34th America's Cup: multihulls!

looks like its going back to my original prediction with multi's
A very slight design difference will create a huge boat speed difference so the racing will be boring

 

Unfortunately, that is imo not avoidable with this type of boats. Back when boats were displacement ones, the max. speed was dominated by the wave drag. 0.1-0.2 kts of speed gain was all that could be achieved with a very careful design. Which is not a bad thing for the technology, contrary to what some might think. The CFD has made big leaps forward thanks to slow displacement hulls and the fact that small differences in boat performance had to be identifiable by the calculations.

At the present level of development of this new class, the speed differences are much bigger because there is no "hull speed" barrier to shave the speed difference peaks between various designs (cavitation might be the next big equalizer), and because the design tools have yet to be fine-tuned (and some have to be yet invented) for the new physics of sailing associated to these vessels. Think about foil ventilation and cavitation, for which I don't think any universal and reliable prediction method is yet available.

In the present situation,, the on-board tactician is nearly useless. This is fundamentally a race between design teams, sailors are there to learn how not to pitch-pole the machine, to learn the correct timing of foil lowering and hoisting, and to pump up the hydraulic pressure.

Things might get better in the next editions, but the leveling of max. speed between racing boats won't be a fast process, imo.

Cheers

 

...

The amount of displeasure and disappointment about this Cup strikes me as slightly ridiculous...

Gripe gripe, ***** *****, whinge, kvetch, groan and moan. Grumble, grouse, niggle.

I read that Larry Ellison told his biographer 'There are people who do things, and there are people who complain.'

 

I think you've slipped your moorings a bit.
This is an internet boating forum, i.e. it is an appropriate place to criticise,
kvetch, groan, moan and discuss the AC.

 

It would be interesting to work out if the negative responses about the racing come largely from the internet and its ability to almost instantly satisfy our wishes instead of some real problems with the boats. In the history of the cup there have been many one sided series that would have been very boring to watch - I remember watching us Aussies lose in 1987 when Kookaburra crossed IIRC in front of Dennis Conner once in the whole regatta. That had all of Fremantle on the waterfront.

Now with amazing developments in the visuals, a whole new type of boat, sailors struggling at the very edge of their competency, virtual eye, huge amounts of data from the boats and very good racing - multiple lead changes, great starting contests, gear shifting and great commentary from sailors we will never be as good I am perplexed (to put it mildly) that anyone can find the spectacle mundane.

I will watch good sailors race anything from Sabots, Moths, Tasars, sailboards, yachts because I love sailing and seeing how good sailors race each other. This is the best sailing I have ever watched. Is it not interesting to see two of the worlds very best teams tussle? Can we not all learn from the Mr Whippy tack and remember times we have tried to pull one out of the hat because we were worried about our competition? Is it not impressive that in a race of 4 downwind legs and only one upwind leg it is the single upwind leg that is seeming to be the crucial one - well after the start. I find it incredible that tacking ability is now proving as critical in these boats as it was in 12 metres. As for being boring I don't get it. Maybe if ETNZ traded Ashby for Langford the results would be closer. Ashby is probably the worlds fastest cat sailor and what he may be doing quietly with the wing may be the difference in straight line speed. We can't tell from behind our monitors.

So put me in the "Thank you for this show" seat. I watched every race of Austalia 2 (including the abandonment) in 1983 and I am not disappointed in this spectacle. I am going for the Kiwis for a couple of reasons but one is that I can go over to Auckland in three years and see this event up close and personal. What a thrill.

cheers

Phil

 

Can anyone quantify why nzilla is so much faster than otusa upwind? Is it the foils, the wing? The front beam fairing? Anyone care to have a crack at the key differences?

 

I think alot of design progress has been made. Who would they would be foilering and match racing to this extent in such a short amount of time.

Maybe next time they could go for partial wing mast una rigs. was there a headsail rule requirement? or design concept/consideration.

I think some ome the knowlege gain could flow on to other boats, watered down a bit and new sailing techiques for racers.

 

It may be the use of the foils up wind, and possibly a form of roll tacking.

 

34th AC

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Very well said Phil-I couldn't agree more.

 

IIRC the 87 defender/challenger trials had some close racing, even if the AC itself was a walkover.

The winning margins so far seem to be about 5%. Surely more than can be accounted for by one bad tack

Looking at the videos I have always thought that the NZ foils made much less spray than the other AC72s, so Daiquiri is probably right. It must be very difficult to design surface piercing foils without using fences

Whoever wins the AC itself the real winners this time have to be the NZ hightech boatbuilders. Probably more people live in the Bay area than in all of New Zealand while LE could probably buy the country. Yet it is NZ that are leading development in wing sails, foils, construction and hull design

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

Groper - Firstly the boats are very even. If you look at the average speeds of each race you will see that they vary from .2% to 2% max. If we assume the boats are even then the difference is easily explained by the sailors are better. The NZ tacking time is better (even spithill acknowledged that, looking at some of the videos it is difficult to get into and out of the cockpits vs the NZ's open arrangment & they are roll tacking. ie they are staying on the winward side so the foil does not have to lift the crew. This allows the foil to lift earlier then they change sides) ) , NZ are covering better and making better course decisions. It could be that simple. If we consider the boats then either the NZ boat is faster close hauled or it is pointing higher. It seems to me that it is unlikely it is faster due to the high parasitic drag design vs Oracles design. So it could be the foils allow it to point higher. This can be acheived by having them deeper or a design decison was made having them wider. (Anyone out there with photos of the width of the daggerboards). Thats my two cents worth! Cheers Peter S

 

Actually Oracle appears to be pointing higher but the Kiwis are getting more speed and less leeway not pinching. It might be a last ditch thing for Spithill to try but those guys have the polar curves and should know what they are doing.....The Kiwis got this one right, I wonder when they developed the concept? And Phil is right, this is fun sailing to watch.

The end plate deck might bring wing decks back into fashion too....

 

I know NZ are tacking better, but it doesnt explain the huge difference upwind alone. In all but 1 race, NZ always gain about 40seconds on the upwind leg alone. The boat just trucks upwind compared to oracle, downwind they seem about the same, perhaps oracle slightly faster. Its like they have less leeway or ability to point higher for the same boat speed... i dont know, i would just like to know why - same question oracle engineers would be wracking their brains over no doubt...

 

Wouldn't it be cool if after the cup is done and dusted they sailed a best of three in each others boats ?

 

Yes, I have considered the same myself. This is done in international horse show jumping. It could get rid of some of the sourness relating to legal BS etc. It is a sport after all.