Foils are allowed, but they have to be fixed. There can be no flaps or on the fly adjustment of the foil like a Moth has.
There will be a performance trade off, and most likely the 72’s will only foil with the kites/downwind ( if you can call it downwind with the apparent wind angle…!)
I understand AC 72’s can foil upwind as well, providing only the leeward dragger board is being used to do so, the windward dagger board must be retracted (see rules below) This is the amazing feat that ETNZ has achievced…Can you imagine the load the would be on lee dagger board when foiling !? In comparision looking at photo’s of O.R their platform looked like it had lot of twist and they sheared their dagger board clean off !! [i]and I don’t think they were foiling at that stage !!!
[/i]AC72 Class Rule Version 1.1 Page No. 14
- DAGGERBOARDS
9.1 Each hull shall have one daggerboard.
9.2 Daggerboards shall penetrate the hull forward of the rudder and aft of the forward watertight bulkhead per rule 6.11.
9.3 The maximum dimension of any daggerboard shall be 7.000 m in any direction, measured along a straight line.
9.4 The lowest load-transferring bearing shall not translate relative to the hull.
9.5 A daggerboard shall not translate longitudinally more than 0.020 m within the bearing referred to in 9.4 above.
9.6 Daggerboards shall not have components such as trim tabs or moveable winglets that can be adjusted while racing; however, a movable or retractable device the sole purpose of which is the removal of weed or debris is permitted.
9.7 At all times when racing, daggerboard cases or trunks shall effectively drain within ten seconds of the hull being lifted above the water level, and shall not be designed to retain water when not immersed.
9.8 Fairings are allowed within the area defined in 6.7©; they shall not be controllable and shall move only passively as the result of the permitted movement of daggerboards and their bearings. Attention is drawn to rule 5.14.
9.9 Daggerboards shall not be designed or used to generate force for the purpose or effect of increasing righting moment when used on the windward side of an AC72 Yacht.
9.10 When fully retracted, daggerboards shall extend no more than 0.500 m below MWP.
47.3 Preventing windward daggerboard increasing righting moment After starting, an AC72 yacht shall have the windward board draft stripe(s) visible so to confirm that the board is no more than 0.500 m below MWP, unless one of the following applies:
(a) the windward board does not penetrate the surface of the water for more than 15 continuous seconds;
(B the yacht is within 300m of a mark;
(C the yacht is within 30 seconds prior to and after tacking or gybing;
(d) the yacht is sailing less than 15 knots;
(e) the yacht is sailing at less than 90% of its performance relative to the other yacht(s);
(f) the yacht is taking a penalty.
you think oracle broke their board as a result of the load it was trying ot carry in an attempt to foil…
Jim, I would have thought foiling downwind would be lot more dangerous going downwind with Kites, the likely hood of pitch poling would be very high if you suddenly crashed coming off foiling mode 
have not been on cat for years but always remember filling my pants when going downwind too quickly through fear of being flicked through the rigging if the nose dug-in (and we were was not foiling at high speeds then)
Cheers Alan
No idea Marc, it was first day on the water and everyone was tight lipped about circumstances which it happened, I hope for their sake it happened while trying to foil, if not they have a really serious problem with design or construction.
saw this when they were testing the AC45’S
“The force on the daggerboards seems to be sufficient to cause the leeward one to bend under load.”
Hi Marc, This is my take or speculation on what has possibly evolved.
Following AC 33 win, O.R they put all their eggs thinking they had big jump on other teams with their wing, it looks like from the launch photo’s of their AC 72 they were focussing their AC 34 platform to be more aerodynamic and were banking on this being the next performance level.
Oracle designed the rules to eliminate the possibility of foiling (they thought) by excluding windward dagger board being in the water (increasing righting moment) however, it appears ETNZ (as always) looks for holes in the rules and looks for other solutions and ETNZ while thinking the next performance level was foiling only on lee dagger board !
After agreement between ETNZ & Prada was signed (reported to be worth 10 million) photo’s started appearing of Prada foiling their AC45 (nothing from ETNZ) and O.R recon picked-up on this development and 3-4 month later we saw O.R testing foiling on their AC 45’s. But the design and construction of O.R 72 had already began was designed to fly on one hull & did not take into serious consideration the possibility of foiling (given how they had rules written) and have been subsequently been caught out with the little Kiwi ingenuity on the AC 72.
As said in earlier post, the foiling of NZL-2 was timed to be around same time as O.R 72 launch to steal some thunder back and demonstrate they had closed the wing performance gap & moved on with unthinkable higher foiling performance, possibly this tactic shook O.R to the core and they pushed their platform too far with their first outing, hence broken foils and they are now back on the drawing board focussing on their 2 nd boat already.
The first OR 72 was a huge mistake (being kind) and will only be good for keeping the boys busy while waiting for the next generation foiling platform….tick, tock, tick, tock only 12 months to go boys ! Reckon Larry will be busting desks with his fists 
Assuming Prada will be at same level of ETNZ with their first AC 72, I’m now wondering (so will OR) what the next surprise (2nd) boat from ETNZ, that will obvouisly not be shared with Prada
Cheers Alan
all good points alan…
it looks like the AC has become much more of a designer’s race at this point… I enjoy seeing the design jumps, but part of me want the AC raced on a true one design platform and lets see who the better skippers are…
Lets put skippers, one on each laser, and see what happens…
You would then see how fast Ainslie would be Rushed in as skipper for OR…
I too have sailed plenty of Cats, when I was a sailing instructor… Now that is terrifying!
As I understand it, the idea is foils will be designed to only work within a certain speed range, and that range would be nearly fully powered up, off the breeze.
Because there is no availability for control, you are only relying on ultimate boat speed to get you foil. Then the crew are playing with the power, trying to manage the beast… And for sure one is going to bite!
I would be a little less worried about pitch poling, as the Kites are cut with a profile that helps lifts the bows also…
In the 72’s (barring breakages) it really will be a battle of who has the biggest goolies…
so is what you are saying that as the teams walk around the docks, the clink of metal you hear isn’t the change in their pockets or the keys to beach house??? 
- 1 :D:D
Or Nose down, pants brown factor !
With totally new format, Design and Technology has the front seat with foils in the water (currently S vs L section foils) together in the air with wings. Of course reliability and boat handling and sailing skill are always critical and probably more so than any previous AC so the goolie factor comes into the picture for this AC. On this point I would put Spithill at the top of the ladder as Barker is more disciplined and not so much of a risk taker, Artemis are good and the Italians are … well mama mia anything could happen with them !
Just out of interest I put together this ranking (10 = Excellent & 0 = Unknown) as anyone of them could be the decider, but the total sum of the parts working as one complete package will win the Cup, not just one element, only hope the legal beagles don’t come into play this time [i](always a game killer)
[/i]
As the other two teams get on the water we can access their strengths and speculate how things change and update monthly ?
Cheers Alan
Well well … now changing rules on the run to try & catch up with ETNZ 
http://www.sail-world.com/Europe/Americas-Cup:-Hinged-foils-approved-by-Measurement-Committee/101999
Now the poodle has approval for new foils design … wonder when they will get their wing ? maybe O.R can lend them their AC 72 wing as their hull is … um under repair
US 17 was back on the water over the weekend after rebuild sailing 30 + with no reports of foiling yet ! [i](note the ETNZ RIB in the background)
[/i]
That’s two AC 72’s up and running now and Prada planning for mid Oct splash ( 2-3 weeks)
Anyone heard the status of Artemis ? (sailing on wing & prayer)
I guess the initial plans were just too good to be true, and just too damned expensive…
Row
oracle on foils…
http://www.oracleracingmedia.com/index.php?lang=en&fn=accueil
doesn’t look as graceful ETNZ
and there appears to be a lot more twist in the frame than ETNZ but it could be the camera angle…
sounds liek the local polico’s got involved… no problem wasting millions of tax payers dollars on a stadium. but god for bid on anything else…
On foils or launching off a wave ? photo makes it look like brewers drup
Arm chair speculators are saying they have purposely designed-in “controlled platform twisting” to have right angle to create lift of foils & T rudders ? sounds kinda weird but we will never know until hull # 2 hits the water, if that still twists I’d believe it, if it does not … you could say hull # 1 was a right F.Up !
though about a wave jump as well… but the seas look fairly calm, and the cat hulls are supposed to pierce the wave …
it ain’t pretty…but at least we got both hulls out of the water… so we got a race at least…