going at all with 45 cm removed was pretty impressive. Mind you, we were sailing in top end conditions and we hope we don’t have to do that again.

So whilst the new foils should see the same loads as the old foils, the lower spans should mean that they have lower bending forces. We believe that this will mean that we don’t really need to use high modulus, pre impregnated carbon fibres. This reduces the complexity and cost of manufacture which in turn can be put somewhere more useful.

I am not going to give away too many details of the new foils. It has cost us a lot of time and money to reach this level of understanding. like most things in life, the answer is easy once you have seen it. We haven’t shown that we have the answers yet but no doubt we will share things as they are truly revealed. In reality we only really understand our Mk1 foils now. Many of the explanations I may have given earlier wouldn’t stand up to our current knowledge. I am as happy as can be with the logic behind our current path. I can’t see any loose ends or aspects that we are deliberately overlooking. In fact, many of the previous ‘weird’ un-explained stuff now ties in with our understanding of the issues.
The tooling moulds will be put under the CNC machine tomorrow and we are pushing to have them ready by the end of the week. This means the actual build of the foils will commence next week. As soon as they are finished they will go direct to Heathrow where they will be accompanied on a plane down to Walvis Bay. Team members will be down there setting up the boat and base a week earlier in preparation. It’s all go. VESTAS Sailrocket 2 is at a stage where we should be able to get up to the high speed stuff very quickly. As always we have to be careful not to make any silly mistakes along the way.

It is pretty exciting from my perspective to be focusing on a return to sailing action. The kiters are planning another record session further down in Luderitz so Namibia is once again going to be the focal point for real high speed sailing action.

In these troubled financial times we have to remain as frugal as we can with our budgets. All our resources have been poured into resolving the design issues with the new foils. There are no retainers, rentals or wasted budgets. It’s a big problem that we are trying to navigate through carefully and logically with a focus soley on the goal. We remain respectfully indebted to all those who have helped us reach this stage, big and small. We set out over 10 years ago to break the outright world speed sailing record and that remains the goal. At times we got pretty close but with Outright records, it’s a one-step podium. We know our subject better than ever and the fire still burns. We’ll get there.

Cheers, Paul

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