Rule expert needed - aisle A

floater

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One of the top tier A Class developer/builders just went public with a - potentially - game changing reading of a class rule.

I'm no expert, but as I understand it rule 8.2 attempts to limit dagger foil geometry by prohibiting "insert from below". Ostensibly this was done to outlaw moth style T foils - but has more recently inhibited AC72 style L foils as well.

I post this here for a few reasons:

- they're getting kind of grumpy over there in the multihull forum

- it is AC related as TNZ went A Class big time at last year's worlds - Outteridge there too

- there are plenty of seasoned rule interpretation experts hereabout with nothing better to do. :)

Apparently - the entire fleet could be exploded by the lack of a single conjunction! Foiling class DNA is at risk - so please weigh in if you have something to add.

Dario Valenza has pushed the button:

only appendages that are movable AND retractable come under Rule 8.2. Ones that move but dont retract need not comply with 8.2. So there is no need to worry about how the appendages are inserted.
...reads like an America's Cup controversy.

http://www.a-cat.org/?q=node/474

 

~Stingray~~

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"only appendages that are movable AND retractable come under Rule 8.2."

Here's hoping Dario is right! :)

It is taking the AC a full cycle to get foiling rules right, hopefully the A rule has a loophole big enough to avoid the same kind of restriction corner.

 
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dogwatch

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...reads like an America's Cup controversy.
No it's the direct opposite. It's about maintaining development and practicality for a class of sailors who mostly sign their own cheques and it's clear those outside the class have little of value to say. Which includes me.

Really doesn't need another thread here.

 
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Tornado-Cat

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Tornado-Cat said:
Simon claims Isaf interprets it differently, if yes where is the interpretation ?
Read the A Class rules.
I read it, where do you see an interdiction of the wand in interpretation 4 ?

As far as the measurer guide lines, you should tell Isaf to correct their mistake in metric system conversion.

"76 cm (3 inches)"(page 2 chapter 2), it should be replaced by 76 mm.

http://www.a-cat.org/sites/default/files/Measurers%20Guidelines%2030-07-2014_0.pdf

At the end, even is the bottom of the box is limited to 76mm, the wand is not forbidden unless Isaf decides otherwise, thus in fact modifying the rule of the class.

 
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floater

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Already answered in the original post. No controversy. I think all the evidence is that Dario is wrong.
Understood - and it would seem that he's not exactly a disinterested party - latest video has his new boat foiling upwind?
But for someone of his stature to make such a claim on the Class website - is no small thing...

 

floater

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...reads like an America's Cup controversy.
No it's the direct opposite. It's about maintaining development and practicality for a class of sailors who mostly sign their own cheques and it's clear those outside the class have little of value to say. Which includes me.

Really doesn't need another thread here.
The A Class made the same exact mistake as the AC72 rule - give me a little lift, but not too much!
As for this thread - nonsense - all topics in AC Anarchy are essentially of no import beyond conversation. But, the topic within the multihull forum may matter - believe that NO actually mentions SA in this vid.

He also takes a dig at rule 8.2. Think that rule has few fans really:

 
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dogwatch

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As for this thread - nonsense - all topics in AC Anarchy are essentially of no import beyond conversation. But, the topic within the multihull forum may matter - believe that NO actually mentions SA in this vid.
Not my point, which was that with the exception of SimonN, nobody on SAAC has much of a clue about the issues, which are complex and technical. In addition, viewing the A-class primarily as an AC training platform is a category error.

 

floater

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As for this thread - nonsense - all topics in AC Anarchy are essentially of no import beyond conversation. But, the topic within the multihull forum may matter - believe that NO actually mentions SA in this vid.
Not my point, which was that with the exception of SimonN, nobody on SAAC has much of a clue about the issues, which are complex and technical. In addition, viewing the A-class primarily as an AC training platform is a category error.
Lighten up - have some fun - live a little!
A Class is hardly a mere AC training platform - but it is a pretty excellent racing class. And a nice place for AC sailors to race - which they do.

But the main parallel with the AC story is about design trumping rule intention. And the class is undergoing convulsive change because of this - right now - in a very similar fashion to the evolution of the AC72s.

A rule was drafted to prevent full foiling - the rule failed. The class is proceeding as a foiling class, but it's proving a bit bumpy and interesting. Competing design going lots of different directions.

image.jpg

Essentially rule 8.2 dictates that any foil must enter from above the hull. Clearly, this eliminates the TNZ style foil. The class also limits horizontal span of the foil - as shown above.

So, you got just a little horizontal window to make the magic happen. Oh yeah - both foils tend to stay wet at all times (so far). And if you squint your eyes and imagine the opposite board down too - you can begin to see a familiar pattern emerging...

PS: Tom Speer has had some design interest here as well, this it ain't your grandpa's A Class anymore...

 

nav

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The 'box' you ^ (and TC) point out is a given (until they change it!)

But are you totally dismissing Dario's point about non-retractable foils?

In this case only appendages that are movable AND retractable come under Rule 8.2. Ones that move but don’t retract* need not comply with 8.2. So there is no need to worry about how the appendages are inserted. http://www.a-cat.org/?q=node/474

And what about his other point about flaps, wands etc? (though video shows they are not required - but may allow for more critical foils I guess)

Seems like the Class still has a few things to get clear - or maybe they will be 'clarified' by the measurers, at some future competition.

* NO said he could trip the leeward board and allow water pressure to retract it - but there is plenty of video showing A's 4x4oiling permanently - so do any boards actually get retracted while racing?

 
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Tornado-Cat

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I wonder whether the 8.2 is not a distraction as Dario (?) points out that the foil can me modified by the water pressure during flight, adapating it to the speed.

 
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Doug Lord

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Wands make foiling easier and more stable with a close second to refined versions of UptiP foils like on the GC32 and Phantom. The UptiP foils are probably faster than 4 down wand controlled foils but nothing says you can't retract the windward wand controlled foil. Retracting the windward foil with uptip foils is mandatory for best performance and that may turn out to be true with wand controlled foils as well-the fewer foils in the water ,the better.

This is a pretty exciting time and cudos to Dario for going public with his position-hope he is proven right!

 

nav

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^ That's one way to look at it - trouble is that they have long ago made a more fundamental choice which was too join a development class - plenty of one design beach cats for them that prefers 'em.

You do not want to address the question Dario raises?

So you you stick with this premise... Essentially rule 8.2 dictates that any foil must enter from above the hull. Clearly, this eliminates the TNZ style foil.

What problem :D

v6.jpg


 
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floater

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The 'box' you ^ (and TC) point out is a given (until they change it!)

But are you totally dismissing Dario's point about non-retractable foils?

In this case only appendages that are movable AND retractable come under Rule 8.2. Ones that move but dont retract* need not comply with 8.2. So there is no need to worry about how the appendages are inserted. http://www.a-cat.org/?q=node/474

And what about his other point about flaps, wands etc? (though video shows they are not required - but may allow for more critical foils I guess)

Seems like the Class still has a few things to get clear - or maybe they will be 'clarified' by the measurers, at some future competition.

* NO said he could trip the leeward board and allow water pressure to retract it - but there is plenty of video showing A's 4x4oiling permanently - so do any boards actually get retracted while racing?
I haven't seen any foils retracted while racing - but this would seem a fruitful avenue for development.
In terms of The Conjunction rule controversy- yes, it does seem absurd to me - but I suppose that's why I asked the question to begin with - should the reading be taken seriously?

And given the class should be doing what the members want - and the members want a beach cat - it seems unlikely that a competitor showing up at a race with a fixed foil plus wands and flaps will be well received.

 
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floater

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^ That's one way to look at it - trouble is that they have long ago made a more fundamental choice which was too join a development class - plenty of one design beach cats for them that prefers 'em.

You do not want to address the question Dario raises?

So you you stick with this premise... Essentially rule 8.2 dictates that any foil must enter from above the hull. Clearly, this eliminates the TNZ style foil.

What problem :D

v6.jpg
Beach cat - beach cat - beach cat!
Yes - TNZ foil hurts the launch. A fixed foil kills it.

The physics problem to solve: how to fly within the confines of the rule.

But it's significant that some of the major builders seem to be giving up on "easy flight" within the rule and are instead proposing a biplane moth...

 
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nav

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...major builders seem to be giving up on "easy flight"

Giving up, or looking for even more efficiency?

Once you are convinced that foils are there to stay, everyone has seen how quickly you can go from zero to hero - as OTUSA proved, by getting foil control more (even superhumanly ;) ) accurate.

I guess Dario either knows, or wants to find out, whether more automated ride height control will give more consistent foiling or allow more critical/efficient foils to be utilised - or both?

 
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floater

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Perhaps it's sheer ignorance - but I am not yet a fan of the wand, flap, or lever. Perhaps it is akin to a snapping batten - but I'm not there yet.

Here is Dario's A with Herbie assisted flight:

https://www.youtube.com/watch?v=qY9lJN4W-F8

And you make a valid point concerning the motivation - only the very best sailors can fly without a Herbie. But, perhaps, anybody can be a Glen Ashby just by strapping one on...

 

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