Tornado-Cat

Different constraints but same objective of minimum drag.

I don't know the Reynolds numbers but I know that the Starfighter which had a very thin, and proportionally wide cord, wing was considered to be have great performances while being the most dangerous fighter.

That sail + mast could be the best solution for a double skin sail at the condition they could close the openings or rotate the sail when tacking. However I think that the pressure can change much more drastically on a boat with a paraglider, so the sail could deflate.

Thick leading edges are not that great. I began flying power parachute with thick wings, it provides lift, it is stable but it is slow and does not fly well. Then I used thinner and longer wings, it is not as stable but you fly faster and much better. If you don't use an engine and you want to use the up lifts, then you can use even thinner and longer wings. So best wings are long and thin but if you want to maximise it and be safe they have to be rigid.

I did not read all the previous posts as, sorry for you, I think the foils will be again the winning factor. That said, if we refer to planes and wing sails, the most efficient are rigid wings, then two skin wings, then one skin. However in the air we control the wind speed, it's the contrary on water, thus a two skin sail may be more flexible and safer than a wing so if we don't lose too much efficiency the trade off will be interesting.

Do you think or have you read somewhere that in displacement mode these boat can reach 16kts with 13 kts TWS ?

SR, this is your last post, still in the house ?

In fact SR last post was Dec 9, 2018 and I was wondering why, I hope w'll see him back, he is one of the best informed poster here, at least on the US side. Too bad I missed him in SF during AC34.

^^ Perhaps but why do they build one ?

TNZ has lead in the design, lead in simulation, delay in the test boat, delay on training on the test boat.

They cannot change the concept of boats now, however I think that they are going to test much more than the sail. Again at this AC the difference will not be made by the sail but by the foils and the control systems.

Correct, you are surely more in the know than I am. I did not say they lied, I just never completely trust any AC team. Anyway, thanks to you answers, we can pinpoint more, here are the possibilities I see in the guess game : - B1 is too advanced to test some new systems - they thought of something else and it would modify B1 too much for the rule - they want to compare two concepts before B2 (my favourite) - it would cost less to try it on a smaller boat - some of these answers at the same time

They could also show misleading systems...

I agree with you but I don't think 2 and 3 are mutually exclusive, they can very well test some solutions before and after launch of B1 knowing it will be used for B 2. As for the crew, the more time foiling on the water the better.

We don't know much but we know they won't tell the real picture as usual, so we may have different possibilities: - they already have a test boat - the new test boat will be sailed before B1 - the new test boat will be sailed after B1 My guess is that all these option will probably coexist. The hoax was that they would only rely only on a virtual simulator.