13320 replies to this topic

[~HHN92~]

Nice vid...

3:28-3:34 certainly shows level controled foiling, so the nay sayers should just move on.

This after what i would call 2 days of real testing with real gear in real breeze!

You can really see the leeward hull pumping while up on that foil. Part of the control system, maybe? It was moving quite a bit and at a high rate to my eye.

[Chris UK]

To all those that said it wouldn't foil........never mind.

Well done OR!

[Robin Wasa 55]

Hmm, lucky coincidence that the daggerboard/foils from DZ was close to the same size as the AC72 required! But sure that must count as new board? Even if the tip is from the board they broke, that must be alot less then 50% of the total board? Even more so if they are gonna change the tips Good idea though about changing tips!

Did we actually see any pics or video of them foiling on the port(original) board? Maybe they dont think its strong enough.

When I saw the video of the bow flexing/fluttering up and down when foiling, it kinda made me think the lee hull takes up all the "bumps in the road", so the rig stays more stable. I just watched the highlights from AC33, and it looks a bit like the same thing with DZ vs Cheesezilla, CZ was hobbyhorsing a lot more, atleast the rig was. Perhaps that is a plus with the twist?

I think it feels like the angle of attack of the foils should change alot if the whole lee hull is changing trim so much and fast? Then again, look at the wings of commercial jet airliner, they bend alot, and still retain flow I guess.. not the same thing, but still Or perhaps its just like jhc said above, trimming the board create some feedback in the whole hull.

[fubaru]

There is a moment in the video when the lee bow oscillates vertically. Appears that the foil trim is being adjusted, and is causing the bow trim oscillation.

If you're referring to 3:27-3:34, I don't believe the movement is regular enough to be an oscillation. My guess is that the lift generated by the rudder foil is varying due to air bubbles in the disturbed water behind the main board.

We already knew the hulls flexed a lot, I'm blown away by how fast it happens

[Tornado-Cat]

Great to see Or foiling, it will be an amazing match.
Still, both teams have a long way to go and about a year to do so.
TZ has to work on transitions and OR on stabilizing the boat first.
IMO, (to come back to a previous debate) OR will sail like TZ : different foils but flat on the water, closer than the pictures we have seen, and with...both rudders in the water, not so much for the righting moment than because foils are designed to have the boats foil flat.

Discussion reopened .

[maxmini]

Great to see Or foiling, it will be an amazing match.
Still, both teams have a long way to go and about a year to do so.
TZ has to work on transitions and OR on stabilizing the boat first.
IMO, (to come back to a previous debate) OR will sail like TZ : different foils but flat on the water, closer than the pictures we have seen, and with...both rudders in the water, not so much for the righting moment than because foils are design to have to boats foil flat.

Discussion reopened .

You got up on the good side of the bed this morning .

I agree with everything you said especially about a long way to go for all concerned. It will make for much company time spent on sailing sites like this one for all concerned

[Dixie]

The shuddering / flex in the platform at 3.32 when foiling looks pretty damn scary !

Watching from the webcam last night they did quite a lot of the extreme bow-up then crashing back down motion - foiling yes but some way to go yet to make it look really effective.

Doesn't really show on the video but I was staggered how much faster she was than the 45's and how much bigger - covered a huge amount of ground incredibly quickly and dwarfed the 45's even when a long way in the distance.

Welcome to SA.

I watched from up on a hill and the difference between the boats mast height and platform size was staggering. And the speed...they were going loads faster than the 45s. I was surprised the shots from yesterday didn't exhibit that but expect today's sail will also incorporate some helo shots and we'll get a real feel for size comparison in photos and video.

[Steve Clark]

The extensions at the bottom of the wing are probably measured as part of the wing.
The top surface of the center structure will have to have some give to it to prevent the wing from binding up and being crunched as everything moves about.Inflating a bit is a nice simple way to do this at minimum weight.
To reiterate class rule 7.2
"No part of cross structure, including fairings or other surfaces, shall move (translate or
rotate about any axis) or be adjusted relative to any other part of the cross structure,
except for normal deflections caused by sailing loads."
This precludes trimming the black thing, but that isn't much of a problem given that the wing is going to spend 90% of it's time on center line and that something can be less than ideal and still be helpful.
I think the same rule precludes applies to active control of the platform twist.

My first impression is that these sailors have huge stones. I have flung cats that are 1/3 that big into the air and had to return to base for cocktails and a change of undies. Given the size of these things it's like learning to fly on a 747, but with half of the flaps disabled. Fun and frightening at the same time. An unbeatable way to spend the day. Larry is making at least some people very happy.
SHC

[Hemi]

Wow, suddenly that twisting looks to me very intentional. To my completely untrained eyes, it looks like the rig is locked in place and the leeward hull is working like a shock absorber.. but then again, shouldn't foils just cut straight through the bumps? Right or wrong, what ever is happening at 3:30 is very different from ETNZ.

Also, is it possible those inflatable white tubes are simply for safety?

[Doug Lord]

The extensions at the bottom of the wing are probably measured as part of the wing.
The top surface of the center structure will have to have some give to it to prevent the wing from binding up and being crunched as everything moves about.Inflating a bit is a nice simple way to do this at minimum weight.
To reiterate class rule 7.2
"No part of cross structure, including fairings or other surfaces, shall move (translate or
rotate about any axis) or be adjusted relative to any other part of the cross structure,
except for normal deflections caused by sailing loads."
This precludes trimming the black thing, but that isn't much of a problem given that the wing is going to spend 90% of it's time on center line and that something can be less than ideal and still be helpful.
I think the same rule precludes applies to active control of the platform twist.

My first impression is that these sailors have huge stones. I have flung cats that are 1/3 that big into the air and had to return to base for cocktails and a change of undies. Given the size of these things it's like learning to fly on a 747, but with half of the flaps disabled. Fun and frightening at the same time. An unbeatable way to spend the day. Larry is making at least some people very happy.
SHC

=========================
Thanks, Steve. We've seen many pictures showing the Oracle platform very twisted. Seems to me if they can't control the twist BUT can predict it (and maybe set it for what they want) then the picture of Oracle foiling with no twist and the windward rudder in the water must illustrate that the windward rudder is pulling the stern down eliminating twist?
heres the no twist foiling pix by Guilain Grenier: (click on photo)

Attached Files

•  AC 72 oracle flying 10-2 guilain grenier.jpg   102.49K   155 downloads

[Psychowax]

Looks a way scarier ride than TNZ!

[pjh]

Given yesterday's photos, it's pretty clear to me that the inflatable structure is an end plate for the wing.

[NorCalHater]

I bet they are using the hull and platform deflection to control the angle of attack on the rudder foil.

Just a guess, but I would say there is something inside that pod that is controlling the amount of platform twist, and there is some automatic devise that is working that control.

Much like the wand on the front of a moth controlling the rudder foil.

[maxmini]

Wow, suddenly that twisting looks to me very intentional. To my completely untrained eyes, it looks like the rig is locked in place and the leeward hull is working like a shock absorber.. but then again, shouldn't foils just cut straight through the bumps? Right or wrong, what ever is happening at 3:30 is very different from ETNZ.

Also, is it possible those inflatable white tubes are simply for safety?

It might just be possible that Oracle engineers may have known what they were doing after all as hard as the SA flexoligists will find that to beleive . What a " surprise " that would turn out to be . There is a reason while some get paid to do and others get to snipe for free Lots more fun and games to come !

[buckdouger]

The extensions at the bottom of the wing are probably measured as part of the wing.
The top surface of the center structure will have to have some give to it to prevent the wing from binding up and being crunched as everything moves about.Inflating a bit is a nice simple way to do this at minimum weight.
To reiterate class rule 7.2
"No part of cross structure, including fairings or other surfaces, shall move (translate or
rotate about any axis) or be adjusted relative to any other part of the cross structure,
except for normal deflections caused by sailing loads."
This precludes trimming the black thing, but that isn't much of a problem given that the wing is going to spend 90% of it's time on center line and that something can be less than ideal and still be helpful.
I think the same rule precludes applies to active control of the platform twist.

My first impression is that these sailors have huge stones. I have flung cats that are 1/3 that big into the air and had to return to base for cocktails and a change of undies. Given the size of these things it's like learning to fly on a 747, but with half of the flaps disabled. Fun and frightening at the same time. An unbeatable way to spend the day. Larry is making at least some people very happy.
SHC

3:22 A good view of a different gap filling section down to the deck/endplate under the wing.
 Gap filler.jpg   75.88K   364 downloads

[Doug Lord]

I bet they are using the hull and platform deflection to control the angle of attack on the rudder foil.

Just a guess, but I would say there is something inside that pod that is controlling the amount of platform twist, and there is some automatic devise that is working that control.

Much like the wand on the front of a moth controlling the rudder foil.

---------------------
Read what Steve Clark says-he thinks it would be illegal to "control" twist-but I think they could predict twist and allow it for a specific purpose like causing the windward rudder to pull down. Just for the sake of clarity, the wand on a Moth controls the flap on the main foil .

[us772]

Looks about 1 second off a massive face plant!

Doug.
1. Glad you can see the guy with the 'joystick' - I certainly can't make him out?

2.1 Twisting pod to align with the wing...? Helllloooo?


But seriously, the inflated thing, while technically cool, makes a complete mockery of the wing measurement rules. Sail area is sail area, and if something not attached to the wing increases the measured area of the wing by even 1cm2, then it is wrong.

It's the Americas Cup I guess. He who has the cup makes the rules.

I don't see how you consider a static end plate as sail area. It does nothing to for propulsion although it cuts tip vortex AKA drag.

[nav]

The extensions at the bottom of the wing are probably measured as part of the wing.
The top surface of the center structure will have to have some give to it to prevent the wing from binding up and being crunched as everything moves about.Inflating a bit is a nice simple way to do this at minimum weight.
To reiterate class rule 7.2
"No part of cross structure, including fairings or other surfaces, shall move (translate or
rotate about any axis) or be adjusted relative to any other part of the cross structure,
except for normal deflections caused by sailing loads."
This precludes trimming the black thing, but that isn't much of a problem given that the wing is going to spend 90% of it's time on center line and that something can be less than ideal and still be helpful.
I think the same rule precludes applies to active control of the platform twist.

My first impression is that these sailors have huge stones. I have flung cats that are 1/3 that big into the air and had to return to base for cocktails and a change of undies. Given the size of these things it's like learning to fly on a 747, but with half of the flaps disabled. Fun and frightening at the same time. An unbeatable way to spend the day. Larry is making at least some people very happy.
SHC

3:22 A good view of a different gap filling section down to the deck/endplate under the wing.
 Gap filler.jpg   75.88K   364 downloads

Yeah but not nearly as good as this one already posted. (although yours shows the internal structure of the collar better)



And can we put this to bed, the deck - it's not inflated, it doesn't move....



It just has two 'D' shaped air-bags strapped to the sides - ok. Jesus!

[rule69]

It just has two air-bags strapped to the sides - ok. Jesus!

Are the airbags just strapped to the sides or do they support the deck?

[Xlot]

^^
The entire deck top flips open - for unexplained reasons

[wkd928]

They only seemed to be foiling proper on the stbd bastardised foil. Interesting the way the leeward hull pogos over the waves.

[Koukel]

The extensions at the bottom of the wing are probably measured as part of the wing.

My first impression is that these sailors have huge stones.

Oh, duh. Measured. If you have too much power, why not bring it down low and help the transitions?. Thank you for saing the obvious out loud so I can get it too.

As to you other point; stones the size of Toyota Corollas.

Koukel

[buckdouger]

They only seemed to be foiling proper on the stbd bastardised foil. Interesting the way the leeward hull pogos over the waves.

Seems like both starboard and port boards are different. Earlier in the video they show shots of the port board up close, and it is the smooth radius transition between the horizontal and vertical portions of the foil. At 3:23 the port side board is definitely not the same.

[maxmini]

They only seemed to be foiling proper on the stbd bastardised foil. Interesting the way the leeward hull pogos over the waves.

Seems like both starboard and port boards are different. Earlier in the video they show shots of the port board up close, and it is the smooth radius transition between the horizontal and vertical portions of the foil. At 3:23 the port side board is definitely not the same.

Testing two concepts at once . Benefit of a cat , " two " boat testing with one boat Time well spent !

[Koukel]

Wow, suddenly that twisting looks to me very intentional. To my completely untrained eyes, it looks like the rig is locked in place and the leeward hull is working like a shock absorber.. but then again, shouldn't foils just cut straight through the bumps? Right or wrong, what ever is happening at 3:30 is very different from ETNZ.
Also, is it possible those inflatable white tubes are simply for safety?

Flex is good, flex is good, just ask your knees.

Don's point sounds right to me too, but these boats are crazily overpowered and in that case a little slop just sounds like one team's way to sail fast.
Me

Or ask me. The leeward hull looks like it's on shock absorbers going over those whoop dee doos... I mean swells.

Koukel

[nav]

^^
The entire deck top flips open - for unexplained reasons

Come on now - we got a photo on unveiling day that looked like that, sure. A large sheet of white material being canted up from the deck.
First and last time seen though AFAIK. Could have been the underside of the open deck, but I see no sign of, or reason for it to open under normal conditions.
Unless you believe the pod is loaded with ultra high tech gadgets of course.

[bruno]

might be nice to have different modes on a racing boat.
if you are overpowered then drag rduction is your priority for speed increase.
impressive, resourceful team, not just throwing money at it in shock'n'awe mode, sophisticated solutions.

[rule69]

^^
The entire deck top flips open - for unexplained reasons

Right. But I'm still not getting if the deck is supported by them when in the down position or if they are just add-ons. The deck looks pretty solid with all those folks on it. I wonder if the pod thing could deflect air into the deck plus inflatable skirts to raise the the whole thing up enough to keep the gap closed but with enough give to allow movement...

[Indio]

Wow so reworked Dogzilla boards
Makes sense.

There are a few seconds of fairly stable foiling there from 3:27 -> 3:34, leeward hull seemingly twisting for wave following?

The replaceable tips are a nice way around the limited daggerboard rule . Less than 50% changed its still the same board who wrote than rule anyway ? Oh ya

Here we go again. When does you boat have to measure in? What can you change without getting it remeasured. All the rule sections have been quoted but there's no consensus on how that will work in reality.

They certainly appeared to replace more that 50% to get to the finished board in the video - so that frankenstein foil is number three of ten.


Maybe the other teams/the measurers will let them get away with what you suggest, but then again??

You're correct. The foils get "measured in" before they're ever allowed on the boat, and this one would certainly be 3 of 10. However, the next tip they put on it, and the next, and the next won't count unless they're more than 50% of the foil.

You get the point I was trying to make . The tips won't count . As to how much of the board was changed for the repair , exterior finish does not count . If 50% of the original construction remains its still the old board .

29.7b a Daggerboard shall be deemed to be new if more than 30% of its mass is replaced.

They're on 3 of 10.

[Xlot]

Indio - that's old. It's 50% now.

But yes they are on 3 of 10 anyway - since they stole the entire vertical part from Dogzilla.

This hack brought to you by Tugboat and crew.

But wouldn't it be symmetrical then?

[buckdouger]

Indio - that's old. It's 50% now.

But yes they are on 3 of 10 anyway - since they stole the entire vertical part from Dogzilla.

This hack brought to you by Tugboat and crew.

But wouldn't it be symmetrical then?

Initially 17 was launched with two mirrored L boards with a radius at the corner. Let's call the port one [1] and starboard [2]. They broke [2], and replaced it with the modified trimaran board, call that [3]. In the video, after 3:23 and earlier, there is a different port-side board visible with a sharp corner and a bulb shape at the corner. Wouldn't that make it board [4] (of 10)?

[nav]

I was hoping I got away with deleting that post - cause you were right about the 30%. Was it the wing they changed from 30 to 50% then?
Anyway sorry about that.

The torpedo and sharp corner sound exactly like the repaired board.

Here's 1 & 2...


here's No.3 Starboard Frankenstein being assembled


The same one AFAIK in action a few days ago


No. 4 of ten yesterday?

[Xlot]

Initially 17 was launched with two mirrored L boards with a radius at the corner. Let's call the port one [1] and starboard [2]. They broke [2], and replaced it with the modified trimaran board, call that [3]. In the video, after 3:23 and earlier, there is a different port-side board visible with a sharp corner and a bulb shape at the corner. Wouldn't that make it board [4] (of 10)?

You're right! Are they mixing shots from the two days then?

[Indio]

Initially 17 was launched with two mirrored L boards with a radius at the corner. Let's call the port one [1] and starboard [2]. They broke [2], and replaced it with the modified trimaran board, call that [3]. In the video, after 3:23 and earlier, there is a different port-side board visible with a sharp corner and a bulb shape at the corner. Wouldn't that make it board [4] (of 10)?

You're right! Are they mixing shots from the two days then?

Disinformation...

[buckdouger]

I was hoping I got away with deleting that post - cause you were right about the 30%. Was it the wing they changed from 30 to 50% then?
Anyway sorry about that.

The torpedo and sharp corner sound exactly like the repaired board.
Can you post photos of all the boards you have seen?

Here's No.3 Starboard Frankenstein

Here is [4], [1], and [2]

Attached Files

•  foils 1 2 4.jpg   101.61K   66 downloads

[pjh]

It looks like both port and starboard boards were the "torpedo joint" type.

Here are bunch of photos from yesterday.

[maxmini]

Indio - that's old. It's 50% now.

But yes they are on 3 of 10 anyway - since they stole the entire vertical part from Dogzilla.

This hack brought to you by Tugboat and crew.

But wouldn't it be symmetrical then?

Initially 17 was launched with two mirrored L boards with a radius at the corner. Let's call the port one [1] and starboard [2]. They broke [2], and replaced it with the modified trimaran board, call that [3]. In the video, after 3:23 and earlier, there is a different port-side board visible with a sharp corner and a bulb shape at the corner. Wouldn't that make it board [4] (of 10)?

Is it a board change or a tip change or is it too early for that ? Its going to be tricky keeping count on that but they wont need to resort to that until much later ,if at all .

[Doug Lord]

It looks like both port and starboard boards were the "torpedo joint" type.

Here are bunch of photos from yesterday.

==================
Thanks for these. Some of them from aft look like the stb daggerboard is more vertical than the port board-anybody else notice that?

[nav]

The original port board, No.1, could have been modified to match No.3 - with a torpedo and removable tip, but without changing more than 30%, so it is not a fourth foil.
So now it's No. 1.1.

[Sparbuilder]

The footage from 3:28 TO 3:33 on this video is how I expect Batzilla to be designed to fly. The way she rides through the waves, leeward hull moving(pitching) with the wave action acting like a suspension system, while the rig and the windward hull(with the rudder out of the water) rides very smoothly and stable. Like a high end luxury car with a sophisticated suspension system riding over a very uneven road surface. INCREDIBLE!!! That simply can't be a coincidence.

Batzilla foils in a very different manner than the TNZL boat. No idea which concept will prove faster in the end, but personally I favor the "Hollywood" boat! That's some cutting edge design work... If they can manage to handle flying this beast on single foil and single rudder, along with the ultra clean Aero work in the platform, I presume they should have the drag advantage both above and below the water.

Bring on Artemis... They appear to be using a totally different foiling arrangement, presumably a surface piercing single main foil/double rudder flat foiler. They seem to have more areo details on the planform than TNZL, but I would venture a guess not as developed as Batzilla and with what I presume would be a higher drag foil setup. WAY too early to tell mind you.

Batzilla is looking pretty good from a technological prespective from where I am sitting...

SB

[buckdouger]

The original port board, No.1, could have been modified to match No.3 - with a torpedo and removable tip, but without changing more than 30%, so it is not a fourth foil.
So now it's No. 1.1.

That is possibly true, but assuming it was the same design as what we are calling [2], and considering where [2] broke, they may not have wanted to replace its tip only, and it may be that bolstering its construction further up the long portion would tip the mass past the 30% amount.

[Tornado-Cat]

We should remember that OR has NEVER been able to control the flight of their L foils up to now, as far as we could hear with the AC45. They have a year to do it.
Waiting to see Artemis new system.

[eric e]

GREAT! video on so many levels

keep'em up

the wave following flex during the foiling facinating

[~Stingray~]

That video Renn posted effing rocks in all kinds of ways. - Yowza!

+1 on how cool the replaceable tips move was. Sounds like they had (close to me) Janicki do the trick? Very cool too.

Early to say what its best foiling attitude will be, ultimately. Speedwise they must surely have reached into the 30's when they flew, that boat is balls-out there for a good ten seconds.

Am getting Bat Cat Fever!

[knarly34]

Quite cool

I do observe how flimsy the boat looks but what do I know?

ETNZ = Rock Solid
OR = Balsa Wood

[KiwiJoker]

The extensions at the bottom of the wing are probably measured as part of the wing.
The top surface of the center structure will have to have some give to it to prevent the wing from binding up and being crunched as everything moves about.Inflating a bit is a nice simple way to do this at minimum weight.
To reiterate class rule 7.2
"No part of cross structure, including fairings or other surfaces, shall move (translate or
rotate about any axis) or be adjusted relative to any other part of the cross structure,
except for normal deflections caused by sailing loads."
This precludes trimming the black thing, but that isn't much of a problem given that the wing is going to spend 90% of it's time on center line and that something can be less than ideal and still be helpful.
I think the same rule precludes applies to active control of the platform twist.

My first impression is that these sailors have huge stones. I have flung cats that are 1/3 that big into the air and had to return to base for cocktails and a change of undies. Given the size of these things it's like learning to fly on a 747, but with half of the flaps disabled. Fun and frightening at the same time. An unbeatable way to spend the day. Larry is making at least some people very happy.
SHC

Steve, most of the fascinating exchanges on this thread are way above my technological pay grade but all this stuff is must-see reading non-the-less. This post is a keeper. You've confirmed much of my intuitive observations but I continue to wonder about the white thing. Nav thinks it's fixed, someone else said it was simply a cushioned area to minimize broken bones when (if) they go arse over teakettle. I'm inclined towards the fixed/cushion camp although I like your idea that it may incorporate some platform flexibility to accommodate movement when they extend the measured area of the wing down to create an optimum endplate effect. Anyone got photo evidence that the platform is fixed?

[coxcreek]

That leeward hull oscillation looked real ugly to me - and it was not from some manual operating crew slipping on his urine, looked too fast, and more like a typically slack hull/beam connection being activated by an out of control foil. If not that, then it is an insufficiently stiff platform. Also if it continues during a race leg, the foil will be SLOW. Imagine it fluttering the same as the bow hull sections were in the video, will be distorted and dragging. Might as well hand the cup over now ... to the Kiwi wool shed mob camped on shore (which is the apparent alternative with the latest news).

[nav]

KJ Post #2018 for one.

The repetition is painful though - and not just to me I'm sure!

[familysailor]

Initially 17 was launched with two mirrored L boards with a radius at the corner. Let's call the port one [1] and starboard [2]. They broke [2], and replaced it with the modified trimaran board, call that [3]. In the video, after 3:23 and earlier, there is a different port-side board visible with a sharp corner and a bulb shape at the corner. Wouldn't that make it board [4] (of 10)?

You're right! Are they mixing shots from the two days then?

In the most recent video? Yes.

[DC_US55]

Wow. That was way cool.

I have rewatched it a few times, and still can't convince myself whether or not the guy on the starboard hull, that's moving in time with the hull, is reacting to, or if he is he manually adjusting the ride somehow, causing the hull movement?

[Rohanoz]

There is a moment in the video when the lee bow oscillates vertically. Appears that the foil trim is being adjusted, and is causing the bow trim oscillation.

If you're referring to 3:27-3:34, I don't believe the movement is regular enough to be an oscillation. My guess is that the lift generated by the rudder foil is varying due to air bubbles in the disturbed water behind the main board.

We already knew the hulls flexed a lot, I'm blown away by how fast it happens

Note Jimmy is wiggling the tiller at the same time, in the way that you would if the rudder ventilated on a skiff and you are trying to reattach the flow. Sphincter tightening moment for sure when you are 72' long and 8' in the air doing 30 knots!

[Doug Lord]

There is a moment in the video when the lee bow oscillates vertically. Appears that the foil trim is being adjusted, and is causing the bow trim oscillation.

If you're referring to 3:27-3:34, I don't believe the movement is regular enough to be an oscillation. My guess is that the lift generated by the rudder foil is varying due to air bubbles in the disturbed water behind the main board.

We already knew the hulls flexed a lot, I'm blown away by how fast it happens

Note Jimmy is wiggling the tiller at the same time, in the way that you would if the rudder ventilated on a skiff and you are trying to reattach the flow. Sphincter tightening moment for sure when you are 72' long and 8' in the air doing 30 knots!

============
That is flat brilliant! I went back and watched the thing several times and the tiller movements are exactly in sync with the bow flutter-he must have felt something to make such quick, hard movements. Great call!

heres the video so nobody has to search: http://www.youtube.c...player_embedded

[Asymptote]

Is he wiggling the tiller or is the tiller wiggling him?

[maxmini]

There is a moment in the video when the lee bow oscillates vertically. Appears that the foil trim is being adjusted, and is causing the bow trim oscillation.

If you're referring to 3:27-3:34, I don't believe the movement is regular enough to be an oscillation. My guess is that the lift generated by the rudder foil is varying due to air bubbles in the disturbed water behind the main board.

We already knew the hulls flexed a lot, I'm blown away by how fast it happens

Note Jimmy is wiggling the tiller at the same time, in the way that you would if the rudder ventilated on a skiff and you are trying to reattach the flow. Sphincter tightening moment for sure when you are 72' long and 8' in the air doing 30 knots!

============
That is flat brilliant! I went back and watched the thing several times and the tiller movements are exactly in sync with the bow flutter-he must have felt something to make such quick, hard movements. Great call!

heres the video so nobody has to search:

As the kids say " hes got mad skillz

[Guitar]

Ok, who has a YouTube distiller to crop out that flying portion and put it into slomo? I can't just keep rewinding that to watch anymore. Need more detail.

[maxmini]

Ok, who has a YouTube distiller to crop out that flying portion and put it into slomo? I can't just keep rewinding that to watch anymore. Need more detail.

I would think there will be more than enough material to go over in the next few weeks . Pleanty of time yet.

[Koukel]

Is he wiggling the tiller or is the tiller wiggling him?

Yes. Tiller wigling him. Him staying cool (stud), For all the bucking and gyrations, that boat looks surprisingly on its feet to me.

Koukel

[Indio]

Is he wiggling the tiller or is the tiller wiggling him?

As Koukel says, it's the shuddering effect..

[Tornado-Cat]

Note Jimmy is wiggling the tiller at the same time, in the way that you would if the rudder ventilated on a skiff and you are trying to reattach the flow.

I am not sure, I have seen that, and he seems to try to feel the boat as we do with smaller cats.

[~HHN92~]

Well, 17sr was quite different or odd as we followed along during its development. 17jr appears that it is going to have its own 'quirks' to get used to as it and the next boat are brought on-line. It is all probably risk and reward; ETNZ have built a solid boat, ORUSA has a flexible one, and Artemis we do not know......yet.

Lot's to come in the next few weeks, and too early to tell who is 'right'.

That leeward hull flexing sure looks odd. But then NZL92 being so narrow that the wheels were cocked to make room looked odd too.

As did an upside-down keel with wings on it...........................

[SimonN]

Note Jimmy is wiggling the tiller at the same time, in the way that you would if the rudder ventilated on a skiff and you are trying to reattach the flow.

I am not sure, I have seen that, and he seems to try to feel the boat as we do with smaller cats.

Got to agree with T-C on this. Not only does that seem entirely consistant with sailing an A, it is also entirely consistant with sailing a Moth. You steer like that for both feel and to keep the boat under you. It seems tyo me that the boat is responding to his steerring, not the other way around and I really cannot read too much into it, other than to say if he can do that, it shows just how responsive the boat is. It seems to be handling ikie a small cat.....not bad for a 72 footer!

[maskirovka]

The footage from 3:28 TO 3:33 on this video is how I expect Batzilla to be designed to fly. The way she rides through the waves, leeward hull moving(pitching) with the wave action acting like a suspension system, while the rig and the windward hull(with the rudder out of the water) rides very smoothly and stable. Like a high end luxury car with a sophisticated suspension system riding over a very uneven road surface. INCREDIBLE!!! That simply can't be a coincidence.

Batzilla foils in a very different manner than the TNZL boat. No idea which concept will prove faster in the end, but personally I favor the "Hollywood" boat! That's some cutting edge design work... If they can manage to handle flying this beast on single foil and single rudder, along with the ultra clean Aero work in the platform, I presume they should have the drag advantage both above and below the water.

Bring on Artemis... They appear to be using a totally different foiling arrangement, presumably a surface piercing single main foil/double rudder flat foiler. They seem to have more areo details on the planform than TNZL, but I would venture a guess not as developed as Batzilla and with what I presume would be a higher drag foil setup. WAY too early to tell mind you.

Batzilla is looking pretty good from a technological prespective from where I am sitting...

SB

[Doug Lord]

It will be interesting to see which team does copy the others foil system since they are so different:
Manual altitude control,fully submerged for Oracle and Surface piercing mostly automatic altitude control for TNZ.

[Rohanoz]

Note Jimmy is wiggling the tiller at the same time, in the way that you would if the rudder ventilated on a skiff and you are trying to reattach the flow.

I am not sure, I have seen that, and he seems to try to feel the boat as we do with smaller cats.

Got to agree with T-C on this. Not only does that seem entirely consistant with sailing an A, it is also entirely consistant with sailing a Moth. You steer like that for both feel and to keep the boat under you. It seems tyo me that the boat is responding to his steerring, not the other way around and I really cannot read too much into it, other than to say if he can do that, it shows just how responsive the boat is. It seems to be handling ikie a small cat.....not bad for a 72 footer!

Amazing that there is enough response in a half-flying 72' boat to do it - but the scary thing is you usually (well me anyway) only do those sort of movements when things are seem to be about to, or are already, going pear shape! An effort to find out why the boat is suddenly loading up weird or feeling funky. Usually in conjunction with a sheet adjustment or a quick weight move fore/aft, or push on the feet.
I had assymetric rudders on an old A-Cat for a while, and it reminds me of the day when in a rush I put them in the wrong hulls! Spent the first lap waggling like this until it got the better of me and I made a quick trip to the beach to swap them over.
Either way, symptom of question marks, not smooth and stable.

Balls like Corollas.

[luminary]

There is a moment in the video when the lee bow oscillates vertically. Appears that the foil trim is being adjusted, and is causing the bow trim oscillation.

If you're referring to 3:27-3:34, I don't believe the movement is regular enough to be an oscillation. My guess is that the lift generated by the rudder foil is varying due to air bubbles in the disturbed water behind the main board.

We already knew the hulls flexed a lot, I'm blown away by how fast it happens

Note Jimmy is wiggling the tiller at the same time, in the way that you would if the rudder ventilated on a skiff and you are trying to reattach the flow. Sphincter tightening moment for sure when you are 72' long and 8' in the air doing 30 knots!

or is it stall on the main foil. I dont think tiller inputs are having an effect. To be that sensitive to vertical wave motion at 1.5/2m below the surface where the horizontal surface is I figure that they have the foils at max aoa and are just bouncing from stall to stall. At least there is room for improvement.

[david r]

The windward hull remains level fore and aft while the leeward hull can crazily lift the nose and get up to full foil position which seems to be a very bow up configuration. Maybe that adds a level of comfort.
That whole leeward hull be up on the foils while the windward hull is down would be hard to get used too in my opinion.

[Tornado-Cat]

You got up on the good side of the bed this morning .
I agree with everything you said especially about a long way to go for all concerned. It will make for much company time spent on sailing sites like this one for all concerned

Good ! you will even be more pleased to hear that, IMO, OR foils are faster in straigth line and for tacking-gybing, IFFFFFFF, they can control it.
Now I am going to tell my wife I got up on the good side of the bed this morning,.... not sure she will agree with you.

[Tornado-Cat]

It will be interesting to see which team does copy the others foil system since they are so different:

OR and TNZ must already be able to compare....

[Scrubhunter]

There is a moment in the video when the lee bow oscillates vertically. Appears that the foil trim is being adjusted, and is causing the bow trim oscillation.

If you're referring to 3:27-3:34, I don't believe the movement is regular enough to be an oscillation. My guess is that the lift generated by the rudder foil is varying due to air bubbles in the disturbed water behind the main board.

We already knew the hulls flexed a lot, I'm blown away by how fast it happens

Note Jimmy is wiggling the tiller at the same time, in the way that you would if the rudder ventilated on a skiff and you are trying to reattach the flow. Sphincter tightening moment for sure when you are 72' long and 8' in the air doing 30 knots!

============
That is flat brilliant! I went back and watched the thing several times and the tiller movements are exactly in sync with the bow flutter-he must have felt something to make such quick, hard movements. Great call!

heres the video so nobody has to search:

As the kids say " hes got mad skillz

I don't know, that flexing structure looks like another piece of engineering that didn't quite work out.

[Ncik]

This looks more the business...



Or Is it a photochop lol

===========
Thats more like it-windward rudder in and flying level!! And with the windward rudder in there is very little twist-just enough to add stability-man is this cool!

windward rudder is not in the water...there is still plenty of twist...

[eliboat]

Omg twist! I think I have a twist boner

[K38BOB]

The footage from 3:28 TO 3:33 on this video is how I expect Batzilla to be designed to fly. The way she rides through the waves, leeward hull moving(pitching) with the wave action acting like a suspension system, while the rig and the windward hull(with the rudder out of the water) rides very smoothly and stable. Like a high end luxury car with a sophisticated suspension system riding over a very uneven road surface. INCREDIBLE!!! That simply can't be a coincidence.

Batzilla foils in a very different manner than the TNZL boat. No idea which concept will prove faster in the end, but personally I favor the "Hollywood" boat! That's some cutting edge design work... If they can manage to handle flying this beast on single foil and single rudder, along with the ultra clean Aero work in the platform, I presume they should have the drag advantage both above and below the water.

Bring on Artemis... They appear to be using a totally different foiling arrangement, presumably a surface piercing single main foil/double rudder flat foiler. They seem to have more areo details on the planform than TNZL, but I would venture a guess not as developed as Batzilla and with what I presume would be a higher drag foil setup. WAY too early to tell mind you.

Batzilla is looking pretty good from a technological prespective from where I am sitting...

SB

Like adrenalin... http://www.youtube.c...h?v=bQpTkLm6T3U

[K38BOB]

quote name='jhc' timestamp='1349198829' post='3883261'
There is a moment in the video when the lee bow oscillates vertically. Appears that the foil trim is being adjusted, and is causing the bow trim oscillation.
quote

If you're referring to 3:27-3:34, I don't believe the movement is regular enough to be an oscillation. My guess is that the lift generated by the rudder foil is varying due to air bubbles in the disturbed water behind the main board.

We already knew the hulls flexed a lot, I'm blown away by how fast it happens

Note Jimmy is wiggling the tiller at the same time, in the way that you would if the rudder ventilated on a skiff and you are trying to reattach the flow. Sphincter tightening moment for sure when you are 72' long and 8' in the air doing 30 knots!

============
That is flat brilliant! I went back and watched the thing several times and the tiller movements are exactly in sync with the bow flutter-he must have felt something to make such quick, hard movements. Great call!

heres the video so nobody has to search:

As the kids say " hes got mad skillz

I don't know, that flexing structure looks like another piece of engineering that didn't quite work out.

thats flutter..

[Indio]

This approval for OR to sail their AC72 appears to be a retrospective approval! Ostensibly dated 2 October yet the document data says 4:55am 3/10/2012.
 RN162-Permission-for-ORACLE-TEAM-USA-to-sail-their-AC72.jpg   93.39K   63 downloads

 RN162-Permission-for-ORACLE-TEAM-USA-to-sail-their-AC72.pdf   79.61K   23 downloads

[Bow Monkey]

It will be interesting to see which team does copy the others foil system since they are so different:
Manual altitude control,fully submerged for Oracle and Surface piercing mostly automatic altitude control for TNZ.

This is all speculation right now, but I'm guessing OR went straight for the faster, but harder to master setup than ETNZ

I'll use an old Top Gear episode as an analogy. We've all seen Richard Hammond show respectable lap times in a 911, which is reasonably easy to control while going fast. Then they put him in an F1 car. He couldn't even get around the first corner. It was much like the vroom-splat issue going on with OR right now. Faster in the hands of an experienced operator, but undeniably slower in the hands of a rookie. They might be rock stars, but everyone's currently a rookie when it comes to airborn AC72's.

[Ncik]

Look at that "rudder" linkage moving! (~3:30 in the video).

[maxmini]

This approval for OR to sail their AC72 appears to be a retrospective approval! Ostensibly dated 2 October yet the document data says 4:55am 3/10/2012.
 RN162-Permission-for-ORACLE-TEAM-USA-to-sail-their-AC72.jpg   93.39K   63 downloads

 RN162-Permission-for-ORACLE-TEAM-USA-to-sail-their-AC72.pdf   79.61K   23 downloads

larry has a stack of approvalls pre signed by IM. Its part of the DP. .

[maxmini]

It will be interesting to see which team does copy the others foil system since they are so different:
Manual altitude control,fully submerged for Oracle and Surface piercing mostly automatic altitude control for TNZ.

This is all speculation right now, but I'm guessing OR went straight for the faster, but harder to master setup than ETNZ

I'll use an old Top Gear episode as an analogy. We've all seen Richard Hammond show respectable lap times in a 911, which is reasonably easy to control while going fast. Then they put him in an F1 car. He couldn't even get around the first corner. It was much like the vroom-splat issue going on with OR right now. Faster in the hands of an experienced operator, but undeniably slower in the hands of a rookie. They might be rock stars, but everyone's currently a rookie when it comes to airborn AC72's.

Best episode ever. Really showed me just how amazing the F1 drivers really are . Back to the topic , sorry about that .

[Bow Monkey]

It will be interesting to see which team does copy the others foil system since they are so different:
Manual altitude control,fully submerged for Oracle and Surface piercing mostly automatic altitude control for TNZ.

This is all speculation right now, but I'm guessing OR went straight for the faster, but harder to master setup than ETNZ

I'll use an old Top Gear episode as an analogy. We've all seen Richard Hammond show respectable lap times in a 911, which is reasonably easy to control while going fast. Then they put him in an F1 car. He couldn't even get around the first corner. It was much like the vroom-splat issue going on with OR right now. Faster in the hands of an experienced operator, but undeniably slower in the hands of a rookie. They might be rock stars, but everyone's currently a rookie when it comes to airborn AC72's.

Best episode ever. Really showed me just how amazing the F1 drivers really are . Back to the topic , sorry about that .

You're actually still right on topic. By the time we see these things race in anger, they'll be boats that'll be all but impossible to control for us mere mortals. Much like the F1 drivers, we'll see just how good the sailors are with these things. (and yes, it was a great episode)

Purely because I'm biased and it's fun to piss off the Kiwi fanboys, I'm just going to assume OR went ahead and built an F1 car, while ETNZ is toiling away in a 911.

[coxcreek]

And why the fuck waggle the tiller around at 6000 rpm? The tiller is not doing anything to the main foil - which is FLUTTERING and out of control, mind of its own, and the reason the lee bow is wanking itself. Spit is high revving the tiller because he's freaking out. The whole platform looks unstable and glued with flexible epoxy, never flies for more than a few moments, then crashes.
However it is most impressive the hopey-changey comments here - have to say you US boys are very loyal ... but just need a bit more honest visual reality.

[maxmini]

And why the fuck waggle the tiller around at 6000 rpm? The tiller is not doing anything to the main foil - which is FLUTTERING and out of control, mind of its own, and the reason the lee bow is wanking itself. Spit is high revving the tiller because he's freaking out. The whole platform looks unstable and glued with flexible epoxy, never flies for more than a few moments, then crashes.
However it is most impressive the hopey-changey comments here - have to say you US boys are very loyal ... but just need a bit more honest visual reality.

Its slighty early in the process but if it makes you feel better to think of what you are seeing as the end result , enjoy

[W.T]

It will be interesting to see which team does copy the others foil system since they are so different:
Manual altitude control,fully submerged for Oracle and Surface piercing mostly automatic altitude control for TNZ.

This is all speculation right now, but I'm guessing OR went straight for the faster, but harder to master setup than ETNZ

I'll use an old Top Gear episode as an analogy. We've all seen Richard Hammond show respectable lap times in a 911, which is reasonably easy to control while going fast. Then they put him in an F1 car. He couldn't even get around the first corner. It was much like the vroom-splat issue going on with OR right now. Faster in the hands of an experienced operator, but undeniably slower in the hands of a rookie. They might be rock stars, but everyone's currently a rookie when it comes to airborn AC72's.

Best episode ever. Really showed me just how amazing the F1 drivers really are . Back to the topic , sorry about that .

You're actually still right on topic. By the time we see these things race in anger, they'll be boats that'll be all but impossible to control for us mere mortals. Much like the F1 drivers, we'll see just how good the sailors are with these things. (and yes, it was a great episode)

Purely because I'm biased and it's fun to piss off the Kiwi fanboys, I'm just going to assume OR went ahead and built an F1 car, while ETNZ is toiling away in a 911.

I'd have the 911. Sure the F1 is quick, but one mistake and the wheels fall off the wagon grand style. I also think that if you are recycling the foils from the old boat just to go sailing, then the team is scrambling. Not a lot of smiling before or after the sailing. Everyone looked stressed and a little frantic. Very different behavior to the smiles and accolades after ETNZ sailing day 4. No one really knows what the design concept is trying to achieve, but the body language between the two team speaks volumes.

[Bow Monkey]

It will be interesting to see which team does copy the others foil system since they are so different:
Manual altitude control,fully submerged for Oracle and Surface piercing mostly automatic altitude control for TNZ.

This is all speculation right now, but I'm guessing OR went straight for the faster, but harder to master setup than ETNZ

I'll use an old Top Gear episode as an analogy. We've all seen Richard Hammond show respectable lap times in a 911, which is reasonably easy to control while going fast. Then they put him in an F1 car. He couldn't even get around the first corner. It was much like the vroom-splat issue going on with OR right now. Faster in the hands of an experienced operator, but undeniably slower in the hands of a rookie. They might be rock stars, but everyone's currently a rookie when it comes to airborn AC72's.

Best episode ever. Really showed me just how amazing the F1 drivers really are . Back to the topic , sorry about that .

You're actually still right on topic. By the time we see these things race in anger, they'll be boats that'll be all but impossible to control for us mere mortals. Much like the F1 drivers, we'll see just how good the sailors are with these things. (and yes, it was a great episode)

Purely because I'm biased and it's fun to piss off the Kiwi fanboys, I'm just going to assume OR went ahead and built an F1 car, while ETNZ is toiling away in a 911.

I'd have the 911. Sure the F1 is quick, but one mistake and the wheels fall off the wagon grand style. I also think that if you are recycling the foils from the old boat just to go sailing, then the team is scrambling. Not a lot of smiling before or after the sailing. Everyone looked stressed and a little frantic. Very different behavior to the smiles and accolades after ETNZ sailing day 4. No one really knows what the design concept is trying to achieve, but the body language between the two team speaks volumes.

I wouldn't be smiling much either if I'd just gotten off a boat that scared the hell out of me. We'll see how things go once they've mastered this little monster. I sure as hell wasn't smiling much my first (and only, so far) time out in a moth. It was a stressful, frustrating experience.

[W.T]

But it is funny that all us Kiwi's give the OR17 boat a hard time when 80% of it was built in NZ by NZers :-) There are so many kiwis on the OR team, you can almost call it Team NZ Mk2.

[Barnyb]

Well seen as the is SA I am going to express my uninformed view.

1. We have seen a very happy TNZ foiling for africa - take the rum race as a good example
2. We have seen a number of photos of OR many of them looking like it is swell jumping
3. The video (around 3.30) shows foiling but with no apparent control
4. Just before that we see it landing hard
5. Like someone above points out, there is not the right body language on the boat. No one is over the moon

I think this boat is a dud and they have been sent out to foil for marketing propoganda.
A boat that looks like it is flapping about like a rag doll in the mouth of a doberman is not "design feature". The boat looks like it will shake itself to death
These are seriously complex boats/campaigns and OR have come out with a theoretical technically superior boat but made a fragile difficult (impossible) to race boat
They are not happy because whilst they should be collecting data and info for boat 2 they are trying to sail something the design team have got wrong.

[Keith]

Both these 72 footers, look awesome..... Time will tell which platform does the best job, then design round two..

Nice to hear an American voice in the video.....

[eric e]

put it this way

you can see why the nz sailing plan for the 72' was cancelled

when the L foils couldn't controllably fly the ac45s

and you can see why they cancelled the hawaiian sailing plan for the 72'

when the 72' initial sailing showed not only were the L foils no more controllable in the 72'

but they were also too fragile

so they will winter over in san fran

and if money and effort can make them work

they'll probably do it

[auscat]

I remember Larso talking about bow flutter on Team Phillips and we know how that ended.

[Indio]

I remember Larso talking about bow flutter on Team Phillips and we know how that ended.

I've watched the video from the 3:00-min mark onwards about 20 times and I still can't believe how the fluttering bows can be a deliberate design objective.

[wkd928]

Well seen as the is SA I am going to express my uninformed view.

1. We have seen a very happy TNZ foiling for africa - take the rum race as a good example
2. We have seen a number of photos of OR many of them looking like it is swell jumping
3. The video (around 3.30) shows foiling but with no apparent control
4. Just before that we see it landing hard
5. Like someone above points out, there is not the right body language on the boat. No one is over the moon

I think this boat is a dud and they have been sent out to foil for marketing propoganda.
A boat that looks like it is flapping about like a rag doll in the mouth of a doberman is not "design feature". The boat looks like it will shake itself to death
These are seriously complex boats/campaigns and OR have come out with a theoretical technically superior boat but made a fragile difficult (impossible) to race boat
They are not happy because whilst they should be collecting data and info for boat 2 they are trying to sail something the design team have got wrong.

+1

[SimonN]

I remember Larso talking about bow flutter on Team Phillips and we know how that ended.

I've watched the video from the 3:00-min mark onwards about 20 times and I still can't believe how the fluttering bows can be a deliberate design objective.

I am not sure why people call it flutter. To my eye, the "flutter" is directly related to the fift off the main foil and doesn't seem that strange to me. The thing i do notice is that because of the flex in the platform, the movement in the foiling hull isn't translated to the windward one. I see that as a big positive as it reduces the problems of inertia. I am wondering whether this isn't having an effect like suspension. The flex creates gradual resistance, rather than solid resistance, and this gives the whole system some extra margin. The more it flexes, the greater the resistance until it reaches a point where it cannot flex any more. Not sure about this, but something feels a bit deliberate about what is going on and, while in the beginning I was convinced that flex could never be a good thing, now I am not so sure.

[Chris UK]

I hope OR is not being pushed suddeny to progress the testing/development programme due to budget or some misplaced embarassment. They've gone from little evidence of flight to what looked like ~30kts. The foils must be difficult to control. Just thinking that there can come a time in a project when the good guys suddenly get a kick from those that do not know better and things usually/can go wrong soon after.

Fingers crossed that what they showed the other day will be enough to keep significant others happy.

Good luck to OR and ENTZ.

[Doug Lord]

Well seen as the is SA I am going to express my uninformed view.

1. We have seen a very happy TNZ foiling for africa - take the rum race as a good example
2. We have seen a number of photos of OR many of them looking like it is swell jumping
3. The video (around 3.30) shows foiling but with no apparent control
4. Just before that we see it landing hard
5. Like someone above points out, there is not the right body language on the boat. No one is over the moon

I think this boat is a dud and they have been sent out to foil for marketing propoganda.
A boat that looks like it is flapping about like a rag doll in the mouth of a doberman is not "design feature". The boat looks like it will shake itself to death
These are seriously complex boats/campaigns and OR have come out with a theoretical technically superior boat but made a fragile difficult (impossible) to race boat
They are not happy because whilst they should be collecting data and info for boat 2 they are trying to sail something the design team have got wrong.

=============================
I think you are dead wrong. The Oracle boat uses a completely different altitude control system than does TNZ. Oracles system is flown by a crew member and manual control of a 72' sailing hydrofoil is a first in history. As in flying anything it takes experience to handle it well. The payoff is that when they get it down they will have a foiling system that is likely to be less draggy than TNZ.
Both boats are extraordinary, both boats use foiling systems that have never been used before-they all deserve a hell of a lot of credit.

Attached Files

•  AC 72 oracles fully submerged altitude controlled system.jpg   26.21K   14 downloads
•  AC 72 Team NZ foil config based on 9-6-12 video.jpg   33.89K   12 downloads

[nav]

I guess you missed the comments from a NZ poster saying they were manually controlling the flight on NZ721.

[JRM]

Please direct me to the correct section of the conversation if I missed it (ok - I was too busy to read 21 pages to see if it had been discussed before - I am sure it has, you lot seem to go into a lot of detail on these things) but doesn't that middle 'hull' look a bit like it would touch the water in the right conditions. Is this still considered at cat?

[valor]

GREAT! video on so many levels

keep'em up

the wave following flex during the foiling facinating

video and editing by Amory Ross

[MT14er]

I’ve been watching the shuddering of the leeward hull on the OR video and trying to compare it to the motions on a moth. In general the ride on the moth is really smooth even in rough conditions. The only time I experience that kind of shudder on a moth is when I cross a large powerboat wave and the boat surges up and down due to the rapid changes in the automatic ride-height adjustment from the wand. Basically the automatic adjustment on the moth overcorrects rapidly as you go up and down over steep close waves. I think what we are seeing on OR is actually the active ride height adjustment shaking the hull. If you watch the OR video and just focus on the hull near the daggerboard you can see the hull going up and down very quickly. The only thing I can think of that would cause that kind of motion on a foiling boat is active rapid ride height adjustments.

[Beck's]

I remember Larso talking about bow flutter on Team Phillips and we know how that ended.

I've watched the video from the 3:00-min mark onwards about 20 times and I still can't believe how the fluttering bows can be a deliberate design objective.

I am not sure why people call it flutter. To my eye, the "flutter" is directly related to the fift off the main foil and doesn't seem that strange to me. The thing i do notice is that because of the flex in the platform, the movement in the foiling hull isn't translated to the windward one. I see that as a big positive as it reduces the problems of inertia. I am wondering whether this isn't having an effect like suspension. The flex creates gradual resistance, rather than solid resistance, and this gives the whole system some extra margin. The more it flexes, the greater the resistance until it reaches a point where it cannot flex any more. Not sure about this, but something feels a bit deliberate about what is going on and, while in the beginning I was convinced that flex could never be a good thing, now I am not so sure.

I agree with you thoughts regarding the “shock absorber” effect.

The bow bouncing up and down reminds me of when I have my moth wand control set up with the gearing too fast and with a very stiff wand and zero free play in all the linkages. What you get in that situation is the boat hard bouncing over every little wave. Now with the moth this is a product of the active height-of-flight control wand-flap system. I’m thinking, like others, that this is evidence of some form of active (over-active) ride-height-control system that must be changing the AOA of the lifting foil on OR.

[nav]

Or the changing depth and water pressure over the foil affects the lift, as it passes through each wave? Jimmy looks pretty relaxed through the whole thing anyway - reading texts from his GF* off his wrist tablet! ZZZzzz



*Edit - I zoomed in and it was actually from Barkley confirming which pier their base would be on when they came back in.

[Doug Lord]

I guess you missed the comments from a NZ poster saying they were manually controlling the flight on NZ721.

=======================
Yeah, I guess I did. At this point I don't believe it EXCEPT that I am certain that they manually adjust the angle of incidence of the main foil for the conditions and then let the surface piercing foil take over. I don't see how they would have constant manual control with such an angled foil. I could, of course, be wrong.