floater

trickle down

Recommended Posts

from FP...

 

Screen-Shot-2016-10-19-at-6.27.27-PM.png

 

Screen-Shot-2016-10-19-at-10.31.01-AM.pn

 

Stb. foil looked extra fine at the tip when I posted this - but could be bad light/video aberration.....

ETNZsurrogate0ct2016_zpsrgctplth.png

Share this post


Link to post
Share on other sites

The front page says those foils belong to an Open 60? Can't find confirmation one way or the other.

 

Thought you knew what J-foils were supposed to look like? Guess again. These from Jean Pierre Dick’s St. Michel Virbac, currently lying in Les Sables D’Olonne getting ready for the Vendee Globe in just two weeks!

Share this post


Link to post
Share on other sites

 

On catsailingnews, the Nacra 17 Class approved full foiling mods - very well detailed in the Factory's presentation

 

http://49er.us3.list-manage.com/track/click?u=df2d2bf709ec92475cd1c89d5&id=f87652be8c&e=19378512bf

 

Quite interesting, particularly at page 26 with a comparison of predicted performance with C and Z boards (4 point) and uptips (3 point)

Share this post


Link to post
Share on other sites

Xlot, very interesting paper -particularly the foil comparison- and, for cryin out loud, the fact that M& M use the word "Uptip" to describe the foil they and TNZ invented. I would have expected as much but very cool to see it in print! Thank you!

Share this post


Link to post
Share on other sites

I can deal with just a capital "U"....

Share this post


Link to post
Share on other sites

On catsailingnews, the Nacra 17 Class approved full foiling mods - very well detailed in the Factory's presentation

 

http://49er.us3.list-manage.com/track/click?u=df2d2bf709ec92475cd1c89d5&id=f87652be8c&e=19378512bf

 

Quite interesting, particularly at page 26 with a comparison of predicted performance with C and Z boards (4 point) and uptips (3 point)

Yes, very interesting. But 27 kts of vmg downwind in 18 kts of wind with the uptip foil ????????????????

Share this post


Link to post
Share on other sites

Performance specs for the uptip foil were just spectacular, but apparently the need to retract the windward foil was a deal breaker? But it sure is cool to have that report around with somebody else-even if it is part of the inventors team- calling these foils uptip like they were originally named. And I imagine those performance figures are likely to pop up here and there! Also interesting to see the numbers for windward foil lift with two main Z* foils in the water.

 

*surface piercing foils

Share this post


Link to post
Share on other sites

What has to be remembered is that the performance figures are PREDICTED not real, and are based on the N17 foils as designed. We have seen in the A Class that predicted vs real doesn't stack up very well. In addition, the downwind VMG speeds predicted for Z foils have already been exceeded. The final point to note is that the Z foils being used on the N17 are very, very conservative. Those who have sailed the boat say it is rock steady, the foils are huge and if anything, it is too safe. Compared with the A, the foils are large and very draggy.

Share this post


Link to post
Share on other sites

All foils were compared with the same possibility of error yet the Uptip(their spelling, not mine) foils came out incredibly faster downwind.Very cool!! To be expected, I imagine , considering members of the original UptiP(my spelling, not theirs) foil inventors team were likely involved. Can't be denied, but I'm sure will be rationalized.....

Share this post


Link to post
Share on other sites

What has to be remembered is that the performance figures are PREDICTED not real, and are based on the N17 foils as designed. We have seen in the A Class that predicted vs real doesn't stack up very well. In addition, the downwind VMG speeds predicted for Z foils have already been exceeded. The final point to note is that the Z foils being used on the N17 are very, very conservative. Those who have sailed the boat say it is rock steady, the foils are huge and if anything, it is too safe. Compared with the A, the foils are large and very draggy.

Ok, that is the explanation. A vmg of 27 kts downwind would mean a speed of around 35 kts (estimate, not calculated), this would mean that the Nacra 17 would do as well as the GC32 or the AC45 F . It would not make any sense with the same type of foil.

The Vampire project is another story, they look amazingly fast, much faster than uptip and even L foils.

Share this post


Link to post
Share on other sites

Going to be interesting seeing how well the TF 10 main hull stays clear of the water -especially in waves.

Share this post


Link to post
Share on other sites

Going to be interesting seeing how well the TF 10 main hull stays clear of the water -especially in waves.

By your comment I gues you've got the answer. Why didn't they ask you?

Share this post


Link to post
Share on other sites

I think he was just thinking about it, not stating anything. You seem very sure he is wrong (somehow), so what's the correct viewpoint?

Share this post


Link to post
Share on other sites

I think he was just thinking about it, not stating anything. You seem very sure he is wrong (somehow), so what's the correct viewpoint?

His comment was sarcastic. I did not say anything about being right or wrong ( text comprehension). I can't talk about something I don't know. But I know where he's going to: starting with all his talk about his firearrow revolutionary foiling system and the lack of main foil in the hull bla bla bla... I repeat I do not know enough to say if its right or wrong, you won't find a single comment by me in this issue. But it pisses me off Doug polluting every single thread with the word foiling in it.

Share this post


Link to post
Share on other sites

When Maserati and Gitana first foiled their Mod 70 the biggest problem appeared to be incidental and frequent contact with the water by the main hull. Maserati solved the problem.

The TF 10 looks like the surface piercing foils are deep enough to keep the mainhull clear-but the real test will be in waves.

Share this post


Link to post
Share on other sites

 

I think he was just thinking about it, not stating anything. You seem very sure he is wrong (somehow), so what's the correct viewpoint?

His comment was sarcastic.

 

That is absolutely false.

Share this post


Link to post
Share on other sites

 

 

I think he was just thinking about it, not stating anything. You seem very sure he is wrong (somehow), so what's the correct viewpoint?

His comment was sarcastic.

 

That is absolutely false.

 

Me thinks she doth protest too much!

Share this post


Link to post
Share on other sites

@Nav,

That is inspiring, some people have the ability to think outside the box the looks amazing.

Soft sails will never be the same IMHBO.

Share this post


Link to post
Share on other sites

Yep, a lot of people have spent time trying to solve that conundrum, it'll be interesting to see how this one goes - and if it crosses over from commercial to recreational use.

Share this post


Link to post
Share on other sites

What an extraordinary boat!!!!

Share this post


Link to post
Share on other sites
22 minutes ago, ~Stingray~ said:

Wow!

Save your emotions, SR: the new foiling   high performance   ground breaking Cup boat is going to be far more exciting ... NOT!!!

Share this post


Link to post
Share on other sites
13 minutes ago, Xlot said:

Save your emotions, SR: the new foiling   high performance   ground breaking Cup boat is going to be far more exciting ... NOT!!!

It could be-Verdier is involved!

Share this post


Link to post
Share on other sites

Plenty of it about if you're looking in the right places. Guillaume doesn't have a monopoly on innovation.

LRArkema.jpg

Share this post


Link to post
Share on other sites

^^ It seems little foil-man has a 'new favourite designer'..........

Incoming quotes!

Share this post


Link to post
Share on other sites
3 hours ago, nav said:

From FP...

PUPZILLA  

Good to see cloth sails apparently working ok

DSC_4541xx.jpg

 

20170330-7.jpg

 

tf10_trimaran_sea_trials_1_copy.jpg?itok

 

20170502-4.jpg

 

(c) http://dnaperformancesailing.com/our-boats/dna-tf10-foiling-trimaran/

 

Not only that they work, but that they are reefed and they still work. Had it been a wing, they probably wouldn't have left the dock.

Share this post


Link to post
Share on other sites
On 20/11/2017 at 11:31 AM, Sailbydate said:

Not only that they work, but that they are reefed and they still work. Had it been a wing, they probably wouldn't have left the dock.

+1

Slab reef hedslz rok

 

But why wishboan level?

Share this post


Link to post
Share on other sites
On 8.10.2017 at 10:39 AM, Sailbydate said:

Plenty of it about if you're looking in the right places. Guillaume doesn't have a monopoly on innovation.

LRArkema.jpg

 

That Mini-class is the right place to test ting - here is the future at display... should also be a Mini-multiclass to - I know the micromultihull-class that was before - and the 8.50 class in Aus/NZ - but in France where the real development is - there mostly big multis where experiments wil be limited - but even then go very fast forward.... 

Share this post


Link to post
Share on other sites

Did any pictures eventually turn up of GTF's experiment with Z foils from the last cycle ?

Just interested to know if there was anything evolutionary or revolutionary they were trying at the time ?

Share this post


Link to post
Share on other sites
8 hours ago, inebriated said:

check out the video

their whole leeward transom broke off

 

The problem is not taking off but falling back with long, fin rudders that can break or break the hull itself

Share this post


Link to post
Share on other sites
Just now, Stingray~~ said:

Event 1 Live-streamed 

 

watching it, it looks as though they need another set of foils, a bit like the 18's had multiple rigs

big time struggles

Share this post


Link to post
Share on other sites

Not AC related, not even sailing related, but I am sure those who enjoy extreme sailing here will enjoy extreme skiing, I do !!!

  • Downvote 1

Share this post


Link to post
Share on other sites

 

  ^ The boorish couple taking a selfie at 0:34 is just perfect

  • Like 1

Share this post


Link to post
Share on other sites
On 2/4/2018 at 12:58 AM, Tornado-Cat said:

Not AC related, not even sailing related, but I am sure those who enjoy extreme sailing here will enjoy extreme skiing, I do !!!

 

 

That makes my P-Tex hurt just watching that!

Share this post


Link to post
Share on other sites
10 hours ago, Rasputin22 said:

That makes my P-Tex hurt just watching that!

Hahahahaha

I keep all my old ski's and board when I replace them, so you can fuck your old gear up and keep the new shit new!

Should see some of the core-shots on my park board >.<

Share this post


Link to post
Share on other sites
2 hours ago, surfsailor said:

^ Very cool boat. 

Hey surfsailor, what do you know about this combo?

10188636.jpg

Share this post


Link to post
Share on other sites
6 minutes ago, Rasputin22 said:

Hey surfsailor, what do you know about this combo?

 

Very cool - kind of an inflatable version of the Kitewing. Pretty sure that's Tony Logosz, the Slingshot foil designer - he's made a lot of interesting stuff over the years. 

I'm a sucker for simplicity, and this really checks a lot of boxes by eliminating both the strings (kites) AND all the rig components (mast, boom, base, universal, battens etc) and really stripping propulsion down to the basics using inflatable LE kite tech. I'm guessing it requires a fair amount of wind for takeoff, but once you're up it should go forever. It's never going to be fast, but I just don't think that's an issue for most people.

The whole industry has really had a fire lit under it with the advent of foiling -  it's really fun to be a designer right now. We're going to see a lot of clever innovation in the beach toy business over the next couple of years!

https://kitewing.com/

Share this post


Link to post
Share on other sites

^ if you let go of the the kitewing (inflatable or otherwise) say when you fall off then how far will it fly away from you? You need to retrieve the wing to continue. Doesn't this raise a safety concern?

Share this post


Link to post
Share on other sites
3 minutes ago, Fireball said:

^ if you let go of the the kitewing (inflatable or otherwise) say when you fall off then how far will it fly away from you? You need to retrieve the wing to continue. Doesn't this raise a safety concern?

Maybe the line trailing behind can have one end attached to the wing?

Cool++

Share this post


Link to post
Share on other sites

 

3 minutes ago, Fireball said:

^ if you let go of the the kitewing (inflatable or otherwise) say when you fall off then how far will it fly away from you? You need to retrieve the wing to continue. Doesn't this raise a safety concern?

He might have a wrist leash of some kind (like a boogie board) - hard to tell from the pic. But even if not, that's plenty of board for self rescue.

Share this post


Link to post
Share on other sites

^  it seems like a tricky problem - there are safety concerns being attached to the kite and there are safety concerns with the kite flying out of control in its own. Having an inflatable kite would be safer for other boats nearby - the kiteboarders seem to injure themselves more often than other people.

Share this post


Link to post
Share on other sites

^ If you connected a leash (with a little elastic in it) to the mid point of the LE , it wouldn't be a problem - it's a very different animal without the long strings and the altitude.

The more I think about it, the more I like it - instead of comparing it to a foiling windsurfer, compare it to a foiling downwind SUP board. That inflatable handheld wing sail would be an awesome addition, and when you're done it packs away in a little bag. Pretty cool.

Share this post


Link to post
Share on other sites

^ Probably should be working on that - I'm guessing the Slingshot design doesn't run afoul of the North patent on a fully inflatable windsurf rig since it's not attached to the board, and doesn't need to tack.

It might be time to yell at our French kite designer!
 

Share this post


Link to post
Share on other sites

It’s a curiously interesting fact that Ashby’s two teammates are Nathan (helm) and Goobs, and that the next best boat (eTech?) is helmed also by an AR guy, Luke Parkinson. Ashby says in one of the SuperF videos that this boat is the closest thing there is so far to the JC75.

 

Share this post


Link to post
Share on other sites
Just now, Stingray~ said:

It’s a curiously interesting fact the Ashby’s two teammates are Nathan and Goobs, and that the next best boat (eTech?) is helmed also by an AR guy, Luke Parkinson. Ashby says in one of the SF videos that this boat is the closest thing there is so far, to the JC75.

 

I really like the idea of a single, central rudder on the AC75 - I think it's safer, and I think it simplifies the control strategy in a good way (no differentials etc)

Share this post


Link to post
Share on other sites
15 minutes ago, surfsailor said:

I really like the idea of a single, central rudder on the AC75 - I think it's safer, and I think it simplifies the control strategy in a good way (no differentials etc)

The single rudder will result in less drag than the AC50’s dual setup and I hope they use flaps instead of rake, for finer control, because of how dang critical it will be to maintain pitch control.

Safety is just about the last consideration behind the JC75, best I can tell. While the AC50’s used a touch of negative incidence on the WW rudder wing to improve RM the possibility of pitch getting loose on the JC75 (maybe even through rudder ventilation if main-foil-controlled ride height is also touchy) could lead to negative attack on the lee foil with Gawd knows what consequences.

Share this post


Link to post
Share on other sites
1 minute ago, Stingray~ said:

The single rudder will result in less drag than the AC50’s dual setup and I hope they use flaps instead of rake, for finer control, because of how dang critical it will be to maintain pitch control.

Safety is just about the last consideration behind the JC75, best I can tell.

The new boats will almost certainly use control surfaces on all 3 foils.

I'm sure the ETNZ design team is taking safety very seriously. A big safety advantage of the AC75 over the cats is that the crew will be in a centralized location rather than running from ama to ama - far less likelihood of a MOB, and they will be in a far more protected space if/when things do go pear-shaped. You can see this same thing on some of the proposals for the in-port foiling Volvo boats - some of them even have fully enclosed 'crew pods'.

  • Like 1

Share this post


Link to post
Share on other sites
5 minutes ago, surfsailor said:

The new boats will almost certainly use control surfaces on all 3 foils.

I'm sure the ETNZ design team is taking safety very seriously. A big safety advantage of the AC75 over the cats is that the crew will be in a centralized location rather than running from ama to ama - far less likelihood of a MOB, and they will be in a far more protected space if/when things do go pear-shaped. You can see this same thing on some of the proposals for the in-port foiling Volvo boats - some of them even have fully enclosed 'crew pods'.

Agree that on AC50’s there was a much higher likelihood in a big wipeout of falling into things from the windward hull. The ETNZ nosedive was bad when the rudders ventilated but, incredibly, people who got thrown didn’t get badly hurt. Sure was close though.

Share this post


Link to post
Share on other sites
7 minutes ago, Stingray~ said:

Agree that on AC50’s there was a much higher likelihood in a big wipeout of falling into things from the windward hull. The ETNZ nosedive was bad when the rudders ventilated but, incredibly, people who got thrown didn’t get badly hurt. Sure was close though.

That looked to me like a glitch in their flight control system - there were a couple different reaching legs early in the event where they almost lost it (before the capsize) - but who knows. For sure their control system allowed them to push their foil designs well beyond the other teams, who were still controlling foils from the wheel, so their stabilzers might have been a little more 'twitchy' as well.

Share this post


Link to post
Share on other sites
11 minutes ago, surfsailor said:

That looked to me like a glitch in their flight control system - there were a couple different reaching legs early in the event where they almost lost it (before the capsize) - but who knows. For sure their control system allowed them to push their foil designs well beyond the other teams, who were still controlling foils from the wheel, so their stabilzers might have been a little more 'twitchy' as well.

In any breeze almost everyone was faster than ETNZ on the reaching starts, I can pull the stats, but they weren’t the only team who had issues with rudders gettting loose although mostly on other (and less fast) legs.

Share this post


Link to post
Share on other sites

^ Yep - but ETNZ was far faster around the course, and consistently hit 100% foiling. It was the way it happened that made me think 'flight control glitch' - there was a kind of oscillation immediately before the rise, I saw that several times with less catastrophic results than the eventual capsize - but it could've just as easily been crossing the aerated foil wake of the other boat, or - as you say - straight up ventilation issues. There's no way of knowing without seeing the data.

Share this post


Link to post
Share on other sites
10 minutes ago, surfsailor said:

^ Yep - but ETNZ was far faster around the course, and consistently hit 100% foiling. It was the way it happened that made me think 'flight control glitch' - there was a kind of oscillation immediately before the rise, I saw that several times with less catastrophic results than the eventual capsize - but it could've just as easily been crossing the aerated foil wake of the other boat, or - as you say - straight up ventilation issues. There's no way of knowing without seeing the data.

Yep.

And the data, while impressive on a graph, does not illustrate the trail left by BAR.

Share this post


Link to post
Share on other sites

^ And BAR's foils looked like they were digging some serious holes in the water in AC35 - wake-O-rama! :)

Is AC36 really going to have an upwind start with no foiling lane? That could be exciting with the new boats!

Share this post


Link to post
Share on other sites
19 hours ago, Stingray~ said:

It’s a curiously interesting fact that Ashby’s two teammates are Nathan (helm) and Goobs, and that the next best boat (eTech?) is helmed also by an AR guy, Luke Parkinson. Ashby says in one of the SuperF videos that this boat is the closest thing there is so far to the JC75.

For whoever is only living in the ACverse: Parko is currently an under-30 on Sun Hung Kai/Scallywag in the VOR.

Share this post


Link to post
Share on other sites
3 minutes ago, Rennmaus said:

Yup

Missed that in the link

... Currently sailing with Team Sun Hun Kai Scallywag in the 2017/8 Volvo Ocean Race – taking two legs off to compete in the SuperFoiler

  • Like 1

Share this post


Link to post
Share on other sites
19 hours ago, Stingray~ said:

Ashby says in one of the SuperF videos that this boat is the closest thing there is so far to the JC75.

 

Considering the breakage they suffer with the SF it's not good news.

Share this post


Link to post
Share on other sites
1 hour ago, Tornado-Cat said:

Considering the breakage they suffer with the SF it's not good news.

"The boat fell apart today in training," said Euroflex skipper and Olympic Gold medallist Nathan Outteridge, "It looks like a can opener has gone along the side of the boat."

"We just started hearing a cracking noise and saw the back of the boat explode as we were squaring up to go down wind. That sound and feeling when you are on trapeze is not ideal," said Euroflex's mainsheet trimmer and America's Cup winner Glenn Ashby.

https://www.sail-world.com/news/202626/Series-leader-Euroflex-out-of-racing-in-Busselton

 

Share this post


Link to post
Share on other sites
16 minutes ago, Stingray~ said:

"The boat fell apart today in training," said Euroflex skipper and Olympic Gold medallist Nathan Outteridge, "It looks like a can opener has gone along the side of the boat."

"We just started hearing a cracking noise and saw the back of the boat explode as we were squaring up to go down wind. That sound and feeling when you are on trapeze is not ideal," said Euroflex's mainsheet trimmer and America's Cup winner Glenn Ashby.

https://www.sail-world.com/news/202626/Series-leader-Euroflex-out-of-racing-in-Busselton

 

Thanks, and that is only one of many.

One could object that the JC75 will be stronger, but the "crew" won't move and the boat will be faster.

What strikes me in the SF is that the trimaran has very short floats, thus the many pitchpole as soon as the foils does not lift. For the JC75 it will be worse, they won't have any float. The question is to know if the main wider hull will help them. Otherwise we will have the "pleasure" to watch 50 kts winward pitchpole.

Some predicted a demolition derby with the AC72, it did not happen. What about the JC75 ?

Share this post


Link to post
Share on other sites
21 hours ago, Stingray~ said:

It’s a curiously interesting fact that Ashby’s two teammates are Nathan (helm) and Goobs, and that the next best boat (eTech?) is helmed also by an AR guy, Luke Parkinson. Ashby says in one of the SuperF videos that this boat is the closest thing there is so far to the JC75.

 

More on Goobs

“I’d say the only boat I have sailed on that is more technologically advanced than this is the America’s Cup boat. As far as a boat with trapezes this is definitely leading the way I think it is an awesome circuit,” Jensen said.

http://www.mysailing.com.au/latest/jensen-jettisons-leading-series-after-busselton#Qr6IVYJM5j6dDrAE.99

Share this post


Link to post
Share on other sites

I don't want to imagine that with JC 75.

In fact I think that if they pitchpole it will mainly be on leeward as here. Having a foil at the exterior with a vey small foat, or worse, with none, is very dangerous. The advantage of cats are the length and volume ahead. But the volume of JC main hull may help too.

 

Share this post


Link to post
Share on other sites

the superfoilers are amazing boats that just need time to develop

talking to some of the builders, no one wanted to sail the boats for the development in sydney

i was there for all the racing in busso and pretty much what happened with euroflex as the top of the rudder post thingie snapped off so the bottom twisted inwards and the broken stump went through the outside of the float

amazing that they got out on the water in time for the last day

literally fixing the boat until they hit the water and then only made the race start by 3 minutes

 

Share this post


Link to post
Share on other sites
On 03/03/2018 at 6:48 PM, Tornado-Cat said:

I don't want to imagine that with JC 75.

In fact I think that if they pitchpole it will mainly be on leeward as here. Having a foil at the exterior with a vey small foat, or worse, with none, is very dangerous. The advantage of cats are the length and volume ahead. But the volume of JC main hull may help too.

 

When one of the Team Pavement crew is climbing back on the upturned hull after their pitchpole he says something like "I'm a bit concussed" (0:12 in the video).

It's not the least bit entertaining to watch young sailors get head injuries.

 

  • Like 1

Share this post


Link to post
Share on other sites
11 minutes ago, Fireball said:

When one of the Team Pavement crew is climbing back on the upturned hull after their pitchpole he says something like "I'm a bit concussed" (0:12 in the video).

It's not the least bit entertaining to watch young sailors get head injuries.

 

definitely not, but that was the fastest crash to date and marginally over the wind limit

i don't think many like that will be happening soon in racing and the boats will only be getting more stable from here

Share this post


Link to post
Share on other sites
15 hours ago, Fireball said:

When one of the Team Pavement crew is climbing back on the upturned hull after their pitchpole he says something like "I'm a bit concussed" (0:12 in the video).

It's not the least bit entertaining to watch young sailors get head injuries.

 

One of that Team Pavement crew looks a lot like the bearded guy wearing Artemis kit in the Wingsail vid.

Share this post


Link to post
Share on other sites
17 hours ago, Fireball said:

When one of the Team Pavement crew is climbing back on the upturned hull after their pitchpole he says something like "I'm a bit concussed" (0:12 in the video).

It's not the least bit entertaining to watch young sailors get head injuries.

 

Close...he says "Ohhhaaahh, I'm a bit cut"

Share this post


Link to post
Share on other sites
5 hours ago, Stingray~ said:

One of that Team Pavement crew looks a lot like the bearded guy wearing Artemis kit in the Wingsail vid.

Can confirm that I was there and you are incorrect. 

The skipper was Steve Thomas, with Lachy gilmour and torvar mirsky

maybe some others jumped in but no one from Artemis 

Share this post


Link to post
Share on other sites

What was first in this age of foiling, successful foiling which changed a whole class to the foiling version?

Moths, ACcats. Cclass, kite surfers?  This is with a mind to evaluating the trickle down from AC.

Rather than starting a fight as to which one was. Please.

Share this post


Link to post
Share on other sites

^

Sorry, efficiency and speed were then very important.  Mostly to get places but man has always been competitive.

I don't think money come into it either in the Early days either.

Share this post


Link to post
Share on other sites
On 3/9/2018 at 4:09 PM, Kiwing said:

What was first in this age of foiling, successful foiling which changed a whole class to the foiling version?

Moths, ACcats. Cclass, kite surfers?  This is with a mind to evaluating the trickle down from AC.

Rather than starting a fight as to which one was. Please.

AFAIK, the Moth class was the first in which a foiling boat was competitive with a floating boat in a wide range of conditions.  In 2000, Brett Burville won two heats at the Moth Worlds in Australia.  That particular configuration was later ruled illegal in the Moth class, but it was the start of competitive foiling.  (It was to be revived to meet the restrictions of the class rule for the A-class catamarans.)  Hydrofoil boats had been raced earlier, but were not very successful.  So, hydrofoils themselves predated the AC, going  back to the 1950's.  Prior to the AC, hydrofoils were stabilized either through the heave-associated area reduction of surface piercing foils, or feedback control systems like the Sam Bradfield invented wand that was first used in Moths by John Ilett. 

There were two big trickle-down aspects to the 34th AC in 2013.  The first was simply the notoriety given hydrofoils by using them in the AC.  This gave a professional cachet to sailing hydrofoils that had previously been the province of amateur experimenters.

The second big trickle-down from the 34th AC was the principle of stabilizing the boat in heave through the mechanism of leeway coupling with L foils.  This principle was discovered by Emirates and OTUSA subsequently discovered it for themselves.  Leeway coupling made it possible to have the vertical lifting portions of the foil be fully submerged, avoiding the ventilation issues that plagued surface piercing V foils, while still having the stability of a surface piercing foil with no moving parts.  

Hydrofoils were attempted in the C-class catamarans, but were not competitive because the T foils used at that time resulted in giving the hulls less beam, and the loss of righting moment more than offset any drag reduction from the foils.  It wasn't until after the 34th AC that hydrofoils became competitive in the C-class, by using the L foils and leeway-coupled stability from the AC.  The L foils allowed the hulls to be at the maximum allowed beam, restoring the righting moment that had been lost to the T foils.

So there's been an exchange of technology both ways, from smaller classes to the AC, and from the AC to other classes.  

  • Like 2

Share this post


Link to post
Share on other sites