34th America's Cup: multihulls!

^^^

I'm also skeptical as to ditching the wings RH. They'll get even lighter and they don't have to be quite as big, they'll keep the stresses on the platform at a minimum.

:idea:

But what was that theory you had which you hinted at on SAAC, about how it came about that Oracle was foiled?

 

In that regard, there's no market in the mass media for sailing in general. Not even for the windsurf racing, which is highly spectacular and is the closest thing to what an average Joe can afford, in terms of money and time. Sailing is still very much perceived as an elitist activity, like it or not - regardless of someone's very personal experience might suggest the contrary. Yeah, I know it is possible to buy a used sailboat for few bucks today, but how many folks actually buy a sailboat? As such, sailing in general has only a minuscule share of the media coverage, and mostly on specialized TV channels and paper magazines. Nothing comparable to soccer, football, basketball, athletics or even swimming (which is not an example of a pop-sport).

The eventual boost in the offer of foiling models thanks to this edition of the AC will not help this situation, quite the contrary. The cost of a foiling boat is necessarily higher than the cost of a mono of a comparable size, without mentioning the more complex handling, which surely won't help the popularity of sailing in general. But yeah, this is way off-topic...

My remark about match-racing being more interesting than drag racing was referred to the word "interesting" intended as "fun to watch", not "interesting for big media".

Cheers

 

Another interesting quote from the Morrelli interview http://www.sailingworld.com/blogs/racing/americas-cup/writing-the-rule :

In fact, when we were developing the Rule for AC34, we’d get calls like, “Well, how many guys are going to be on board?” or, “You’re not going to put that engine on board are you, because that’ll displace about eight guys.” Some of these guys had made their livelihood off the Cup for 30 years.​

 

Copied from another site to get forward re AC 72's

ETNZ are still running scared despite getting a gift from plants they could have organised.

And now more BS from Grant.

Hope this Cup never comes to New Zealand.

Posted: Thu Sep 05, 2013 10:58 am














Joined: Sat Sep 03, 2005 1:54 pm
Posts: 833
Location: Home from Cruising, Now Gulf Harbour




APPLICATION
1. On 3rd September 2013 the Jury received an Application from Emirates Team
New Zealand (ETNZ):
2. ETNZ seeks a ruling from the Jury „that the Measurement Committee
effectively amended rule 19.1 of the AC72 Class Rule (“Class Rule”) and
therefore exceeded its jurisdiction when it issued Public Interpretation 54
(“PI 54”).
3. In view of the short time remaining before the commencement of the Match,
ETNZ requests that „the Jury in the first instance instigate a mediation
under Article 15.4(j) of the Protocol.‟
MEDIATION
4. The Jury‟s preliminary view is that this Case is not suitable for mediation.
DIRECTIONS
5. The Jury invites Parties to submit a Response to the Application. Responses
shall be e-mailed to all those on the Service Address List via
jurycomms72@americascup.com by no later than 18h00 PDT on Wednesday
4
th September 2013.
HEARING
6. The Jury envisages holding a hearing on Thursday 5th September 2013.

That bit is all fact. ..

Here is my current understanding of what is going on (could be completely wrong!!)
The ETNZ protest is about Oracle's foil control systems. Apparently Oracle can set the required angle of attack for the foils, and that is maintained automatically by the hydraulic control systems. ETNZ beleive this breaches the Automation rules.

Also,

Oracle still have no boat for Sunday’s race 1. Neither of their boats have measurement certs, and are therefore not eligible to compete.

The main issue for them for boat 2 (their primary race boat) is a protest by ETNZ on the 3rd Sept re the control mechanism for the primary foils. ETNZ believe that the Oracle system breaches the automation rules, and therefore excludes the boat from measuring. This is a critically important aspect of vessel safety and control. If Oracle are forced to change it at this stage, it will make their boat less safe, and more probe to a catastrophic event.

Jury decision due tomorrow...

All IMO, info via various sources, none of it substantiated. But it seems logical...

 

Didn't mean to be rebutting you.

Agree on much of what you posted.

IMO there are two disconnects. The first one is trying to relate the AC and the boats used in the match to any part of sailing in general. You could do it if the AC was related to regular sailing at all. It isn't. The AC is a grudge match between very large, very wealthy people that happens to be contested in sailing machines that once bore a passing resemblance to other sailboats of the day (as Chris has pointed out many times). The other disconnect is trying to make sailing into a more popular spectator event to make the ROI attractive to sponsors (other than elite brands like LV, Rolex, Mumm, et al).

The AC72 has sparked some interest in the non sailing public and the coverage of the AC45's and the Red Bull Youth America's Cup events has been very good. Extreme sailing as a public attraction is a possible way forward. The AC72 is very good in that respect. As far as creating a viable professional sailing event they are headed in the right direction IMO.

Hence I agree with Doug that ETNZ winning and taking steps back from winged foiling machines would be a mistake. The AC will always have a core audience and will always work as part of elite branding. It may well be that 3-4 challengers against the defender is about the 'right' size for the event.

Joe the plumber doesn't want and won't buy a foiling extreme anything. They don't even want boats as mundane as TP52's.

It is the personalities and the high stakes drama complete with rule tweaking that makes the AC interesting. You don't have to use mainstream boats to have that. The AC is an absurd concept that does not play well to a large audience, that is much of it's charm.

The AC72 might just be the best AC boat in that respect. It is larger than life, totally impractical and does things routinely that no one thought possible a year or two ago. The AC is fantasy. A show put on at insane expense for our entertainment. The AC72, 'bigger than a 747' winged, foiling sailing machine fits that fantasy quite nicely.

R

 

"The AC72 might just be the best AC boat in that respect. It is larger than life, totally impractical and does things routinely that no one thought possible a year or two ago."

+1 for that. It's called "Technical advancement". ie:- Progress.

 

===================
I wouldn't say "no one" (!)

 

Watching the AC72 boat development with all of the non-team videos has probably been the best part so far. But I can't wait for what comes next.

Of all of the "could have / should have / would have" type comments, the Steve Clark position that simply reducing the beam would have reduced the safety risk for this size make the most sense to me. Alternately with a slightly smaller boat, a pitch pole does not seem to be as big a deal.

However, what will be one the water this weekend will be a pair of incredible super fast cats that come pretty close to being the "best boats" being sailed by the "best sailors" at this point in time.

In this context the best sailors will probably just be who can better "tame the beast" (getting the fullest potential practical) instead of the tricks and tactics of what many have stated they would prefer to see. Both endeavors are very worthy challenges, but as an engineer I admire the "they figured their boat out better" accomplishment more than either the "they polished their execution better" or "they outsmarted the other guy" types of accomplishments.

Lets all hope that it will be fun / inspiring to watch and that both teams keep their boats sailing and their crews safe through to the end.

 

Disagree. In NZ 1 in 4 people own a boat.

Mass market.

In the south Pacific [ Oceania ] alone in the season there is 40,000 or more cruisers at a time , A thats not counting the boats that are in the marinas and on moorings in their home ports.


Tell your story to Garmin they have just sponsored Robin Knox Johnson by themselves.

 

Wing Tuning

Hi Blackburn
An AC72 wing is 260m2 and weighs about 1325kg. This means its average weight is 5kg/m2 (or 50N/m2). If you look at the lift from a 1m2 of sail say at 20kn then this works out to be 60-100N depending on how you look at it. So its a really good way to rough tune a wing (or any rig) by using gravity to act as a simulated air load on it by placing it horizontal. I've done this with many skiff rigs and it works out quite nicely. Its a great photo thanks for showing it...Regards Peter S

 

Peter, what are your thoughts on the greater number of elements in the Artemis wing? the team had next to no time to really come to grips with it but apparently if offers some tuning advantages?

 

Last night I delivered a Q&A talk to our local multihull yacht club. The Multihull yacht Club of Queensland which was a Challenger in this AC34 but could not raise the many $$$$ to get a team going. The Q&A revolved around the question of who will win AC34 and why. But at the end we started talking about the next AC and it seems that the Wing has been trumped by foiling & flying. Morelli and others have said that using a soft sail will only slow them by 2% and that they will point slightly lower, which I agree with. Plus the wing is too powerful for the platform, they general sail it with the top panels feathered. So the general thoughts are that the platform is great but we drop the wing. This will reduce shorecrew costs, hanger space, cranes etc etc. So the short term future seems to be soft sails and flying.

Corley has asked about the artemis wings. No1 wing was very sophisticated & ambitious with 6 rear panels and a slot control. Unfortunately it went overboard. No2 was much simpler either by time restraints or by experience. Simple is best. Due to the sheer size & efficiency of the wing it is way overpowered for the boat. It would have been better to choose the smaller wing rather than the bigger (in hindsight). But hey generally bigger is better!! They really didn't understand how powerful these things would be. As a general statement the more panels the wing has the more control you should have. But the complexity and control and powering requirements kills you. As the wing had to be split in half for transport the answer is 2+2, 3+3 or 2+3(on top ). Seems the answer by evolution is 2+2. Also remember that 7 or 8 of the sailors are effectively motors (grinders) and this limits how many controls you can have. If the wing survives and they figure out how to automate the twisting etc then the panel count may go up. Or if they get clever with materials they may find a way to twist the rear panel with no joins (such as morphing) Currently if you twist a panel the skin wrinkles badly and upsets the airflow. We will find out this in the C class over the next couple of years as all the wing development will accelerate here. Cheers Peter s

 

I've supposed that they also test these wings in wind tunnels, and I wonder if they have arranged to photograph it with smoke while sailing - or would all that be obsolete on account of computer simulations?

 

Wind tunnel testing is nearly at the end of its line. I realise thats a big statement but computer simulation is very very good at the moment and its unlikely that they did development work in a tunnel. The reason for this is the scaling factors. Building things at scale means that the small scale airflow effects get missed. This is because although we scaled the geometry we did not scale the air molecules. So boundary layers, turbulence, vortice etc do not scale well. So a wing in a tunnel may give various answers in the big scale that are correct but on the little scale are totally wrong. The big things can be well predicted by manual calcs and by simple computing these days. The little things have to be done full scale or by computer. Computers are quite good at turbulence, boundary layers and structure/fluid interaction so this is the way to go. But we still break the problem down into small questions so the computing is efficient. We do not build a model that tries to predict everything in the one model. One day soon this will be possible. So we build a model that answers the big questions, then a new model that adds a bit more detail and then another that answers the next layers of questions etc. My area is structures and this is exactly what I do. Build global simple models get an idea of what the structure is doing (say a AC72 platform) refine the platform big issues. Then make a new model adding extra detail getting better answers (this is called drilling down into the problem) then creating sub models and detail models etc etc. This is because we need answers in hours in the early project but the really big models especially CFD models may take days (weeks) to run, interogate, rebuild and run again to get the answers we want. I doubt wind tunnels or towing tanks where used this time around. Also this time around the boats are load celled and data logged to the max. So they are comparing calculations and reality daily, so they are tuning their modelling to the real world. Morelli said their first models were quite wrong as they had years of tuning to monos. So it took months to retune their software to multis. Seems they did a good job!! Cheers Peter S

 

^^^
Upon receipt of such an informed and interesting reply, I must go find another nice wing photo.







....

Here's a new vid from ETNZ, on the occasion of their 100th day sailing the boat(s):




...

First AC34 finals racing tomorrow, Saturday.
I should go out and get some champagne for the occasion!
I've been following the lead up to this event and posting various comments on it here and there since February 2010...

Which was long before even this thread got started!