AC 36 Foiling Monohulls

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Great find. To the extent its not photoshopped it looks very good-except, of course, if you get hit by the raised axe....

 

This is a very interesting AC related older thread--before 2013(which makes a huge difference!). Worth a read.....
America's Cup sailed with Multihulls https://www.boatdesign.net/threads/americas-cup-sailed-with-multihulls.12019/

Imagine- we've come full circle back to leadbellies--or have we?!

 

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More on this story from Pressure Drop and StuffNZ:
(NOTE: Briand expects his very cool little boat will need 10kts of wind to foil--not too good....)
Stuff NZBreaks The News

A noted French yacht designer has produced the first scaled down version of the new foiling America's Cup monohull with an eye on the public market.
Phillipe Briand has designed more than 12,000 boats and been heavily involved in the America's Cup programme since 1986. He has six Cup campaigns to his name since his first design involvement as an 18-year-old.
Briand has talked up the radical concept introduced by Emirates Team New Zealand for the 2021 America's Cup in Auckland and replicated the main features in a 6.5m version called "Flyacht" that can be sailed by a crew of two.
"Both my team and I are passionate about the America's Cup, having been 'main designer' of no less than six campaigns. This is why we were among the first to design the concept of an AC75 and complete a preliminary project," Briand told La Stampa in Italy where interest in the Cup is building with the prospect of two challangers.
"The flying monohull is the ideal solution if we think that one of the objectives of the Cup is to allow technological development to always be at the forefront of the sailing world and to ensure that the America's Cup remains the most important sailing event in the world."
Briand said he had been "pushed to the limits in my work as a designer", in a quest to transfer the benefits of innovations from the racing sector to a wider market, but keeping costs reasonable.
"What I want is to make the generation of 'millenials' understand how much fun and how much adrenaline there can be in sailing. And the first step towards this dream will be to see the AC75 in action in 2021."
He said the new boat combined the best qualities of multihulls, with their high speed and innovative design, with the navigation modes of monohulls."
Like the AC75, the "Flyacht" features T-foils coming out of the two sides of the boat and a soft wingsail.
He believes his smaller version will be able to foil in 10 knots of wind.
The America's Cup teams, with the class rule now in their hands, are busy working on their first AC75s. They are allowed to build two for the 2021 Cup with the first to be launched after March 31 next year with an eye on the America's Cup world series events still to be announced.
The teams' second boats can only be launched after February 1, 2020.

- Stuff

 

Heaven forbid that a sailing publication should apply even the most cursory critical analysis to things it's reporting. Saying the designer "has produced a version" makes it sound like he's actually built one, "has designed" might be accurate (though no evidence of the design was presented). It's not the first either, since the designers of the AC75 (the name doesn't seem to be mentioned much) say they designed (not produced) a 39' version for a private buyer before the AC75 was even announced. The qualification of "the public market" doesn't absolve that.

Foiling in 10 kn of breeze for such a boat would be a very good achievement (but I'll believe it when I see it).

 

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I think that would be going backwards in terms of foiler design. It's only been relatively recently that some recreational foilers have been produced that
can take off in light air-4-6 knots. For those contemplating purchasing of a foiler ,telling them that the thing won't fly until there is 10 knots of wind could be a deal breaker. That was part of the problem with the first production recreational multihull foilers-they couldn't fly in under 10 knots and people didn't much like buying a foiler that wouldn't fly in their "normal" conditions.

 

I think you've put that notion forward many times in different threads on various forums and it's received zero support. Not every new foiler needs to outperform every existing foiler by every possible criterion. Look at some light Moth world championship races where one or two boats manage to foil but 98% of the fleet can't. That should tell you that anecdotal evidence of, say, a Quant 23 foiling in 4kn winds (with no scientific rigour to the reported windspeed claims) doesn't mean anyone can, or even that the same boat and crew could repeat the effort in similar conditions.

I presume you've done market research to backup your claims of why foiling multihulls aren't selling like hot cakes? And that "normal" conditions for "people" is less than 10kn? I expect the issues are many, from higher cost, weight sensitivity, higher risks associated with higher speed and how to manage higher winds. Criteria for purchasing a recreational boat are likely far more varied than "will it foil in 4kn?"

A 6.5m monohull that will reliably foil in 4kn would likely be a one–trick pony that was very expensive, at the extreme of materials technology and consequently require high maintenance and careful handling and storage.

Those criteria suit AC boats because the owners expect to spend $100 million plus on boats that will be molly coddled by an expansive and highly skilled maintenance crew and not last past their last AC race. They are also stupidly difficult to sail at anything like the performance of their highly skilled crews. It's like expecting an average driver to jump into an F1 race car and get it to 300k/h on their first lap. They would be lucky to get it out of the pit lane. And they have to find two or three crew with suitable skills every time they go sailing.

Do not underestimate how difficult these boats are to sail to anything like their potential. Last weekend I watched an experienced and well performed 505 sailor be humbled when trying to sail a 16' skiff in testing conditions (I'll just say there was a lot of swimming, though less than the first twenty or so times I tried to sail a Moth). On the same day, the Sabot kids had no issues beyond keeping warm and there were more of them (in terms of sailor numbers) on the water.

 

Several foiler builders including the Quant 23* , Whisper and others have made a point of the fact that their boats will takeoff in light air and sail well in stronger wind so that the boat can be sailed on foils in close to the same range of wind a non-foiling sailboat sails. Thats a business decision because a foiler that only has a limited range of flying won't sell especially in wide areas of the US where the wind is predominantly light.
Boats designed to start foiling in 10 knots of wind or more won't sell and that is a major motivation to improve light air performance even at the cost of top end speed.
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I'm not sure, but I think one of the TNZ people suggested that the new boats would need 9 knots of wind to start flying and that the wind limit would be around 20 knots. That is just plain silly, in my opinion. Good luck with finding a venue that has such a narrow wind range but as I said I'm not sure who made those comments and maybe Auckland is the place.

* According to the builder the Quant 23 will takeoff in lighter air than a Moth or A Cat---and that's a keelboat!

Quant 23 in very light air:

 

You continue to focus on a single issue. Whether a Quant 23 managed to foil in circumstances where someone nearby in a Moth or A Class couldn't is interesting but doesn't prove your point. That some people can foil in Moths when others can't doesn't suddenly mean everyone wants to sail that brand of Moth. Are Quant 23s now outselling all comparable sports boats as a result of their low–wind feat? Is any low–wind foiler dramatically outselling their Archimedean competition because they can foil in light winds?

If not, then your claim that light wind performance is the key to foiling success is not supported by evidence. You also ignore that even if a Quant 23 (or any foiler really) can be made to foil in conditions where the average wind speed is 4kn, it can likely only do so at a very specific apparent wind angle by very experience sailors. So as long as you want to go in that direction (and it changes moment to moment depending on the breeze), fine. But if you're constrained by wanting to go somewhere else for whatever reason then you're back to floating.

Anyway, this is a pointless discussion and nothing to do with the AC75 Class, so I'll leave you with this:

 

Geez, what a great find! Thats all there is?!
UPDATE: Ok, I've searched all over for this picture and more of the story-where did you find it? Please........
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Just noticed that unlike the TNZ renders and the Briand render, the pivot point of the foils is much higher up....

 

From Scuttlebutt Europe:

Two Weeks to End of America's Cup "Challenging Period"
The "Challenging Period" ends on 30 June. Three challenges have been submitted and accepted:

Circolo della Vela Sicilia Luna Rossa, Challenger of Record
New York Yacht Club American Magic
Royal Yacht Squadron Racing INEOS Team UK

Other potential teams have been in the news, but none is known to have submitted a challenge:
France: Team France
USA: US One
Italy: Adelasia di Torres
China
Norway
Challenges can be accepted until 30 November 2018 with a $1 million "Late Entry Fee Payment." -- Jack Griffin

cupexperience.com

 

The British Challenge:

 

AC Light Air Foiling-- If I remember correctly the limits with the 50's in 35 were 6 to 26 knots. That was good. Unless they enforce a lower limit of 9 knots for 36 I'd bet the NZAC75's could effectively takeoff in 6.

 

A bit more…



The deck spreaders are interesting, as are the hydraulic rams on the top of articulated foils (next to deck spreaders).

The float at the top of the mast means someone has doubts about its stability

 

Where did you find it?
It seems it would be a whole lot simpler and not too much slower to use a narrow deep fin keel like the Gonet Monofoiler or the Quant 23.
Then the movement of the foil struts could be cut in half(they wouldn't have to be moved straight down) and the complexity of weight in the foils eliminated.And the ballast on the keel could be less than the total of the weight of the two foils together. The hull could be narrower than the NZAC render hull because of the deep keel and that would make up for the wetted surface of the keel(before and at takeoff) so the boats might wind up about the same speed with one much, much easier to sail than the other.
On smaller versions dual independent wands could be attached to the inside of the struts eliminating the need for manual altitude control.

 

If the design brief was for a test boat or prototype AC75 (I don't know that, it's only an assumption) it wouldn't make much sense to include features that are obviously inconsistent with the class.

Discussion of features that are clearly inconsistent with the AC75 class rules are off topic here.