"Mayfly"-A Class Catamaran-Fischer

Mayfly is named after one of the pioneering hydrofoil designs of the 1970-by Philip Hansford. The boat is being built by the Polish "Exploder" group. Martin Fischer designed this boat with some pioneering features- twisted curved main foils and lifting rudders- which are hard to learn more about. Here is an article with a copy of a paper by Martin Fischer that has some detail including that Fischer has filed for a patent on the foil system: http://catsailingnews.blogspot.com/2011/06/class-mayfly-technical-paper-by-fischer.html

Excerpt:

As most of the current A-Class designs the Mayfly is equipped with curved daggerboards. But in contrast to most other designs the boat uses also lifting surfaces at the rudders. Thus the boat is gradually pushed up if boat speed increases which reduces the hull drag. The lifting rudders provide additional lift, they reduce pitching and they increase the longitudinal stability, compared to a conventional A-Class design. According to our simulations the foils and rudders create about 60 kg vertical lift while sailing upwind in about 10 knots of wind. We therefore tested all hull candidates not only for 150 kg displacement, but also for 90 kg displacement: Note: so "foil assist" is approximately 40% of total weight in 10 knots of wind!

Foils
It was already mentioned in the previous section that the boat is equipped with curved foils and with lifting rudders. We won’t go into details on the foil and rudder design, just a few hints: The radius of the foils is not constant and they are twisted. The size of the foils and the rudders was set such that they provide a stable configuration for pitch and sinkage variations. Such a configuration enables stable flight in stronger winds, without the need fors a mechanical surface sensor as used on the Moth. We have filed a patent for this type of configuration.

more here: http://catsailingnews.blogspot.com/2011/08/class-worlds-2011-ultimate-weapon.html
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click on image:

 

Mayfly-dgrbd position

Check out the daggerboard position on the Mayfly vs other A Class Cats:

> It appears to me that the daggerboards are significantly further forward on the Mayfly compared to other A Class cats and that they are a bit smaller suggesting to me that Fischer may be using a version of Bill Roberts shared lift concept. And just for the heck of it take a look at this and myrough sketch in post #2: http://www.boatdesign.net/forums/multihulls/racing-cat-shared-lift-curved-foils-37544.html
This is pretty cool and could result in MUCH greater pitch stability, more "foil assist" than just a curved daggerboard, and maybe quicker tacking.



3rd picture from left is the Mayfly-compare it's daggerboard position with the others--(also see Mayfly pix in first post-definitely much further forward than usual)-

click on image:

 

Mayfly-A Class Worlds

From Catamaran racing blog:

Mayfly:
Martin sent me his feedback. As I pointed yesterday after following live gps he was leading/keeping the pace with the top 10 on the first race of the championship with good winds, but after some drop in knots the innovative platform couldn't keep the pace anymore.

Feedback from Fischer:
"In light winds we have a speed problem upwind. Below 12 knots of wind the daggerboards are simply too small. I went a bit too far with that. From 12 knots onwards it’s fine and from 14 knots onwards we are really quick.

More here:
http://catsailingnews.blogspot.com/2011/08/class-worlds-2011-day-results-anderson.html

 

This was posted at Sailing Anarchy this morning from SimonN. http://forums.sailinganarchy.com/index.php?showtopic=126563&st=25

Simon's comments are preceeded by a quote from Doug Lord, as shown below:

Posted Today, 09:41 AM

Doug Lord, on 22 September 2011 - 07:38 AM, said:
It seems to me a design to watch is Martin Fischers "Mayfly". Though it did poorly at the worlds Fischer says he was off on the area of the curved(and twisted) daggerboards. He used rudder "J" foils as well. He also used a variation on "shared lift"(Bill Roberts) pioneered on the Arc 21(and Mirabaud ,for that matter) by moving the daggerboard quite far forward and changing the relative areas of the board and rudder.
Info, pictures and link here: http://www.boatdesig...cher-39616.html

SimonN wrote:
"The boat proved to be a total disaster. One of the guys I sail with regularly sailed the other Mayfly and came back saying that the whole concept was deeply flawed. Contrary to what Martin reported, there was never a time that the boat was OK upwind and while downwind wasn't a disater, it wasn't that good. To give you some idea, Chris would have expected to be well inside the top 20 (he is an Olympic medalist and his past results are up there) but he gave up half way through the regatta having finished in the 60's and 70's and having spent a lot of time each day trying to find ways to get the thing to work. Martin believed that the problem was that the boards weren't long enough, but that wouldn't cure some of the problems. Because of the placement of the boards, the boat tacked so slowly it was a joke. I believe that the upwind speed was comprimised by the shape of the daggerboards because of the vertical bit added to the bottom part at the end of the C section. This has the effect of making the boat perform as if it is narrower. You get this problem with normal curved boards, but the net effect is too small to have a real impact. On the Mayfly, the shape of the boards probably makes it sail as if it is over 10% narrower. Chris also reported that he felt the rudders were hugely "draggy". He did suggest, however, that the hullshape had possibilities and I believe that the builder is now modifying it to take conventional boards and rudders fitted in a more conventional position. The only person left who believes the idea has any potential is Martin.

I really feel for Chris. He spent all that money to go to the worlds and the trip was a total disaster."

 

Mayfly

Martin Fischer is one of the top catamaran designers on the planet -Simon is not. Simons original comments about curved foils way back-was highly negative(in his own words). I think that a boat like "Mayfly" -with its numerous features- deserves better than to be written off at this early stage in its development.
Note: the comment about the rudders being "hugely draggy" is interesting since one of the top A Class sailors uses rudder foils. There is much more to this story.

 

So, you are willing to overlook the fact that the person sailing the boat in competition is an Olympic medal winning sailor and was anticipating a top 20 finish? And also step past the fact that Simon is this person's good sailing friend and that there is probably a whole lot more he could tell about the struggle involved on the water and did not do so out of respect for Fischer's body of work?

Perhaps it would be good to understand that even guys like Fischer create less than powerful designs every once in awhile?

Lastly, I would ask you what specific experience you have sailing the boat in question?

 

Mayfly

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I think Fischer's assesment of the problem is worth ten times Simons.......

 

And this just posted, again at SA by Samc99us:

"I agree that Martin Fischer shouldn't be ignored, however even the best designers have failures. The Mayfly is a radical concept, one that likely needs 2-3 years of development. Perhaps with a few tweaks it will be back like the Nikita."


As simple as it sounds out loud, it's apparently very difficult to comprehend.

 

Now, a bit later in the day and another well-regarded posting member, C-Class Cat World Champion, known on SA as Blunted, had this to say with an accompanying photo (see foiling cat photo below)

Blunted said:

"The performance of this boat sounds very similar to another woofer I was involved in..."


In the meantime, SimonN has checked in again with a response to a post made by our friend, Mr. Lord...

SimonN said:

"Everybody acknowledges who Martin is and what he has done previously but that isn't a guarantee that he is on the right track with this. In fact, there were a fair number of us who held off buying new boats because of this design and because of the claims that Martin was making about it. I would not make the comments I have made lightly. I have spent a significant amount of time discussing the design with one of the few people who has raced it properly, in order to understand what can be learnt from it. By way of example, before the boat was even launched, one of the big questions was how it would tack. Martin claimed that it took practice, but Chris says it wasn't a case of practice but a case of accepting the boat tacked super slow, losing huge amounts of ground with every tack. This is not a fine tuning matter. It needs a fundemental repositioning of the boards and as soon as you do that, the concept begins to fall apart.

Before the worlds, Martin was making some pretty amazing claims about the performance. These claims were never substantiated at the worlds, although I note that Martin does claim one good downwind leg based on GPS speed. The problem with that is it isn't VMG but straight speed and as such, meaningless. The other Mayfly sailor claims he never had speed downwind.

It seems to me that we are seeing yet more evidence of the age old foiling problem, namely that the drag generated to get the lift leads to a greater speed loss than is gained from the lift. Chris described the whole thing as being very draggy. Overall, there are too many issues to tackle to warrant worrying about this concept being a serious contender any time soon. Martin remains the only perosn who believes that something can be salvaged out of this and I wish him all the best in proving me wrong. However, I think it will be a long time before we can get any positive confirmation that we should be taking the ideas seriously."

 

Mayfly

The sailing anarchy thread: http://forums.sailinganarchy.com/index.php?showtopic=126563&pid=3411465&st=25&#entry3411465
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Martin Fischer is a world renown catamaran designer who is being castigated by a few because his new design didn't work as well as hoped for first time out. I ,for one, am not ready to give up on his brilliant design and I have every confidence that he will come up with a viable solution as development continues. He sure as hell won't give up.
And comparisons to the C Class 4-foiler "Rocker" are ludicrous*, in my opinion. Fischers design, as specifically illustrated above, is a "foil assist" design-not a full flying foiler-big, big difference. (post 1, excerpt 1, above)

*Rocker used 4 sets of t-foils with surface piercing daggerboards. Because of her configuration "veel heel" was not possible. But back to the foils: On Mayfly the lifting foils have a single tip producing drag-4 tips total. On rocker with the T-foils, there were EIGHT such tips. There is simply no viable comparison between the boats.
-Also, you can read how the effective aspect ratio of a foil is decreased by using a t-foil configuration and increased with a curved foil or "J" foil with a curved transition. See post 54 and the paper linked there from Greg Ketterman who helped me understand this:
http://www.boatdesign.net/forums/sailboats/dinghy-design-open-60-influence-36401-4.html

 

Pretty tough to call the boat "brilliant" if it didn't work worth a hoot

I suggest that you invite Blunted to the BD.net forum, where you two can go toe to toe about Blunted's knowledge on the subject. There is, however, an argument that you'll have to overcome, besides the irrefutable credentials and experience that are possessed by those whom you have chosen to call ludicrous. That is the suggestion you make above, that one four foiler is an assist boat and the other is a considerably different flying foiler AND that they do not have the same fundamental issues to overcome in the eyes of the reading members here. Maybe you can entice both Fred and Magnus, the reigning World Champions in C-Class Catamarans, to step into the discussion, just in case they don't see eye to eye on these matters.

Anything less is just a quoted passage war of words without the juicy bits represented by close quarters interaction.

 

Mayfly

Lest anyone be confused: the discussion is not about whether curved lifting foils work on the A Class. There is concensus that they do and the results speak for themselves, according to "Simon N" * and many others.

Another thing that there is little doubt about is lifting foils on the rudders-
Simon says: " However, I believe that you are right that wings on the rudder can help and Landy has added these to his last 2 boats, claiming a worthwhile benefit." post 16 on the SA thread. Thats in the A Class-they have been used successfully on many boats for many years.

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Among the major innovations on Martin Fischers "Mayfly" are:

1) curved(not constant radius) and twisted daggerboard foils,
2) a vertical tip on the curved foil(similar to those used for years on big tri's)
3) "J" rudder lifting foils,
4) forward movement of the daggerboard as compared with other A Class cats.

From Fischer:
Foils
It was already mentioned in the previous section that the boat is equipped with curved foils and with lifting rudders. We won’t go into details on the foil and rudder design, just a few hints: The radius of the foils is not constant and they are twisted. The size of the foils and the rudders was set such that they provide a stable configuration for pitch and sinkage variations. Such a configuration enables stable flight in stronger winds, without the need fors a mechanical surface sensor as used on the Moth. We have filed a patent for this type of configuration.

*This guy is the guy who disparaged curved foils when they first came out. Now he disparages the work of Martin Fischer before enough development has been done to support those conclusions especially in light of the next post.

 

And again: (Note that the comments from the catsailingnews guy backs up Fischer and not this "SimonN" character)

 

I'm just curious about the function of style in this discussion, as it looks right now to be a format in which continuous modifications are being made to the posts in order to make it look as if specific elements of an argument were present all along, when they were nowhere to be found in the initial posting.This isn't about typographical errors, or simple mistakes in grammar/punctuation, but complete rewrites of the content in an effort to better position an argument being made at a later time.

To wit, I refer you to post #10 in this discussion sequence. It has been altered considerably since my last post. I wonder what the purpose is for that particular strategy and how one is to conduct a proper discussion when alterations of this sort are being made after the fact?

I am going to invite Fred and his partner Magnus to join the discussion from the SA forum, but I must suggest that this kind of, altering of history, practice is not going to fly well with them should you wish to entertain a serious conversation on a public forum.

Why do you do this when it is not acceptable in professional level discussions? I know that Cut Once has asked you the same question in many interactions and I do not recall ever seeing a proper response. Please clarify your purpose before I invite two World Champions to the discussion forum to engage in what could be a truly great sharing of knowledge for the rest of the members here. Additionally, I will also invite SimonN, as it is he who initiated some of the more definitive elements in contrast to the Fischer oriented material available here.

 

Chris Ostlind: why are you here? You're back to the same old stuff. Don't you think Jeff will catch on pretty soon? Where did "Hussong" come from?
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Hussong, I always edit my posts in a constant effort to be sure they are the best they can be. When I find new information I include it it the relevant post so as to help keep the thread on track and better inform people who are interested in the material. I've done it ,as necessary, for years and will continue to do so.