AC72 foil control secrets
Some people have questioned whether Oracle Team USA had a secret (and illegal) foil control system in their AC72 that helped them defend the America’s Cup.
OTUSA has released drawings and photos of their system, which used a simple “mechanical feedback” loop to allow precise control of the daggerboard rake. Helmsman Jimmy Spithill had buttons on the wheel to rake the daggerboard fore and aft in precise increments of 0.5° giving him better control over lift for hydrofoiling.
OTUSA designers Dimitri Despierres (mechanical systems) and Eduardo Aldaz Carroll (electronic systems) began work in late June 2013 to help the team gybe better. The goal was to reduce distance lost in a gybe from 150 meters to 30 meters. To do this the engineers needed to deal with the problem that board movement varied depending on hydraulic pressure, making it impossible to control lift. What they needed was a way to move the board a fixed amount independent of the pressure and drag load on the board. Within a month, mechanical engineer Alex Davis developed a test bench with a servo control, hydraulic valve and hydraulic ram to simulate movement of the daggerboard box (see photo below).
Once the test bed system worked, the system was tested on board. Accuracy was fine, but it reacted too slowly. Mechanical engineer Neil Wilkinson and hydraulics specialist Rolf Engelberts improved the system to improve response speed and make everything more reliable and robust.
AC72 daggerboard controls on OTUSA Boat 1
The hydraulic ram for rake is not visible in the photo below, but you can see the rams for board cant, as well as the daggerboard cage and daggerboard box. The box moves within the cage, which is fixed in the hull.
Rendering of AC72 daggerboard cage below. The cage is fixed in the hull. The daggerboard box moves fore / aft (rake) within the daggerboard cage. The daggerboard cage moves inboard / outboard (cant) within the hull.
Controversy and protest by Team New Zealand
OTUSA wanted to make sure their system complied with the AC72 Class Rule. They filed a “Public Inquiry” to the Measurement Committee and got approval on 8 August 2013 – only a month before the America’s Cup Match was to begin. Team New Zealand then tried to have OTUSA’s system ruled illegal but the Measurement Committee stood by their initial decision and the International Jury ruled that New Zealand’s protest was made too late, but would not have succeeded even if it had been filed on time. The marked up schematic below was part of Team New Zealand’s submission. OTUSA eliminated the spring labeled “Component X” making the TNZ protest moot.
Ah ha I knew they cheated
Hi Matt,
I think my article shows that they did not cheat and that their system complied with the rules.
Could you please explain specifically how you think they cheated?
Regards,
Jack
if they had this system all along, then why did they lose those first races ?
Hi Brett,
Thanks for your question. Have a look at 2 short videos that show the improvements Oracle made. The board control system was working fine in the early races – that is what allowed Oracle to gybe so well and to be faster on the downwind legs. They lost the early races because they had not yet mastered the "roll tack" and because they had not yet moded the boat for a low and fast mode upwind. Changes in wing configuration also made a big change upwind.
Regards,
Jack
Video on improved tacking:
http://www.youtube.com/watch?v=o4X64GlSvO0
Video showing how close the racing was, right from the first race:
http://www.youtube.com/watch?v=yF0SgsOvoqE
It’s interesting and probably mostly true. What is odd though is that the photo of Jimmy’s control buttons is about 6 months out of date. He didn’t have anything like that during the Cup racing.
What is odd is that their major advantage came in being able to foil upwind, where minute and constant adjustments to the foils is needed to maintain stable flight. However if you watch video of Jimmy helming upwind he steers using the rim of the wheel and one of the spokes, where there are no buttons. So who, or what, was really controlling the daggerboard rake???
The same goes for during a gybe. Jimmy was crossing the boat during a gybe and Slingsby was on the leeward helm. There are two boards at that moment in the water but Slingsby is controlling both of them??? That guy must be a god.
Sorry Oracle, this is a nice step but you don’t really tell us anything that matters.
He did have control buttons on the wheels during the AC finals. I shot dozens of photos showing them. The reason you may not have noticed them is because they were moved from their original more visible position and not their original "Yanmar red" color.
As far as the accusations of cheating via new systems, it’s entirely possible and much more realistic to assume that Oracle simply reached a point where everything came together, through trial and error and lots of practice. Call it an "Aha moment", and it is very common when dealing with new systems and new workflow in racing.
We should never ignore the fact that just about everything on these boats is new and relatively undeveloped and unexplored. The increase in speed and control grew every time the boats were out there. Calling those leaps "evidence of cheating" without much more solid information is both unfair and naive.
Hi Nigel,
You are right, the photo is out of date. But as Chuck Lantz pointed out – those buttons were on the wheel during the racing. I have some images from the race video where they are clear to see:
http://cupexperience.smugmug.com/Sports/Sailing/Cup-Experience/i-XcJCLbV/0/M/R14%20downwind%20both%20buttons-M.png
Regards,
Jack
Hi Nigel, Here is a photo of Jimmy with his left hand on the spoke of the wheel and his right hand on a button.
http://cupexperience.smugmug.com/Sports/Sailing/Cup-Experience/i-PkP8wXD/0/M/R14%20upwind%20L-hand%20spoke%20R-hand%20button-M.png
I’ve done some more research and learned that Simeon Tienpont had controls in his cockpit for board height, rake and cant. So board control was shared among Spithill, Tienpont and Slingsby.
I think you could ask the same question about how ETNZ controlled their boards in a maneuver. The difference for Oracle was the precision of the board adjustment – 0.5 per click – not who was pushing the buttons.
Regards,
Jack
Wouldnt of spithill have had a bit of a task playing around with that whilst trying to helm too….?? i thought the other boats had full time guys checking where their rake was at and pressing buttons…?
Hi Bat Man,
Thanks for your question. Luna Rossa and Artemis both had controls on the wheel for the helmsman to control rake. ENTZ originally had buttons on the wheel. I am not sure how their system was controlled during the LVC and AC Match.
Regards,
Jack
Nice back-end story from Oracle to try and legitimize their system which, in reality, no-one got to see.
The issue with Oracle’s system was not how it worked, rather how it seemingly didn’t work at all for half of the regatta and then suddenly made their previously far slower upwind boat untouchable and implausibly stable while foiling upwind. No amount of truly manual control could achieve that which is why ETNZ went for a more stable sailing mode and weight dist that would be more easily managed with the manual foil controls they had on their boat.
Hi Bob,
Thanks for your comment.
The measurers got to see Oracle’s system, and they agreed it was legal.
The system was working well even at the beginning of the regatta – that’s where they got their downwind speed. Upwind they needed to learn the "roll tack" and reconfigure the wing to eliminate lee helm. They also managed to foil upwind, which ETNZ never completely mastered.
Regards,
Jack
Ha Ha, I knew there was something fishy. They will not be caught this time, however I think we know they were not on the up and up. Enough said
Hi Frances,
Thanks for your comment.
What was the fishy part? They sent a schematic and parts list to the measurers and the measurers inspected the installed system on their boat.
Regards,
Jack
Brand new boat. Brand new systems. Brand new processes. Brand new input. Brand new and constantly upgraded playbook. Brand new, exceptionally short time-window for execution.
But, then again, it’s much more simple to just accuse them of cheating, right?
If this system was deemed "Legal" then why not just make the A.C. rule legal to have radio controlled models! – This is not men and woman sailing anymore, it’s a guy pushing a button which, removes the skill of the helmsman and his crew. If the measurement committee cannot clearly see this as an automated system (all be it pretty simple) then this sports has truly lost its way and its time for a radical change.
Oracle’s cheating in the world AC 45 series was proof that this team will go outside the rules to win matter what. This is just another example where they have exploited the rule and used timing to their advantage, little if anything was able to be done. Very sad for Grant and the boys
Hi Bruce,
Thanks for your comment!
Sounds like you don’t like the rule. But even so, the Oracle board control system complied with the rule. ETNZ exploited the rule when they got the measurement committee to agree to weigh the boat with the boards not submerged. This was the loophole that allowed ETNZ to develop a foiling boat. Finding loopholes is part of the competition, whether we like it or not.
Regards,
Jack
Personally, I’m of the opinion that gyros are involved.It’s easy to have them powered by the hydraulics,they would dampen a lot of the porpoising,and when added to the 0.50 degree adjustment it would smooth out the ride.And a smooth ride was the key. I don’t think Oracle cheated as such,but they were definately playing well and truely in the grey areas.The one design rules need to be better defined and enforced.
I live in SF,and as a kiwi I naturally supported Team NZ, but living here I know Ellison seems to believe that winning is primary,and rules are just annoying suggestions
Hi Steve, on what do you base your opinion? I’ve done quite a lot of research on this. Did I miss something?
Where in the schematic would your gyros be connected? What would they control?
How do you suppose the measurers did not see them? After the AC45 cheating, they inspected Oracle’s AC72 very carefully.
Regards,
Jack
Well, this system seems to be okey! But the thing is that they used this thing called "little herbie" to control this system! It’s weird how they after the half cup just gets the knowledge how to use some f*ing buttons on the wheel! Just hope that ETNZ kicks ass and wins the 35th cup!
/Calle
Hi Carl,
Thanks for your comment. I’m still tracking down the source of the "little herbie" urban legend. There were some "notes" published by Richard Gladwell, but without attribution. Richard pointed me to his source, and I’m still waiting for a reply from that journalist. The "notes" had obvious errors, but were repeated in the media, unfortunately.
I hope and expect that TNZ will be a formidable challenger in AC35.
Cheers,
Jack
Hi, I personally wrote as soon as PI 49 came out that I thought the measurers had got it wrong and that this system was against the rules. As you write above "OTUSA has released drawings and photos of their system, which used a simple "mechanical feedback" loop to allow precise control of the daggerboard rake." I have no idea how or why the Measurers allowed it or if they were pressured in some way. After the 2003 Hula fiasco with some of the same guys it is a shame it happened again.
consider rule 19
19.1 Only manual power (the force exerted by crew) or the effect of direct contact with wind
and/or water shall be used for the adjustment of rigging, wing, soft sails, rudders and
daggerboards.
19.2 The use of stored energy and non-manual power is prohibited, except:
(a) for small springs, shockcord, and similar devices;
(b) low pressure hydraulic or gas accumulators of less than 6 bar which provide back
pressure to a hydraulic system to prevent cavitation, but do no significant work
themselves;
(c) batteries to power electric bilge pumps, provided the total capacity of all pumps is
not greater than 200 l/min; and
(d) batteries to power instruments, on board crew communication and ACRM media
equipment; and
(e) for electrical operation of
(i) hydraulic valves. These operations shall only provide the input for the
position of the valve;
(ii) drive clutches in winch systems.
The valves and drive clutches referred to in (i) and (ii) above, shall be commercially
available and Competitors shall have had these approved by the Measurement
Committee for use via an issued interpretation.
The operation for (i) and (ii) above, shall not receive external input from any source
other than manual input. Any data acquisition system, associated sensors or
electronics shall be physically separate and completely isolated from any electrical AC72 Class Rule Version 1.1 Page No. 23
operation referred to in (i) and (ii) with the exception of the voltage supply. The
manual input may latch the valve(s) or clutch(es), operate multiple valves or
clutches, and /or provide variable position. Valves and clutches may be operated
from multiple manual inputs.
These systems may be hard wired directly between the manual inputs and shall be
hard wired between the manual inputs and the valve(s) or clutch(es). Wiring shall be
clearly identifiable. Electrical energy used for this shall only be stored in batteries,
including small capacitors.
So, specifically a "mechanical feedback" loop means that instead of the crew pressing a button to control things with their fingers, it means that the control is not manual. The rule says that electrical operation is allowed, in case of fly by wire situations that a button is pressed and an electrical signal passed that along to a valve, but this is quite different the feedback loop keeps looking for its target after the command is given and with no need for the crew to see how it goes because it will find its target automatically.
In essence I think that OTUSA put one over the Measurers and got away with it. Much the same as often happens in all sports such as football or any sport you can think of where from time to time the referees will make a mistake. It is regrettable that in this case the Measurers had time to correct their mistake (still well in advance of the Cup) but in saving face they made the situation a good deal worse for everyone including themselves.
I don’t think the OTUSA system reflects well on their team in any respect of the friendly competition that the AC was setup for, but following on from 1988 catamaran debacle it is nothing new and since the Measurers let it through, then they certainly OTUSA had every right to use it and were obligated to try as hard as possible to win.
I find it pretty lame to see the constant claims of cheating. Have any of you watched the races? It was clear to me that in the LV finals, the Kiwis were sailing their boat better than the competition. At the same time the 2 Oracle boats "raced" each other, and I was surprised to see they were not at the same level as the kiwis when it came to boat handling.
Through the first few races of the AC finals, the kiwis still had the edge, bit in a very short time the Oracle guys clearly changed the way they were sailing the boat. Oracle improved more in that finals series than the Kiwis. If you can’t see this, then you either didn’t watch the racing, or your knowledge and experience in sailing is lacking – either way you are not qualified to make the claims of "cheating"
ETNZ were also very unlucky, twice denied due to the weather on the day. It was a very even match and all involved in both teams should be very proud of what they achieved. Those that repeatedly make claims of cheating are simply sore losers and need to pull their heads in and get out on the water.
I feel I’m qualified to make the above comments in an unbiased manner. I did watch ALL the races in the LV and AC finals. I have raced sailboats most of my life, ranging from offshore yachts (Sydney to Hobart etc) and a range of OTB boats from skiffs to high performance cats. I have friends that were on both OTUSA and ETNZ, and was on the edge of my seat in every race wishing the best for the guys on both teams.
To the naysayers – this gadget is noi more automated control than the powersteering system on your car. In fact they are very similar in principle. The use of mechanical feedback to achieve precise positioning is a standard bit of mechanical engineering, and to some extent I am surprised it was not there from the beginning.
Stable un-adjustble hydrofoil systems have been around for over 100 years and sailboats have used them for some 60 or so – Google "Icarus catamaran" for example. With a system like this, there is a risk of "over-control" (from the humans) which can lead to instability, and which easily explains the early poor performance.
In fact I have heard a rumour that Oracle used the lay-day to go back to the engineers and ask them how the systems were meant to be used. Or to put it another way – if it doesn’t work, go read the ** manual!
Simon