Tornado-Cat
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I did not have time to finish the translation, here it is, really worth reading it.TNZ
- My first meeting with TNZ was in 2009
- I begain to work in 2010
- I have aneye on everyting on the boat but works part time because busy on other projects
- I give ideas but it’s a lot of work, you have to develop it each idea
- I like a small team because it’s efficient, we are even too many, lots of people coding, too many, we have to keep a global vision
AC75
- One day day Ray Davis asks me to meet Howard Spencer, willing to get a fun 40 ft.
- I design a foiling mono
- Ray says that the keel is too much
- I tell him it’s possible, however we need stability
- I remember that a french architect, Martin Defline has made two queels boats who are pretty efficient, so we can do the same thing with ballast at the end of the foil
- It’s counter intuitive to put weight where we want a lift but calcules show it is 50% more efficient that with the keel for the same mass.
- The project doesn’t work as too expensive
- The Italians want a big mono for AC36, we could have a had a smaller boat for economic reasons
- Ray Davies puts my drawing on the table, everybody laugh. He tells us: I give you one month to test the concept to test If it works in a simulator. I was not there, I did not test, Bobby tested the design and they said it was a fun concept and it works
- They tried other concepts but came back to the initial one
AC75 rule
- I was willing two rudder foils for better stability to avoid diagonal heel instability like the hydrotère.
- I was against it but we went to one rudder for a good reason: to avoid cutting a crew falling in the water. That is also why the rules prevent going on the bow.
- I did not write the rule, Dan Bernasconi did it, I gave my advices.
- We chose a close rule to avoid mistakes, it took us a year
- We were very reassured to see that the british model worked, simulation works but is not always reassuring.
- We surely took some advance compared to the other teams but I don’t think it was so much
- Once I chose a concept I like to push it to the end.
- We got symetric foils at the end only in order to learn as much as possible
- The bulb at the end of the foil arm is just to put ballast, it has nothing to do with hydro but with the rule
Our AC75
- We are given a rule that I hate, the inertial stability in the harbour that imposes a wide flotation beam
- I understand it but it was not required with the ballasted foils in the water, we did not need that. 10’17
- I understood that it was obvious that we have to make a central tube like a trimaran hull and a wide ass for the rule and stability, I don’t think other teams understood it right away: narrow hull and wide as far on the back as possible.
- So we have a narrow hull in the front like a trimaran and a wide ass for static stability in the harbour.
- Not a big evolution between B1 and B2, B2 is even more like a multi
- We want a boat easy to foil that lift the stern first and get early on the foils for lower drag asap
- The brits were capsizing when bearing away as they could not get enough lift from the foil vs the pressure. They were afraid of the transition and they were right to have a first boat with more stability.
- B1 was an hydro dynamic concept, B2 an aero + hydro
The foil
- The dihedral is more equlibrated and does not require a big “shaft” that maintain the foil and which creates drag
- On the other hand a flat design is simpler and has lower drag. Both concepts are good.
B
Link: https://voilesetvoiliers.ouest-france.fr/regate/coupe-de-l-america/america-s-cup-guillaume-verdier-du-vendee-globe-a-la-coupe-de-l-america-sur-tous-les-fronts-16505d9a-7daf-11eb-a530-8257a05e6295?fbclid=IwAR1NxsAj3wAuWdzn6_P7iVTxshZyq76ZeZcZfnogKPj0O9F0JBzZQrROne8
What the secret of TNZ success
- When I begun in 2010 what really asthonished me was the horizontal organization, people can speak, there is no real boss. It has advantages but it can be the mess sometimes too, nobody is responsible of anything and everybody responsible for everyting. It works with a small structure, it is not a pyramidal but horizontal structure.
- The is no restriction to possibility to speak, sailors are integrated to the design team. They often take the decision. They are part of the design meetings.
- When we decide the piece to design we give ourself a time table and we don’t come back on our decision, we finish the construction as decided. In other places people sometimes come back on their decisions and want modification before finish which causes further delays, not here.
- We don’t subcontract the construction of the boat, it’s integrated in the team to we control it directly
The simulator
- The simulator took less place that in the previous edition
- We did less design on the simulator than the last time, we did more fondamental design
- We modified the simulator
- Some speak about artificial intelligence, in fact it’s not ture it’s everything but intelligent and very artificial. However we have many persons working on scripts in order to automatize the calcules
- We use the artificial intelligence for foil profile. We give an objective of lift on a section of the foil, or an objective of ratio of lift vs drag + a few variables. We let the computer work all night, it will draw a part of the section. Then the computer tells what section is best when we give it a criteria. So in fact the machine does what we ask it but if we think well ourself we can do the same. We have to think and not let the machines do stupidly any objective or it can be very dangerous
How do you find your ideas?
- We learn the different knoledge in different fields like paragliders who need loft of lift or wing profile of aerobatic plane who need a lot of tolerance to the requirements.
- We mix all that, we have to look at what is done in other fields of aerodynamics. We are lucky as we can find everything on the net now, NASA studies, European Space Agency.
- Everything is here and for free. When I remember that when I began to work I had to go and try to buy some book in bookstores. We can even fin Excel sheets with lift/drag, cavitation calcules. All students work on that in all universities
Is there a Verdier method ?
- No, I work from home, we are a group of architect working from home, the lock down had had no impact. I don’t like working in an office with people around, I prefer working alone.
Do you have a way to approach a project ?
- Yes, but I can’t tell it is the good one. When I am asked to work on a design I like to work on the full project and I have a feedback loop very quickly, I draw my design very quickly. In some other methods differents persons work on different bricks of the pyramid and it takes months. For me I draw the AC boat in 3 weeks, I judge it, I see the caveouts and do another loop immediately. I want to go quickly otherwise we spend too much time on a detail and another, and another, for me I want to work on the global vision and refine it at each loop.
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