I think you could make some comparison to early microlights and even hang -gliders which initially were single surface wings. Clearly double surface allows a "proper" aerofoil shape but then that shape is highly dependent on the phase of "flight". A slower speed a deeper section and high speed shallower -once they are foiling these boats are so fast that really they probably would not require any depth of section. Would there be any gains for all the gear involved in a variable section. My guess is very little. Anyway certainly interesting concepts. Cant wait for the action to start. Go ETNZ!!

@@peterwilson6363 I think that the main benefit, once foiling, is still indirectly related to the depth of the section. What I mean is that the athwartships strength required from the mast, given the apparent wind strength is generally hurricane force, inevitably forces the leading portion of the aerofoil profile to be deep, with the result that two skins are the only way to provide a sufficiently fair profile on both windward and leeward surfaces to maintain laminar flow all over . Otherwise, for one thing, the drag at those ultra high apparent wind speeds would kill the chances of a foiling tack.

😁

That’s a beach??🥵🥵

Yes, I think the thing they failed to factor in is active mast rotation, which I don't doubt is being used(with careful detailing of the battens and their connections to the mast) to deepen, flatten and even invert the draft up high, while the cunning twin sheet system can do the first two things for the bottom section.

When you're at the point of chasing 0.x gains even the bottom 20% of the sail would be huge if there was any significant benefit.

Doesn't it depend upon how much energy it takes to make these changes and how rapid it is needed? It could be to a point of diminishing returns

Ha, I'd spent the week before sailing a Merlin and was chatting to Dave about it before we pressed record so it was likely stuck in his head!

nah they never said that the twin skin was more efficient than a wing. it's not. the reason they introduced it is to try and quiet some of the haters saying bring back the old 12 meters by bringing it closer to traditional sailing so people can relate to it more, while still preserving some performance benefit.

I thought that too!

I did, but conclusions are still internal to Red Bull

But if the laminate thickness has minimum limits, is this not a common issue?

​@@BRMCaptChaos And how mutch load and bend your mast. Of course every team could break his mast.. with to mutch pressure on it.

@@Silvius.2 much ! .. but yeah agree'd

That's a buoyancy bag to stop the yachts turtling if they capsize. They're one design so not really for sail shapes although I guess could impact it a bit if inflated to much

⁠my guess is the rule-writing Kiwis will show up in Barcelona, with a surprisingly adaptable safety-balloon between the main skins. Maybe it just overinflate, can be moved around or it is attached to the rotating mast for effect in the upper part of the sails. Really cool if the bladder controlled little valves so the twin-skin main could blow up like a foilkite for 3d shape in the middle/top section.

No, not this time. Last cut you could actively control the top 3m, but actually moat teams didn't and chose to save weight

Haha! Beachhuts

Are you saying that's not fast? Or is your point that they should be able to continue indefinitely raising the bar, with no ceiling imposed by the laws of physics? The only sailboats which currently go faster do so with virtually no other objective than speed. No practicality, no ability to manoeuvre, mostly they can only sail unassisted on one tack and one true wind angle, and in flat seas next to the beach with very strong offshore winds, conditions either found almost nowhere, or hardly ever. And with all those limations, they're only a shade faster, maybe 12 percent at most. What's more, that record has not been matched for three times as long as the new AmCup rule has been in operation. Physics is a tough mistress...

@@Gottenhimfella ,I’m asking ,what are the present top speeds?Basically,went away from cats that cost a fraction of these boats that don’t have any PRACTICAL use.Clever technology but the spin off to the general boating community 🧐🧐🧐🧐

@@user-ce9gm7fq6m Couldn't agree less. Top speeds are limited by cavitation to about the same for both classes, and size for size the cost is similar, so that's not a decision factor, but these foiling monos seem to me far more likely to spin off tech to other sailing, firstly because of the fact they allow rapid and safe reduction or removal of sails, (compared with wings which require low wind, sheltered water and a massive crane to get rid of the "sail" area), and secondly because you can recover from a capsize in a matter of minutes, and usually without damage.