34th America's Cup: multihulls!

Perhaps the AC should be sailed in Buccaneer 24's built by the crew

 

Energy efficiency is not a sensible measure unless you define the boundary conditions, ie. back to the Statement of requirements. Any measure of energy efficiency extracted from the wind is also the cost of the energy extraction.
But also to take task.....The Power Drag equalisation has nothing to do with acceleration, GZ curves of monohulls are not max at 90 degrees, inverted multihulls are not safe platforms in heavy weather.......

Unfortunately you don't appear to understand the physics of sailing, neither the basics of monohull design, You are very confused about intact stability (and imagined downflooding angles). You also don't appear to understand optimal design coefficients for monohulls.

I think you would get a lot out of reading some basic sailboat design texts and then you might see through some of the hype that you are posting.

 

Over at Sailing Anarchy two very clever mathematicians, one US, the other French, working from videos and measuring over a distance of 550 metres, established:
BOR - 11 seconds to cover distance
ETNZ - 9 seconds same
which equals:
BOR - 26 knots
ETNZ -31.5 knots
so to the horror of OR fanboys ... ETNZ is the faster boat; also crew work and helming during gybes is much smoother and quicker.
Interesting - but still early days.

 

I think that great many posts in this thread should go here instead: http://www.boatdesign.net/forums/boat-design/multi-hulls-vs-mono-hulls-47013.html

So I propose to use this thread for specific AC-related topics, and to move the general mono vs. multi discussion into the other thread.

Cheers

 

I don't think that the spirit or the tradition is important, if it is true that this is just a rich-men's playground with victory at any cost as the only objective. The current format and choice of boats has taken a direction which will be difficult to change in future. We have foiling multis now and we'll probably have too keep them in the future. Otherwise, another similar racing event will be created for big foiling multis, and the AC will lose a big part of it's importance and prestige.

So, we have foiling multis now, and we know that they can go extremely fast. Which means - they can be dangerous. A temporary fix was found now, wind-speed limit, to try to keep the safety indside acceptable limits. But, as this discussion has shown, it is a fix which goes against the original premises of this event. These boats were supposed to race in much wider wind-speed range, and that promise has been broken because the resulting vessels have become dangerous for the crew.

In my opinion, if the AC organizators want to maintain this direction (rigid-wing multihull foilers), then the best way to keep the promise of racing in high wind-speeds and in variable sea conditions is to introduce the possibility to have an automatic flight-control system (yes, these vessels are essentially airplanes with sails) which will take care of fast aero-hydrodynamic corrections necessary to counteract effects of wind gusts and irregular waves, and which will maintain the vessel in a nearly constant flight attitude as external conditions change.

If you have recently flown on a modern jet liner, and if you bothered to look at the wings during the flight, you will have noticed that there are a range of fast-moving control surfaces (ailerons, spoilers) which keep moving, sometimes quite erratically, during the flight. They are controlled by the auto-pilot and serve to mantain the aircrat attitude against external disturbances. The reaction time of these control surfaces is very fast, making much faster corrections than a human pilot could perform.

That, imo, is a kind of system which fast foiling sailboats will need in the future, if the current trend to increasing speeds is to be maintained.

Opinions?

 

Petereng has mentioned the WSL above, here's some more on that:

What AC34 looks like today, had its inception in the plans hatched up before 2007 by Russell Coutts and Paul Cayard; plans which I would describe as their brash 'takeover attempt' of big-league multihull sailing, with a format that they hoped would allow them to sell tickets, and to cash in on long term multihull developments in which they personally had played no role whatsoever.

The World Sailing League project was announced in February 2007, and VPLP unveiled their 70-foot design for the WSL in July the same year. Coutts' and Cayard's multihull circus idea thus started well before Bertarelli and SNG had won AC32 in Valencia, and long before the brawling about the Deed-of-Gift AC33, evolving into Dogzilla v. Cheezilla, got started.

Paul Cayard, Russell Coutts and Lagos announce World Sailing League

World Sailing League unveil new 70ft cat

(to see VPLP's presentation go to VPLP.fr/Projects/Racing Yachts/WSL70)

Already in 2004 there was mention of Coutts and Cayard having ambitions of starting a new class, if you read press releases of the time related to Bertarelli's sacking of Coutts from Alinghi:

I do not know what kind of boats Coutts&Cayard were envisioning in 2004, neither of them then had any multihull experience, and Coutts launched the RC44 the following year. Coutts started skippering the D35 Banque Gonet in August 2005, taking first place in the Bol d'Or 2006; this D35 involvement by Coutts leading to bitter arguments within the D35 class and Banque Gonet's withdrawal in 2008.


Anyway, the WSL 70 did indeed look like a bigger D35, so I imagine that Coutts' Banque Gonet experiences gave him ideas on how to enlarge on that design and make it suitable for windier locations (than Lake Geneva).

... But now I find I'm neglecting my other duties today, and I will have to continue bashing Coutts some other time.

Lol.

 

RR. What a great idea.

 

I take great exception to that Pompous quote.

I took a four year course in Naval Architecture, majoring in small boat design.
I decided not to become a designer as the legal pitfalls were too great in these times, as Brett Crowther found to his cost.

Rather, I used my new knowledge to evaluate other designers works and separate the Gold from the Dross--and believe me there is a lot of Dross around. .
I also wrote several books. "Modern Catamaran Design" was one. I was the Canadian secretary of the AYRS for several years, and the late Edmond Bruce is my yacht design Guru.

Your designs are fine. No problem. They appeal to cruising people who are comfortable with boats they understand and are not challenging.

Designer/Builders like Gary Baigent are at the cutting edge of modern technology and they understand that we now live in a fast moving new age where Cruising monohulls of the type you carry are quite simply OLD HAT.
The spinning jenny was superceded by the weaving loom, but the Luddites were hard pressed to accept the change. They disappeared beyond the event horizon of history and were never seen again.
Monohulls will not Die. The modern monohull will evolve into a new form without doubt. Just ask Doug Lord. He is way out front in this matter.

 

This is also an example of a very narrow-minded opinion.

A boat type and shape come from requirements which a specific boat has to fulfill. Saying that a certain type of cruising boats is an old hat because we now have wave-piercing catamarans or Volvo ocean racer monohulls is like saying that cars are obsolete because we have jet airplanes.

... get the point?

 

Sorry Daiquiri.
You are quite right. I get the point.
I was rather angry at Mikes insulting quote.

 

No, I am sorry for the knee-jerk in the previous post. I have realized it is pretty offensive, so I beg your pardon for that.

But it frankly gets on one's nerves to see always the same non-sense non-argument "this is new and cutting-edge, all the rest is old and obsolete", as if one particular kind of sailboat is a cure for all the transportation problems. Real life is much broader than that, and laws of physics governing ship motions are still the same.

Cheers

 

Yes, my post was poorly worded and yours captures my intent precisely, thanks. For the record: I see nothing inherently wrong with giant foiling cats if that's what the people writing the checks want to play with. I see a lot wrong with testing and racing such craft in San Francisco Bay.

Cheers,

Earl

 

its a poor craftsman that blames the tool,these guys have maybe fifty day at best sailing the some of the most technologically advanced boats out there.Jet pilots don't learn thier craft in 6 weeks. give it rest its not the boats it's the sailors

 

There is too much pomposity and slagging off from the mono cranks here; really you're whinging about your loss of establishment power and influence.
There has been a massive change in yachting with the arrival of the foiling AC72's. Repeat: a massive change in yachting.
Get used to it and get over it.
Also another word in your quivering shell-like ears; all sailors appreciate past yacht design developments and history, all types of yachts. Repeat again, all types of yachts. Your excuses and slagging off - time to move on, chaps. The ride you might find enjoyable, contrary to your ingrained prejudices.

 

I’m sorry if you take offense but your post is so full of misinformation, ignorance and distortion that it would take a tome of naval architecture to actually address each issue properly. Hence it’s better if you go and read one.

But perhaps instead of grandstanding about books and qualifications you could look at what you posted. Someone who signs himself as an engineer and now also surprisingly as a grad of a 4 year NA course should be able to see immediately what’s wrong with several statements in your prior post, which is just the litany of hype that’s dished up ad nauseam. It needs challenging whenever it's promulgated.

Also if you really think the opinion of two extreme foiling enthusiasts counts as a valid critiscism of a vessel type you are sadly mistaken. Also are you really implying that a foiler could make a sensible offshore cruising platform ?

Monohulls have had their revolution, maybe you missed it? For very sensible reasons people still often choose heavier boats over light displacement whether Cats or Monohulls. It's a matter of the compromises, which is what sailing boat design is all about. Ultimately it's up to the individual, that person shouldn't be labelled offensively as a luddite because they don't match you very myopic view of the ideal cruising boat.

And as for the industrial revolution, please look up “False analogy”.