AC 36 Foiling Monohulls

Interesting article from Nov. 2017-I don't think its been posted here but forgive me if it has been:
L'AC75 vu par Quentin Lucet VPLP - https://www.cuplegend.com/lac75-quentin-lucet-vplp/

 

I eventually can propose you a full translation here attached (rainy Sunday works).

 

Thanks for your effort ,Dolfiman!

 

Thank you for the translation. Regarding the last part:

It seems certain to me that after the next AC, we will have a very different vision of sailing monohull Foilers from what it is today.​

It may also have been proven just how impractical they are! Loads of over 100 ton on the lever arms seem extreme, how do they compare with the loads in a canting keel maxi?

 

I do find it exciting, my concern is the potential for capsize, if mechanical features of the design fail. where does all the energy come from to raise and lower the foils? All that said I would love to be able to cruise on a foiling boat above the waves, it could make power boating a dinosaur.

 

The translation of Jean Sans' estimates linked by Dolfiman provides some details (well, guesstimates) indicating that sufficient stored electrical power isn't an issue.

E.g. Sans estimated that around 6 kWh is required to raise and lower both foils 100 times. A 10 kWh battery weighs 85 kg so it seems very doable in a 7 tonne boat. Even if the mechanism is only 70% efficient (no idea if that is realistic) and additional movements are required for stabilisation other than tacks and gybes (such as will certainly occur during the pre–start), then maybe the required power is at least double at 12 kWh. Even doubling the battery allowance to 170 kg doesn't seem to be an issue.

However engineering to deal with the rather massive forces generated in raising and lowering the ballasted foils (around 107 kN each) will be an issue, as will how to prevent collisions while still allowing close racing.

One issue not addressed in Sans' estimates is that the activating force is not always perpendicular to the lever. It must operate over a wide angle, which at the extremes will be 60° rather than 90°, increasing the power requirement by 20% or so. And that only covers the range between foiling position and raised, getting to the "navigation" mode when floating increases the angles much, much more. But maybe there will be a second system for that range.

 

Interesting article and video: America's Cup: Team New Zealand face challenges in AC75 class rule development http://www.nzherald.co.nz/sport/news/article.cfm?c_id=4&objectid=11978376

And another: America's Cup - Crucial process gets underway in Auckland http://www.sail-world.com/news/201247/Americas-Cup-base-development-plans-lodged

One more: America's Cup great predicts new boats to break 50 knot barrier http://www.nzherald.co.nz/sport/news/article.cfm?c_id=4&objectid=11968221

 

I don't necessarily agree with Mr. Hancock, though I do think the boat is overly complex and will be expensive and may be too much for some teams. Other than that I think its pretty cool.
I think there are much simpler and equally effective ways to design a monofoiler that would be nearly as fast as the current TNZ version.
I thought the artwork below was hilarious.....
------------------------
Brian Hancock from last article above:
I have always gone with the notion that pretty boats sail fast...This design is anything but pretty. It looks like some kind of space alien."
art work by Mike Trim:
TNZ Attacks!(dl)

 

Dunno about the loads, but we know that canting keel maxis have proven to have the worst safety record and be the least popular grand-prix maxi class in modern history. We also know that the people who used to claim that canters were going to be popular were completely wrong, and that the people who have spent the last decade and a bit claiming that foiling boats would become popular are wrong.

So since monos that cant are unpopular, and foilers are unpopular, it seems highly likely that a canting foiling mono will be extremely unpopular. I recall that GD said that he wanted to look on Auckland Harbour in the future and see a couple of boats using AC technology. To hope that such a tiny percentage of the sailing world would be able to benefit from AC tech seemed to be a very low bar, considering the money that is thrown at the event.

I wonder how our vision of monohull foilers will change after the next AC? Hopefully we will start seeing people realising the limits of a vision that promotes an inaccessible, enormously expensive part of the sport that is open only to people who sail in certain areas. Then we can get back to a vision of an accessible sport using simpler boats, and the sport may stop shrinking.

I keep tabs on the popularity of sailing by looking at the number of people turning up to national titles. Since the IACC monos were chucked out of the AC and replaced by faster boats, the UK's national title fleets have fallen by about one third. The situation isn't much better, if at all, elsewhere.

While it's not a perfect measure, it seems to be an indication that the foiling hype is certainly not helping sailing, and may actually be killing it as a widespread participant sport.

 

Funny how Melges decided to adopt such an unpopular technology on their new canting keel 40 footer. Then there is the fact that many ocean racers from the Mini on up use canting keels. Interesting 2008 article about canting keels pointing out the major effect hostile ratings authorities had on canting keel race boats when the benefits of canting keels were so great: Stuck On Centerline https://www.sailingworld.com/racing/stuck-centerline
--------
Foiling is permeating every aspect of sailing from windsurfers, to kite surfers to Mini's to larger keelboats(mostly foil assist so far) , from small multihulls to the largest racing multies in the world. Must be pretty unpopular to have been adopted by so many different types of boats--and this is just the beginning.
--------
You think participation in major sailboat racing championships is a good indicator of participation in the sport of sailing?

correction--( also: probably should have mentioned that the Volvo and Vendee-the two biggest round the world races use boats with canting keels exclusively)
------------------------
Older thread-interesting list:
List of Canting Keel Racing, Racer/Cruiser or Cruising Sailboats https://www.boatdesign.net/threads/list-of-canting-keel-racing-racer-cruiser-or-cruising-sailboats.39460/

 

"Most ocean racers from Minis on up use canting keels"???

Completely and utterly wrong. Take the world's biggest major ocean race, for example - about 25 out of 300+ boats have canting keels. How on earth can anyone pretend that less than 10% is "most"?

How many canters are among the 15,000 PHRF boats in the USA? How many canters are among the 5000 boats racing under OSIRIS/HN? How many canters were in Australia's biggest regatta (quick tip, the answer appears to be ZERO)? What proportion of boats in the ORC worlds are canters (quick tip, it's less than 1% I think)? How many canters are at Spi Ouest, or among the hundreds of boats in the FFV's HN series (last times I checked it was zero and zero, respectively).

The article you referred to notes "the lack of sustainable success of any production boats with this technology." The Schock 40 died. The little 5.5m sportsboat from Germany died, I think. There's probably not a single production canter in the world today. And the basic point of the article is wrong - the authorities did not ban canters other than briefly and in a few regattas, nor have they penalised them as shown by their success under IRC. The simple fact is that the vast majority of active sailors and owners - as distinct from bystanders who have never owned an ocean racer and often never sailed on them - don't want canters.

No, foiling is NOT very popular. It is done by a tiny proportion of the world's sailors, as demonstrated by the fact that non-foilers are sailed more vastly often and sold vastly more often.

Yes, I believe that participation in major championships is a pretty good indicator of participation of people racing at a high level. Another good indicator is sales of craft. Another one is the number of people active at club level racing. By all of those indicators, canting and foiling are only very small niches in the sport as a whole.

The Melges 40 website shows just five teams. The most popular production 40 footer was about 150 times as popular. The most popular 40 foot racer was about 30 times as popular. It is bizarre to apparently try to use a class of just five teams as evidence that canting is "popular".

Since canting and foiling have been heavily promoted, activity in sailing has been rapidly declining. You probably wouldn't have noticed because in that period you don't seem to have actually raced or owned a full-size racing boat, nor have you apparently travelled to a major sailing area or tried to keep track of what people are sailing, rather than what people are advertising.

 

As regard canting keel for Mr Average boat, there is actually a lot of con's arguments :
- takes volume in the center of the cabin,
- hydraulic system (= source of worries)
- need 2 additional daggerboards taken also volumes inside
- the most important perhaps : in case of system failure, with the keel blocked in the wrong side, in bad weather >>> high risk of capsize, of humans loss may be : no boat builder want to takes responsibility for that kind of risk.

Same kind of arguments for the water ballasts systems

On the other hand, some foil assistance like the one experimented by Figaro III could be promising as option on boat regular models :
- seems very easy to deploy / to retract (see video on the Figaro III thread), needs no specific skills and a wrong use leads just to more drag,
- beyond speed gain itself (when conditions are for), one can have more pleasant behaviour in waves,
- takes not a lot of volume inside the cabin, not a lot outside when docking
, but more costly of course, is speed gain worth this extra cost ? It is the interest of this new design.

On the debate on foilers and non foilers, I think for the foilers we have to distinguish between full flying needing high skills, and foil assistance which can be easily in the skills of average sailors.

 

It certainly isn't a perfect measure - you're more likely to be measuring people's income in difficult times. It also makes little sense to blame the AC or foilers (although the new AC boats don't appear to be taking things in any useful direction for anyone who wants advances to be passed on down to practical foilers for normal people - I have no interest in them at all, and I'm a fan of foiling).

If any part of the problem isn't financial difficulties (while govenments blow all our wealth on unnecessary education which puts people in heavy debt for the rest of their lives just so that they're qualified to sell hamburgers), the real issue is how you can educate the public about what sailing is and what it can do for their lives. The AC has no impact on that because no one normal sees it - in Britain, for example, it was hidden on the BBC's "red button" channel 601 which appears in no listings magazines, so you had to know about the event already and want to see it before you would even look for it using the electronic programme guide, and even then you would often find that the programme has been broadcast an hour early due to a change in the schedule since you looked it up the night before. They didn't even start covering the event until the British team was out. So how is the type of boat used harming sailing when hardly anyone sees it anyway? It was even harder to see any of the AC before it moved to foilers.

What about coverage of the Olympics then? Did the Nacra 17 damage sailing by flying on foils? The entire Olympics went through last time without me seeing a single race, even though I wanted to see them and had time to spare for it too. The sailing simply didn't punch its way through the other sports to appear on the main channels, which meant that only people with satellite dishes or cable had access to them. That's a real measure of the problem, and a lot of it caused by the Olympics being too big - the Summer Olympics needs to be divided in two to make it more affordable to host and to give more events decent TV coverage. There should be three Olympics every four years, one for snow and ice, one for land, and one for water. That would get a lot of coverage for sailing without other sports obliterating it, and most of it would involve non-foiling monohulls of the sort normal people sail. But sailing also provides an opportunity to do something that other sports can't, and that is to have children involved (because it doesn't require them to train to excess to develop lots of muscle) - there should be Mirror dinghies in the Olympics and each one should be helmed by a child (with an adult crewing). That would sell sailing better than anything.

 

Sure, David, it's not a perfect measure. There doesn't seem to be any perfect measure. Note, though, that I am also looking at new boat purchases. They also show that foilers (which are great craft) and canters are definitely not "very popular", making up only about 2% of the International boats sold.

Any link between "difficult times" and the current issues with national titles appear to be difficult to support on the available evidence. Times were more difficult around 2008, during the UK's worst recession since WW2, and yet over 5,000 boats did national titles in the UK compared to 3,000 plus now. If the economy is the issue then why has sailing also dived in Australia, which is currently in the longest economic boom known to mankind?

Yes, the general public hasn't been able to see much foiling. That may show that the claims that more spectacular boats will create more publicity and bring more people into the sport are completely baseless. As you've noted before, the Olympics haven't increased overall sporting activity in the UK and activities like sea kayaking, which get little TV, are growing.

What concerns me is also the promotion inside the sport, where the media and industry are trying to promote an expensive, inaccessible form of the sport and therefore arguably harming the practical classes that people can sail. We have become so used to the sport promoting an elitist model that we've arguably forgotten the way things used to be when the sport was big. The other day I picked up some old America's Cup books in which leading sailors were complaining that the 12 Metres were too exotic and too expensive. That was in an era when an AC campaign cost about $10 million, inflation adjusted, and when former AC boats were so mainstream that they were racing in the main fleet of the world's biggest race and the UK's top race. Now an AC budget is around 10-20+ times higher and the former AC boats, far from racing in local club fleets every weekend, are sitting on shore as museum pieces.

One other thing - if keen sailors cannot afford to spend a few hundred or so to go their national title, we can't expect them to spend the many thousands that are required to upgrade to a foiler. Foiling is fun, no doubt about it, but while people (not you or Dolfiman) are over-hyping it then some of us will try to bring reality into the discussion.