34th America's Cup: multihulls!

With all the attention on flying, people are forgetting that there's roughly equal time spent sailing upwind with a hull in the water, compared to sailing off the wind with the hulls free of the water. The daggerboards provide leeway resistance 100% of the time. Flying, while spectacular, really is a secondary function of the daggerboard. A boat can race without flying (although it may not be competitive in the current environment), but it can't do without the leeway function. So I think it's still fair to say the primary function of the daggerboards is to provide leeway resistance.

There's still a lot of drag associated with the side force due to leeway, and a great deal of the daggerboard design is concerned with minimizing that drag. It drives how the boards are operated, such as what cant angles are best for upwind vs downwind, how much immersion the boards should have, etc.

I don't think flying violates the Design Rule. I think 1.4.e is more descriptive than proscriptive. I think the daggerboards were intended from the start to provide some vertical force. Flying is a difference in degree rather than a difference in kind.

 

Your explanation does make sense and is well-argumented, thank you.

 

A bit of a conundrum for you , if NZ wins they have said they will return to monohulls since they are cheaper and will attract more competitors. And intrinsically safer to race in variable weather and won't need severe weather restrictions, and will reintroduce sportsmanship in close sailing combat rather than drag racing duels.

The only way it's going to continue with these platforms is if the US wins. Then we'll just see a rerun of this farce again next time. So lets hopw NZ wins

 

35th AC

Yeah, it's going to be an epic contest with a whole lot at stake. I hope Oracle
wins every race.
Go 17ers!

 

Monos?
The genie is out of the kettle.
Sorry.
But maybe foiling monos. With spread foils a la trimaran configuration - something like Lac Leman designs.
There won't be anymore lread mines.

 

35th AC

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Dalton said monohulls someplace-would he go for a foiler?

 

A monohull foiler has already been built for the Americas Cup. Back in 1988, Blue Arrow. Sadly it wasn't allowed to race

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

35th AC

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But most people wouldn't consider it a monofoiler. If I remember correctly didn't it have long crossarms with foils at the end?

Blue Arrow pictures from Scuttlebutt:

 

Anyone on the sidelines must be wondering why the AC72 is pretending that what has been known about foils for the last 40 years has been forgotten for these boats.

What did Slingsby say...reading between the lines we cant or dont know how to adjust our rudders when sailing DOH!
IMHO Doug 'they are at the cutting edge' doesnt have many members in that club?

the AC is stuck either they say no foiling or delay and re write the rules for proper foiling....could this have ever happend with lead mines..I dont think so

 

34th AC

NA Doug Schicklers take on the rudder foil situation-from Catsailingnews: ( http://www.catsailingnews.com/2013/07/ac-34-rudder-elevator-dispute-technical.html )

"The editor of Catsailingnews.com asked me to review the late stage changes to the design rule. This is an attempt to separate the technical matters from the more emotional. The idea is to understand and parse the rule changes, how they matter to the safety of the yacht as well as to its performance. Words like sportsmanship, cheating and fairness are not part of this discussion. The authority of any particular party involved in this cycle, relative to the Deed of Gift, the Protocol or any other document will not be addressed. Please note that elevator and stabilizer are used interchangeably.

Some background is useful. ST is a design and engineering partnership, founded by Doug Schickler and Davide Tagliapietra in the period of the 32nd America’s Cup in Valencia. Throughout the span of time from the end of the 32nd to now, we have remained close to the design and engineering details, and have taken a particular interest in the nature of the class rules used in the AC. Our professional experience with multihulls, cruising and racing, and with foiling craft has been peaking of late, offering a good chance for comparison.

We were both colleagues and friends of Bart Simpson at +39 in Valencia. His death was something we experienced with shock and distinct sorrow. I was unlucky to hear the news from SF in nearly real time. This piece is not a discussion of the loss of Artemis Racing’s first boat. It is about the choices being made as a result. A limited amount is known about how the longitudinal stability of Artemis Racing affected the outcome of that tragic day. Loick Peyron is on record in the NY Times as saying it was a capsize event in a bear away. But he hastens to point to an unacceptable structural failure as the real issue. Rudder elevator performance, at the heart of this discussion, was not part of his commentary. See http://www.nytimes.com/2013/06/28/sports/despite-fatal-training-accident-artemis-moves-forward.html But, in any case, it is clear to all observers, than nothing good comes of a pitch pole. The consequences are dire for crew and support staff.

Let’s say the story starts with the proposed
, and now essentially endorsed, safety recommendations. It is virtually certain that this list was compiled with input from all of the competitors. What proposals, if any, were not included is not known to me. Two of these safety recommendations are still subject to a protest to the International Jury at the time of writing. We could as an alternative, also start from the standpoint of the AC72 class rules as written, and/or from the interpretations published on various topics related to foiling on a big cat in the way we have seen. But that process has happened, thus far, as one would expect. The design rule was made, and then modified / interpreted numerous times for a number of reasons. An example of this would be the elimination of the “small” wing from use. Another would be PI 19, which ruled out the kind of adjustment to stabilizers being explicitly allowed now.

The Regatta Director, the GGYC, and the ACEA together made an application for an Event Permit, which included 37 safety related proposals. See http://cdn.sparkart.net/americascup/content/documents/Recommendations-22.5.13-1 To the best of my knowledge, not all of the recommendations were fully detailed at the time of the application. For example, the nature of the structural review was not clarified. Therefore, the recommendations were not carved in stone at that point.

At the time that these were first released, the recommendations were grouped as Yacht (9), Personal Equipment (7), Support Equipment (9), Race Management (12). Of the 9 related to the yacht, the third, Rudder Elevators, stood out in its specificity, raising some red flags as a result. The other controversial fifth item, Maximum Sailing Weight, is also specific, but does not amount to much if one assumes it is a margin added so all teams could add the recommended equipment without changing anything else. It also clearly gives leeway for some reinforcement if a team thinks they can strengthen the boat. I have no way to understand if any of the yachts are in any difficulty from a weight stand point relative to the rules as there have been no certificates posted on the official notice board.

The text of the third recommendation reads:
1.3. Rudder Elevators:
a) minimum total area 0.32 m2 per rudder;
b) minimum depth of elevators on rudder span of 2.1m;
c) maximum elevator span of 1.4m;
d) rudder elevators to be symmetrical in plan form and allowed to extend beyond maximum beam of the Yacht; and
e) elevators permitted to be adjusted until warning signal.

That Event Permit has now been granted. See http://noticeboard.americascup.com/wp-content/uploads/2013/06/SF-13-1035-1039.pdf It is clear reading the text of the permit that the USCG wants no part of the responsibility for safety of the event, bar that they may stop any race at any time, as they see fit. The 37 recommendations are not enumerated in the permit; there is only a statement that “Regatta Directors Recommendations” were received as part of the application. Additionally, the Permit leaves a door open to amend the application. The ACEA would be required “to immediately inform the Coast Guard if circumstances necessitate a change to any component of your safety plan” and explain. In other words, some room for revision may still be available.

Let’s start with the bigger picture of rudder elevators (stabilizers) and then break down the points. With partial or total foiling, rudder elevators have a significant stabilizing effect on the AC72. The same can be said for a lot of catamarans, A class, C class, all recent foilers, in fact. The usefulness of elevators seems, therefore, clear and self-evident. We don’t think it is even argued that stabilization of the yacht is worth all the drag they create, and with full foiling their drag is little compared to the hull coming free of the water. There are a few ways to execute such elevators, as has been seen in the fleet. Active control, adjustable but passive, and fixed passive would be my designations. The original rule was written not to eliminate any possibility of stabilizers, but to limit their articulation dramatically – fixed passive being the rule for racing.

What then is the meaning of each of the points above?
a. The minimum total elevator (stabilizer) area of 0.32m2 per rudder could be put forward as a mandate for a minimum level of the aforementioned stabilizing effect. We have no way of telling if this sub-point is a controversy for some, because we do not know the area of the solutions attempted. Certainly, a significant increase in area of the foil, beyond what is deemed necessary for the safe operation of the yacht, is just drag. This performance impact is a function of other design decisions. An analogy could be drawn from aircraft. How can a regulator determine the stabilizer area required of all 300 passenger aircraft in the absence of more information about the center of gravity, flight speed, and wing positions for example? There have been, however, no great indications from the protesting competitors that the area mandate is at the heart of the problem. Quite the opposite, the minimum area has been endorsed by ETNZ, who have protested the recommendation 1.3 overall.

b. The elevator depth on the span of the rudder of 2.1m is a similar situation. It can be instructional based on the experience of the teams who are either partially or fully foiling that a foil placed too shallow does not help the longitudinal stability enough. This is therefore to eliminate the temptation for design team to limit drag of this foil or conversely to limit the loss of rig efficiency when sailing with the leeward hull in the water but heeled. This topic has also been broached by ETNZ, and they have acceded to this point even though it makes one of their rudder sets invalid. See http://www.kiwiyachting.co.nz/dean-barkers-blog/8-days-lvc

c. Maximum elevator span of 1.4m (Note: not clear if span is tip-tip or root-tip.) This limit would seem to have the opposite motivation, at first. It would appear to impact the design for reasons other than safety. Longer thinner (high aspect ratio) foils are more efficient. So limiting span could be detrimental to those teams that may have created highly efficient stabilizers. But, limiting aspect ratio can also be in the interest of a broader range of effectiveness. Longer chords will be more resilient to non-optimum angles and speeds, generally. Another interpretation is that this section can effectively be a limit put in place to prevent extreme loading of the rudder stock when the stabilizer hits the water surface. This possibility seems unlikely, as a rudder is, by nature of its purpose, there to produce moments. It can be for the integrity of the elevator itself. The area/span combination can enforce more robust stabilizers, enhancing their ability to accept extreme loading. In other words, there can be justifications for limiting span. We have no way of determining that it affects any of the current rudder configurations.

d. Symmetric plan form and max beam exemption. This point or points is clearly more controversial. In my own commentary elsewhere, this aspect was flagged as one having less to do with safety than with performance. In fact, as it turns out, the symmetry aspect will not be enforced, at least at first. A regatta notice was issued a few days ago, essentially allowing asymmetry that is supported with calculations. This would in turn indicate that the original intent was to prevent asymmetric loading for stabilizer integrity. How can that be a realistic point of view, given that the elevator can quite easily be loaded on one side only, as the foil enters or leaves the water? This new modification to the recommendations, allowing asymmetry for now, has established some load cases for consideration. It is not known if these load cases represent a hindrance for any equipment. Probably not, it seems like a compromise.

The ability to put the stabilizer out past the maximum yacht beam can be seen as a result of the enforcement of symmetry. Any team that had chosen asymmetry did so for reasons of maximum beam, apparently. So if they needed to produce symmetric plan form, they would be seriously burdened by the maximum beam. If the symmetry is moot, as it seems now to be, it should stand to reason, and one would hope, that the maximum beam exception is also moot. It is also not known with certainty that any current yacht has a stabilizer past maximum beam. If so, it does not appear to be by much.

The argument put forth by a challenger that this step is much more dangerous for any crew that fall overboard is a bit far-fetched. Yes, it all comes down to the likelihood of being struck. Men broke their backs and were hospitalized hitting the rudders of V5 boats, fully under the boat. The idea of getting hit by any part of an AC72 rudder is truly frightening, and the ca. 40 centimeters of difference involved don’t change that fact any significant amount. If this is sincerely a concern, where is lobbying for lifelines over and above the crew restraints recently recommended?

e. Elevators adjustable up to the warning signal. This is one of the more confusing changes seen. It has perhaps also been misunderstood and vilified by commentators. This moves the rule standard from being fixed passive to adjustable passive, while many have commented as if this equals active control.

Have teams made elevators with active control? Yes it seems to be the case, motivated by testing schedules. Can this be used racing? No, that is not what the recommendations are calling for or contemplating. It can be argued that active control is even safer, though the Regatta Director stopped short of allowing or mandating active control. Such a step would not only have disrupted the imminent racing, as the equipment is not available in the short term, it would also have perhaps had a greater impact on the relative performance. So a compromise solution was taken, one that could technically still work with the wording of the class rule 8.6. Not the safest of all possibilities, but a bit safer perhaps.

Taken together with the range of winds now accepted by all the competitors, likely with some arm twisting, it seems the intent was to delay the “setting” for the given day or race. This could enhance the effectiveness of the adjustable fixed stabilizer if conditions do not change or are predictable. We think this was the intent. Likewise, it is a performance advantage to be able to optimize your setting later rather than earlier. This is a consequence, and others can and will surely debate if this was intended or not.

Correctly however, attention has been given to enforcement of using an active control elevator as a fixed passive one. How can such a fixation of an adjustment be policed? Well, in the old days the use of ballast water was also a policing issue, and it resulted in some DSQs. So too here, there are technical ways to handle this. A seal placed on the control, photographed at the warning signal with a timestamp, and checked at the finish line before it is unsealed? Some relatively practical and reliable method can be imagined.

The most striking problem with the recommendations detailed above, taken all together, is not the specifics of each detail. It is the depth of the change at this late date. It morphs into the problem of potentially forcing competitors onto the race course with untested, or under developed equipment. That would dramatically reduce the benefit that was intended. In terms of reliability, and most of all in terms of boat handling, one should walk before running.

Beyond this, the questionable call of allowing later pitch setting of the elevator has an effect on the event’s legacy. Why this compromise, for limited return, at this time, when the result could easily be a Match that is subject to debate, not to mention possible litigation after the fact?

From my point of view, the points on rudder elevators each have their plausible justifications. It is a charged topic with the injury and death of crew members as ample motivation, even if there is no certain cause and effect. It must be said that we do not have all of the facts in that regard. As an aside, for me the structural integrity of the yachts should be very much more in the limelight than the rudder stabilizer.

The intent of all the recommendations may be sound, but the effect with regard to rudder elevators ultimately incompatible. It seems with the compromise on asymmetry having been struck, and the minimum area not being hotly contested, the teams currently sailing their race boats can use their proven equipment. The key aspects being protested then are the maximum beam exclusion and the late setting of an adjustable passive setup. The former is dimensional limit change, which is not in itself a necessity, but tied to the discussion of asymmetry. The latter is viewed by me as more performance than safety, even if some safety effect is acknowledged. In my opinion, it was and is possible to create safe racing yachts with the original rules as written, amended and interpreted, and that is what should be done. Moreover, I think if the International Jury rules in that way, the Event Permit leaves some latitude to make it so".

Doug Schickler for Catsailingews.com 01-07-2013
'Schickler Tagliapietra Yacht Engineering & Design Studio' www.styacht.com
http://www.styacht.com/about/profile/

 

thanks Doug

so its a complete fiasco as we thought but it is the AC after all...

 

34th AC

This is the complete transcript of what Iain Murray said today. It certainly shows that the hysteria accusing Oracle of cheating was false-and I think a lot of people owe Murray and Oracle an apology. It also shows a disingenuous side to TNZ -particulary Grant Dalton and Dean Barker-something I would never have believed:

"I made these recommendations to the teams on May 22, over six weeks before the first race of the Louis Vuitton Cup,” he said. “At that meeting, all of the teams agreed to all 37 of the safety recommendations. Grant Dalton (managing director of Emirates Team New Zealand) walked to the front of the room, shook my hand, and told me, ‘Good job. You won’t get any pushback from us.’”

But on June 28, Emirates Team New Zealand filed a protest with the International Jury over the changes. Yesterday afternoon, Luna Rossa Challenge did the same.

Murray also states plainly that claims saying that the Italian and Kiwi boats would not measure as AC72s and are thus ineligible to race are false. He says the official measurers have informed him that both Luna Rossa and Emirates Team New Zealand are fully able to comply with the AC72 Class Rule.

“They can race on the first day, Sunday July 7, with their equipment as it is now because it already meets the minimum requirements set out in my Safety Rules,” he said.

“So this isn’t about teams not being able to comply. This is about two teams trying to gain an advantage from changes I’ve implemented to make all of our racing safer.”

On the issue that seems to be most contentious to some of the teams, the requirement to have deeper rudders with larger winglets, Murray says these are important Safety Rules.

“This to give crews more control. The new Safety Rules allows the angle of the rudder winglets to be adjusted up to five minutes before a race instead of by 8.00am on race days.”

That allows for a more precise setting in the prevailing wind conditions at start time. What the teams are protesting about now are features they had previously requested.

“Dean Barker, the skipper of Emirates Team New Zealand, emailed me in December of last year asking for the period when teams could adjust the rudder elevators (wings) to be extended from when they left the dock in the morning (under the original class rule) until up to the warning signal for racing (as it is now, under the Safety Recommendations),” Murray continued. “He suggested the boat would be safer, and easier to control, if the final adjustment could be made just before the race start.

“When the Safety Review Panel met with the teams in May, all of them acknowledged that deeper rudders, with larger wings, add more control. Luna Rossa Challenge wiped out twice at 36 knots of speed during training because they lost control and rounded up head to wind. More surface area increases control.”

“Now can you see why I’m frustrated?” he asked.

The protests say that Murray exceeded his authority in imposing the changes to the Class Rule without the unanimous consent of the teams. Murray said that when mediation failed he had no choice but to proceed with the safety recommendations.

“I was appointed Regatta Director by the challengers, and accepted in that role by the defender. I work on behalf of all the teams,” Murray explained. “In this case, I’m really saving the teams from themselves. Not one team likes all of the recommendations.

“Disappointingly, for competitive reasons, two of the teams are now protesting over some of these safety recommendations. But I don’t believe you can pick and choose. These safety recommendations are a package and together they increase safety for our sailors and they are now Rules of the event.”

The International Jury is scheduled to hear the Emirates Team New Zealand protest beginning on Monday July 8. There is no schedule yet for the Luna Rossa protest.

Read it yet ,Gary, Slavi etc etc etc....?

 

34th AC

Coutts tells it like it is: http://mybrctv.net/news/read/catego...ap-americas_cup_champ_coutts_defends_rules-ap

Gary, with your false accusations now exposed ,you should read this and the other stuff I posted today. And maybe ask your buddies what their plan is?

 

Maybe they should be saying the Oracle boat is not safe but the others are?

 

The rotting rat in the room is bringing rudder changes up a few days before LV begins.
If changes were suggested months back, why was it not continued?
If, as most people saw/see it, new rudder designs are to be mandated, that means quite radical, last minute changes need to be implemented on LR/ETNZ, the two only legal, tried and true, safe boats in the AC.
So something stunk. And still stinks.
Especially if the IJ agrees with O and A.
But that won't happen.
An aside: Coutts and Dalton are not good Kiwi mates ... but all this crap fighting going on ... is just the publicity SF needs to grab by the throat viewer interest.
Maybe it has all been cunningly staged.