A-class has hydrofoil problems!

The A-class is a development boat but after 30 years of development the class is stable and you can use the same boats for several years and still be able to finish close to the top. The original rule for the A-class was only length, beam and max sail area, but a min weight of 75 kg was added a couple of years ago to avoid the most fragile designs. Hydrofoils could give big speed gains and to keep the class stable a rule was added to keep them out. But all rules have loop holes and now an A-class builder managed to build " banana" shaped centerboards that was legal and that boat is sailing in the current A-class europeans. The boat is maybe 10% faster than the other boats!!!!

Good or bad for the class, what do you think?

/hakan

Good.

It is a development class or it isn't. Pics??

If it obsoletes a lot of boats, bad! The A class has been a very stable class lately and that is probably part of why people have bought into it. Most sailors wants stability to protect their investment. That is my thoughts..


PIIIIIIIICSSSSS! Pretty please?

I don't have any pictures yet but the design is done with a constant bending radius of 1.5 meters which gives and approximate angle at the tip of 45 degrees. The centerboard goes through the middle of the deck and extends through the center of the hull. I've talked to Marstrom today and there are a lot of discussions at the Europeans right now about this.

/hakan

I know that they have been used successfully with both the C-class and the Orma 60's. Who built the boat?

Checkout the one in the foreground, it looks a bit suspicious. Is that it? Do I win a prize? <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" /> :

IMHO you take a risk when sailing a development class cat, and these things will happen.

Nils Bunkenberg is the designer and builder according to my sources. Bunkenberg saild with a similar boat this year and had excellent speed until he broke the centerboards. He switched to straigh centerboards and got "normal" speed. The centerboard slot in the hull is wide at the top and can use both straight and curved boards. They sailed against the boat today and when he pulled up the boards on the downwind he had the same speed as every one else but when he pushed them down he just walked away!

/hakan

It might make a lot of older obsolete boats competetive again
regards

Thare was a boat at the '05 worlds in France with banana boards. I don't recall that it was in the top finishers. Apparantly someone has refined the design since then. If it is large boost in speed for the average sailor, I can see it worth a refit. If it takes the top sailors to achieve the benefit from it then it's a moot point for me. I can't keep up with them using the current equipment.

Gordon

Exactly.
Fitting new cassettes require skill and the total cost isn't irrelevant. Still, the refit is relatively simple and probably inexpensive compared to a new sail (for example).

I say its a small chance that it will be a world beater.

Look at all the fuss over Ben Hall's solid wing sail, it wasnt faster in practice.

Clearly the class association has it's eye on growth of the class while maintaining a certain level of freedom of development. Foils were excluded when it was clear they were a large advantage. I bet the jury is still out on the Banana foils but if it does show a dramatic increase that is not easily retro-fittable to the existing fleet, I suspect the class will move away from them or develop a sub-class. Don't get excited yet.

Curses upon you horrible trouble makers!

Here are the current results:

http://cnbpp.free.fr/A_class/A_CLASS_A_EUROPEANS_2008.htm

Who's the one with the banana board?

GER 14 BAIER Bob


/hakan

Well if this does prove to be a real improvement in speed, then I would say that many of the top competitors in the class will look at modifying their boats. I though that Lars was playing with banana foils last year or the year before around the time that he convinced me to join the class. As to Ben's rig, I thought that downwind he was doing extremely well, but was struggling to find speed upwind and in certain wind conditions. I may have it bill, since you are active in the fleet and I am not.

This is merely someone's successful attempt (so far) to "take advantage" of an apparent loophole in the rule which was passed specifically to outlaw "lifting" boards, which at one time were being utilized by a few sailors to gain an advantage. In that case they were canted straight boards (I believe also asymmetric?). They offered a clear advantage but would have, it was felt, obsoleted all the current boats and increased costs considerably, neither of which was felt to be in the class's best interests at that time. Ben's wing shows promise- very fast on reach and quick downwind. But if it ever becomes a big advantage then, I agree, there will be either a "Super, open A class" and something like the current one, or wings will be outlawed. Remember "Wild Turkey"? The winged 18 sq meter? Totally killed the thriving open 18 sq class within a year. And wings are even "retrogradeable" but they are such a PITA!! Need special trailer (see pics of Ben's on various sites) and several people to assist raising/lowering which Ben did almost immediately upon hitting shore and didn't raise until time to leave beach. If you capsize and it gets water in it <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" /> <img src="http://www.catsailor.com/forums/images/graemlins/confused.gif" alt="" />
As mentioned, this is a "loophole" that will likely get closed at next class meeting. In the "A" history there are multiple examples of "special boats" being built for the World's which have, sometimes, proven very successful and if felt "bad" for the class the rules were changed and they disappeared- The reason there is a minimum weight rule is due to some well healed persons building flyweight, essentially "disposable" boats for the World's. Won too- so bingo! minimum weight rule passed. In fact the Flyer itself when it debuted at the World's was "new" and guess who had a large hand in designing that one and sailed it in it's first World's to great effect?? Right! Nils Bunkenburg! Class couldn't figure out how to outlaw a hull shape so now almost all boats since have been an attempt at modifying/improving that shape-- must have been pretty good since a Flyer2 won this year!

Kirt

Isn't this something we all want to see though? I mean development has to be done somewhere so we all can move forward, technology wise, right?

I would rather pay for (and use) banana boards, if they turn out to be superior, than build a wing sail, no doubt, but I'm glad there are some smart guys out there who will spend the time and money working on that stuff.

Somebody has to be first, right? Else we would all still be sailing Hobie 16's, not that there's anything wrong with that, but look at all the speed improvments since that boat came out. If the bananna boards turn out to be superior, would it cost all that much to buy (or build) a set? Or would the hulls need to be modified to accept the bend too? That might set you back a few bucks.

I don't see it as that big a threat, look at sail development, nobody was complaining when guys started building with mylar instead of dacron, even though mylar was lighter and held shape better, and it cost more, but now we are all using it. Would we want to go back to dacron mainsails?

Same goes for wing shaped masts, mid pole snuffers, T foil rudders, etc. so why not bananna boards?

Timbo,

development is good. However, radical development in an established class could obsolete a lot of boats. The members in that class could find it hard to sell their boats afterwards and the class might eventually fail. I am not saying that is a likely scenario for the A-cat class, I am speaking generally. It is all about what ones personal risk is. The owner of a competitive A-cat might have a different viewpoint on banana board development in the class then us outsiders.
When that have been said, I am very happy to hear that somebody are testing this. Good theoreticans have said that using banana boards to lift the hulls will generate more drag than without. Would be fun to hear that banana boards did work for small beachcats.

Darryl Barret asked a good question once. It was something like this: When you put beachcats on hydrofoils, is it still the same sport? I think that is a very good question and I dont have the answer.

My A is competitive on a local or regional scene but would not be competitive on a national or worlds scene. I own a boyer MKIV and prior to that a well built Waterat. I think that putting banana boards on might help the boat sail faster, if it would only improve my sailing abilities as well, I would have the modifications done. With that said, to use banana boards you do need to modify the trunks to the shape of the boards and this could easily be an expensive proccess. I am only guessing, but if I asked Lars to do this modification I am assuming that boards included this could cost between $2,000-$3,000. For me, that is not something that I would want to spend right now on the boat. I though am not sure that I am against this development. Whose boat is using the banana boards?

Beyond that, if you look back at photos from the 2006 Worlds and Glenn Ashby's geltek Flyer, it would appear that he had canted boards at that time.

If the A-class descide to allow "banana" boards there will be changes all over the boat until it has reached the same level of refinement as the current boats. Imagine the number of foil designs that needs to be tested combined with position and hull shape. The changes needed will make the boat even more expensive once it is stable, but the big problem is to convince the sailors to stay until things are stable again.

I doubt that you will be able to compete and top level with a modified boat. You will probably need to move the trunk and make reinforcements around the trunk since there will be other types of loads from the board.

The best thing is to have a ballot and check what the sailors in the class want. If they sailors thinks banana boards are ok I think we should concider another option, to remove the foil ban completely. The banana boards are using a loop hole in the rule, and it might be a more expensive solution than to have full freedom when designing foils.

/hakan

Hakan,

What is your boat now?

I agree with you Haken, and I also think a full up T foiler, board and rudder, would be cheaper and easier to build and maybe easier to make go fast as well. <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" />

I know that dave carlson has an older Cal Fuller on foils. I think it is a Cal Fuller. Lars Guck was also playing with foils for an A at the time that they were banned. As far as the loophole is concerned, everyone should have seen this coming because lifting foils were not banned. Hydrofoils were. The reason for the banana foils coming into existence was simply to have a lifting foil that did not exceed the B-Max of the class rules whether it was on A's, C's or Orma 60's. Canting daggerboards had limited lift capabilities especially when you could not exceed the B-Max. To do so meant that you shortened the beams if you desired a greater angle of attack on the blades.
8. Hydrofoils are permitted.



The following rule was passed by ballot 28th February1998 and will take effect from 1st April 1998:



9. Minimum weight in full sailing trim shall be not less than 75 kilograms.



The following rule was passed by ballot August 15, 2001:



10. Hydrofoils shall not be permitted in ‘A’ Division. (Approved 2001)

I don't believe this is new. One of the Dutch boats at the 2006 Sweden Worlds had banana boards. It was measured and allowed to sail.

The only boats at that worlds that had measurement issues were the ones where the top of the centreboard case was at the extreme beam and the board at an angle. Meant that when the board was raised it was outside the max beam and part of the board was still in the water.

But the banana board boat wasn't any quicker and Ashby won all races (except for last which he didn't sail) on the Flyer 2.

Here's a good shot of the CB in question.

I more interested in the amount of twist this boat has, that can't be a good thing.

If you look at the pic, the board is a long ways forward as it should be so that its infront of the LCG or the board will just lift the stern for zero advantage.


To balance this forward position you have to increase the area of the rudders to drag the lateral centroid aft so you don't have a bad case of weather helm. An example would be the foiling moths where the rudder is the same chord as the board and just 2-300mm shorter, plus its on a gantry which helps also.
The net result is that you have nixed your light air performance with the added wetted area and made the boat a bit more difficult to tack.

What looks like a good solution for the use of banana boards comes from VPLP and the WSL boats that (see below) that I believe should be launched next month.


The web site is web page

When you split the hull in two parts and place them far apart, is it still the same sport?

When you put a Moth on hydrofoils, is it still the same sport?

I believe the three cases are evolutions within the sport.

However, this is not enough to justify a rule change allowing hydrofoils in the A Class. The situation of boats/people who would not upgrade for any reason has to be considered, as well as the development time to return to "state of the art" level.

The loophole being exploited at this level only means that beachcats with asymetric foils will eventually become popular. The A Class can choose 'to be or not to be' the first ones.

I know for a fact that changing out the daggerboard trunks in an A-cat of ANY age costs a bit more than $1000. The shape of the hole won't change that cost very much. New symmetrical 70 mm boards are about $1000 per pair. Banana boards might cost a bit more than that, but you might have a competitive boat again for 2+K dollars, then adding a good sail. This seems like a fantastic bargain to me, noting that some sailing skill is involved.
The wingsail is pretty to look at, but rather like Paris Hilton, I wouldn't want to own one, class legal or not.

The "foiling" boat had normal speed yesterday, probably due to lower wind speeds. There are several boats wind banana boards in the Europeans and they are positioned on different places on the boat, but the most successfull boat has the board close to the normal position.

/hakan

I seem to remember many tirades on this forum on how the A-cat had only a few very open rules and allowed "fantastic" development and modification of boat and that it was therefor the king of all cat classes.

Yet, everytime something REALLY interesting is being tried we see the class for what it really is. Scared shitless of any REAL development.

Now I don't mind if the class decides to progress either way (development or a strictly controlled class) but can we please also cut the BS about the A's being such an open class with only 3 to 4 class rules (length, width, weight, sailara area) ?

Personally I always felt the A-cat anti-foil rules were insufficient in preventing any projects in this direction. The definitions were not precise enough and left open alot of grey area.

Personally I would not even have any trouble if canted or curved boards were to be introduced in the more strict formula classes like F18's and F16's. If it works it works and as somebody else has said. We already allow alot of sail design and rig changes, why disallow boards changes ? Such a thing almost resembles a double standard.

Wouter

Yes, would be great to see them introduced to the F16 class. It would be better if they prove far superiour to the other F16s and imediatly obsolete ther rest of the fleet. Should make a lot of happy current F16 owners. Should be really benifical to the growth of the class also.

Oh and Doug.... Sorry Wouter

STFU

Wouter, what is with the 'holier than thou' attitude? Seems to be quite a few tirades in the F16 class in the past few months. Maybe sort out your own house first before casting stones.

But to keep this thread on track, what position did the hydrofoil boat finish? And what range of conditions did it excel and what range did it not?

Seems to some information coming out of France, but the reporting is quite crap really compared to the last worlds in Florida.

But if the banana board/hydrofoil boat seems to work, will this change the actual design of the A. Perhaps no need for wave-piercing as the hydrofoil holds the boat up. Or even further reductions on hull size may come into fruition. This would certainly reduce windage and increase performance.

So it's not just me.

Which is it? A) The rules leave "open a lot of gray area" or that B) the A-cat rules stifle development as you so eloquently put it; "cut the BS about the A's being such an open class"? You present both opposing opinions as evidence for the basis of your argument which leads me to believe you are simply angry about something. The rules are incredibly simple - I believe there are 9 in total and they'll fit on one sheet of paper and they do leave open a lot of room for creativity.

The foil rule was undoubtedly left gray so that it wouldn't completely stifle development.

Go crap on your own parade.

Clearly the interest here is, as in F18 and should be in F16, to present a moderate and acceptable progression of development such that it keeps things interesting but doesn't price people out of the class. Whether you like it or not, the organization has some responsibility to the people and opinions they represent.

I built my boat this way to allow for any future boards which might require more room in the trunk. Changing boards would be a simple process and the only cost would be for the slot at the top and bottom of the trunk.

As far as the Ben Hall wing sail, I saw some recent pictures of him sailing a soft sail, the word was that the wing pitched too much in any kind of chop.

Latest image of Wouter

Just to make one thing clear after Wouters inflammatory soap box speak. The F16 rules dont allow any meaningful use of banana boards. Boards can not deviate more than 6 degrees from the vertical. But this discussion is about the A class.




I agree with Jake, and I think most others do.
I have no doubt that the A-class will manage this well, just like they have in the past with the Wing and other things.

We have heard many claims of that extent in the last year alone. The LR2 A-cat was going to roll the A-cat Worlds, otherwise the solid Hall spars wing would. The C-class competition was going to be dominated by the full foiling entry. The Moth foilers were going to destroy the moth class once and for all !

Yet in all these instances, the outcomes were directly opposite.

I mean did the introduction of the carbon mast kill the A-cat class in the early 90's ?

Why are we all so scared of NOTHING !

You will all find out once more that I'm right were you all are wrong.

Halve of you don't even really understand what you are talking about.

The other halve is to dumb or lazy to look up past experiences with similar projects and make a balanced judgement. Lots of things have been tried before and by far most of them have been found wanting. It is only the predictable hysteria about "obsoleteness" that gives many of these projects alot more weight then they deserve. Give them a few more months and 90% of them will quietly disappear into the background, never to be heard off again.

When ohh when do we smarten up ?

Wouter

For the technical engineerting types out there, I have a question about these bannana boards. Seems to me the only reason we use daggerboards at all is to prevent sideslip, am I correct?

And for the past many years, the development of boards has been aimed at making the boards more efficient, in the way of lift vs. drag, is that correct? (please stop me when I get off track) and we are trying to get the boards to be as "high aspect" as possible, like the wing of a glider, to both prevent sideslip and also create lift to the windward mark, ie. upwind lift, (not lifing the boat out of the water), but keeping the boat from sliding downwind, as in better VMG to the windward mark, correct?

Now we see these curved boards, which seem to me to be a small step backwards in the whole development of higher aspect, better vmg type boards. Seems to me, with the board curved up under the hull, you are losing some amount of side-slip reduction, in the way of vmg to windward. As I understand these boards, their purpose is to lift the low hull up out of the water a little bit, never clear of the water, but up a little bit. But what about sideslip?

We see these boards on the ORMA tri's but they have a deep daggerboard in the center hull for vmg type lift, their bannana boards on the Ama's are to help keep from stuffing the ama's, or so I thought. They are not there to generate lift to windward, that is the job of the much larger, deeper, center hull daggerboard, or am I wrong here?

I don't see how bannana boards on a cat, with no other daggerboard to help generate vmg to windward type lift, will help you get to the A mark faster.

But I'm not an engineer, just a pilot who has never seen -curved- upward (or downward) wings. <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Tim,

what about the 777? That wingspan flexes upward a good bit when flying (something like 15 feet?). I'm sure they planned that (probably for stability), but it does look weird...

I'm sure it's not the same thing....

Tim,

Finally, somebody who is using his brain !

The only cat that has been succesful in fleet racing has exactly that setup Tim. A seperate set of daggerboards and angled (bruce) foils.

This is John the Vries White formula 20.

Interesting to note that the F16 class rules state that only a pair of daggerboards may be used, not a quad ! Prophetic vision, maybe. Or just a cold hard analysis and judgement that was had 6 years ago, by someone who tried hard to seperate the emotional from the hard technical facts ?

Time and you all be the judges of that !

Wouter

The boat with the boards in front is not build or designed by Nils but designed by Martin Fisher and i do not know who build it.
The banana boards is also not new in A-class because PJ of the Dutch A-class did used the banana boards already 2 years ago and he found out that there was not a real advanced better performance of the boat with the boards.

I also think that every body was getting nervous because the guy who was in front a couple of times ( Bob Baier ) using the
banana boards and they had the idea that this was the big trick but they forgot that he trained the last couple of months 4 days a week , so he is really a trained sailor and a good sailor and when the wind conditions where changing he did not win the races anymore, so are the boards really the trick. I don't think so and to be honest on what i have seen it is NOT the trick.

The class rules on boards is also set and it is not allowed to have the tips of the banana boards closer together then with a gap of 1,5 meter when they are full down and they have to stay within the boat width when they are in the hulls at the bottom so this makes it already more limited.

I think everybody is seeing a bigger ghost then there really is.

Cheers,

Hans Klok

Jay, you are right, it's not the same thing.

The wing flex of a big airline type plane is engineered in for several reasons,

1. The plane would be too heavy to build a solid wing with no flex.

2. The ride for the passengers would be extremely rough in any kind of turbulence if the wings didn't flex at all (the are like shock absorbers)

3. Using today's building materials (aluminum) it is most "cost effective" to build -for- the flex instead of trying to build -out- the flex.

But, the new 787's are being designed and built of Carbon Fiber, to save weight. I'm not fully aware of what they are doing with the wing on that, but less flex at takeoff would give it more lift, ie. higher payload, which is what it's all about in comercial aviation.

Wings do flex quite a bit at takeoff, ever seen a fully loaded 747 take off? WOW, those wings really flex up!!

But some amount of lift is lost as they bend up, no doubt. Once the plane levels off at cruising altitude, the wings are not so bent, only when you hit turbulence will you see the wingtips flapping up and down! Quite funny to see really, but necessary to give a smoother ride.

I know there are some guys on this board who actually work for Boeing so maybe they can help me out here with a fuller explanation on how they engineer them.

Why are you so angry?

I believe Ben Hall made it quite clear that he didn't know what the wing sail was going to do and nobody in the class jumped and banned it. I don't recall anyone (with any real information) claiming it was going to kill the class. Same thing with the foiling C-class...it certainly had a buzz around it but everyone knew that it was new and there were going to be teething problems. This is the normal progression of things.

I look at instances like this and really feel good about the way the class is running things. They don't jump to conclusions; they didn't shout and have a knee-jerk reaction to Ben's wing...they let it play out. They're very likely going to do the same thing here...let the bannana foil either prove itself or not. The class will decide something only when there is enough information to decide something. Beyond that, this is all conjecture and fun to consider.

I do firmly believe that a rigid wing could be made to be faster than fabric sails and that a foiling C-class will eventually perform better. All of this is only a matter of the time and effort required to hammer out the details and do the development. Currently, the challenges seem to be slightly beyond the motivation of these development minded individuals. But motivations will change, things will progress, and we will move forward.

I think you are right Jake. I watched the Moth Foiler develop. At first look, I thought, no way, it'll be too hard to sail...now everybody's doing it.

I think we may see that next in cat speed development, if we allow it. I think it could eventually be done cheaper and easier than bannana boards, or the wing sail, but I like the idea of both, when it comes down to a total package for the future.

But for now, if we could just get the price of carbon fiber down to equal regular fiberglass... <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

No? Well if you accept a tail as a sort of wing, have a look at the attached picture.

If you want to create lift and sideforce, canted or bended wings are a good solution. You can use two boards, one for each job. But with a single bended or canted you save a lot of wetted area, which is drag. As long as the board can carry the loads, it is a good solution.

Cheers,

Klaus

... and a second picture. Showing wing tips, again not pure 0° and 90° but something in between.

On spot, but the quoted sentence may be misunderstood. The boards are not supposed to create unlimited "lift to the upwind mark", only the necessary to keep forces in balance. The boat automatically adjusts the leeway angle (angle of attack) so the underwater lateral lift component is kept equal to the aerodynamic lateral lift component (sails).

I would also like to add some important details, however obvious for some of you:

1) Some designers prefer to separate vertical and horizontal foils in order to optimize each specialized foil independently (example: Rave and Trifoiler).

-Vertical boards are optimized to generate lift with minimum angle of attack and drag.
- Horizontal boards are optimized to generate a definite lift to keep the boat at the desired attitude (lift = part of the boat weight) or foilborne (lift = total boat weight)with minimum drag, regardles the angle of attack.

2) Other designers prefer canted boards/Bruce foils because they make it easier to self-stabilize the boat. Their lift is in the general direction of the sails' center of lift, so the boat almost wouldn't heel when foilborne. Take a look at Hydroptére.

3) If we disregard weight, complexity, price and other practical aspects, the best performance should be with a pair of vertical asymetric foils for lateral lift, plus a pair of canted/banana foils or horizontal foils (not sure which one) for horizontal lift.

4) It is not for performance reasons that ORMA 60 tris use curved/banana boards instead of straight boards: it is for practical reasons. My 27 ft tri has straight canted boards and the most difficult task on board is to insert and remove them from the amas. I can't imagine doing that on a singlehanded 60ft tri.

- It is a lot easier to handle a large curved board than a large straight board. Ian Farrier was probably the first to notice this and designed the F27 prototype with curved foils. The straight foils hit the dock when up, so you can't dock unless you take them out or live them in the water.
-The advantage of canted/banana boards vis-a-vis horizontal foils is the ability to reduce their span (raise partially or totally).
- It is a lot easier to raise a curved board than a canted straight board. A curved foil can be "hoisted" from the shroud or mast, but how do you pull a long and heavy straight board to the outside of a float?



Photo taken after the first sea trial: the board doubles as a backrest for the crew after the first attempts to pull it out failed. The applause is sarcastic.

Regards,

and finally
[img] ]http://www.a-richter.de/bilder/foto/moewe.jpg[/image]

I would appreciate if somebody could tell me how to embed pictures directly in the postings.

Cheers,

Klaus

Somebody mention wings curved upwards?

Hobie Hawk, circa 1973:

Yes, it's on the winch, but the wings curve upwards without the loading.

NASA's Helios, electrically powered flying wing.

Geeesh....What DIDN'T Hobie build at one time or another?

At the risk of going farther off topic:

Aren't winglets at the end of wings more for stability, and to reduce wingtip vortices that can partially stall the wing? It can't directly be a lift thing.

I have always been told the upturned wingtips, blended or otherwise, were to reduce the tip votex's and thereby reduce drag, not to increase lift.

And on the gliders, again, it would be too heavy to build a stiff wing that didn't bend at all. If you build it light, it will bend. I don't see how the bent up wings can increase lift in the vertical, as lift acts perpendicular to the lifting surface, correct?

You realize that the tail of a conventional airplane like the picture of the V tailed Doctor Killer actually "lifts" in the downward direction, to point the nose up and balance the airplane about the center of lift, which is somewhere in the main wing. It is actually acting against total uplift. It is exactly like our rudders on cats, you push on the tiller, make the stern of the boat go down (or away from the direction you want to go), so the bow will go up, like a teeter-totter, it pivots about the daggerboards (wings).

That is why Rutan designed canard type airplanes, (they tried this on an earlier America's Cup boat back in the 80's too, putting the rudder in the front to increase lift when turning) where the canard is in the front of the main wing, and does help to lift the total weight of the airframe along with the main wing. And he designed it so the canard would stall before the main wing stalled, so it was much safer. I don't know why Boeing never built one too.

Here's some light reading on the subject of Burt Rutan's designs. Now, if we could just get him to design catamarans... <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

http://www.rutanaircraft.com/htmlpages/airplanes.html

The following quote from See How It Flies, 3.12.1 affirms that the winglets are used to increase lift:



Edited to display the key statement in bold.

The following quote from See How It Flies, 6.1.2 affirms that the tail's lift is not necessarily downwards:

Tim,

They don't.

Curved foils are used in trimarans instead of straight ones for practical reasons only. They enable docking with the boards in any position and can be "hoisted", unlike the straight ones.

Curved wings in planes/gliders are similar to dihedral, they generate slip-roll coupling. As far as I know, slip-roll coupling presents designers with a dilemma: it increases roll-wise stability, but decreases (Dutch) roll damping.

Take a look at See How It Flies, 9.1 and 10.6.1 for more details about dihedral and slip-roll couple.

Rgrds,

Must be so tough going through life and dealing with idiots everywhere. Everyone being wrong/incorrect/stupid all the time. How do you do it? And more the case, who appointed you?

Is Wouter the messiah or just a very naughty boy?

without being racist the mix of dutch and engineer spell for a very naught boy.....at the ned of the day we are all wrong & only one person is right? Right.!

Give them a few more months and 90% of them will quietly disappear into the background, never to be heard off again.


Wouter [/quote]

do us all a favour and become an honorary life member of that 90%.

Last year on the int. A Class site there was a provisional rule on the hydrofoil subject which allowed for daggerboards to be bent or angled to the extent that the distance between tips of the daggerboards when fully down may not be less than 1.5 meters. I have since then not found any further mention of it, I am not sure if this is still current or not. If it is there cannot have been too much fuss about the bent boards.

Daniel

Does not sound like a class that is "Scared shitless of any REAL development."

Wouter, you are a very angry man. I find it amusing that someone with little real life competitive racing experience thinks he knows better than seasoned racers and then continues to tell them all what they are doing wrong and how they should be sailing their boats / running their class.

No wonder why many people look down at the F16 class with you being the Internet ambassador for them. Please do us a favour and STFU as I am eagerly awaiting to join the F16 class (or A Class) and would not like to see you tarnish the classes image even further.

Jake,




If indeed I'm angry then I'm not angry at the A-class, but rather at a sizeable portion of its sailors who at some instances celebrate the open, cool, development nature of the A-class, but when a new thing is tried become hysterical and almost immediately start throwing about "obsolete old design" and "kill off the class if not banned" kind of statements.

Most of them also reason along lines that are far less certain then they feel is the case. Hence my carbon mast example. Even if a given project results in significant jump in performance (carbon mast ?) then it is still not a given that this will impact negatively on a class (the A's in the 90's). This while many simply believe this to be something akin to a law of nature. Another example are the foiling moth, a obsolete making jump in performance if there ever was one, but the moths actually grew spectaculary internationally because of it. In deed such a development can also have very positive effects for a class. Interesting enough, there are quite a few examples of that, Upgrading the Tornado with a spi and double trapeze is another example. Still, these example are suddenly and completely forgotten whenever a new development is introduced.

Personally, I think the "raison d'etre" of the A-class is indeed development. Without it is will fall back to just a single sail solo sailor class that in time will be surpassed by other faster classes who do allow development. That is why I have so little patience with scared sailors in the A-class. If ever they get the upper hand and lock the A into a given setup by adding more rules and banning real development then they will have struck the biggest blow to the A-class in its 40 year existance. And we'll all loose an important part of the catamaran scene.

Wouter

How about you name those A class sailors. Not someone on the internet that wishes to talk about the A class, but the active racers.

Thanks for that Hans. Wasn't sure which Dutch sailor it was, and wasn't go to pick random names. Remember that in Sweden wasn't too much concern about the boards PJ used.

The results of the "hysterical" boat from the Euros:
32: Bob Baier (Allemagne) 190 points (Détail courses : 53,1,D+SC,DNS ,2,1,36,22,DNC ,)

Crazy coincidence it is a similar end placing to the wing in Florida, but there were more boats there.

The wind/wave conditions of the 1, 2 and 1, were they any different from the 53, 36 and 22? And training of course makes a huge difference.

But does someone have details on the hydrofoil committee results of a few years back? They set this 1.5m separation between the boards and should have discussed banana boards. This will stop Wouter's (and others) alarmist tendencies that seem to frequent internet forums.

So Wouter.... How about the 18 Skiff. Should they have brought in the OD hull and increase in class rules or should they have remained a very open development class.

Are the Foiling Moths seeing greater numbers racing then they did when Moths were sea-huging Skiff Moths or even Scow Moths?

Did the A Class make a mistake by introducing a min weight.

Better to race in a healthy fleet then be a one off racing on handicap with others.

The A Class have not rushed into any decision, but will look at it carefully. If it does look like the bannana boards will have a large advantage, obsoleting all other boats in the class.... Do you think it will be healthy to allow it to happen. Would see a lot of sailors turn away from the class.

Just as a tangent.

I'm not in any way or form an official or ambassador for the F16 class. I'm my own man and my statements can only reflect back on my person and not some class that some may want to tarnish for unrelated personal reasons.

Additionally, I don't THINK that I know better, I KNOW that I know better. And the usual people frustrated at my persona will find out soon enough that once again the comments I've made are alot closer to the truth then theirs. And last time I checked you were still not a world class or seasoned sailor yourself Stephen. You are just an amateur like the rest of use. But even if you were Glenn Ashby and stating publically on this forum something that is verifiably untrue then I would still have no inhibitions to write that down in public.

Interesting thing of course is that guys like Ashby never seem to make such untrue or dumb statements. They know the limits of their expertise in contrast to sailors much lower on the food chain like yourself.

Sorry mate.

The only way to go about it. This decision should be made by the sailors...... Not people on the interweb that think it would be cool to see what happens, with no regard to those with a financial interest in the class.

Why on earth is anything to do with foiling "real development"? and everything else insignificant. As you say, the class has been around for more than 40 years, how many quantum leaps are you still hoping for? You have to look hard to see the difference on F1 cars, but they get faster every year. The A cat has evolved substantially over the last 5 years and has got quicker still.

Looking at it practicaly, its one thing talking about a 25 kg Moth that can be carried into the water with its foils by one person and a totally different matter rigging and launching an A cat in some breeze with meter long foils attached. The days of going sailing without assistance would be over, that has nothing to do with being scared. If foils were allowed, I would not convert, the ballache factor is way to big.

Me thinks, the last C Class event was not a terribly good advert or inspiration for ordering foils for my A, it was facinating and respect to the gentleman involved for not spamming up the internet with theory and actually trying it. Pictures of anglegrinders cutting off foils have scarred me for life.

Daniel

Moths is a no brainer dude. Gone from 30 at the Worlds a decade back and the same people each time, to possibly 80+ in Weymouth next week. To get a new Prowler is a 12 month waiting list, and Bladerider is prob 4 to 6 months. And the other manufacturers are similar. But the moths went from being possible footnote in history to one of the most popular things happening in sailing.

A-Cats on the other hand had one of their most successful worlds outside of Europe with 98 boats.

But the old skiff moths can be retrofitted with foils rather easily.

For the A, rebuilding a centreboard case (and possibly moving to another part of the hull) is a different story. Does the boat have the structure to take loads in an area not previously designed for it? And development of boards would start in earnest.

The condition in the race not sailed well by Bob where diffferent from the races he did good but he had also some luck to make the right side of the course. When i did see Steven go around the first mark as 40 and see him finishing as 3th with a standard type boat then what was better the curved board or the straight boards. I think the skill of the sailor did the most and making the right choices on the difficult course with wind going around the place was more critical then the boat or boards used.
The fact that Bob did good in a few races made everybody nervous and because he was using something else was firing up this. The other Nikita's did have also curved boards and did sail on the place the skipper should be in that type of conditions and when the trick should work then they should be further in front then the real did.
So every body is seeing ghosts is my opinion.

Cheers,
Hans Klok

Ahh finally some factual argumentation (when in only part of your post anyway)




I'm convinced that if the banana boards are proven to have a "large" advantage that the A-class should adopt this feature fully. I don't think the old boats are made obsolete that easily and if they are then I also don't believe this to be a major issue for the class. Mostly because local fleets will transition much slower then the top of the fleet who are changing boats very often anyway. Also a curved daggerboard trunck is quite an acceptable modification to any older A-cat. It is on a par with upgrading to a new design mainsail in cost. And nobody when ballistic over that either. And again, I think such a step to be comparable to the carbon mast introduction that obviously did not kill the class or prevent it from growing internationally.

I think the core of the class is the active racers at the top. Keep those on boards and the recreational sailors will follow anyway despite pretty vocal declarations to the contrary. I refer to the Tornado upgrades as a prime example of that. 2/3rd voted the changes down but 2 years later over 2/3 ofd the fleet had changed to the new voted down setup anyway, with the class now just as strong as before.

I truly and honestly believe that the core of the A-class is largely unregulated development. Without it the class would have died as a 100 kg alu masted single sail singlehander years ago. Another class like the inter-17 or F16 would have replaced within 1 or 2 years of its introduction. And that has nothing to do with either the inter-17 or F16 class and all with the inability of such an A-cat class to remain exiting in a scene where other classes progress to new levels of performance and attractiveness.

In fact, I will even be a large supporter of allowing curved boards in other classes like the F18's and F16's once the design has stabilized. In a similar way the square tops replaced the old pinheads.

As an engineer however I don't see curved boards to be able to result in a "large" performance gain. There is not enough percentage associated with the hulls in the old-fashioned setup to justify such an improvement. Of course the drag related to the (straight) daggerboards remains as this is closely linked to the sail force of the rig that isn't changing in any significant way.

I classify the curved daggerboards much more as a refinement then a breakthrough. This because its effects are far more in the field of damping the boats movements then lowering the overall drag. I also feel the latter is already partly adressed by inward canted straight boards. (whatever happened to outward canted boards guys, the hot and exiting development of a few years back ?) And there are some conflicting design problems that are not obvious at first glance. One of those is that simply curving inwards the boards doesn't do that much to lift the boat when the foils are symmetric. In the way of damping movement they will be effective that way. In order to create meaningful lift (in this case, enough of it to matter) assymmetric profiles are needed or a permanent angle of attack of say 4 degrees. At low speeds or when having two boards down these characteristics are actually a disadvantage. That is why patient lady C-class design, raised one baords and lowered the other after each tack. Patient lady is one of the very few examples of a sufficiently succesful implementation of curved daggerboards as a performance enhancing item.

I think I have answered all your questions.

Wouter

Based on what.... your extensive competitive racing experience or “because I am an engineer and you are not”



Don’t pretend to be top International..... Not even close. I am only an amature, but a seasoned racer who has raced extensively at a National, State and local regatta level, along with 2 World Championships and other International events. At the top level, I am mid fleet...... But still a seasoned racer.

I am not some wannabe that avoids racing regattas and in quality fleets.

My sailing experience would run rings around yours and there are plenty of people here that are better sailors than me that you presume to know more than.

Just look at the bloody numbers mate !

Get beyond the "gutt feeling" side of "engineering" and look at the data and models already available.

And pick the needle off the "extensive competitive racing experience" broken record. Having the skills to make a boat go fast on the water is not the same as having the skills to design a fast boat.

But I'm not even adressing the more difficult engineering aspects here, we are still stuck in the obvious rookie mistakes. My small nephew even understands without a formal engineering education that when a hull represents only 20% of the total sailboat drag that a 25% lifted hull (due to partial foiling) can never result in more speed gain then 2.5%. And that is when given optimal conditions for foiling. By the way 25% lift on an A-cat equates to about 40 kg of created vertical lift which is alot for a curved foil as used currently. A straight bruce foil will need to be angled to 22 degrees to match that given the close link of vertical lift to the given sideways resistance to sailforces. There is a pretty tight interaction there.

2.5% is about a minute per 45 minute race. Of interest to the absolute top of the international A-cat fleet but pretty unimportant for 85% of all others. Of course in not optimal conditions the setup may well be a drawback making a sailor actually slower then its competition. Curved foils will most definately show such a characteristic with the obvious drawback zone being low hull speeds (light winds)

You don't have to be a Glenn Ashby to understand this.

Wouter

Hey Wouter,

I do not have a problem (if the foils do prove superiour)with the A Class adopting them, or if they decide to outlaw them. The descision will be made by the class and it's sailors...... The guys that matter.

I do have a problem with you unsustained statements about the A Class and it's sailors such as....








Notice how I had little to say on this subject until you started smack talking the A Class.

How about you wander off to the next A class event and spew this BS.

Don't forget your foundation to cover up those black eyes.

By the way, I have never stated that the foils will be quicker or should be outlawed. What I have said is that the class will do what is right for it's sailors first and formost.

I will also say again, you no sweet FA about what would be healthy for the class. The A class has been around for a long time and built itself up into one of the most successful and cometitive catamaran classes in the world.

I have every confidence the class will take the correct path on this issue and you can just STFU because your opinion does not matter.

No man, you have a problem with me !

All the rest is just window dressing to make your dislike (disgust) of my persona seem more respected.

Like I always say. I have absolutely no problems if people hate my gusts on the internet or on public forums. I only care about factual correctness and I've got a pretty shiny public track record on that.

Now lets get back to curved foils discussion and factual statements. I certainly hope you're not out of those !

Wouter

And I will not argue that



I am not part of that debate.... Only commenting on what would be good or bad for a class IF they are proven significantly faster.

I would rather discuss your justification for the following BS comments. Please explaine why you felt it necessary to attack a class and it's members like you did below.







Please don't disapoint me Wouter........ Please answer.

Don't run away dear Wouter

Stop baiting him........

BTW - you need a new signature now!!

"Land Lubber Alive" <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />

At least we're not talking about airplane wings anymore. <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

wouter

you make it very difficult to find you an even vaguely likeable person. The only way to justify your sublime and regularly self acknowleged talent is to get out on the water and prove us wrong, with or without your numbers, put up or shut up. I would prefer the latter, the former is not really possible is it?
you and Doug Lord deserve each other

Daniel

Boatless Alive (or will be in another 2 weeks)

But hopfully I can fix that fairly quickly

May be a quick change of the logo from an 8 to a 6

Oh, BTW..... Strong result from Storky at the Euros.

Congrats Stevie

oh....i thought the boat was gone allready.!

who is storky?

When bent daggerboards produce too much lift....

Torsional stiffness must be quite difficult to achieve with the thin foils used at the moment.

Steve Brewin.

But please defer to Mr Factual in case I am incorrect.

You can't score 1,2 one day and then end up in the middle of the fleet the next and call it a ghost! The conditions was ligher when the boat ended up in the middle of the fleet.

The two extrems in the beach cat worlds are probably Hobie 16 and the C-class and they attract different kind of sailors. The A-class have moved from the "C-class" type towards the "Hobie 16" type the last years which means that some sailors has left the class and but more have joined it. If the A-class goes into a new development cycle it will move towards the "c-class" type again, the last time it happened was the wave piercing design. The question is if the class can take this "beating" again without losing to many sailors? Since the class has been stable for many years now it has attracted sailors that like to sail, not to build, and will those sailors stay until it has stabilized again?

/hakan

Wouter you hang crap on the A's every time they are having a successful comp. Just because the A's are a success it doesn't make your boat bad. Next time the A's are racing why don't you crack 10 beers and relax.
regards

The Moth and A-Cat are the 2 development single-handed classes. Both have increased in numbers over the past years. Moth due to foil development, A-Cat due to being a hi-performance lightweight boat.

Now the Moth allows development in foils and no min weight. Hull development really out of the question in future development, but possibly development in minimising air resistance like the Swiss mecano set recently launched. However the Moth has a mast height restriction which in some ways limits rig development here. Not possible to move to the refinement that is seen in the A-Class rig.

A-Class only has a sail area restriction, which means that this area will always be a potential area of development. We saw that with Ben Hall's wing mast recently. It was amazing downwind in a breeze to see, but the excess weight aloft caused a pitching effect which hampered it in other areas. Also the A has hull development on its side. The worlds in Florida saw 9 to 11 different hull shapes, and there are other designs in Europe that weren't there.

So maybe leave the moth to develop foils and go down that path. If that is your thing.

The A will look at further refining the rig and hull shape.

So each will fill their own niche and will attract those interested in those areas. In some ways no point in competing in the same development area as they are fundamentally different boats (cat v mono).

Awwwww come on! The A-class rules are 9 items long. That's nowhere near "becoming the H16"...that's a bit of a stretch don't you think? It's only one notch separated from the c-class - the only difference is the hydrofoil rule and a really light minimum weight.

The boats look different and the rules are few, but it reminds more of a one design since you can buy good boats several manufacturers that all have the potential to win the worlds. As a sailor this reminds more of one design than c-class.

/hakan

So what about some information from one who actually was there and has curved dagger boards...

I was there and I just got a Nikita (designed and build by Nils Bunkenburg) with the curved boards.

First about the rules.
Hydrofoils are not allowed, and that means that you may not add a foil with the only purpose to generate lift.

Then there is the question about the dagger boards, cause all newer boats (maybe except the Marström) have canted dagger boards, and they will provide some kind of lift. You might even angle them a couple of degrease so they aren't parallel to your sailing direction, if you think that will give you an advantage.

The hydrofoil commission was formed in the IACA to look into this matter, and in 2006 they came out with this text:

"Measurement control

The extreme beam shall not be more than:
2.3 meters (7 ft 6½ inches)

The beam shall be measured at right angles to the centre line of the craft at the widest point and including all fixed or adjustable
apparatus with the exception of a normally accepted trapeze or retractable seat. (adjustable apparatus such as foils must be measured both completely down and completely up flush with the bottom of the
hull). In addition, no part of each hull or the respective fixed or adjustable apparatus shall come closer together than 1.5 meters below the static waterline. If necessary the static water line shall be found by floating the boat fully equipped without the sailor on board."

During their work it had been in the text that boards should be straight, but they took this out of the text - SO THIS HAS BEEN CONSIDERED...

Therefore as things are today, CURVED BOARDS ARE LEGAL. The text about measuring the boards “flush with the bottom” should take care of T-shaped boards, as they won’t be able to be flush bottom.

The Boats.
The boat on the pictures in earlier posts is not the Nikita, it's the Martin Fisher boat, and it has take a more radical approach placing curved dagger boards in front of the beam and even making them self tacking in a lose case. It had some fairly good races and some not so good. I really don't think that's the boat everybody got so scared of.

Then there are the Nikitas. We where 3 of them at the Europeans. Two of them where finished by Nils Bunkenburg (Jörg Horns and my own) and our dagger boards leave the hull vertically, meaning the case is in the center at the bottom and further towards the middle of the boat at the top of the hull. These are not as extreme as Bob's where. The top and bottom openings are more or less over each other on he’s boat, taking the tips of the boards closer to the allowed 1,5 meter than on my boat.
Looking at the effect I think the conclusion is simple. In perfect conditions (as in a test tank) curved dagger boards are an advantage, but the more extreme you do it, the worse they get as you move away from ideal conditions. In light air (at low speed) you will drift more sideways. In choppy conditions you will have more turbulence. But in ideal conditions - you are slightly better of.

The racing area:
Conditions where quite special. Usually one side of the course had a huge advantage due to tide currant at wind shifts, and if you got the best start and went to the side that had the advantage, you had a great lead. Not being able to challenge the leaders by going the other way on the next upwind makes it difficult for the fleet to challenge the leaders if they are good sailors.

The results:
I can only speak for my self, but at the last Europeans in 2007 and the worlds in 2006 I was battling with Chris Field where we where always at a tie before the last race. This year he was 5 points in front of me before the last race, where I managed to turn it around. So no changes there. Last year I often sailed faster that Donald Beinke who ended up in front of me here. So no really big changes for me.

Maybe we should stop blaming the success of Bob in a couple of races on the boards entirely and maybe give him some credit for sailing well and setting he's boat up perfectly for the conditions and trimming he's new sail well. He's not a nobody in sailing who suddenly makes a good result!

About the rules:
Let's keep the rules open. If the rules had been narrowed in every time someone got faster then the rest, the A-Class would still be a wooden boat with a triangular Dacon sail and non of us would care to race it. Let's remember why we where attracted to the class in the first place...

Regards Thomas Paasch

Thomas,

Thanks for your insight and experience. I believe you will find that the people that have been most excitable or shown the most dramatic reactions about this development here are not a-cat sailors.

Finally some real info--thanks!

Thomas, this must be descided by the class not by individuals which means a ballot. If the majority of the sailors thinks this is the wrong direction for the class, then I guess you have to accept it and rebuild your boat. On the other hand if we descide to keep the rule as it is, then the rest of the A-class sailors needs to dig deep in their wallets! The majority of the A-class boats don't have banana boards and rebuilding them will be expensive and the result will probably give less than optimal performance. That leads to outdated boats with low resale value and a hard time for the builders to supply new boats to the next big event, great!

About the rules: Two rules has been added, min weight and hydrofoils. Why not remove them again so we don't end up as the only non foiling development class?

/hakan

Hakan, you are right, what ever the class decides everybody else has to live with. But then again the management of the class has to decide what's worth having a ballot about, and I trust them to make the right decision about that - no worries.

I guess the key point I was trying to make is that over an average of different conditions you are as well of with your streight boards as with banana boards. And you should now how marginal these small differences are. If you still have your old Marström you don't have canted hulls and your daggerboards go vertical through your hulls while almost every other A-Cat builder has had canted hulls and angled daggerboards the last 10 years - and still a Marström is as competetive as any other A-Cat.

Don't forget that the main reason for a boat going fast or slow is still the sailor. Glenn Ashby, Lars Guck or Pete Melvin will probably come and beat us all again at the next worlds with a stock boat with no modification :-)

Here are some pictures of the Nikita at the Europeans - I couldn't find any ones showing the boards better. Maybe the hull shape is part of the success as well...

Thomas is saying exactly the way it was out there so i have to fully agree with his good and stated report he wrote.The best sailor did win not the boat.

You can say that the value of boats are going down when this change to curved boards is going to happen, if it will happen but what i do not understand is that when Marstrom made the new model A-class he had the change to put some things in it like the canted boards or canted hulls and he did not , for his reasons ,but the development of the class is not stopping. Maybe he created for him selve the problem of getting a boat which is loosing money in re-sell because it has not canted boards or hulls. But i think the boats will keep there value because they are build very nice.
He did ofcourse a lot of money investement to get the new boat out but he did now that the canted boards where already there and can give some advantage, so you can not yell to the class now and try to stop some developments. The ballot track is the only way to do it and the proper way to do it and i did understand they made a proposal for a ballot so let wait and see what will happen. <img src="http://www.catsailor.com/forums/images/graemlins/smirk.gif" alt="" />

Cheers,

Hans Klok

Yep, Steve Brewin

Humm, have you ever seen me run-away, Stephen ?


Well, allow me to clearify may earlier statements.

It is as I have written in the later posts. I have little appreciation for A-class members who don't really understand that the A-class is a full-on development class and can be seen to prefer tighter rules and banning of experiments that have not yet proven to work or be a giant leap forward.

My very first statement was intented to convey that, but I see that it partly fails on that account. So consider that corrected.

I'm personally of the strong conviction that the A-class should remain as it was somewhere in the middle of the 90's. I truly believe that to be its strong point and indeed its selling point and path into future succes. I also feel that much of the "obseleteness around the corner" scares are largely unfounded.

The hydrofoil rules should be dropped in my opinion as it is will technically speaking very challenging to make it work with sufficient gains anyway. Much like Ben Hall's solid wingsail. Indeed, I'm in favour of removing similar rulings from other classes as well include the one my persona is often associated with.

I truly don't understand why the A-class would allow items like carbon masts in the past but not allow "vertical lift" producing foils. This seems inconsistant with their philosophy and indeed history to me. In the words of another poster, how many giant improvements in A-cat design are we still expecting. The beast has already been refined for over 40 years now. The changes of any breakthrough are much reduced now simply because the "standard" performance is already so increadiably high.

On the other hand, "attacking a class and members" is an weak ploy when debating a given topic. But since when have we all grown such weak persona's that we can't take a little heat in the discourse of a debate ? I think I'm coping with alot more of that without a single compliant. Am I such a hardened individual or are you all just such fragile souls ?

Wouter

You are still assuming that banana boards are an advantage. It's really early in this game and while I might agree that their could be some advantage in certain conditions I don't think they're going to be the ultimate end-all performance gainer.

Buy an A (any ol' one will do), become a member, vote at the AGM and overturn this rule. You said the same thing when there was numerous debates about the F16 weight.

The A has only a small number of rules which Jake pointed out, and the class is as popular as it has ever been. So something must be working.

And TA will be back tomorrow to resume normal banter. Little distraction in the Canetoads beating the ****.

Precisely. It would seem that the vertical lift obtainable under the present rule is not enough to justify the use of banana boards, so there is no need to change the rule.

I still favor hydrofoils, especially for seaworthiness. The pitch and roll damping they provide should not be overlooked. As Tom Speer once wrote: "hydrofoils don't make a slow boat fast, they make a fast boat more seaworthy".

Hans, the new Marstrom has canted hulls, strikerless main beam and changed hull shape. The discussion here will of course be biased depending on if you have a boat with banana boards or not, or if you don't have an A-cat at all and just wants those poor bastards to pay for foil deveolpment that you can pick later on for your own class.....

If you have such a boat you will of course try to say that it isn't faster to avoid any rule changes. My information is also from people that where there sailing and the result from the races gives an clear indication that that boat has a very good combination of hull shape and centerboard for some conditions. 1,2 one day and mid fleet the next day.

/hakan

I think you have a good point there. Easy to have adamant opinions when you dont risk anything.

Agree with you Rolf. A-Cats have been leaders in the past. Maybe the status quo of developments means that either cats aren't attracting the out-of-the-box thinkers, or we are on the cusp of the next development but it hasn't been thought yet. The past 5 to 10 yrs has been evolution rather than revolution. But if you look at the A history there have 2 major developments in the past 20 yrs. Taller rig accompanied by carbon mast development, and move to wave-piercing design. But with 9 to 11 different hull designs at recent worlds mean people are still working on one aspect of that. Steve Brewin specifically requested that the Tool he has in Oz had the front beam moved by a foot compared to the standard Tool. Not sure whether that was the case for his Euro's boat, but shows that rig/boat balance is critical and not as an obvious development as something which is being launched out of the water by foils.

Looking at F18/17/16, they are really evolution of ideas rather than pushing anything new. Tornados have pushed the envelope with the adoption of the kite and new jib/main configuration and sail development which has filtered down. But chasing the elusive Olympic medal will do that.

So- to move the thread along in the same direction.. Tornados have been pitched out of the next Olympics for no good reason. Thus there will be ample 8-years time for a new A-cat derived Tornado sloop with surface-piercing hull design to be perfected... with hull-lifting banana boards! I would love to work on developing such a modern creation.

Now that would be a great olympic event!

People, look closely at Dacarls photo above and to the left, you will see that is his A cat up on foils.

Any bigger pictures you can post here Dave?

Since you asked, from wwww.fastsail.com/catcobbler
avatar old wooden A-cat flying,
Hobie 18 flying on foils and Hobie 16 on foils, totally amateur pix. Curiously, nobody has come by and asked about sailing these rigs in the last 7 years. Note: these are obsolete foil designs, but still a great bunch of fun.

Hi Dave and all --great thread .

I'd like to see the rule allow foils outside the max beam --as long as foils are being added .

I think with the more box sectioned hulls out now an A foil might work best --or U foil in this case .

It would consist of 2 board slots in each hull at the sides of the box rather than center with the bottom foil as shown in the A foil pics .

With canted hulls this would have greater lifting capability and better stability {I,m guessing}

What do you think .

Scroll down on the site past the T foil to the A foil for a pic .

http://www.yachtboutique.com/BentleyYachts/Advanced_Hulls.htm

Thomas,

Do you have some pictures of the Nikita and a way to contact Nils. I would like to have him on my a-cat yahoo group under the builders section. http://groups.yahoo.com/group/A-CatWorld/

Thanks,

I think that the one neccasary rule that the class voted in was the minimum class wieght. I have not heard a great deal of concern over Ben's wing or lifting boards. The hydrofoil rule was put in place to ban vertical lifting foils, but not banana board or canted boards. Over the winter I will be modifying my A for canting boards, not because it will improve my sailing abilities, but because I want to use it a a development platform. I am also looking at hydrofoils that can be removed for competitions. Again as a test platform. For the most part, this class seems very open to development, from ben's Wing, to Pete Melvin's paint on his black A-3 to new sail plans, differing hull shapes and configurations and many other designs and thought to get speed out of the boat. So much of this thread is spent on stating that this class isn't really open to develpoment. Nothing could be further from the truth. It would be better to focus on how the top sailors in the class do find their speed, from glenn Ahsby, Steve Brewin, Lars Guck, Pete Melvin and the other gr3eat sailors who chose this class to race in and to help to develop.

I don't know how the flexible wings of RC gliders got into the conversation. But with that in mind take a look at this.
http://www.youtube.com/watch?v=mxFOHoy-UNQ
These gliders work at a relatively low Reynolds number (compared to a cat centerboard) and in this situation it is lightly loaded.

I was sailing the Europeans in La Baule (with no good result unfortanly) and i do sail A-class already from 1981 when the first Bim made a big change in the A-class these days when most people where sailing Unicorn.
I was with my boat next to Marstrom at the beach and to be honest i did not see that the boat even used by Erik or by Goran where having canted hulls. I only noticed that Goran had a bid different boat than Erik and this was not with the canting and the others who where sailing Marstrom boats had no canted hulls. If they have it ,it is almost nothing and maybe less then 1 degree, it is not noticable.

I can tell you ( i was there ) that it was very tricky to sail and you had to made the right choice in going the good way of the course and when you made the wrong choice you where mid fleet. Maybe the boat of Bob together with his skills where on some days a good combination but Landy was also good in some days and made the right choices, he told me that he was lucky one race to have the good side of the course which was a first place. He was flying in the first race and nobody could beat him.

The only thing why i can see people are against it or afraid for it is that it can have affect at the price of the second hand boats with not having this banana type future. When you just made an investment in a new design or modified design you want to try to protect this investment, i think personally that is the discussion.

I will make some and try them on my boat to see if there is a real advantage because i can have a look at others but you have to experience it by your self to be sure if it is better.

It was by the way a nice sailing event with good atmosphere and good sailing and a lot of discussion as always. <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Cheers,

Hans Klok

Hans,

It doesn't say anything about you sailing A classes on your wikipedia page. Someone is going to have to fix that.

http://en.wikipedia.org/wiki/Hans_Klok

<img src="http://www.catsailor.com/forums/images/graemlins/tongue.gif" alt="" />

I am not the same guy, he is having the same name but that's not un common i think.
He is good with card tricks.

Cheers,

Hans Klok

[color:"brown"] Ah yes.... Go the Toads [/color] <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Wouter is not even sport any more. I'll leave the mad man to rant to himself for a while now...... Atleast until the next time I am board. <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />

Hi Hans.

The boat of Erik is the old version, it doesn't have canted hulls. Marströms new boat has, but the changes from the Marström M4 to M5 are not that eyecatching, it's more in the detail that you see the improvements. But if you see a Marström with a thick strikerless front beam - it's the new version.

Like Landy in this picture:

What a load of crap. We all know who is adressed here and it is simply not truthful.

When we wrote the F16 class rules we specifically DID NOT rule out any hydrofoil devices. We specifically written the rules such that T-Foil rudders and such were allowed. In fact, all the way up to last years ballot (were I voted against the rule change) the F16 class had significantly more open rules regarding foiling then the A's. And indeed, items like T-foils were implemented. During the framing of the rules we regarded it as an attractive refinement on a short hulled boat; much as Luiz is quoting about the ability of angled foils to improve seaworthyness.

So for 6 years we (I) did indeed run the risk and I'm personally still willing to run it now. I feel the F16 ballot last year was heavily inspired by what went on in the A-class rules which I feel is largely based on fear and not technical reality. I'm very much opposed to such crossovers and actually have written a parting brief specifically addressing such a travisty (before the ballot was held).


Hakan, find something else to hit me with because this simply won't fly.

Lets get away from trying to discredit any given person by quoting falsehoods and progess the discussion with scientific arguments.

Wouter

The "and such" is a generalisation which doesn't fit into your squeaky clean technical/factual image.

But had a look through the F16 rules. You don't want to hold a F16 regatta in SE Asia. You don't want to see what kind of boat I would turn up with! Would certainly be an exploiter of those rules.

Give me a break Wouter, everything is not about you.....

The level of competition in A-class is a higher than in F16-class which means that small changes in the performance of the boat makes big changes in the racing results. That's not the case in F16 right now but it could change and I bet that those sailors at the F16 worlds also would like a bit stricter rules so they can focus on sailing.

The international canoe is an example of a class that is divided in three types of boats now with different rules. IC (the original), AC (added a spi) and DC (development). The last worlds had 21 IC, 3 AC and 13 DC but they could have had 37 boats racing together.

/hakan

Interesting thread --thanks .

A general question for any .

Why should the A class be limited to developing radius lifting foils only {banana boards} ?

Wouldn't a simplified A foil type configuration on canted hulls further sailing craft development moreso.

I realize C Class development allows this type of development within its 14 ft beam limititation per C Class rules and some may argue foil development can occur in that very expensive racing class .

Given that and the fact that the A class seems reluctant perhaps it is time to resurect the 18 square class as the foiler class or perhaps a new 20 ft development class for that purpose .

The catamaran version of the Moth class in effect .


What was described previously was a simple version of the A foil that could be built stationary or retractable in 2 slots in each box sectioned canted hull .

This would seem a superior configuration or at least one with greater potenial on box sectioned canted hulls .

pic for any interested

http://www.yachtboutique.com/images/A-foil2.jpg


-

I don't think that we can say in general that the A-class is reluctant to changes. In this thread we have seen examples of sailors from both sides.

The A-class has moved to a bit stricter controlled rules since the type of sailors racing this boat has changed. There are more "racers" than "builders" right now and that is reflected by the rule changes.

/hakan

Hakan
In the USA, I think the growth has been driven by racers joining the class for the racing and the concept of a light singlehanded, single sail performance boat. We are getting new boats from 4 basic builders.

Class growth is not driven by sailors with a better design idea and the skills to go build it.

We are buying boats that are percieved as basically competitive from a domestic builder group that is really quite small.

Within this box, I can think of Ian Lindahl and collaborators and Steve Clark and collaborators building the LR and DK boats on the edge of design. Vectorworks is building the XJ's and Moreeli and Melvin A series. The exchange rate has put a real hurt on the import of Marstroms and Aussie Flyer's 1 and 2 or anything from the EU.

Future growth requires keeping the existing racers and adding new converts. The cat racers moving from 2 man boats or dinghy sailors are choosing between the A class, the single handed spin boats; F16 and F17 spin classes or the traditional Hobie 17 class.

A revolution in design that fractured the class would really change this growth forcast and the dynamics between the single handed cat classes.

How much interest is there in buidling a flying catamaran class?

The case about making the A-Class a flying catamaran is closed. We have a rule stating that Hydrofoils are not allowed, this means adding "something" with the sole purpose of producing vertical lift.

The reason for this is that once you are flying, it really doesn't matter if it's a cat or a monohull.

The box rules about the dagger boards has limited the way you may shape and/or cant your dagger boards, and having the text about measuring the beam of the boat with dagger boards all down and up flush with the bottom, takes care of T-shaped foils - cause they can't be all up flush bottom.

So what we are talking about here is a max beam of 2,30 meters and boards that may not come closer than 1,50 meters from each other. It's fair to assume that the hole for the dagger board at the bottom of the hull is placed approximately 15 cm from the extreme beam, leaving us with 25 cm per side to cant or curve our boards!

It's really not that much if they still have to be able to come up through the dagger board case.

In my opinion this gives enough room for playing around and maybe improve slightly, without being able to create revolutions that will set everybody else out of the competition...

The rules as they are today allow all that and restricts all that, so let's not change anything. (If it aint broken don't fix it)

I think it's marveless to have a class that over 50 years only has seen the need for 9 rules. Let's not change that - having to many and to often rule changes also frustrates the sailors (ask F18 sailors about that...)

I've heard from both Marstrom and Wouter that the curved foils should have a damping effect, but I fail to understand the mechanism behind it? See Wouters text below.

/hakan

/********** From a post from Wouter ***************/
I classify the curved daggerboards much more as a refinement then a breakthrough. This because its effects are far more in the field of damping the boats movements then lowering the overall drag. I also feel the latter is already partly adressed by inward canted straight boards. (whatever happened to outward canted boards guys, the hot and exiting development of a few years back ?) And there are some conflicting design problems that are not obvious at first glance. One of those is that simply curving inwards the boards doesn't do that much to lift the boat when the foils are symmetric. In the way of damping movement they will be effective that way. In order to create meaningful lift (in this case, enough of it to matter) assymmetric profiles are needed or a permanent angle of attack of say 4 degrees. At low speeds or when having two boards down these characteristics are actually a disadvantage. That is why patient lady C-class design, raised one baords and lowered the other after each tack. Patient lady is one of the very few examples of a sufficiently succesful implementation of curved daggerboards as a performance enhancing item.
/***************************************************/

I would love to see (Thread 1) Steve Clark's explanation of this critical element about PL-4 and the apparent success of its NON-SYMMETRICAL banana boards: i.e.: "It lifted at speed".

New Thread for Hakan - Steve told me that the boat he raced in Canada last fall was about 12 years old, basically unmodified and too heavy due to its older construction methods, compared to the new Canadian boats. Maybe the wing was heavy too.

CANTING THREAD: IMHO, having personally raced A-cats, straight boards canted out are useless when doing the Wild Thing. I was there when Charlie Ogletree slalomed through the fleet of other A-cats after the A-mark like a snow skiier--- In not enough air. Note that I was ahead of him at the A-mark, but after that, not so much!

Hakan,

I believe Wouter's quote is exact except for one detail: in my opinion pure pitch damping can be obtained from symmetric foils at zero angle of incidence, like the pitch damping provided to a plane by a symmetric section stabilizer at zero angle of incidence.

It is intuitive that a flat horizontal board damps pitch. It is also intuitive that the flat board (as the hydrofoil) will increase the boat's total drag. I guess the only requirement for a pitch damping board to work is that it is placed fore or aft of the CG.

The mechanics of the pitch damping effect from hydrofoils can be described this way:

When the boat pitches down, the foil moves downwards and its angle of attack increases, also increasing the existing upwards lift force, which counteracts the downwards movement.

Drag usually increases with the higher then normal angles of attack that occur in this case. This is relevant only to understand the difference between a hydrofoil and a flat board.

When the boat pitches up, the foil moves upwards, its angle of attack decreases and lift is reduced or even inverted, counteracting the upwards movement with the reduction of upwards lift or increase of downwards lift.

Added drag is less of a problem in this case, for the angle of attack is being reduced at first. It is only when it becomes negative and relatively large that drag will surpass the levels associated to horizontal motion. This explains the difference between a hydrofoil and a flat board at pitch damping:

The horizontal board forces the boat to decelerate its horizontal motion during pitch up or down damping, regardless the pitch direction. Interestingly, the hydrofoil will allow the boat to accelerate due to less drag while damping the pitch up movement, and force it to decelerate due to increased drag while damping the pitch down movement. There's no magic in it, though: the hydrofoil was sailing with higher drag than the board from the begining, due to its initial angle of incidence or asymetric section.

Hydrofoils work almost exactly like wings on a plane. There is an excelent (and free) online book that teaches a lot about lift, drag, stability and damping from wings (read "foils"). Just follow this link. and enjoy.

Hi there,
I looked into the canted and curved boards and did some math. I'm attaching what I calculated; I tried to make it as clear al possible so it's understandable.

Enjoy!

Cris

Nice work but...for a "same length" board, from what I got out of that, the straight board, at a 25 degree angle creates more lift than the curved board, right?

The first part of your conclusion makes sense. From my personal experience, curved boards are used instead of straight boards for practical reasons: they are easier to insert, lower and lift. Otherwise, straight ones are lighter, easier to build and less draggy.

As for the second part, I would look for benefits in terms of added stability and damping, not in terms of drag reduction. The additional stability and damping improve seaworthiness and may save some energy from unnecessary pitching, heeling and yawing motion. Alternatively, it would allows for a more powerful sail plan.

All the best,
Luiz

Yes. Figure 5 is the 'same length' case. If you match the side force Ly of a 45 degree curved board with a 25 degree straight board your lift Lz will increase from roughly 0.33 to 0.38. The drag will stay very much the same since the board area didn't change. You will exceed the maximum with rule when trying to fit it by a lot!

Since you've done all the math, about how much of an angle would you have to put your daggerboard at to lift the entire weight of an A cat (165lbs) plus say, a skipper of same wt. for a total of 330lbs. clear of the water, at say, 10 knots boatspeed? For computing purposes, figure the two daggers will lift equally, and we will also have T foil rudders which also will (theoretically) lift the same amount as the daggers, or 25% lift on each of the 4 "foils". (so each foil has to lift about 82.5 lbs. at 10 knots boatspeed)

Dave Carlson, did you do similar math when you built the Jackalope foils? <img src="http://www.catsailor.com/forums/images/graemlins/confused.gif" alt="" />

Well, if I did the math right, with the sailor sitting on the windward hull the side force on the sail is roughly 43 Kg (421 N). Each foil will have to supply 10.75 Kg of side force and lift 37.5 Kg (367 N). So your ratio of vertical to side force is 37.5/10.75 or an angle of 74 degree. If you do all the math for alpha=11 degree (gamma of 3 degree), lift coefficient of 0.1 per degree, board aspect ratio of 10 and a speed of 5.1 m/sec you get a cord of 0.1 meter. The board will be one meter long and you would have four of them. Sounds believable...

I would like to give my two cents opinion here, I am not a competitor but I love A class sailing and I love to fix problems on the boat year after year and to make some big homework like realize a triradial sail for my "old modern" A class cat.
I have red entirely the thread, a lot of discussion, a lot of speculation on big advantages or on resale value of "outdated boats"
well my idea is that I love A Class because it is more technologically advanced than any other beach catamaran commercially available, it is fast and pleasant to sail
I think I would like to try an hydrofoil assisted boat able to enjoy myself in the 4-30 knots range in summertime (I think it would be reaaaaally difficoult to get that with a banana board...)
you say: but this wwould outdate new boats ! well, here I don't see the problem, given that me myself I would be in trouble because I could indifferently decide to change my old modern a cat for the new hydrofoil assisted boat or equally I could decide to buy an almost new "traditional" boat at a sale price.
Given the class as it is now, I WOULD NOT CHANGE my 9 years old woderful and performant carbon a class for nothing new... such as a wavepiercing and similar refinement (usefoul "maybe" only for talented sailor to race in the international arena)
I told you, I love pleasant sailing and the certainty of sailing something technologically ahead in respect to other friends' boat (in other words smarter...)

all this to say that in my opinion A class it is not anymore developmental class but a perfectionated class of a previously developmental class

everything in the end has a cost, either maintainig the class stable as allowing sudden changes

;-)

In practice the boards are designed, angled and placed so that their lift resultant points toward the sails' CE in order to minimize (neutralize) the heeling moment. In this case they are true "Bruce foils".

I believe you will need less than four 1m boards at work to fly an A Class at that speed. Maybe half of it. Also, it makes more sense to use one slightly larger canted board aided by a small horizontal foil in the rudder.

Regards,
Luiz

An original effort with large, externally-fastened surface-piercing foils on a Tornado in UK in the 1970s involved 4 foils. They soon abandoned 4 foil approach. Boat didn't turn.

Dave, does you Jackalope A cat have T foils on the rudders too or just the two Bruce foils up front?

Yes- old Hobie fiberglass rudders have T-foils. The obsolete aluminum surface-piercing foils are located at the front cross bar to provide lift. It works.....
So again- when are you going to appear at Lake Santa Fe this fall to fly it? Ya can't spend the whole year on-line.....

BTW- the foiling A-cat seen in my avatar is 34 years old- epoxy/tortured marine plywood: going strong. In contrast- See the old Tornado discussion ongoing- fragmentary boats not worth restoring or messing with.

Gougeon cold moulded cedar tornados are still good, 30 years later. It is not the boats, it is the building methods and materials. Not many polyester/glass A cats from that era is still in use. Wood is an excellent material for boats, but time consuming and as such uneconomical for manufacturers.

Dave, I will get up there some day, I just hope there is enough wind when I do! BTW, about how much wind does it take to get it up on the foils and how fast does it go when you do?

I will be at the Wildcat regatta in Eustis, Oct. 4-5 (I think) will you be there? Can you bring the Jack a lope or will you have your other A cat?

I'm trying to get both my twin daughters into Florida for next year (one is at Auburn in Vet School now spending a new set of sails every month) so if I can get them in, I will be up there quite a bit, at your house, as soon as I drop them off!

Thanks. Tim

See private mss.

I'm tempted to say two words: Financial aid (or maybe 'student loan').

From what I'm hearing from financial gurus it's better to build your nest egg rather than fund their post-graduate education unless you're 100% positive they will be paying for your entire retirement. If they go off and raise a family, you're not guaranteed they'll pony up (pardon the pun) when you would like to sail off into the sunset...

There are way more options to fund education than retirement...

I like Dave's foil concept. Is it stable in chop/wave action?

Could something similar be designed for a sloop rig with spin? I think it'd be neat on an old Taipan 16 footer that didn't fit the F16 rule ...

Or even better, if you could just switch out the F16 compliant daggarboard/rudders with foils so you can sail either way... But that's probably asking way too much...

I just sold my Marstrom A-class with gennaker, I got an offer I couldn't refuse. My plan is to buy a new Marstrom during the spring and that boat will probably have "banana boards". Marstrom are working on moulds for the boards right now. I will of course fit the boat with the spi snail that I will use for distance racing. Marstrom has a smaller snail now designed for the 17 m2 size of gennakers instead of the M20 version I've been using so far.

The majority of the A-class sailors seems to think it's ok with banana boards and then it's just to follow the class or change class. I decided to stay in the class and upgrade boat. Older Marstrom boats can probably be rebuilt to handle "banana boards", more news about that later when I have facts.

/hakan

I am looking at what the cost is to modify mine right now. I do not think that I want to tackle the issue myself this time. Just too much work and no time to do it. I think that it is good that this is happening and that most of us agree with the decision. In the US we took an informal poll across the country fleet by fleet. I know that there were some disenting votes, but the majority of the class in the states seemed to be of the opinion that this is truly no different than the canting boards that are already allowed. those of us at the back of the fleet have more to worry about than this issue. We need to be able to spend more time on the water and sharpen our sailing skills much more before this issue has any real impact upon us. This issue will play out at the top of the class somewhere between the top 20-40 sailors worldwide. If this truly has the impact that some believe it will, then it could be the deciding factor in National, Continental and World championships.

Hi guys !
After read most of the thread above , i am quite surprised about this fuzz.

How many guys of you did actually raced a 'banana borads 'boat or did race against a banana boards boats with a canted straight boards boat ?

i had the first curved boards a class flyer mk1 in 2004. tested it , raced it in all european regattas and 2004 -2007 worlds etc.
Also sailed last european in La baule agianst Bob baier with his Nils Bunkenburg designed Nikita with the curved boards .
( last two season i race a normal fLYER mk2 ( Egner) with normal canted boards ad are faster then on my old boat with the curved boards which i still owned untill last month)

I can assure you it is really difficult to judge if there is a difference at all between curved boards an sthraight ones , an even more , if it is faster or slower.

There might be some circumstances that it feels faster , there might be some circumstances that is might feel slower .

But clear is± difference between straight old style ´in the hull plane´ boards and common canted board like all new boats is BIGGER then difference between the 'normal'canted boards and curved boards .

When you have EXTREMELY curved boards ( let say Radius 1200 mm) , then off course vertical lift vs lateral is a difference you can detect , but the downside becomes also clear...

so , what makes the differcence then ??

DOWNWIND SAILING TECHNIQUE!

There is much more then 'going flat 'or 'going wild'

There is some 20 degrees of sailing angle in between where you can fiddle around : going mild , or whatever you call it .

Highly dependable on
-waves / chop
-stable or gusty winds
-current/ wave, wind direction
-windspeed of course
-sailors weight : 70 kgs or 85 kgs makes a hell of a difference is the choose of optimal angle downwind.
-rig set up/ mast rake

my impression is that most sailors ( incl myself) are are 'too much sailing wild thing' as you understand what i mean . Quite often sailing slippery down at deep angles pays off better . Lighter guys can do that easier off course then the big guys .

Thats a differerence no curved / straight or canted board will make in a 100 years...



PJ

PJ,

Nice post! You bring up some good points with through your own experience. Thanks.

Tom,

Why would you make this modification now? My boat has square trunks and I could easily add curved boards, but I'm going to wait to let someone else do the experimentation before I go cutting my boat up.

Plus are you racing the boat? Do you really think curved boards are going to make a differience in your results?

I'm not beating you up, I'm just asking because I was going down the same path. I wanted to add curved boards until I started having these same conversations with guys in the class, my sail designer, etc, and the consensus is the I need to work on my technique first, rig second, everything else is a distant 3rd.

Bill

Bill,
I did not say that I am going to do this. Right now I have someone looking at the cost of doing one of two projects. The first would be straight boards, canted and the second is to look at banana boards. I do race the boat, but not enough right now for it to make a difference. I am planning on racing it quite a bit more over the next 12 months. If you read through my post it does state what you say which is that I need to put more into getting time on the water and that everything else can wait. How do you like your new sail?

Yes the A-cat with external foils is quite stable in a fresh breeze. Small sloop with spin and foils? If you are trying to run a spin at 20 knots across the wind- it will be difficult to manage.
Re versatility:
As previously stated, I put the hydrofoils on this boat in the thumbnail pic for the 38 mile Mug Race last year: little wind= poor result. This year I ran it in the Mug Race with a Hobie18SX spin in light air, and was only beaten by 5 larger, much more expensive cats.

To quote Pieterjanned28: >normal FLYER mk2 (Egner) with normal canted boards are faster then on my old boat with the curved boards. Now we get to the point of the matter!

In Europe, apparently "Normal canted boards" are canted in. So I believe that is what he it talking about. In the US, existing A-cats have obsolete vertical trunks or trunks & hulls canted out like my Italian-built 2005 XJ. We have not seen many of these canted-in boats, except on Glenn Ashby's import with which he won the Worlds. I was there, and he was very effective downwind: No bugs on him upwind either.

hi guys ,
In europe all boats build from +/- 2004 till now have hulls canted out by +/- 4 degrees and daggerboards canted in by +/- 7 degrees ( all relative to the vertical plane ).
all boats fit the box rule of << 2300 mm when pulled fully up and >> 1500 mm tip to tip when down
actually most canted boards are +/- 1700-1800 mm tip to tip.

the most extreme curved boards on Bob baire boat are 1580mm tip to tip.

as you see no huge differences between the curved and canted boards

pj