• Announcements

    • Zapata

      Abbreviated rules   07/28/2017

      Underdawg did an excellent job of explaining the rules.  Here's the simplified version: Don't insinuate Pedo.  Warning and or timeout for a first offense.  PermaFlick for any subsequent offenses Don't out members.  See above for penalties.  Caveat:  if you have ever used your own real name or personal information here on the forums since, like, ever - it doesn't count and you are fair game. If you see spam posts, report it to the mods.  We do not hang out in every thread 24/7 If you see any of the above, report it to the mods by hitting the Report button in the offending post.   We do not take action for foul language, off-subject content, or abusive behavior unless it escalates to persistent stalking.  There may be times that we might warn someone or flick someone for something particularly egregious.  There is no standard, we will know it when we see it.  If you continually report things that do not fall into rules #1 or 2 above, you may very well get a timeout yourself for annoying the Mods with repeated whining.  Use your best judgement. Warnings, timeouts, suspensions and flicks are arbitrary and capricious.  Deal with it.  Welcome to anarchy.   If you are a newbie, there are unwritten rules to adhere to.  They will be explained to you soon enough.  
pacice

Foiling Monohull - what would it look like?

Recommended Posts

23 hours ago, MR PLOW 270 said:

ok, fair point that the netting would be shitty for aero

we aren't talking about the 72 though, we're talking about the 50

considering the netting now, then yeah, the 75 may have a little bit less aero drag than the 50, but a lot less drag if they find out a way to streamline the bodies, like Oracle did in the 72/ ETNZ in the 50

this being said, i still don't think that the 75 will be faster than the 50

the 75 has less beam across the foils (i think??!), ie less RM from the foils alone

the 50 could provide RM from its rudder foils, it doesent look as though the 75 can

the 50 weighs much less, also meaning less foil in the water, giving less drag (unless windward rudder is providing shit tones of RM)

the 50 has just as much weight to windward as it has providing balance in the foils, albeit further inboard, but not much

the wingsail is more efficient than a soft sail

and if we're talking about all around speed, not top speed, the 75's will be a dog to foil in light winds and the manoeuvres will be much harder (i don't think we'll see 100% dry time this cycle)

I think a few people are going to be shocked with what can happen.

I know on the kite foilers in 5 to 6 kts wind speed, they are logging  25kts speed,  with 17-18 kts VMG upwind

In 5 to 6 kts

 

 

Share this post


Link to post
Share on other sites

Happened into the long-forgotten FP, and saw a picture of new Rambler's 21' canting keel - as well as of the remarkably short opposite lever. I told you guys: leave this to the specialists

 

Share this post


Link to post
Share on other sites
9 hours ago, dachopper said:

I think a few people are going to be shocked with what can happen.

I know on the kite foilers in 5 to 6 kts wind speed, they are logging  25kts speed,  with 17-18 kts VMG upwind

In 5 to 6 kts

 

 

Again, apples and oranges... You can't compare a kite foiler, with a 75 ft. 7 ton classic rigging monohull

Share this post


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

Again, apples and oranges... You can't compare a kite foiler, with a 75 ft. 7 ton classic rigging monohull

On a Micro scale apples and oranges, On a macro scale not so much.

 

Both are designed to ride on their hydrofoils and not on their hulls, and are wind powered. 1 uses crew weight, the other one probably won't, but will use something else instead

Since there are no rules set.... and they said they would change the rules to make it work.

Who is to say it will be 7 tonne,  ' classic rigged ' , that they will stick with soft sails if they aren't going to work, or if they are going to use conventional or wing sails at all.

 

They did set out their goal, and said they would alter the design to achieve it.

Two different designs for sure, both using the same principles of motion.

Share this post


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

56a380c08fe489d5dcb00bc035a609f5--ship-f

She seems devoid of a personality, but what should we expect from someone whose partner spends so much time on SA

  • Like 1

Share this post


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

On a Micro scale apples and oranges, On a macro scale not so much.

 

Both are designed to ride on their hydrofoils and not on their hulls, and are wind powered. 1 uses crew weight, the other one probably won't, but will use something else instead

Since there are no rules set.... and they said they would change the rules to make it work.

Who is to say it will be 7 tonne,  ' classic rigged ' , that they will stick with soft sails if they aren't going to work, or if they are going to use conventional or wing sails at all.

 

They did set out their goal, and said they would alter the design to achieve it.

Two different designs for sure, both using the same principles of motion.

yeah, but there are plenty of reasons why the kite foiler is so fast, hardly any drag and an efficient sail that reaches more wind

there are nearly no advantages from the animation that can be seen over the ac50 apart from the beam

Share this post


Link to post
Share on other sites
Quote

with almost no room for an internal lever arm

That's engineer speak for "it will be a little tricky to fit it inside, but we'll make it work".

Share this post


Link to post
Share on other sites
On 1/7/2018 at 9:55 PM, etienne.billiet said:

Jean Sans has further worked on take off, flight control, and stability steadiness. An additional technical brief will be posted in theh coming day on our french site https://www.uncl.com/courses/technique/. Will "google english" be OK or shall we sppenf time at translating?

Here, is the French version that can be google translated via the right panel widget https://www.uncl.com/2018/01/10/techniques-innovations/nouvel-ac-75-nz-jean-vol/

a main news here, will we see winglet or not on the foil?

real translation is still available on demand.

  • Like 1

Share this post


Link to post
Share on other sites

Thanks, Etienne - plenty of food for thought :)

A very first comment: in this version foil arms are solid carbon, while the foils themselves are steel. This would seem to be the obvious combination, I hadn't realized that this was reversed in the initial version

Share this post


Link to post
Share on other sites
34 minutes ago, etienne.billiet said:

Here, is the French version that can be google translated via the right panel widget https://www.uncl.com/2018/01/10/techniques-innovations/nouvel-ac-75-nz-jean-vol/

a main news here, will we see winglet or not on the foil?

real translation is still available on demand.

More to the point, this illustrates the issue with using a lever to raise and lower the foils. In the "racing mode" diagram (see below), the lever is shown as angled to the main strut so it can be raised within the physical constraints of the hull. In the "navigation mode" diagram (below below…), the lever is omitted because if it was per the racing diagram, it would be through the hull.

Will it be hinged? Seems unlikely, or is there some other method of raising and lowering the foils that either

A. Hasn't been worked out yet, or

B. Is sufficiently novel that the designers don't want to show it yet, or

C. There's a slot in the side of the hull that is open to the water so the lever just sticks out

I'm guessing A.

Racing mode:

AC75_JS_Foiler2.png

Navigation mode:

AC75_JS_Foiler3a.jpg

 

 

Share this post


Link to post
Share on other sites

Really comprehensive, will take some time digesting it. It's the first time I see stability discussed taking into account the moment due to the sail's COE being so high up.

When he talks about a "fletner" on the stabilizer trailing edge, I assume he does not refer to Flettner Magnus-effect rotors, a trim tab perhaps?

Also, he seems sure transversal stability will require a winglet on each main foil  Wonder if there's something to be learned from kite foils on this

 

Share this post


Link to post
Share on other sites

Seems to me the pivot point might do better if it was raised to the sheer line rather than at the chine. At the very least that would get part of the mechanism out of the water.

  • Downvote 1

Share this post


Link to post
Share on other sites
1 hour ago, Doug Lord said:

Seems to me the pivot point might do better if it was raised to the sheer line rather than at the chine. At the very least that would get part of the mechanism out of the water.

I was just looking at the picture wondering the same thing, Move the pivot up near the deck , now you have much less of a problem of lever arm, because it has the room to move a lot more into the hull, and outside the hull - which means it can be longer if needed due loads.

 

Don't know why you would need winglets..... you have a large enough rudder + Main foil mast section to provide lateral resistance, and to resist roll from each other. Can't really see the big picture of why you would add winglets?

 

 

 

Share this post


Link to post
Share on other sites
33 minutes ago, dachopper said:

I was just looking at the picture wondering the same thing, Move the pivot up near the deck , now you have much less of a problem of lever arm, because it has the room to move a lot more into the hull, and outside the hull - which means it can be longer if needed due loads.

 

Don't know why you would need winglets..... you have a large enough rudder + Main foil mast section to provide lateral resistance, and to resist roll from each other. Can't really see the big picture of why you would add winglets?

 

 

 

The author seems to be talking about the case where wind changes are going to heel the boat more? or push it sideways more, and the comment about higher speeds downwind seems to be a different issue.

 

My 2 Cents is that a single foil needs to be trimmed to generate the target lift at target max speed. That way before the max speed either longitudinal Angle of attack, OR features like flaps or deploying 2 foils at once are able to boost the low wind AoA until they are retracted. Then you won't end up stuck at an uncontrollable elevator at max speed

 

 

Share this post


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

Really comprehensive, will take some time digesting it. It's the first time I see stability discussed taking into account the moment due to the sail's COE being so high up.

When he talks about a "fletner" on the stabilizer trailing edge, I assume he does not refer to Flettner Magnus-effect rotors, a trim tab perhaps?

Also, he seems sure transversal stability will require a winglet on each main foil  Wonder if there's something to be learned from kite foils on this

 

In german flettnerruder is synonymous with trim tab. Probably both rotor and tab from the same guy: Anton Flettner

Control-tab.png

Download.jpg

Trimmruder.png

Share this post


Link to post
Share on other sites

 

  ^ Thanks, K - servo tabs, then?

Winglets: haven't worked out whether leeway coupling with main foil would be positive or negative. But add them to the docking position section - ouch! Also, they'd increase max. width with foils raised

But mainly, unless I'm missing something Jean Sans still considers take-off at 16 kts, on equally loaded main foils. How can this be achieved other than on a dead run? The alternative (load on a single foil) would raise take-off speed to 23 kts!

Share this post


Link to post
Share on other sites

Jean tried to dig in the concept from the stability standpoint. The 16 knots minimum speed for take off is an input hypotesis and need VPP simulation to get confirmed. It is clearly an area that has to be studied on its own.

Regarding the foil mechanism keeping the levers within the Hull shape, it has also to be reviewed and may end with a 2 positions one: one for docking + one adjustable for sailing.

What is in the article are mostly thoughts around stability forseeing if it can work and how. There are still many studies and calculations to be run by the design teams and their computing power. So open to debate and further proposals...

Share this post


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

 

 But mainly, unless I'm missing something Jean Sans still considers take-off at 16 kts, on equally loaded main foils. How can this be achieved other than on a dead run? The alternative (load on a single foil) would raise take-off speed to 23 kts!

Just make sure the owner has deep pockets:

 

003.png

slatsandflaps.jpg

  • Like 1

Share this post


Link to post
Share on other sites
On 1/11/2018 at 4:01 AM, dachopper said:

I think a few people are going to be shocked with what can happen.

I know on the kite foilers in 5 to 6 kts wind speed, they are logging  25kts speed,  with 17-18 kts VMG upwind

In 5 to 6 kts

 

 

One area where the AC75 is going to blow the last boats out of the water is foil cant range. 

This is where the kiters are getting the amazing upwind performance, almost all lift changed to horizontal.

Foil trim surfaces is going to be the other game changer. Think elevons, this will be a game changer getting around the small ranges that the foils had last cycle. I had heard some amazing top numbers from ETNZ early in their game that never appeared during racing, probably due to the high takeoff speeds that true high speed foils entail. Smart control systems and elevons.

EDIT: i see that is being discussed now after i posted.

Share this post


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

Seems to me the pivot point might do better if it was raised to the sheer line rather than at the chine

Then you can't droop them vertical & you lose the monohull illusion.

Share this post


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

I imaginine they will also actively trim the lifted wing, to minimize resistance to the apparent wind?

AC75_JS_Foiler2.png

The more I look at the drawings, the more insane it looks to me...(guess no one  cares). Raising and lowering those 1750 kgs. 3mts obove the water seems nuts

Share this post


Link to post
Share on other sites
1 hour ago, jorge said:

The more I look at the drawings, the more insane it looks to me...(guess no one  cares). Raising and lowering those 1750 kgs. 3mts obove the water seems nuts

Don’t feel bad. If this is the actual idea, it’ll be a shit show that only Dougy will love. I feel so bad for his mom. The mess she’s going to have to clean up is going to get silly!

  • Like 1
  • Downvote 1

Share this post


Link to post
Share on other sites

these foils have small trim tabs, just like the elevators on the moth right?

i would imagine that the foils would have a locking mechanism in the raised/ lowered position, seeing as the trim tabs will be doing all the work in adjusting the lift of the foils

this would mean, similarly to the ac50, they could provide lift, both + and - to help the foils through the water reducing a lot of work to be done by the rams until maybe the final few degrees of getting the foil down, which would have to be controlled, then the foil would be locked off.

this seems to be the best idea in my mind but let me know if i'm making any mistakes

Share this post


Link to post
Share on other sites

Has any working boat been built with a lifting foil that had a hinge outside or at the edge of the hull? I guess you would say kanting keelers, but that is just the pivot point, not an actual hinge of some kind.

Share this post


Link to post
Share on other sites
1 hour ago, inebriated said:

these foils have small trim tabs, just like the elevators on the moth right?

i would imagine that the foils would have a locking mechanism in the raised/ lowered position, seeing as the trim tabs will be doing all the work in adjusting the lift of the foils

this would mean, similarly to the ac50, they could provide lift, both + and - to help the foils through the water reducing a lot of work to be done by the rams until maybe the final few degrees of getting the foil down, which would have to be controlled, then the foil would be locked off.

this seems to be the best idea in my mind but let me know if i'm making any mistakes

Here is another thought....

On Kite foilers, the foils are effectively fixed AoA before getting into the water. Balance is achieved through weight distribution fore and aft, in response to how the foil was setup in the first place, but the weight distribution is just changing the Angle of incidence and Rake of the entire underwater getup as one piece to achieve longitudinal stability. 

It would be easier I would have thought, to engineer either a single piece pivot foil, or split piece limited movement  pivot foil. A hinge inside the Main foil mast near the Leading edge, and internal torque tube near the aft edge.

The Lift / AoA curves of most of the foils lend themselves to numbers like a 5 degree change in angle of attack = 300% change in the amount of lift. So we are only talking small movements required to achieve stability over a massive speed range.... like 10 kt ( Two foils required ) , 20kts -  1 foil required at 5 AoA, 60 kts 1 foil required at 0 AoA. These same foils also have negligable change in Drag Coefficient in their design AoA brackets.

 

The other issue is 

Extremely basic, but weight movement to balance the pull of the kite, is minimized as the riders arms are moving in and out, but effectively holding an amount of pressure - which directly relates to kite lift. As gust hits, line tensions and bar moves out when arms are pulling at a certain pressure, that minimizes the board response needed for the abrupt changes in wind strength or direction - Board position changes in that respect are mainly to increase or decrease the ballast position in or out through lean angle + stance distance to foil, and again they are pretty small in size.  Maybe some kind of pressure trimming feedback mechanism / winches that hold line pressure set by the trimmer would be the simplest interpretation. 

Share this post


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

Here is another thought....

On Kite foilers, the foils are effectively fixed AoA before getting into the water. Balance is achieved through weight distribution fore and aft, in response to how the foil was setup in the first place, but the weight distribution is just changing the Angle of incidence and Rake of the entire underwater getup as one piece to achieve longitudinal stability. 

It would be easier I would have thought, to engineer either a single piece pivot foil, or split piece limited movement  pivot foil. A hinge inside the Main foil mast near the Leading edge, and internal torque tube near the aft edge.

The Lift / AoA curves of most of the foils lend themselves to numbers like a 5 degree change in angle of attack = 300% change in the amount of lift. So we are only talking small movements required to achieve stability over a massive speed range.... like 10 kt ( Two foils required ) , 20kts -  1 foil required at 5 AoA, 60 kts 1 foil required at 0 AoA. These same foils also have negligable change in Drag Coefficient in their design AoA brackets.

 

The other issue is 

Extremely basic, but weight movement to balance the pull of the kite, is minimized as the riders arms are moving in and out, but effectively holding an amount of pressure - which directly relates to kite lift. As gust hits, line tensions and bar moves out when arms are pulling at a certain pressure, that minimizes the board response needed for the abrupt changes in wind strength or direction - Board position changes in that respect are mainly to increase or decrease the ballast position in or out through lean angle + stance distance to foil, and again they are pretty small in size.  Maybe some kind of pressure trimming feedback mechanism / winches that hold line pressure set by the trimmer would be the simplest interpretation. 

ok, yeah

that wasn't quite what i was talking about i don't think, i was mainly addressing the issues of small lever arm and high loads to get the foil in/out of the water and keeping it in

for that, i was suggesting a locking mechanism and using positive and negative lift to get the blades up and down

interesting stuff though

i know that the ETNZ guys read this stuff, GD said hit himself, but i wonder if they've actually been influenced by what we have said and have made design changes because of it

 

Share this post


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

i would imagine that the foils would have a locking mechanism in the raised/ lowered position

Do canting keelers have one?

Share this post


Link to post
Share on other sites

Is it that different from a Moth ??

Trying to "reverse engineer" the rational behing this canting foil system, which, at first glance seems a bit complicated and not very "sailing friendly", finally I think it is not very different from the Moth, it just has been adapted to the size and the related constraints:

Mimicking  the Moth's central T foils system would have lead to a boat, very likely to fall windward in any lull.

With the hull volume windward of the active foil instead of above like for the Moth, in a lull, the hull is likely to touch the water before the rig, and that is probably better for the racing show.

Just my 2 cts

 

Cheers

Share this post


Link to post
Share on other sites

It seems to me that to be anywhere near cost effective for the participants these boats -especially the "swing" foil system- will have to be one design. If that's the case it is very disappointing because there are MUCH simpler(and equally effective) ways to do a monofoiler than with ballasted swing foils! If they give the teams the latitude to design their own system we could see real monofoiler development with "trickle down" potential.

NZAC ONE-
1) main foils: carbon ,unballasted and fully retractable for light air and in-the-water boat stowage. Foils as shown below allow light air takeoff(5-6mph wind). If that isn't desirable they could be smaller.
2) If racks were legal-and they probably should be-then this -as is- would be close. Otherwise they--- and buoyancy pods--could be eliminated(requiring a wider hull). Racks protect the boats and crew in the event of contact.
3) Keel ballast could be reduced by making keel cant but, to me, that is mostly additional complication that isn't required for foiling.


NZAC ONE     9-25-17  dl 002 - Copy.JPG

  • Downvote 2

Share this post


Link to post
Share on other sites
9 minutes ago, Doug Lord said:

It seems to me that to be anywhere near cost effective for the participants these boats -especially the "swing" foil system- will have to be one design. If that's the case it is very disappointing because there are MUCH simpler(and equally effective) ways to do a monofoiler than with ballasted swing foils! If they give the teams the latitude to design their own system we could see real monofoiler development with "trickle down" potential.

NZAC ONE-
1) main foils: carbon ,unballasted and fully retractable for light air and in-the-water boat stowage. Foils as shown below allow light air takeoff(5-6mph wind). If that isn't desirable they could be smaller.
2) If racks were legal-and they probably should be-then this -as is- would be close. Otherwise they--- and buoyancy pods--could be eliminated(requiring a wider hull). Racks protect the boats and crew in the event of contact.
3) Keel ballast could be reduced by making keel cant but, to me, that is mostly additional complication that isn't required for foiling.


NZAC ONE     9-25-17  dl 002 - Copy.JPG

imagining that it would be a bit tricky to match race doug?

Share this post


Link to post
Share on other sites

Not at all-certainly easier, simpler, less costly and more fun than the "swing foil" version....."NZAC ONE" was done way before the TNZ "swing foil" version so the hull would be shorter, the buoyancy pods could be eliminated as well as the racks. Max beam no greater than the swing foil version.

  • Downvote 1

Share this post


Link to post
Share on other sites
47 minutes ago, Doug Lord said:

Not at all-certainly easier, simpler, less costly and more fun than the "swing foil" version....."NZAC ONE" was done way before the TNZ "swing foil" version so the hull would be shorter, the buoyancy pods could be eliminated as well as the racks. Max beam no greater than the swing foil version.

So its a 75 foot version of the quant 23 ;)

https://www.2luxury2.com/european-yacht-of-the-year-2016-winners-prizegiving-at-boot-dusseldorf/quant-23-kielboot/

 

Share this post


Link to post
Share on other sites
12 minutes ago, dachopper said:

Sure, fairly close except for the hull, racks*, buoyancy pods* and pivoting foils.Definitely inspired by Hugh Welbourns's work... MUCH simpler, cheaper and easier to sail than the swing foil version! Can be sailed in light air with the main foils fully retracted(like the Quant 23).

* can be changed/removed (with some consequence for the hull shape)

  • Downvote 1

Share this post


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

imagining that it would be a bit tricky to match race doug?

Oh FFS, he's been posting and reposting that on multiple threads, often multiple times on the same page. It is irrelevant to the AC 36 and AC75 class.

If you must reply, please use a minimal quote (or none at all).

Share this post


Link to post
Share on other sites
7 hours ago, dachopper said:

It's a munge of Quant and KZ1 (27th AC in 1988). Already discussed, which would have been apparent had the poster linked to the previous discussion rather than trying to start it all over again.

KZ1 27-1988 sm.jpg

Share this post


Link to post
Share on other sites
42 minutes ago, RobG said:

It's a munge of Quant and KZ1 (27th AC in 1988). Already discussed, which would have been apparent had the poster linked to the previous discussion rather than trying to start it all over again.

 

No its not-not at all like KZ1 or any of the Quant boats-completely unique. The only things it has in common with the Quant boats are:

1) uses surface piercing foils that don't develop lateral resistance,

2) unique system allows complete retraction of the main foils for stowage and light air sailing.

3) inspired by Hugh Welbourns work with foils.

As to KZ 1- the flare in the hull in the NZAC ONE sketch would not be anywhere near as proportionately long(fore and aft) as the Kzed flare-in the latest version it would be much shorter-more like the strut on CQS but one forward and one aft on each side designed specifically to support the racks-should they be used.

The NZAC ONE concept is much less costly to develop than the swing foil version, much simpler to sail, and potentially nearly as fast since it sails on only two foils like the current version. 

  • Downvote 2

Share this post


Link to post
Share on other sites
42 minutes ago, RobG said:

Oh FFS, he's been posting and reposting that on multiple threads, often multiple times on the same page. It is irrelevant to the AC 36 and AC75 class.

If you must reply, please use a minimal quote (or none at all).

You're dead wrong: its extremely relevant since it is so much simpler that the "swing foil" renders put forward by TNZ.

  • Downvote 4

Share this post


Link to post
Share on other sites

More like this perhaps Doug? <_<

6.5-meter-trimaran-building-project-in-n

6.5-meter-trimaran-building-project-in-n

 

@RobG the original thread he made & multi-posted it on got nuked for reasons unknown shortly after the JC75 concept was announced.

Share this post


Link to post
Share on other sites

NZAC --simpler, less costly, easier to sail, safer, nearly as fast:

--two main foils-retractable-boat can sail w/o foils immersed for light air.

--single rudder t-foil-possibly rotatable to remove t-foil for light air

-- minimum ballast keel--for lateral resistance. Could be canting with adjustable keel pin axis.

NZAC ONE     9-25-17  dl 002 - Copy.JPG

NZAC revised deck plan     1-12-18 001.JPG

  • Downvote 3

Share this post


Link to post
Share on other sites

Doug, since the JC75 won’t be anything like your idea then why not wrap your brain around that instead?

What happens when the boat falls out of foiling speed with the ww foil lifted? It’s going to be radical, it deserves imagination.

Share this post


Link to post
Share on other sites

S, the more I've looked at the TNZ renders, the more convinced I am of the incredible complexity of the foil system. That seems like it will have to result in a one design foil system which is too damn bad. A simpler , less costly system and open design would potentially result in some trickle down tech which I don't believe will happen with the current version.

The current version is just way too complex and if you remember the design development saga of AC 35 that started out with the AC 62 and went to the 50 there is hope that at some point the new version could be simplified to be less like a War of the Worlds invader.

  • Downvote 2

Share this post


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

 

What happens when the boat falls out of foiling speed with the ww foil lifted? It’s going to be radical, it deserves imagination.

I guess they will try to keep a negative angle to the arm for better RM and positive to foil so that if they fall to ww they will try to rebound !

Share this post


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

Doug, since the JC75 won’t be anything like your idea then why not wrap your brain around that instead?

What happens when the boat falls out of foiling speed with the ww foil lifted? It’s going to be radical, it deserves imagination.

Which boat?

The trimaran Doug keeps on posting, or the foiling monohull concept ETNZ intends to use in AC36?

They have nothing in common, except both have foils and are wind powered.

Share this post


Link to post
Share on other sites
7 minutes ago, Doug Lord said:

That seems like it will have to result in a one design foil system which is too damn bad.

One-design system with freedom to design the foils & hull is much better than one-design hull with freedom to design structure & systems IMO.

I do side on the JC75 concept being overly complex though.

Share this post


Link to post
Share on other sites
On 9/13/2017 at 4:52 PM, GauchoGreg said:

For years, we have been hearing how most sailors sail monohulls, and because of the that, they can't relate to catamarans in the AC.  That most people are not interested because they can't put themselves in the shoes of those sailing the cats.  Anyone think that what they eventually come up with, if it is to be compelling at all, will end up being any more similar to what the EveryDayJoeSailor is familiar with than the foiling cats?  Either that, or we end up with boring as shit boats and crap racing where maneuvers are so heavily punished that the races end up being nothing more than drag races... but hey, they will be "sailors" on them.

It just seems as though the people making the decisions have lost their connection to what is important in exchange for some warped concept that they are going back to a more traditional boat/event.

Why have a crew at all?  You obviously want a drag race rather than a test of human skill.

Share this post


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

Why have a crew at all?  You obviously want a drag race rather than a test of human skill.

I think you missed the point of his post .

Share this post


Link to post
Share on other sites
16 hours ago, Doug Lord said:

It seems to me that to be anywhere near cost effective for the participants these boats -especially the "swing" foil system- will have to be one design. If that's the case it is very disappointing because there are MUCH simpler(and equally effective) ways to do a monofoiler than with ballasted swing foils! If they give the teams the latitude to deNZAC ONE     9-25-17  dl 002 - Copy.JPG

He who owns the gold makes the rules...when will you ever learns?!?!

Share this post


Link to post
Share on other sites

After Australia II victory in 1984, Alan Bond, who was obviously upset by Dennis "Conner fairplay", said that for the next cup in Freemantle, it will be mandatory for challengers to have their boats built from domestic industry and ressources, and all sails would have to be made from kangaroo skin.

Cheers

  • Like 2

Share this post


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

 

  ^ Interesting. Last question, they're in talks with a team, won't say which one. LR?

My guess too. 

In the recently posted Cammas interview he said they are paying no designers so far, only that Desjoyon (sp?) was toying around with ideas.

Rolf Vrolijk (sp?) is another guess of mine, for being included in the LR camp. 

Share this post


Link to post
Share on other sites
On 12/01/2018 at 1:56 AM, Monkey said:

Don’t feel bad. If this is the actual idea, it’ll be a shit show that only Dougy will love. I feel so bad for his mom. The mess she’s going to have to clean up is going to get silly!

:P

Share this post


Link to post
Share on other sites
On 1/12/2018 at 11:35 PM, Justaquickone said:

I think you missed the point of his post .

I think you missed MY point.  And you neglected to state your reasons..have any?

 

Share this post


Link to post
Share on other sites
20 minutes ago, Tornado-Cat said:

Yep, AC34 and 35 boats were faster than kites on a circuit, w'ill see if it's the case with AC36

The JC75’s may hit top speeds above the AC72s and AC50s in wind above 18 knots but will beat kites only if they don’t capsize while trying!

Share this post


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

The JC75’s may hit top speeds above the AC72s and AC50s in wind above 18 knots but will beat kites only if they don’t capsize while trying!

There was a lot more potential in both the AC72s and the AC50s .. How much faster would ETNZ's AC50 be if they had more time to make stronger foils or even learn how to sail their boat.

  • Like 2

Share this post


Link to post
Share on other sites
35 minutes ago, Terry Hollis said:

There was a lot more potential in both the AC72s and the AC50s .. How much faster would ETNZ's AC50 be if they had more time to make stronger foils or even learn how to sail their boat.

Yes, and I think the NextGen AC50’s will be even faster.

They will also be safer than FirstGen JC75’s, probably. Can you imagine a pitchpole or a windward capsize on one of these freaks? Yikes!

Share this post


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

Yes, and I think the NextGen AC50’s will be even faster.

They will also be safer than FirstGen JC75’s, probably. Can you imagine a pitchpole or a windward capsize on one of these freaks? Yikes!

I am not so sure about the safety angle .. certainly if the windward boat does not keep clear it could get messy but having a bit of ballast under the hull will limit the chances of pitchpole and I can't see how you could capsize to windward .. the leeward foil will provide a decent restoration moment if it lifts out of the water.

Share this post


Link to post
Share on other sites
14 hours ago, oobilly said:

I think you missed MY point.  And you neglected to state your reasons..have any?

 

GG never expressed anything regarding autonomous sailing . It was more about the perception that the AC 50s were just  drag racers and yet the JC 75s look 

to be even more heavily inclined to that style of racing .

But  at least it resembles a monohull .

Isn't that what its all about ?

Share this post


Link to post
Share on other sites
On 1/12/2018 at 6:39 PM, dachopper said:

Here is another thought....

On Kite foilers, the foils are effectively fixed AoA before getting into the water. Balance is achieved through weight distribution fore and aft, in response to how the foil was setup in the first place, but the weight distribution is just changing the Angle of incidence and Rake of the entire underwater getup as one piece to achieve longitudinal stability. 

It would be easier I would have thought, to engineer either a single piece pivot foil, or split piece limited movement  pivot foil. A hinge inside the Main foil mast near the Leading edge, and internal torque tube near the aft edge.

The Lift / AoA curves of most of the foils lend themselves to numbers like a 5 degree change in angle of attack = 300% change in the amount of lift. So we are only talking small movements required to achieve stability over a massive speed range.... like 10 kt ( Two foils required ) , 20kts -  1 foil required at 5 AoA, 60 kts 1 foil required at 0 AoA. These same foils also have negligable change in Drag Coefficient in their design AoA brackets.

 

The other issue is 

Extremely basic, but weight movement to balance the pull of the kite, is minimized as the riders arms are moving in and out, but effectively holding an amount of pressure - which directly relates to kite lift. As gust hits, line tensions and bar moves out when arms are pulling at a certain pressure, that minimizes the board response needed for the abrupt changes in wind strength or direction - Board position changes in that respect are mainly to increase or decrease the ballast position in or out through lean angle + stance distance to foil, and again they are pretty small in size.  Maybe some kind of pressure trimming feedback mechanism / winches that hold line pressure set by the trimmer would be the simplest interpretation. 

you forgot the big advantage the kiters have is to fly patterns/loops that influence apparent wind angle..never gonna get that with a sail. watched a top 10 foiler last week tack with no loss of speed, or ride height, and huck himself 10m into the air when board with no problem at all. Foil kiting dev is moving fast.

Share this post


Link to post
Share on other sites
7 hours ago, Justaquickone said:

GG never expressed anything regarding autonomous sailing . It was more about the perception that the AC 50s were just  drag racers and yet the JC 75s look 

to be even more heavily inclined to that style of racing .

But  at least it resembles a monohull .

Isn't that what its all about ?

Im not a foiler.... thats just the sport trying to get the public to watch. Fails everytime they try it.

Until the races make sense to a layman it wont ever fly... and until then,  it just upsets the traditional diehards who are 80% of the audience. 

Whoever led around the first mark won it ...thats a drag race. 

The AC needs to realize they arent the top trophy in the sport and havent been since the first cat appeared.

 

Share this post


Link to post
Share on other sites
17 hours ago, Tornado-Cat said:

Yep, AC34 and 35 boats were faster than kites on a circuit, w'ill see if it's the case with AC36

I can't help but wonder, ...... The kite foils that guys are now riding, and the Race kites would decimate that thing Bryan rode against the ac72 5 years ago..... Which is why no0one competes with tube kites on race circuits any more = guaranteed loss.

 

17 / 18kts upwind VMG in 5 - 6 kts........ I don't think the AC72 would stand a chance until the wind was cranking.....  actually after checking, it appears that 17/ 18kts is the VMG max upwind displayed on the AC72 polars, in 20 + kts

Share this post


Link to post
Share on other sites
4 hours ago, oobilly said:

Im not a foiler.... thats just the sport trying to get the public to watch. Fails everytime they try it.

Until the races make sense to a layman it wont ever fly... and until then,  it just upsets the traditional diehards who are 80% of the audience. 

Whoever led around the first mark won it ...thats a drag race. 

The AC needs to realize they arent the top trophy in the sport and havent been since the first cat appeared.

 

Sorry you feel that way .

The AC has always been about building a faster boat than your competitor .

Im still hoping that the new boats are an advancement on the previous in terms of speed and raceability .

Peddling hampsters or pedastool  hamsters it's a boat race that I'm still going to watch .

Share this post


Link to post
Share on other sites

Alex Caizergues 57.97 kts , non-foiling, inflated leading edge. 14/11/17 youtube

sails on sticks will never keep up to kites.

found some polars here of foilers in light winds 8-10kt..15kt VMG up and perhaps 22 down wind.

The foilers would kill the AC72 in 20kt. The author says "In more breeze even the local lads in Perth are doing 20knots VMG upwind and 25+ VMG downwind. "

 

Share this post


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

Alex Caizergues 57.97 kts , non-foiling, inflated leading edge. 14/11/17 youtube

sails on sticks will never keep up to kites.

but the thing that you're not taking into account is that every AC boat has had to perform manoeuvres and be a course racer

the boys that set the kite speed record have asymmetrical boards and optimised, custom made lakes to set these records on

look at the Vestas sail rocket, blew the kites out of the water

i'd say that the AC50 could get into high 50's too if they modified the boat for straight line high speed records

Share this post


Link to post
Share on other sites
6 hours ago, Justaquickone said:

Sorry you feel that way .

The AC has always been about building a faster boat than your competitor .

Im still hoping that the new boats are an advancement on the previous in terms of speed and raceability .

Peddling hampsters or pedastool  hamsters it's a boat race that I'm still going to watch .

you're talking out of your butt i see...

Ted turner never built a boat...he won in Courageous. So no it was only in the 80's that new boats were being built. 

I was there on the water watching him and hood battle it out...although not much of a battle really. Turner was that good.

I have met Ted hood and my Dad won the 1973 one ton cup with him in Sardinia. One of the only races they beat Turner was in the marblehead halifax race.

So back to my comment and why I said what I said. If the boat is the deal..then you should just race remote control boats with lots of algorithms. But if you believe sailors make a difference then why not test for that.

Study the history before you spout nonsense.

  • Downvote 1

Share this post


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

but the thing that you're not taking into account is that every AC boat has had to perform manoeuvres and be a course racer

the boys that set the kite speed record have asymmetrical boards and optimised, custom made lakes to set these records on

look at the Vestas sail rocket, blew the kites out of the water

i'd say that the AC50 could get into high 50's too if they modified the boat for straight line high speed records

Agreed, AC50's are heavily rule bound, they are nowhere near their maximum potential.

With modifications outside of the AC50 rule set they would definitely be faster than now even as manauverable course racers, heck if they just had movable ballast that would probably be enough to increase their speed significantly, throw in control surfaces, throw out foil size, shape and usage limitations , throw out all the minimum requirements for weight, balance, centre of mass etc...  Throw out the rules around rig size, shape, number of elements etc, etc... Throw out the rules around what you can and cannot aero shape.

Yeah there would be plenty of go fast modifications left on an AC 50 if you really wanted to do it, no idea what the maximum speed possible would be, but they certainly aren't there with the current setup (although they may be close to the maximum within the rule set).

Share this post


Link to post
Share on other sites
On 13/01/2018 at 9:01 AM, Doug Lord said:

S, the more I've looked at the TNZ renders, the more convinced I am of the incredible complexity of the foil system. That seems like it will have to result in a one design foil system which is too damn bad. A simpler , less costly system and open design would potentially result in some trickle down tech which I don't believe will happen with the current version.

The current version is just way too complex and if you remember the design development saga of AC 35 that started out with the AC 62 and went to the 50 there is hope that at some point the new version could be simplified to be less like a War of the Worlds invader.

It's actually not that complex, you just aren't smart enough to wrap your head around it.

You claim to be capable of understanding the fact people cant 10 tonne bulbed keels, but cannot understand canting a 1.5 tonne foil.

A rule being too complicated for Doug to understand is hilarious. Can anyone else wait for how stupid this shit he says is going to get this time around? 

Doug, Team USA changed the rule because they were afraid of being beaten by TNZ and Luna Rossa, so they made it 1 design, and claimed that the reduction to 50' was about cost saving and would bring in more teams, but they only did it so they didn't get beaten by as much. There is no hope this will be reduced in size, because the people in charge want big monohulls, that look like traditional monohulls on a mooring. They don't want multiple hulls, bouyancy pods, Q foils, reverse shapes in the hulls (they want literally the opposite of your drawing).

They want something that looks like this does on a mooring.

admin-ajax1.jpg

But sails like this.

yandy73174.jpg

  • Downvote 1

Share this post


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

 

Doug, Team USA changed the rule because they were afraid of being beaten by TNZ and Luna Rossa, so they made it 1 design, and claimed that the reduction to 50' was about cost saving and would bring in more teams, but they only did it so they didn't get beaten by as much. There is no hope this will be reduced in size, because the people in charge want big monohulls, that look like traditional monohulls on a mooring. They don't want multiple hulls, bouyancy pods, Q foils, reverse shapes in the hulls (they want literally the opposite of your drawing).

 

what the fuck are Q foils?? hahaha

Share this post


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

you're talking out of your butt i see...

Ted turner never built a boat...he won in Courageous. So no it was only in the 80's that new boats were being built. 

I was there on the water watching him and hood battle it out...although not much of a battle really. Turner was that good.

I have met Ted hood and my Dad won the 1973 one ton cup with him in Sardinia. One of the only races they beat Turner was in the marblehead halifax race.

So back to my comment and why I said what I said. If the boat is the deal..then you should just race remote control boats with lots of algorithms. But if you believe sailors make a difference then why not test for that.

Study the history before you spout nonsense.

Lets see if i get this right .

1974 defence ,Turner on Mariner [ inferior boat ,inferior sails ] Vs Hood on Courageous [superior boat ,superior sails] - Courageous Wins.

Courageous white washes Southern Cross  in the Match [ inferior boat ,inferior sails]  - Fastest boat Wins .

Turner buys Courageous ,Hood largely copies and try's to improve with Independence .

1977 Defence ,Courageous [ similar boat , superior sails ] Vs Independence [similar boat , inferior sails , plus poor sail selection ] - Courageous Wins .

Courageous white washes Australia in the Match [ inferior boat , inferior sails ] - Fastest boat Wins .

By the way Courageous is my all time favourite 12 metre yacht .

Still looks fantastic even with guard rails on .

Share this post


Link to post
Share on other sites