34th America's Cup: multihulls!

34th AC

Good article by Sail-World: http://www.sail-world.com/USA/Ameri...ations-not-expected-to-be-an-easy-meal/109794

Highlights:

1) The new wind limit of 20kts for the Louis Vuitton Cup Round Robins creeping to 23 kts for the America’s Cup Match will still need a Protocol change. The new limit is a couple of knots below the international standard used in the Olympics and World Championships. Although it applies before the start only, the racing can still be cancelled after the race has started for safety issues.

Even with the reduction in the wind limit, the AC72's in just 20kts of breeze will be sailing at around 40kts, and dropping the wind limit won't have slowed the boats at all. 'The boats are going to be still plenty powered up, but they are not going to be over powered by as much as they would if they were racing in 33kts of wind,' says Ehman.

Contrary to other reports the lower wind limit for the regatta has not changed – and cannot except by a majority vote of the teams. Of some concern is the ability to have variable start times, possibly based on forecasts but also with the perspective that one team might try an influence the start time to get 'their' conditions.

Ehman points out that if the teams do have concerns in that respect, all they have to do is to get together as sort out a new and stronger lower wind limit. 'It is not a safety issue,' he adds.
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2)
Elevating the Rudder ( see picture in article of Oracle rudder T-foil with flap)

The most curious of the changes lies in the Recommendation 1.3 Rudder Elevators. These are the winglets attached to the ends of the rudders and look similar to the tail flaps on a plane, or adjustable spoilers on the back of a race car.
What is believed to be an adjustable rudder is visible by Russell Coutts’ right foot in mid-March 2013 -
The term is a new one in the Class Rule, in other words, Rudder Elevators didn't previously exist in the AC72 Class Rule. They do rate a mention in Rule 8.6 which says that trim tabs or moveable winglets, which can be adjusted while racing, are prohibited. No size or dimensions are set on these.

The Recommendation (introduced under the guise of safety) does set some parameters for so-called Rudder Elevators of area and (wing) span and minimum depth below the boat.

It also allows these to be adjusted before the warning signal for the race, but can’t be adjusted in the race itself.

One would have thought that if such features were a safety device that they could have been deployed during the bear away maneuver which has triggered both capsizes to date. Effectively to do a hand-brake turn at the top of the course.

The rudder elevators may have been able to be pulled on in such as way as to try and reduce bow-down trim which would reduce the chances of a pitch-pole. But that is not the case under this Recommendation – which only permits the elevator to be set several minutes before the start, and the crews would then have to suffer the drag of the preset elevator for the remainder of the race, creating drag and slowing the boats.

To bring such a change in just 40 days before racing is very significant for the Challengers. The Defender Oracle Team USA is believed to have had the rudder devices fitted for some time. Nothing illegal about that as the AC72's are just in test mode, but as the rules currently stand they mist be removed to race in the match in September.

 

.

I think this could perhaps have waited until the service has been held next Friday for Andrew Simpson,
whose short career with Artemis lasted only from February 27th until May 9th.

Much of that time the Artemis 72 was undergoing modifications.

 

34th AC

I think whoever issued that should have waited out of respect. Was it Yachting magazine?

 

No. The 'Yachting' in the headline is just in regard to the sports category, and this is one of several New Zealand sports news sites which are relaying what Peter Montgomery (PJ to the locals) had said. PJ being an authority on America's Cup stories:

Peter Montgomery

 

America's Cup ... I heard something about San Francisco in the summer, multihulls, and foiling. Pretty cool. Might be worth a look.

Then I heard 20 knot wind limit? After sailing in SF for over 20 years they don't even limit juniors in El Toros to 20 knots.

Someone has turned the America's Cup into a very expensive public joke.

Sad

Randy

 

34th AC

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I'm just about at the point of agreeing with you, Randy. I remember the old Cups with the wind limits-hard explaining how the state of the art boats in sailing have to sail in 23 knots or less. I'm wanting to hear what the crews think..... The good may be that they figure out how to go faster in lighter air.
Did you see the 18' Flying Phantom thread and recent video? They did 26 knots in about 9-11.4 knots of wind using an AC foil configuration(single main foil/ windward foil retracted)-watch that video if you get a chance. The thread is here: http://www.boatdesign.net/forums/multihulls/flying-phantom-f-18-catamaran-43898.html last post....

 

All of the recent videos (all boats since the break) show "mixed bag" results for altitude/attitude control. Sometimes they are steady, others they are not.

Numerous gybes show an occasional "good/smooth" with others being Yuck!

Some of the Yuck (both gybes & runs) may be the result of a "let's try this" others look more like the stability problems are a basic the inability to handle variable wind conditions.

I think they are all still on a steep learning curve for boat control.

All of them seem to have the promise of winning speed. However, for now, I would say that the the fleet race winner would be the one that stays at full speed for the highest percentage of the time.

These "crash, waddle, swing around, swing back and go" sequences are just SLOW.

 

http://www.stuff.co.nz/sport/1387882

 

I would leave it to the experts to decide on the top wind speed limit for these boats. Basing it on what El Toros or any other boat can handle does not make sense to me.

I bet I could handle 40knots if I was placed on a barge with my handkerchief up for a sail but that would not make me a better sailor!

regards

 

I don't know if this has been posted and I don't have time to peruse 90 pages but here you go:

http://www.wimp.com/overwater/

 

34th AC

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Thanks, Steve-thats a video of Oracle before they had their new foils. The new foils use a curved daggerboard with a more horizontal "L" foil.

 

Cheer up Randy, they won't be sailing slowly regardless. Given that it is a new development class, and such humongous boats, I sort of empathize with the reluctance anyone might have to subject them to higher wind ranges.

Back when I spent a little time in a far smaller development class, populated with self-builders spending 95% of their time building/preparing and 5% sailing, nothing would have cheered us all up so much as a promise that we'd be sailing in no more than 10-12 m/s.

lol

And when expenses are running so high that even Ellison, Törnqvist, and Bertelli are complaining about it, then something less than 33 knots wind is reassuring on that level as well, don't you think?



Here's that video of Oracle's and New Zealand's first close encounter:

http://www.youtube.com/watch?v=Yz2PIGL7Plg

 

The point is they *knew* where the races would be when they wrote the design rule. It is always posible to sail a fast boat slower. If it is blowing 20-30 just slow the hell down and finish ... just like every other sailor has to do at some point.

Changing the upper wind strength limit *after* the design, build, and sailing teams have displayed a lack of seamanship or common sense is just stupid.

Your design cut the scantlings too close? Simple slow down or don't race.
Builder get the lamination schedule wrong? Simple, build a new one correctly.
Sailing team can't figure out how to sail at 100% without crashing? Simple have them sail at 85-90% until they figure it out.

Lower the wind speed limit? Never. Most of the world has used upper wind limits to scoff at the AC for over a century. In 1920 they created a race for real sailors after an AC match was called off for too much wind. Is that where we want to go with new cutting edge designs?

If the rule makers, designers, and builders can't create a rule and boats that are relatively safe to sail in known SF Summer conditions, we don't want to advertise this incompetence to the world by adding a speed limit to a race.

 

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Geez, thanks Randy- I had no idea the wind limits went so far back!

 

LOL ... yes people have been poking fun at sail racers for quite a while.

Lets be clear: If they had put a 22 - 25 knot limit into the design rule from the start I would have no problem. The playing field is fair and even.

The problem for me was all the lip service they gave to real world winds and that these boats would be different. That these boats would not need artificially low wind limits. These boats were supposed to be different.

Now it looks like we are being sold more of the same ...

It was supposed to be 10+ boats? We have 4?
The boats were supposed to sail in SF Summer conditions? Now they might not?

Half the cool factor of these boats is lost once they get branded as fragile, expensive toys.

Just my opinion.

R

PS- The schooner Bluenose won every race she entered. She is on the Canadian Dime and half of Canada thinks that Bluenose won the AC at least once.