International C Class Catamaran Championship Falmouth 2013

Bench Warmer · October 1, 2013

From my candid standpoint, I would say that the C-Cup has lived an historical change

With the attendance of big corporate sponsors:

it has moved from the "Gentlmen Drivers era" to the "professional ages" , do not see anything pejorative for the gentlmen.

Hydros-Team communication demonstrated a great "ethical commitment" to keep the "Spirit of the Class"

as pionneered by Steve & Fred and Hydros looked a bit like the "missing link".

Special thanks to Jeremie & Stephane and to Lombard-Odier.

North-American (USA/ CAD) teams were as open as usual, whatever you were a rocket scientist or a candid tourist

and deserve grateful thanks too.

If C-Class becomes a kind of baby AC, we can expect for the next one, to see all tents closed with

guards & security dogs..... for sure it might be slightly different.

Best regards

Benchie

Dave S · October 1, 2013

To be fair to the French team, their tent wasn't always closed; after being spotted peering through the open door, we were explicitly invited in and told we could look at anything we wanted so long as we didn't touch...

Catfan · October 1, 2013

Thanks all for yr "temptative" explanations.

If I were there I would be technically overwhelmed too.

I know what you mean. One of the SHC wings took me about an hour to work through, and honestly, I would not be surprised at all if I was way wrong in the end.

In a word no! I don't know why, but I was kinda overwhelmed technically, and while I hope I was looking with reasonable eyes at some of the stuff, like hull profiles and some aspects of the wings, I'm conscious *now* of how much more escaped me. I think you - or I anyway - really need to be pretty familiar with the boats and tech to understand properly what's going on.
Also these days I don't have quite the interest in complicated strings I once had. But still, even tho' I missed stuff, it was still not wasted time being there, plus ran into a suprising number of old mates...

I know what you mean. One of the SHC wings took me about an hour to work through, and honestly, I would not be surprised at all if I was way wrong in the end.

>

Jim
Did you figure out how her canting rig system is devised and how it works?
In a word no! I don't know why, but I was kinda overwhelmed technically, and while I hope I was looking with reasonable eyes at some of the stuff, like hull profiles and some aspects of the wings, I'm conscious *now* of how much more escaped me. I think you - or I anyway - really need to be pretty familiar with the boats and tech to understand properly what's going on.
Also these days I don't have quite the interest in complicated strings I once had. But still, even tho' I missed stuff, it was still not wasted time being there, plus ran into a suprising number of old mates...

JimC,

I know what you mean. One of the SHC wings took me about an hour to work through, and honestly, I would not be surprised at all if I was way wrong in the end.

Giles · October 1, 2013

Team Eaton (Canada)

There was awesome craftsmanship on all the boats, but the Canadians were the ones who left me feeling the most inadequate... The rudder head in the first pic was fabricated from around ten separate pieces of carbon plate, all glued together without filler readily visible and of course they had four of them. Wonderful stuff...

Rob Paterson and Christian Pavey of Paterson Composites.

Tucky · October 1, 2013

Thanks Steve for your honesty, as always. Best of luck in the future.

jorge · October 1, 2013

Now that I have broken radio silence, maybe I should give a Cogito Project report .

Groupama kicked our collective ass. Those guys are awfully good at everything they do, and with the exception of Franc's unwillingness to participate with the rest of the fleet and the normal interactions before, after and around the sailing ( such as the prize giving) really showed us how comprehensive a program they can run.

The Cogito effort this time around was way short of the mark. Lars and Max sailed very well and probably got almost everything out of Cogito. But their results were hampered by the fact that the flap blew up on day one and essentially a limited them to a top placing of 3rd no matter what had happened. Flaps have been giving me fits for the last two years, I thought I understood what the loads are and how to build them, but it's pretty obvious I have not got it right. Aethon suffered a similar flap failure on Monday, and had the repair fail on Tuesday, so we were in the shitter from the get go. This is no way to run a railroad or do well in a regatta, and the mistakes were all made long before we shipped the boats. Bad project management bites you in many ways. Other commitments and other opportunities meant that we didn't focus enough effort early enough to have any reserve readiness or even enough practice time. Readiness and practice are the capital of confidence, and confidence is a precondition of trust and success. This resulted in friction on board and in the tent. Oliver's response was a complete loss of trust in me, to all this doesn't mix at all well with my preexisting conditions, so by the end of Wednesday's racing, I was so fucked up I couldn't move my arms let alone hold a tiller. Fortunately, Adam May was able to sub in for the remaining races and the boat could be competently helmed.

The long and the short of it is that the deficiencies of the Cogito Project as currently constituted were manifestly demonstrated. A period of reassessment and evaluation is necessary before we move forward. Three years ago, I felt we had an excellent boat and team encountered some bad luck, now I have no such confidence. Aethon showed some speed, but never had a chance because the entire project was badly managed. I failed to muster appropriate resources at times when they could make a difference and as a result we missed too many targets and deadlines. In the end we showed up with a team and boats that we're not capable of winning the regatta, or even competing with Groupama.

The old saw is that you learn more from your failures than from your successes. While I value learning a great deal, right now I would prefer to be a lot less well educated.

SHC

Very honest report made by you, not many people can do it, less make it public. But as the saying goes, being able to recognize the problem is the best way to find a solution. Best luck for tne next one.

invictus · October 1, 2013

The real reason Invictus was late, Grommit got over-zealous guarding our trailer!

STYacht.com · October 1, 2013

To be fair to the French team, their tent wasn't always closed; after being spotted peering through the open door, we were explicitly invited in and told we could look at anything we wanted so long as we didn't touch...

lucky you. we were told very much otherwise.

Wess · October 1, 2013

Seems the PR face of Franck Cammas and Groupama has maybe (?) slipped a bit. Was quite surprised to see him nowhere to be found in the awards video when that went up a few days ago. Now the comments on this thread. That seems a bit of a shame given the traditions and history of the class and those that came before. Money and a PR smile only go so far; actions speak louder than words.

Perhaps it is not so wonderful for the ICCCC to become the breeding/proving ground of ideas for the AC.

cms · October 1, 2013

I have rarely seen Franck as open and "friendly" as he seems to have been in Restronguet. His world is a bit different from any of the others competing. This event was life for many others, whilst he has a few other irons in the fire .... Yes, a pity he was not at the prize giving, and yes we have for years wished he could be more forthcoming. But ... he wins things, organises better than the best and has incredible focus. He demands the best from himself and those around him. The C Class was mostly a project to keep the design team together and buzzing and clearly that worked. I am sure he did not expect to have such an advantage on the water, but, hey, he did.

Why?

PS - if you think it was only money, then you are barking. I don't suppose he would be any good in a Nacra 17?

JimC · October 1, 2013

So, it would mean that if you let loose the w/w side and easy the rig off to l/w, and you are taking up the other side in a loop, then when you tack or gybe over, the constrictor is holding already.

I have a head on mid tack photo in which the rig is clearly canted to what will be new windward while the helm is just getting to the windward hull and the forward hand is still doing something in the daggerboard area on the now Lee side hull...

buckdouger · October 2, 2013

It's interesting that analysis we're getting from a lot of the teams that might have been expected to do better with their new boats highlights self-inflicted wounds/errors.

Steve's candid post was interesting and refreshingly honest; Blunted admitted that they shot themselves in the development foot with some early decisions, notwithstanding trying to bluff loyal SA followers, and clearly something almost prevented the Invictus team from getting to the start.

I think it just goes to show how hard it is to pull these boats together, all the more so when team members have other lives and aren't professionals in this field.

atg · October 2, 2013

So the question for you all, can we put a "little herbie" on a C Class???

The real question should be how can you foil upwind without one.

F1 has been down this road (pardon the pun), When you go with active electronic suspension controls and traction control, the driver is removed somewhat from the behavior of the vehicle, in favor of a computer. This may permit things which are otherwise humanly impossible to occur, but it doesn't necessarily make for more elegant or creative designs, or for better racing.

It also raises the bar for entry, as you need a programmer and electronics team to get that working and reliable.

When the role of the human input is limited, the sporting achievement is similarly limited. In the Oracle case, it hinges upon the specifics, but basically when you insert electronic input to the foil control loop you open yourself up to the criticism that the sailors are not sailing the boat anymore, which conceptually is an own goal when it comes to selling the romance of it all to the public. What's next-androids crewing the thing? Great. That should sell well.

Cars can race themselves, but so far (outside engineering circles) there seems to be limited interest in watching them do so. As the technology becomes more refined there will be even less interest, and zero sporting interest.

I think people can understand mechanical design achievements more readily than electronic ones, mainly because most mechanisms are inherently inanimate, whereas with electronic boxes and enough processing power fairly humanlike behaviors can be emulated. With respect to foiling, any number of active mechanical control solutions would have worked perfectly well for the AC 72 foils, had they not been prohibited by the rule.

Well since ETNZ was able to foil upwind without one I don't think thats the question. The real issue is that what works on a 72'er isn't neessarily going to work on a 25'er. I think the Hydros approach of a fully articulating board that can be trimmed by the crew might be an answer And you would learn to do it by first traiining in lighter air on reaches and progressively tightening the reach

ETNZs upwind foiling efforts were sort of a dog's breakfast from my perspective. Obviously the boat cannot get too high or it starts to slide to leeward. So the heave control needs to be very tight, with the hull only just clear. ETNZ appear to have been "skimming" with only a bit of hull touching and regulating the height. When they went for full foiling, the boat would get too high. Oracle somehow managed their heave control much better and were able to sail with the leeward hull completely clear much of the time upwind. That seemed to be the big difference.

atg · October 2, 2013

The good news for sailing is that there is always a place for the crew because the crew is bringing the weight and so are very much a dynamic part of the system. And they still have to steer the boat and react to what ever is going on around them, so I think it's OK if they do this while the boat adjusts its trim angle. In fact, watching the C class videos, I think if the boats could reliably foil under most points of sail while the crew focussed on everything else, it would make for fantastic sail boat racing.

Though I agree with your comment I would still say limiting foil control to mechanical systems using only wind, water or manual power is preferable, from a sporting perspective, to electronic sensors and programmable controls.

Phil S · October 2, 2013

Though I agree with your comment I would still say limiting foil control to mechanical systems using only wind, water or manual power is preferable, from a sporting perspective, to electronic sensors and programmable controls.

Totally agree but make that direct mechanical linkages with no method of storing energy. ie No hydraulic reservoirs and no batteries.

Should apply to all sailing boats not just foilers.

Bench Warmer · October 2, 2013

CMS,

You are probably very right, C-Cup is just a duty among other for Groupama Team, the whole team must abid to internal code of conduct, bylaws and other NDA, just like for any other competition they are involved in, This can explain that !!

For sure it has a taste of professionnalism, with some funny details: ie: as soon as the boat was back on the green in front of the tent, they first bring a paperboard and make the "to do" list with a marker.

Franck is not only the winner , he is also a great manager, and his team members are probably among the best in their roles

Only one question remains: Will they get a similar bonus like in Groupama bank ? honestly they deserve it.

Best regards

Benchie

MR.CLEAN · October 2, 2013

Heya Benchwarmer. Nice to have met you and looking forward to that article we discussed!

Amazing the stories that happen around a Little Cup.

I am working on two things now - the first is pulling and assembling the 'live' clips to get the best stuff to petey for his 'reality show' highlight clip.

The second is getting the full race days re-streamed so everyone can watch them in a comprehensive way.

Still in darkest england though, and for some reason the internet and weather pretty much always suck here. At least when I am around!

Börni · October 2, 2013

i really like this approach. i think Alan Smith did some research on those angled t-foils with his kooee models. His site is down for a while so you don't find a lot of information in the web. have you been in contact with him? Would be great to have some one give that configuration a go.

Has anybody considered a main foil arrangement as per the sketch below?

I see it using Moth style lifting foils with trailing edge flaps controlled by wands. The supporting foil, that doesnt take any side load, is curved to allow the windward foil to lift neatly up under the hull. This arrangement effectively mimics a Moth going to windward.

The angle of the main lifting foil to the horizontal would be pre-set to take the combined side (wing) and vertical (weight) loads at maximum righting moment. Note that I have put a little tweak in the top of the supporting foil to allow for reduced righting moment downwind and a little more water clearance.

Some potential benefits of this arrangement I see are:

Ability to foil up and down wind.

Efficient foil deep under water doing all the hydro work

Active control of ride height

Simple foil slot in hull (no need for any foil cant mechanism etc)

The downside I see as the ability to reduce the friction in the wand cable down the curved foil. Maybe a straight supporting foil would be simpler and the lifting foil would stay at its angle to the horizontal when lifted.

Bench Warmer · October 2, 2013

Hi Alan,

As agree, I have to deliver.

But if you dont mind, I d like the guy which will be mentionned gives his agreement before any publication.

Also, writing is not my best skills, so it might be a bit short to give something to chew for your Anarchists.

I'll try to make my best

Cheers

Doug Lord · October 2, 2013

i really like this approach. i think Alan Smith did some research on those angled t-foils with his kooee models. His site is down for a while so you don't find a lot of information in the web. have you been in contact with him? Would be great to have some one give that configuration a go.

Has anybody considered a main foil arrangement as per the sketch below?

I see it using Moth style lifting foils with trailing edge flaps controlled by wands. The supporting foil, that doesnt take any side load, is curved to allow the windward foil to lift neatly up under the hull. This arrangement effectively mimics a Moth going to windward.

The angle of the main lifting foil to the horizontal would be pre-set to take the combined side (wing) and vertical (weight) loads at maximum righting moment. Note that I have put a little tweak in the top of the supporting foil to allow for reduced righting moment downwind and a little more water clearance.

Some potential benefits of this arrangement I see are:

Ability to foil up and down wind.

Efficient foil deep under water doing all the hydro work

Active control of ride height

Simple foil slot in hull (no need for any foil cant mechanism etc)

The downside I see as the ability to reduce the friction in the wand cable down the curved foil. Maybe a straight supporting foil would be simpler and the lifting foil would stay at its angle to the horizontal when lifted.

Here is another foiler under development with angled out t-foils:

F1 foiler specs:

Length 18 ft. / 5.5 m

Width (when beaching) 12 ft. / 3.5 m

(foilborne) 16 ft. / 5.0 m

Sail area 150 sq.ft. / 14.0 m²

Weight 306 lbs / 138,4 kg

Technical info-in German: http://www.enzmann.net/ueber_HydrofoilerF1_de.htm

video from Dusseldorf Boat show:

blunted · October 2, 2013

Team Eaton (Canada)

There was awesome craftsmanship on all the boats, but the Canadians were the ones who left me feeling the most inadequate... The rudder head in the first pic was fabricated from around ten separate pieces of carbon plate, all glued together without filler readily visible and of course they had four of them. Wonderful stuff...

Rob Paterson and Christian Pavey of Paterson Composites.

Not forgetting to mention Steve Killing Design who draws such pretty boats and details and MTC, or Multimatic Technology Corp, who fabricate our big bits, or Billy Gooderham doing all the string bits this year. It's a team effort and all played a big and very valuable role in making it look so slick and work so well.

Note, FYH did not have one single break down during the event itself, OK, I put my knee through the 3Di tramp while towing in one day, but that was not really the event, and it was an operator error. That boat performed very well from a reliability perspective, very well indeed. a testament to all who laid hands on HANDS.

Thanks again team, awesome effort, sorry we let you down on the design conceptualization front and the light air sailing was a bit weak this year, but that's another story.

blunted · October 2, 2013

The big question: can foiling and canting tech be retrofitted to the older hulls?

Saw, check,

Carbon fiber, check,

Epoxy, check

Bog, check

Extra strings to make it work, check

I would say yes they can, the trick is where exactly to use the aforementioned items. The area around the trunks needs work, the main beam will need additional work, the whole rudder area and hangings will need work, the crew training and understanding of flight dynamics will need work too.

It's all pretty straight forward on paper, once the rubber meets the road its starts getting complicated quickly, but it's doable for sure.

anyone want to buy Orion? It would be a great boat with foils, solid little used well build platform awaiting some tricks to make her sing.

blunted · October 2, 2013

I know it seems like this stuff is on topic, but it's easy to get into the weeds from here.

My suggestion to all is, go try the wacky ideas yourself, and if something works, come back and tell us.

It's nice enough for people who are out there doing things to contribute here without having to weigh the merits of every zany concept.

At this point everyone may as well "zany concept" away as the event is over. Think of it as crowd sourcing ideas, some may win the prize and actually get built. To your point, we always like to see people build their own and figure things out first hand themselves.

I would only suggest that the C-cats are going to be in no rush to change their rules, E.g. stored power is not allowed, so no motor or servo driven foil systems etc, and no more sail area, for any reason, and no changes to total dimensions of the platform, or t ain't a C-cat anymore. We have precedent for wand systems and active control of all sorts, so those are cool.

Let the next design contest begin.

Wess · October 2, 2013

Let the next design contest begin.

Be interesting to see which way people go.

Foil of not for the light air lake? Did you get any idea of a transition wind speed between the two approaches from this year's regatta?

blunted · October 2, 2013

Let the next design contest begin.

Be interesting to see which way people go.

Foil of not for the light air lake? Did you get any idea of a transition wind speed between the two approaches from this year's regatta?

5 knots for GA, perhaps 5.5 to 6 knots TWS for Hydros, perhaps 6 for FYH. With some work I know we could bring ours down for our present set up and if we returned to the old foils I know we could go a shade lower. Earlier this summer we did 22.5 knots in 6 knots TWS as measured by our tender. It was just not super stable flight however.

At those speeds it's very very difficult to "get it up" as it were, it's a real art to coax the boat into it and it will cost you a lot of angle on a race course sailing on a beam reach to get to the required lift off speed. Once you are up and foiling, you can sail into less TWS and possibly keep it up, but its all a bit challenging. Once you are up on foils you can slowly turn down to some more sensible angles on the race course, you had better hope you picked the right side of the course too because a gybe is costly in terms of VMG etc. Better to overlay by miles (a few seconds) so you know you can sail back to the gate at a hot angle.

Designing a boat around a very low TWS for take off will mean some big compromises on top end speeds.

david r · October 2, 2013

Maybe Geneva will just be a race between Cogito and Canaan?

My question is; did any one get details on what caused the "we lost a rudder and the boat went into a jibe" hydros flip-over early in the regatta. i am wondering what would cause all that lee helm instantaneously? He said he pushed on the helm hard enough to bend something but the boat wouldn't head back up.

BalticBandit · October 2, 2013

To me what I remember of the video is that he didn't have much rudder in the water.

JimC · October 2, 2013

Foil of not for the light air lake?

The mothies I was watching with were in no doubt at all about that - that the gains vastly outweigh the losses. I was at the far end of the course and couldn't see clearly, but had the definite impression that Groupama lost the Weds race more through a tactical error of some kind like sailing into a hole or a big shift rather than just being boatspeeded. As I recall a huge lead was converted to a big defocit between wmark 2 and wmark3. What do the sailors think?

Of course the optimisation of design and foils for less wind or more is a huge design decision on itself.

On a diff topic, I thought Groupama's leading wing element was noticeably thinner than others, and I wonder if that could be related to their start line climb out mode. Is there a hint or two in the book of numbers, or are you guys letting the wounds heal before you study that?

Wess · October 2, 2013

Blunted,

OK so most could get up on foils in 5 to 6 TWS but had to run hot angles to get up. I am assuming your upwind or downwind VMG was always better foiling than not... is that correct?

Jim C's question on Groupama's upwind height is a good one. I gather that's not end plate related. Is it canting, leading edge, other not related to the wing???

Wess

MR.CLEAN · October 2, 2013

Franck and Louis after their win (and before Franck jetted off back to France). Hey at least he gave us his shirts!

wizdeas · October 2, 2013

Heya Benchwarmer. Nice to have met you and looking forward to that article we discussed!

Amazing the stories that happen around a Little Cup.

I am working on two things now - the first is pulling and assembling the 'live' clips to get the best stuff to petey for his 'reality show' highlight clip.

The second is getting the full race days re-streamed so everyone can watch them in a comprehensive way.

Still in darkest england though, and for some reason the internet and weather pretty much always suck here. At least when I am around!

It was good to meet you and shake hands - in passing- on windy Friday. Sorry you're "stuck" here - some of us live here and quite like it most of the time...drop in for a beer in Bristol if you are around this friday. Thanks again for all the great work.

STYacht.com · October 2, 2013

Franck and Louis after their win (and before Franck jetted off back to France). Hey at least he gave us his shirts!

Adam May, you and Dirk Kramers looking very conspicuous in the background of this video. Adam, please share the pics. I did not get nearly enough good ones of the wing operation of Groupama C!

kbaack · October 2, 2013

Blunted- not sure if you were serious about buying Orion, but if so I would be interested (not sure i have the funds, but well find out).

This and the last I4C have got me really excited about the class, can't wait to see what happens next.

Poseidius · October 3, 2013

Selection of photos taken during the 2 weeks of Little Cup by Challenge France : https://plus.google.com/b/112555696760210214992/photos

Enjoy

Nicolas

STYacht.com · October 3, 2013

Selection of photos taken during the 2 weeks of Little Cup by Challenge France : https://plus.google.com/b/112555696760210214992/photos

Enjoy

Nicolas

Nicolas,

Seems like the link is not to a shared directory? Can't view the images or gallery at all.

Cheers,

STYacht.com · October 3, 2013

On a diff topic, I thought Groupama's leading wing element was noticeably thinner than others, and I wonder if that could be related to their start line climb out mode. Is there a hint or two in the book of numbers, or are you guys letting the wounds heal before you study that?

JimC,

If it was thinner, and I don't think it was in % chord terms, it is magnified by the root tapering of the wing. This was pretty clear on G-C as being concentrated on the first element. Hydros also did not have the max chord at the root, but it was subtle in comparison.

Catfan · October 3, 2013

Franks big advantage upwind is three things

1. Canting rig with a shade more projected area and a slight increase in righting moment

2. End plating very effectively, makes him more slippery and thus he can point like a mofo, insane height

3. Great aero fairing package nice little wing and fully faired platform, again low drag which again can be taken to the back as either more speed or point, his choice

They are quite secretive about the chanting system, much of which hides inside the front beam fairing, I managed to snap a few pics one day when she was undressed and they were quick to put it all under wraps

They drop the cant before the corners then turn but they seem to be able to move it over under some decent laid too without killing themselves, it is slick for sure, no lack of brainpower in that camp

Blunted

as you likely know in the past quite a few worked on canting rig systems in many catamaran classes to no avail.

Therefore I suppose that it is of general interest to find out how Groupama's team solved the problem.

You stated that you managed to snap a few pics when Groupama was undressed and I am sure you got an idea about their canting system.

Would you like to share?

Thanks in advance

Tornadosail2012 · October 3, 2013

Overall, this was a great event to watch from afar. I wish work had allowed me to make the event. I think it is great that Lars sailed Cogito to third overall and there is no bitching about time limits here. The clock ran out on that race and that is it. Go over to the AC threads and you will hear over and over about time limits. It is what it is, move on. Steve, I hope that you get it sorted out and decide to continue with the ICCCC since you are the one who kept the class alive over the waning years. Do all of you who participated in the event this year see this as a moment in time where you might be changing as a class and seeing some more professional teams with full corporate sponsorship? Again, thank you to all for putting on a great regatta. TTS

blunted · October 3, 2013

Franks big advantage upwind is three things

1. Canting rig with a shade more projected area and a slight increase in righting moment

2. End plating very effectively, makes him more slippery and thus he can point like a mofo, insane height

3. Great aero fairing package nice little wing and fully faired platform, again low drag which again can be taken to the back as either more speed or point, his choice

They are quite secretive about the chanting system, much of which hides inside the front beam fairing, I managed to snap a few pics one day when she was undressed and they were quick to put it all under wraps

They drop the cant before the corners then turn but they seem to be able to move it over under some decent laid too without killing themselves, it is slick for sure, no lack of brainpower in that camp

Blunted

as you likely know in the past quite a few worked on canting rig systems in many catamaran classes to no avail.

Therefore I suppose that it is of general interest to find out how Groupama's team solved the problem.

You stated that you managed to snap a few pics when Groupama was undressed and I am sure you got an idea about their canting system.

Would you like to share?

Thanks in advance

Well I am back in the "real world" now and at my desk, supposedly doing actual work (hint, I don't draw boats for a loving,it's just a past time). We'll be taking a few weeks to digest what went down, what worked for us, for other teams and boats and likewise what did not work and what the jury is still out on. Part of that will be evaluating various systems on different boats, part of which involves drawing each of the subject boats and their systems we are interested in. It takes time, skill and effort to do properly.

In respect of the GA canting system, I do have some photos that are going to need some touching up to bring out the contrast and the color and then some time to decode what it all means, and how it all relates to what was above the deck. I am not going to rush this process. Similarly I am going to, for the time being, respect GA's desire for "privacy". Now to be clear, this runs counter to the ethos which we tend to espouse in the class of being "generally and broadly" open with our design developments and thinking etc. A request has been put in to the GA design team by someone notable to expand on how that particular system works for all to see. If they (GA) choose to share, well that would be great, we'll let them do it on their own schedule. If they choose not to share, we'll see where things go.

My basic understanding of the system has already been talked about here in enough detail to draw a system but I will encapsulate it, in words, again, for your benefit.

shrouds come down to big purchases under the trampoline. One on either side of the centerline, likely fastened to the center of the front beam.
I imagine those two purchase systems are one continuous loop, which saves rope and auto-tails itself. Thus it is lighter and simpler.
There is likely a trigger (line attached to a rope clutch or something is what I would do, it holds the line between the purchases and prevents the load from running from "uphill" to "downhill") that lets the loaded line run freely from one side of the purchase to the other, this is when the "dump" the rig before a tack or gybe.
I imagine when they hit that trigger it would simultaneously release the clutch at the hounds and let the forestay loop slide over at the same time, the loop clutch someone has already linked to in the thread. I assume as discussed here that there is in fact a clutch at the hounds and the forestays run in a loop. The alternative is that forestays come down and tie back into the shrouds at deck level which they most obviously did NOT.
Once the rig has been dumped to the leeward side they release the trigger, or pull a line that explicitly and authoritatively locks the system in place, "system" in this case meaning both shrouds and forestays. This is important because you don't want to tack, then find your rig dropping down to leeward again, it would take a fuck ton of work to pull it to center line, never mind to windward. Also, as already noted in the thread, the forestay loop needs to be locked off to maintain a four stay king post arrangement on the platform, so the bows don't go merrily bouncing up and down opposite each other with every wave the boat sails over (Think of the floppy version of OR V1.0 and how it looked in the water). This is common to all C-cats and A-cats that we have two shrouds, two forestays and a stiff rig, and this all keeps the platform torsionally stiff through waves etc. Those poor sods with Jibs don't get this benefit unless they go through some additional hoops.

There are a few other small nice details I imagine may be in there that allow for some certain kinds of fine tuning on the fly. But as we tell many others, "Do your homework". If you are really interested in the system go build yourself a "dry" mock-up of the system on your subject boat. This is one reason I keep a bunch of model boats around, it's very easy to mock up systems to test the ideas. Likewise I frequently build "bench" versions of systems to test the loads and the friction in proposed systems. Our adjustable idler system was done this way on my bench in my basement with a bunch of 5 lb weights hanging from it, so I could quantify the friction in the system.

I am not going to divulge every little detail I think of, or that I manage to extrapolate from other systems I see or race against. Working out these little details is really actually important to learning how to sail a high performance boat like a C-cat. We expect people to do their homework when getting into the class because if they don't, they fail, really very quickly, because they will have no idea how a system works, and they will fuck it up pretty quickly, many times before the boat even gets wet. Some of this was demonstrated at the last event unfortunately, it makes me a bit sad.

So that's all I am going to share, just this moment.

blunted · October 3, 2013

Ellison's Stradivarious had a sail that canted all over the place, but everything that did it was out of sight. At least this was the case when she sailed 20 feet from us on her 2nd day of sailing. Since at that point she looked like a big 60, maybe looking at Open tri canting systems might give an idea at least of a starting point for the GAC?

I kind of posted this over in MA, but why do hydrofoils need to exit from the DB trunks in the C class? You need stability when the wind comes up, not when it's light. Except for a small window, hydrofoils give you stability when the wind picks up. Flying a hull is considered essential in light air, so why not bring in the hulls a bit in beam, making it easier to fly a hull in the light stuff, and deploy the hydrofoils outside both hulls to Bmax when you need stability? Trap off racks, which could be part of hydrofoil support. Might be easier (and easier?) than all the contortions through the DB cases and shapes the foils are going through now? Keep the straight DBs for light air stuff. Leave the hydrofoils on shore for the light stuff. Might be a way to retrofit older boats?

This may be an early (now illegal) foiling Moth, but I think it generally shows this approach (it helps to ignore the hull and concentrate on the rack system). (I think)-

http://www.ayrs.org/Catalyst_N02_Jul_2000.pdfhttp://www.ayrs.org/Catalyst_N02_Jul_2000.pdf

Well we all agreed last November to only one set of foils for this event, "you run what you brung". Otherwise we'd all be playing games swapping out gear all day long and he with the most toys might win, not he with the best configured boat for a week of sailing and racing. We did allow that if you wanted to measure in four foils, fine, but they all live on the platform all the time when you race. As for why they exit the trunks in the hull? convention I guess, there is no rule about anything like that, just be in the box is all.

Trapping off racks, etc? Well we tried that one before, our experience was that you give up 10-15% of your RM in lighter conditions, or whenever you are in Archemedian mode as you center of buoyancy just moved inboard. so you gave up critical speed making potential, which it turns out is useful all the time. Sure the boat rolls sooner, but we are two up on the wire in 6 knots TWS and depowering from there onwards. Upwind foiling does not really kick in until the mid teens in boat speed which is a little higher up the wind range.

Likewise in the light stuff where the hull is on the water, the end plating on the foil from the hull is very nice on induced drag reduction. Our boats with rudders hung under the hulls feel quite different (Slippery) compared to the transom hung boats. No reason you could not do as suggested with outside hung foils. But you'd still need to hold them with something, that needs structure, it also causes some kind of drag either water or air. Plus if you plan on canting inboard, well you need the real estate to actually cant the thing and not hit the hull, not go outside the Bmax box etc.

For retrofitting older boats, I would personally rather cut out and replace a set of trunks(Add about 5 lbs+-), then I would ..........shorten a set of beams (highest loads on the boat, no change in weight after splicing), build and bond a set of racks (Call it add ten lbs), build and install a whole new system to actually hold the foils (Call it add 15 lbs) and trim down the trampoline (-1.5 lbs), then make a narrower shroud base (20% increase in compression loads on the rig, add 1-2 lbs to be safe). Have a narrower final sheeting angle on the wing (Shrouds came inboard so you cannot ease as far now), we could accept that the canting rigging would be a wash for both approaches. I would wager the aero drag of the platform with racks will be higher than a regular platform as well, aero drag is going to keep being more and more important as everyone goes faster as well.

Life could be simpler (Lighter) if you don't cant your foils, but if you don't cant your foils, you miss out on a ton of benefits of the system in respect of heave control, so you better have some really good ride height control on your program to make up for it, as we found out (By not having it on FYH).

So yes you would get better all up RM once up on foils (This is good for sure) both as a function of the center of lift being further outboard and the unused big fat assed board being a little further to windward (Loads just went up around the boat as a result of better RM etc so better build for that all over too).

So some people simply (GA and Hydros for example) cant the foils upwind so they are at the very outside of the Bmax box when fully immersed and the canting is turned off, and you get many of the benefits that your initial suggestion offered, namely better RM as a function of moving the center of lift outboard as much as possible. Even FYH when her foils are fully "down" essentially has the foils at the very edge of the Bmax box.

It's an interesting suggestion however, worth drawing up

Bruno · October 3, 2013

Isn't there a 14' beam restriction so all foils have to be inside that, as well as racks, etc? So there would be a major loss in RM hanging anything significant off the sides?

What little I saw of the 60s shroud adjusterslooked like big vectran or something strops that went around massive sheaves on the decks of the floats, older boats had hyd cyl on the aft side of the beams, newer ones were recessed in float decks, put the floats in a lot of compression. I believe they were independently adjusted? Single forestay that was not adjusted in a tack unless the rake was changed?

So the principle transfers but totally different mechanics i guess.

JimC · October 3, 2013

When foiling, doesn't RM come from the foil?

Mmm, but draw up the boat head on with say ten degrees of heel and see where the weights go. I suspect one could use up a pad or three of A4 graph paper thinking about C class foil configurations. The more I think about it the more complicated it seems to get...

maldonmud · October 3, 2013

Great that such a mix of interest in Mylor during the week.

Including early catamaran innovators greeting the C class fleet back in after the fogged off first Sunday 20th Sept

James Wharram & Hanneke Boon

lukepiewalker · October 3, 2013

Could you have a board with a second foil half way up, giving extra lift for foiling in lighter winds, then as speed increases it is raised out of the water to reduce drag?

oioi · October 3, 2013

When foiling, doesn't RM come from the foil?

Mmm, but draw up the boat head on with say ten degrees of heel and see where the weights go. I suspect one could use up a pad or three of A4 graph paper thinking about C class foil configurations. The more I think about it the more complicated it seems to get...

One daft thought i had was to submerse the windward foil and use that to pull the windward hull down providing righting moment. But drag would one problem, the second being the likelihood of a capsize when it popped out. Whilst in stasis you could see the forces working, dynamically...

blunted · October 3, 2013

When foiling, doesn't RM come from the foil?

RM comes from a foil only if you have a foil to windward pulling down in the Z-axis. Nobody is currently configured that way in the fleet. The only exception might be if you are sailing along with suction or down force on your rudder elevators, then the windward one could be making a modest contribution to RM.

I tend to think of RM in terms of direction of forces and leverage. If you bring the center of buoyancy inboard, the weight of the crew and everything else to windward of that point, has less leverage to hike the boat flat (The essence of RM).

So RM when foiling, still comes from the same thing, the weight and leverage of everything to windward of the boats center of rotation, which when foiling is no longer the center of buoyancy, it is the hydrodynamic center of lift developed by the two or three foils that are wet, assuming they are all lifting. so that is usually about half way along the span of the main lifting foil that is wet, and likely a few chord lengths behind the main foil, due to the contribution of lift from the rudders, if they are not neutral at the time. So when you foil, you already start to lose leverage vs when you are floating, because the foil is a fair bit inboard of the center of buoyancy of the leeward hull, so you go from 13'4" distance from COB to the weather rail, to perhaps 11 ft., plus you now have a 70 lb hull on the wrong side of the center of rotation causing HM not RM. Note: you can calculate moments from any arbitrary point in space relative to the boat, it all adds up the same, but for general conceptualization I personally always use the point that everything is resting on in a gravitational sense, and balance the forces from that point, which is the hydro center as mentioned.

Likewise as you begin to foil, the lever pushing the boat over (Heeling moment from that big wing looking thing) is also getting longer, so there is more heeling moment to contend with for the same amount of side force. When the boat is floating the majority of the side force comes from the strut or vertical portion of the foil (We don't attribute any side force to the hull as that is slow going through the water sideways, even by a little bit, so we let the foil do all the work, meaning zero leeway), So the point of the center of side force in the water is perhaps 2 ft below the LWL and the center of force from the wing is say 22 feet up for a total lever arm of 24 feet.

Now hop up on foils, and the boat is all of a sudden another 1.5 feet in the air, but the center of force below the water has not moved up that much, so now your HM lever is longer, and it just got harder to keep the boat flatter. At the same time as you load your lifting foils more you are losing RM as discussed, so you start getting into a less available power loop. That's one reason you want to foil really really low if you can upwind, to minimize loss of power due to this coupling of forces. Moths want to foil high, because they can heel so far to windward as to overcome a lot of these effects and turn them back in their favour, but on a C-cat, you'd need very long (Heavy) foils, to get any kind of angle to make it worth while, so riding low gives more leverage for upwind work.

Make sense?

blunted · October 3, 2013

teaser..

SimonN · October 3, 2013

Love your work, Blunted!

As for the canting rig, I think you will find that Paul Larson trialled a system very similar on his A Cat. Never saw the final iteration, but his ran above the tramp and the purchace, which didn't have to be so great and was only 2:1 was between chain plate and shroud. I never fitted it to the A because of the need to uncleat and cleat the system when tacking and gybing. It was too easy to end up with the whole system uncleated and needing to crash tack/gybe. However, the "game changer" is the clutches or constrictors. Pull one rope just before tacking and the rig then automatically tacks itself and recleats. Very cool. I have just ordered some constrictors!

Doug Lord · October 3, 2013

teaser..

FYH wand-01.jpg

Cool ---- would you try it again?

Catfan · October 4, 2013

Love your work, Blunted!

As for the canting rig, I think you will find that Paul Larson trialled a system very similar on his A Cat. Never saw the final iteration, but his ran above the tramp and the purchace, which didn't have to be so great and was only 2:1 was between chain plate and shroud. I never fitted it to the A because of the need to uncleat and cleat the system when tacking and gybing. It was too easy to end up with the whole system uncleated and needing to crash tack/gybe. However, the "game changer" is the clutches or constrictors. Pull one rope just before tacking and the rig then automatically tacks itself and recleats. Very cool. I have just ordered some constrictors!

I found a short video which explains better than words how the Constrictor works.

http://www.sailmagazine.com/pittman-innovation-awards/cousin-trestec-constrictor

Simon

don't forget to keep us in the loop about yr trials with the canting rig!!!

atg · October 4, 2013

I know it seems like this stuff is on topic, but it's easy to get into the weeds from here.

My suggestion to all is, go try the wacky ideas yourself, and if something works, come back and tell us.

It's nice enough for people who are out there doing things to contribute here without having to weigh the merits of every zany concept.

At this point everyone may as well "zany concept" away as the event is over. Think of it as crowd sourcing ideas, some may win the prize and actually get built. To your point, we always like to see people build their own and figure things out first hand themselves.

I would only suggest that the C-cats are going to be in no rush to change their rules, E.g. stored power is not allowed, so no motor or servo driven foil systems etc, and no more sail area, for any reason, and no changes to total dimensions of the platform, or t ain't a C-cat anymore. We have precedent for wand systems and active control of all sorts, so those are cool.

Let the next design contest begin.

Begin? You guys are several years late to this party. Admittedly it has been pretty small until now. =:-)

Tornadosail2012 · October 4, 2013

Blunted,

Thank you again for all the effort you put into the class and for your taking the time to respond to all of us who sometimes ask you repetitive and even dumb questions in hopes of learning a little about what you guys know and do. You are a class act. Thanks, TTS

blunted · October 4, 2013

Blunted,

Thank you again for all the effort you put into the class and for your taking the time to respond to all of us who sometimes ask you repetitive and even dumb questions in hopes of learning a little about what you guys know and do. You are a class act. Thanks, TTS

Cheers, my pleasure, sorry if I am a bit snippy from time to time or exceedingly sarcastic, lots on my plate most of the time.

Glad you enjoy.

Foghorn77 · October 4, 2013

Blunted,

Thank you again for all the effort you put into the class and for your taking the time to respond to all of us who sometimes ask you repetitive and even dumb questions in hopes of learning a little about what you guys know and do. You are a class act. Thanks, TTS

Cheers, my pleasure, sorry if I am a bit snippy from time to time or exceedingly sarcastic, lots on my plate most of the time.

Glad you enjoy.

Next to the tech the sarcasm is the best part.

Tornadosail2012 · October 5, 2013

Next to the tech the sarcasm is the best part.

Agreed! We wouldn't be hanging here on SA if we didn't accept sarcasm, some BS at times and a little righteous anger when someone is pushed too far. But I meant what I said, Thank you, you are a class act as is Fred and Steve.

Mal Smith · October 6, 2013

teaser..

FYH wand-01.jpg

As I understand it, one of the big tuning issues on a Moth is fiddling with the wand linkage system to minimise flap movement whist still maintaining control. Basically flap movement = drag. The boats that are the fastest are the ones that are barely under control (this is in accordance with Mal's law: "The boat on the edge of control is the fastest" ). In this respect, passive foil systems are potentially faster than active ones if you can learn to maintain control with them. Furthermore, surface piercing foils offer the potential of higher top end speed than can be achieved by fully submerged foils, due to reduced wetted surface area. Personally, I would be a bit disappointed to see passive foil systems dropped at this early stage of development, mainly because they are a simpler and more robust technology which might more easily be applied to lesser boats than C-Class cats.

JimC · October 6, 2013

Furthermore, surface piercing foils offer the potential of higher top end speed than can be achieved by fully submerged foils, due to reduced wetted surface area

Wetted area maybe, but can that really be a bigger factor than all the other types of drag?

MR.CLEAN · October 6, 2013

teaser..

FYH wand-01.jpg

As I understand it, one of the big tuning issues on a Moth is fiddling with the wand linkage system to minimise flap movement whist still maintaining control. Basically flap movement = drag. The boats that are the fastest are the ones that are barely under control (this is in accordance with Mal's law: "The boat on the edge of control is the fastest" ). In this respect, passive foil systems are potentially faster than active ones if you can learn to maintain control with them. Furthermore, surface piercing foils offer the potential of higher top end speed than can be achieved by fully submerged foils, due to reduced wetted surface area. Personally, I would be a bit disappointed to see passive foil systems dropped at this early stage of development, mainly because they are a simpler and more robust technology which might more easily be applied to lesser boats than C-Class cats.

A combination of active and passive controls will probably be the way forward; even on the very stable Groupama, lots of "zero lift events" seem to take place regularly, and it just ain't fast to splashdown.

Once a C is rolling around the course, touching down only in the tacks, it will be time to take a serious look at taking the drag out of the system. But to compare to the Moth - the Bladerider system was massively draggy. The Mach 2 system much less so, but still full of far too much play for many of the top mothies, who have gone to great lengths to figure out how to remove both hinge drag and play drag from their systems, giving them significantly higher top speed while maintaining better control. But it's taken a decade to get this refined, and there's still plenty of development to go.

MR.CLEAN · October 6, 2013

We're finally getting the race video sorted out, and teams are getting their footage together - I hope to see some fun videos from everyone, and am excited for what Petey can pull together for his final reel.

Here's races 1-3. Plenty of downtime, but be careful if you fast forward too much; you might miss one of our great guests that pop in and out all day on the good ship Cornish Pussy.
Video streaming by Ustream

BalticBandit · October 7, 2013

teaser..

FYH wand-01.jpg

As I understand it, one of the big tuning issues on a Moth is fiddling with the wand linkage system to minimise flap movement whist still maintaining control. Basically flap movement = drag. The boats that are the fastest are the ones that are barely under control (this is in accordance with Mal's law: "The boat on the edge of control is the fastest" ). In this respect, passive foil systems are potentially faster than active ones if you can learn to maintain control with them. Furthermore, surface piercing foils offer the potential of higher top end speed than can be achieved by fully submerged foils, due to reduced wetted surface area. Personally, I would be a bit disappointed to see passive foil systems dropped at this early stage of development, mainly because they are a simpler and more robust technology which might more easily be applied to lesser boats than C-Class cats.

Well I question the "less wetted surface area" - a

As PhilS pointed out somewhere, there is efficiency to by had in being able to adjust camber shape rather than doing it with AoA. So for a given amount of "take-off" lift that you need, you can run a smaller immersed horizontal foil.

Now add in the lost lift due to dihedral (which in essence becomes nothing but drag, and for a flat foil you have as your drag sources

Surface area of lifting foil D_{Lifting Surface Horizontal}
Amount of lift D_{Induced Drag Horizontal}
Surface area of the vertical strut D_strut

Whereas for the Surface piercing foil you have

Surface area of the vertical lift component D_{Lifting Surface Horizontal}
Amount of lift D_{Induced Drag Horizontal}
Surface area of the horizontal lift component of the dihedral D_{Lifting Surface Vertical}
Amount of Lateral lift D_{Induced Drag Vertical}

Essentially for a Surface Piercer to be less drag than a immersed foil you need to say that

D_{Lifting Surface Horizontal} + D_{Induced Drag Horizontal} + D_strut>= D_{Lifting Surface Horizontal} + D_{Induced Drag Horizontal} + 2 ( D_{Lifting Surface Vertical} + D_{Induced Drag Vertical} )

Reducing we get

D_strut>= 2 ( D_{Lifting Surface Vertical} + D_{Induced Drag Vertical} )

And that won't be true for all configurations

Mal Smith · October 7, 2013

Furthermore, surface piercing foils offer the potential of higher top end speed than can be achieved by fully submerged foils, due to reduced wetted surface area

Wetted area maybe, but can that really be a bigger factor than all the other types of drag?

Some info from Tom Speer's site, an analysis of several types of foil systems:

http://www.tspeer.com/Hydrofoils/generic.pdf

MR.CLEAN · October 7, 2013

Races 4-6, light air.

Video streaming by Ustream

Races 7-9

Video streaming by Ustream

Designers/Builders Cocktail Hour:

Video streaming by Ustream

F18 Sailor · October 7, 2013

Clean,

Can you sort the links out to the designer video please? The first cocktail hour is here: http://www.ustream.tv/recorded/39517227

For that matter a full listing would be great thanks!

MR.CLEAN · October 7, 2013

Working on the listing sam - petey still not done with the gpama and hydros boat tours...

this is designer video, yes?

http://www.ustream.tv/recorded/39517227

F18 Sailor · October 7, 2013

That is the excellent first designer video yes, thanks again for that!

Can't wait for Petey's boat tours.

MR.CLEAN · October 8, 2013

should be today for boat tours.

MR.CLEAN · October 8, 2013

Ustream guide thus far.

'Cocktail Hour' Talk Show: The Designers/Builders of the C with Martin Fischer, Ben Muyl, Jeremy Lagarrigue, Alex Udin, Steve Killing, Simon Shaw

http://www.ustream.tv/recorded/39517227

'Cocktail Hour' Talk Show: The Future of the C-Class

http://www.ustream.tv/recorded/39290272

with Steve Clark, Duncan MacLane, Jeremy Lagarrigue, Mischa Heemskerk, Fred Eaton, Magnus Clarke, Franck Cammas, Will Howden

Qualification Races 1, 2, and 3

As Recorded Live

http://www.ustream.tv/recorded/39516589

Qualification Races 4,5, and 6

As Recorded Live

http://www.ustream.tv/recorded/39581922

Qualification Races 7,8, and 9

As Recorded Live

http://www.ustream.tv/recorded/39581792

Fleet Race Finals (petit fleet) Races 1 and 2

As Recorded Live

http://www.ustream.tv/recorded/39582466

Match Race Finals, Races 1 and 2

As Recorded Live

http://www.ustream.tv/recorded/39582471

Awards Ceremony

http://www.ustream.tv/recorded/39407127

piv · October 8, 2013

You can get stable fast flight from inclined (dihedral) surface piercing foils. The lift off speed can be very low and top speed very high. 2D section shapes are very important. Upwind performance is phenomenal when its set up right. Brett Burvill and I sorted this out on the Windrush Moth back in 2000. The boat at the 2000 worlds had some control issues and after the worlds we worked them out by adding rudder elevator adjustment and vertical tips on the front foils and implemented similar ideas on Spitfire. However the Moth class killed that line of development and forced the central T foil arrangement. We did try a T foil off each wing bar in the early days and felt that the surface piercing arrangement was better, lower takeoff speed, higher top speed, simpler, more robust, no moving parts. There is some loss of righting moment as the boat rises.

Was off your rocker ever tried with just the lee T foil in the water and the windward one pulled up? Also the report I read on Off Your Rocker mentioned NACA 4 digit airfoils (from memory), there are other (probably better for that application) foil sections, were any others tried?

Does anyone know or want to divulge what 2D hydrofoil sections are being used on the various boats?

Doug Lord · October 8, 2013

Thanks for putting all that stuff together ,Clean!

Doug Lord · October 8, 2013

You can get stable fast flight from inclined (dihedral) surface piercing foils. The lift off speed can be very low and top speed very high. 2D section shapes are very important. Upwind performance is phenomenal when its set up right. Brett Burvill and I sorted this out on the Windrush Moth back in 2000. The boat at the 2000 worlds had some control issues and after the worlds we worked them out by adding rudder elevator adjustment and vertical tips on the front foils and implemented similar ideas on Spitfire. However the Moth class killed that line of development and forced the central T foil arrangement. We did try a T foil off each wing bar in the early days and felt that the surface piercing arrangement was better, lower takeoff speed, higher top speed, simpler, more robust, no moving parts. There is some loss of righting moment as the boat rises.

Was off your rocker ever tried with just the lee T foil in the water and the windward one pulled up? Also the report I read on Off Your Rocker mentioned NACA 4 digit airfoils (from memory), there are other (probably better for that application) foil sections, were any others tried?

Does anyone know or want to divulge what 2D hydrofoil sections are being used on the various boats?

Piv, if you don't have the Steve Killing C Class analysis e-mail me-it's too large to post here. Won't work in a PM.

====

Do you think that the surface piering foil configuation-given the same level of development-could be faster than the bi-foil arrangement on a Moth?

piv · October 8, 2013

The numbers suggest either arrangement (surface piercing or submerged) can be about equally fast but have different off design characterisitics. Its the off design point stuff that is important and the one that has the least "badness" will generally win the race, even if top speed is a bit lower. Another option for the C class is to go with a Moth style tandem foil on the centre line arrangement. This could be linked to a canting mast so the mast and foil strut cant together or the strut and rudder could be fairly long to allow windward heeling like a Moth. This is potentially a really efficient arrangement, particularly given that you could really build the whole boat a lot lighter due to the lower loads, better load paths (no board torque on hulls), lower volume hulls and fewer components (less foils, less cases, fewer lines..). The rumour that current Moths are about as fast around a course (anyone raced a Moth against a C class?) suggests there might be merit in this. Local racing here suggests well sailed flying moths are faster than F18s and Tornados. Also it would be possible to retrofit to an old boat, just external to the hull changes, carbon tubes etc, you could even weld up a prototype aluminium case. You could probably carry a light wind straight board for sub 5kt wind. There are sailboard fins that dont cavitate at 50 knots, they work, so there is a long way to go yet. I have a suspicion that a centreline tandem foil arrangement might be the race winner even though it has less horsepower and lower top end speed. Otherwise full submerged, wand controlled foils on each hull, with both of the windward ones lifted clear, leeward ones long enough to heel to windward. But I think the complication, weight, extra drag in tacks etc, will still mean the centreline foils might win the races. Just think about how you might sail the two boats around the course. Ultimately the answer will be found on the race course.

blunted · October 8, 2013

You can get stable fast flight from inclined (dihedral) surface piercing foils. The lift off speed can be very low and top speed very high. 2D section shapes are very important. Upwind performance is phenomenal when its set up right. Brett Burvill and I sorted this out on the Windrush Moth back in 2000. The boat at the 2000 worlds had some control issues and after the worlds we worked them out by adding rudder elevator adjustment and vertical tips on the front foils and implemented similar ideas on Spitfire. However the Moth class killed that line of development and forced the central T foil arrangement. We did try a T foil off each wing bar in the early days and felt that the surface piercing arrangement was better, lower takeoff speed, higher top speed, simpler, more robust, no moving parts. There is some loss of righting moment as the boat rises.

Was off your rocker ever tried with just the lee T foil in the water and the windward one pulled up? Also the report I read on Off Your Rocker mentioned NACA 4 digit airfoils (from memory), there are other (probably better for that application) foil sections, were any others tried?

Does anyone know or want to divulge what 2D hydrofoil sections are being used on the various boats?

Yes Rocker was tried in the configuration of having the WW foil lifted. I roll my eyes as his has been asked a thousand times as if we would not have tried something that obvious. Yes it was tried, yes it was marginally better, but it was also a giant PITA on the course as in that boat the link between the wands and the foil was made at the deck, and was part of the deck, so pulling up a board meant disconnecting the entire wand system. As such, this approach was never used in anger on a race course, it was strictly a straight line test against Alpha. Another test was simply leaving the foil down, but disengaging the wand system, sort of half pregnant.

Yes windward heel was also tried in that and other configurations, the maximum heel achieved to windward was about 13 degrees. Foils need to be very long on a C-cat, even one with reduced platform beam, to get meaningful heel to windward. I would imagine now, given the speeds that can be achieved, that the loads would get even more silly on the foils, so it's a structural issue for the most part making it all happy.

NACA 64-412 would likely have been the foil section for the lifting foil, 64-012 for the strut, they were symmetric as they both stayed down most of the time.

For the newer boats sections have been getting thicker, so that chords can be shorter, for better span efficiency and thicker, simply to carry enough structure. We have historically on our team developed boards of two skins with a shear web, on Canaan we got them down to 6 lbs or so. Now foils are solid carbon for at least two of the teams, and they are running about 6 times as heavy or more, simply to have adequate structure to deal with all the load cases, even then they are frequently getting broken and the joint detail at the elbow is causing many sleepless nights. The cost of foils has gone up, in a linear fashion relative to the weight of the foil and an exponential fashion relative to the size and shapes of the foils.

F18 Sailor · October 8, 2013

Welcome to the modern foil world....my understanding is the new F18 boards are solid carbon, and the price reflects this ($1300/board vs. $700/board for the old style). Is this cost worth it in a non-development class? Question for a different thread.

I am sure that elbow junction isn't fun, dealing with the torsional loads and horizontal loads as they make a transition to vertical is extremely compelex. I personally would take your approach blunted, and mostly go build. The teams that chose titanium were smart, determining the carbon layup even with the best FEA is non-trivial.I bet the AC guys spent close to $1 million in engineering dollars on those junctions.

blunted · October 8, 2013

Welcome to the modern foil world....my understanding is the new F18 boards are solid carbon, and the price reflects this ($1300/board vs. $700/board for the old style). Is this cost worth it in a non-development class? Question for a different thread.

I am sure that elbow junction isn't fun, dealing with the torsional loads and horizontal loads as they make a transition to vertical is extremely compelex. I personally would take your approach blunted, and mostly go build. The teams that chose titanium were smart, determining the carbon layup even with the best FEA is non-trivial.I bet the AC guys spent close to $1 million in engineering dollars on those junctions.

hahahaaaaaa, $1300 per board, that's essentially free in our world!!, That is more than, a lot more than an order of magnitude less then what we are talking about on FYH. sure, if we built enough the cost might come down some.

Amati · October 8, 2013

I can envision a C with one huge twisting beam tube....

It would be a ride on the traps!

MR.CLEAN · October 8, 2013

The Fog Of War - First Day Cancelled Due To Fog

As Recorded Live

http://www.ustream.tv/recorded/39649992

MR.CLEAN · October 8, 2013

Hydros Full Boat Tour

svendson · October 8, 2013

Wow, those Hydros guys put on a good tour. Nicely documented.

Mal Smith · October 9, 2013

Here's another idea for Moth style tandem centreline foils. Mount the foils on a tube that can rotate (roll) about a longitudinal axis. Link the tube directly to the rig so that when the rig is canted to windward the foils cant to leeward.

JimC · October 9, 2013

I just can't see centreline foils working. You're giving away so much righting moment, all sorts of things.

A slightly narrower platform and foils that are angled outwards seems to maked more sense to me.

There are some horrible engineering complications though. It feels to me that all the challenges are in transitions... I can readily visualise a boat flying with leeward hull db and rudder angled out say 20 degrees, but

Harder to see how two people are going to tack and gybe it...

F18 Sailor · October 9, 2013

Welcome to the modern foil world....my understanding is the new F18 boards are solid carbon, and the price reflects this ($1300/board vs. $700/board for the old style). Is this cost worth it in a non-development class? Question for a different thread.

I am sure that elbow junction isn't fun, dealing with the torsional loads and horizontal loads as they make a transition to vertical is extremely compelex. I personally would take your approach blunted, and mostly go build. The teams that chose titanium were smart, determining the carbon layup even with the best FEA is non-trivial.I bet the AC guys spent close to $1 million in engineering dollars on those junctions.

hahahaaaaaa, $1300 per board, that's essentially free in our world!!, That is more than, a lot more than an order of magnitude less then what we are talking about on FYH. sure, if we built enough the cost might come down some.

Lol, guess I shouldn't complain! That might cover the carbon for one half of one FYH vertical board segment...tooling cost is killer...

invictus · October 10, 2013

Hi Magnus, Fred

Are you up for sharing the story and pictures of the slat system you tried? We saw some early development shots, but what did the FYH system look like close up? You said it was faster than Canaan, but you didn't use it, would it have helped in light airs as we unexpectedly found in Falmouth?

N

MR.CLEAN · October 10, 2013

A taste of things to come...

PL3 · October 10, 2013

_Gnarly

invictus · October 11, 2013

Where's the commentary from the MC?

SC65 · October 11, 2013

piv,

I sailed A-Cats before floating, bathing and finally foiling in a moth and a firm believer (and nothing more than just that) that an A-Cat using a moth like center board T hydrofoil with flap and wand as well as similar moth like rudder would probably sail faster and safer than a moth while still benefitting from being able to heel to leeward etc... and since the moth already outpaces the A when the breeze allows the moth to foil, such an A would outpace in similar conditions conventional boarded and heeling As, despite the lack of similar righting moment.

It would probably be also the cheapest way to retrofit old platforms, but it would nowadays be non class legal, so there is very little benefit for someone even considering this approach. But I am hijacking the beautiful C class thread here...

ita 16 · October 11, 2013

piv,

I sailed A-Cats before floating, bathing and finally foiling in a moth and a firm believer (and nothing more than just that) that an A-Cat using a moth like center board T hydrofoil with flap and wand as well as similar moth like rudder would probably sail faster and safer than a moth while still benefitting from being able to heel to leeward etc... and since the moth already outpaces the A when the breeze allows the moth to foil, such an A would outpace in similar conditions conventional boarded and heeling As, despite the lack of similar righting moment.

It would probably be also the cheapest way to retrofit old platforms, but it would nowadays be non class legal, so there is very little benefit for someone even considering this approach. But I am hijacking the beautiful C class thread here...

already exists in this boat, is smaller than Class A therefore also more difficult to fly, but he has already excellent results with flight wand system.

blunted · October 11, 2013

A taste of things to come...

Ah the things we do for love...

piv · October 11, 2013

I think an A cat size foiler and even a moth (put two Moth hulls side by side to make it a cat) are C class legal since they fit in the box. Maybe not in the spirit though. Ita16 I have been watching with great interest your foiling and planing developments. I love it. Well done. The A cats would do well to follow the C cats and reduce the number of rules to the bare box rules. One thing on the side of the Moths is size, small boats are light strong and powerfull with low windage drag. Its the square - cube law. Also once foiling, length is not a direct influence on speed and is less important for pitch stability. However rig height is important because of the wind gradient, stronger wind up high. So this means the optimum C cat once flying may actually be smaller than a box filling C cat. Its unlikely, but possible that a tall rig, max beam, centreline foils, shorter than max length, (to save weight and wetted surface and windage drag when flying), boat may be the new optimum C, now that foiling seems likely. An interesting optimisation will be to determine a good foil area to ballance low speed and easy take off versus high speed drag. The Moth is a short boat with a low hull speed so the foil is big enough to take off at low speed. I dont know of anyone examining really low speed take off for a C cat size boat but with the next big event in Switzerland, low speed take off might be important. I think whoever flies first, in light wind or out of a tack will have a huge advantage. That might mean that take off speed will be lower than the length limited "hull speed" which might lead a design spiral that goes shorter, lighter, lower take off speed, shorter lighter lower take off speed. I think the limiting rule is sail area and the new optimisation problem for C cat foilers is; what is the optimum foil area, foil span, hull length, beam and rig height for a 300ft2 sail area? I wouldnt assume that max length is a given.

BalticBandit · October 11, 2013

That looks like fun.... until you hit the thing that hurt...

piv · October 11, 2013

One good thing about the Moths is no trapeze to swing you back into the boat, you just get flung off and land in the water. Its swinging back and hitting the boat that hurts. Glen Oldfield with his Whisper Moth has no stays and loves the safety of that, much safer crashes. Maybe the C cats should consider sailing on racks rather than trapeze, at least when testing new foil configurations. I know, weight, structure, cost, windage, but it sure beats getting stitches. Might save a lot of boat damage too. Are all the current C class teams carrying on? Any new ones? Any ceasing?

ita 16 · October 11, 2013

PIV , +1

BalticBandit · October 11, 2013

One good thing about the Moths is no trapeze to swing you back into the boat, you just get flung off and land in the water. Its swinging back and hitting the boat that hurts. Glen Oldfield with his Whisper Moth has no stays and loves the safety of that, much safer crashes. Maybe the C cats should consider sailing on racks rather than trapeze, at least when testing new foil configurations. I know, weight, structure, cost, windage, but it sure beats getting stitches. Might save a lot of boat damage too. Are all the current C class teams carrying on? Any new ones? Any ceasing?

kevlar body armor... from the Motocross world

blunted · October 11, 2013

One good thing about the Moths is no trapeze to swing you back into the boat, you just get flung off and land in the water. Its swinging back and hitting the boat that hurts. Glen Oldfield with his Whisper Moth has no stays and loves the safety of that, much safer crashes. Maybe the C cats should consider sailing on racks rather than trapeze, at least when testing new foil configurations. I know, weight, structure, cost, windage, but it sure beats getting stitches. Might save a lot of boat damage too. Are all the current C class teams carrying on? Any new ones? Any ceasing?

I actually had a "holy shit hook" on during that crash. A steel hook into my trap belt, attaching me to the back on the boat, so when we stuff it, I would not get launched around the bows. In this particular stuff of the bows, I bent said hook clean open with my mass x acceleration, thus I found myself out in the nether regions where I am not supposed to be. I knew this immediately when I saw the forestay telltale pass my head in a giant cloud of spray and I thought to myself, "Oh fuck, I should not be seeing that thing right now".

This was followed by an impending sense of doom. "Damm, if I am way up here in front of the boat, chances are I am going to pull it down on my head in a nice big pitch pole". Which was momentarily followed by the sentiment, "Huh, perhaps it won't pitch pole, I am coming back towards the boat, Hope I don't hit the forestay on the return trip".

Not long after that I was thinking to myself, OK, well that's good, it hasn't pitch-poled on my head so there is hope that we won't screw up the wing just a few days before the event".

Followed by, "Oh this is gonna hurt". My hands came up automatically as you can see in the video and whammo, I hit the beam, my shin it sees hit the strap which is where I got my nice big laceration, through a 5mm wet suit. suffice to say I had some considerable bruising here and there too for good measure.

I was surprised to find myself conscious at that point, sort of smeared over the front beam. I was still hooked on, so I couldn't just let go and drop under the boat. So I wanted to get up on top of the trampoline, but I am very cautious about applying any kind of non-design load to the carbon strap under the beam, as a failure of the strap would mean an instant "boat taco" and a complete destruction of the boat. I also was trying to get my legs out of the water as I didn't want the boat to trip over my legs in the water, and pitch pole on my head after having got through the worst of the wipeout with the initial impact. So I was madly kind of walking backwards in the water. What you don't see in the video is me looking over my shoulder at the rapidly approaching rocky shore, that the boat is bearing away to, thinking, "great, it's going to hit the rocks at 10 plus knots THEN pitch-pole on top of me". So then I am looking for Fredo, waiting for him to head the boat up into the wind to stop it when I finally realize, "Oh Geeze, Fredo has left the building". I determine this when I see is bright orange hat some 200 M behind the boat. Eventually the tender pulls along side, the guys grab the forestay and we pull her up into the wind like a horse.

So, moral of the story is you don't have to completely reconfigure the boat to meet some safety goal (Go sail lasers if that is your concern), you just need a bigger f-ing hook to hold you in your position when experiencing high-G moments, which was of course installed later that day.

Now we are foiling, I make a point of not sitting or half trapping directly behind the trailing edge of the foil that is pulled up to windward, it's the most dangerous thing in the area, or directly behind the standing rigging for that matter. I'm either on the tramp, inboard, where I can shoot straight forward into the piss if required, or out on the wire completely, with the newly improved and upgraded hold back hook on, so then I can just crumple a bit on the rail, and not hit things in anger. Plus, the PBO rigging is a lot nicer to run into than the old piano wire shrouds and forestays.

GauchoGreg · October 11, 2013

One good thing about the Moths is no trapeze to swing you back into the boat, you just get flung off and land in the water. Its swinging back and hitting the boat that hurts. Glen Oldfield with his Whisper Moth has no stays and loves the safety of that, much safer crashes. Maybe the C cats should consider sailing on racks rather than trapeze, at least when testing new foil configurations. I know, weight, structure, cost, windage, but it sure beats getting stitches. Might save a lot of boat damage too. Are all the current C class teams carrying on? Any new ones? Any ceasing?

I actually had a "holy shit hook" on during that crash. A steel hook into my trap belt, attaching me to the back on the boat, so when we stuff it, I would not get launched around the bows. In this particular stuff of the bows, I bent said hook clean open with my mass x acceleration, thus I found myself out in the nether regions where I am not supposed to be. I knew this immediately when I saw the forestay telltale pass my head in a giant cloud of spray and I thought to myself, "Oh fuck, I should not be seeing that thing right now".

This was followed by an impending sense of doom. "Damm, if I am way up here in front of the boat, chances are I am going to pull it down on my head in a nice big pitch pole". Which was momentarily followed by the sentiment, "Huh, perhaps it won't pitch pole, I am coming back towards the boat, Hope I don't hit the forestay on the return trip".

Not long after that I was thinking to myself, OK, well that's good, it hasn't pitch-poled on my head so there is hope that we won't screw up the wing just a few days before the event".

Followed by, "Oh this is gonna hurt". My hands came up automatically as you can see in the video and whammo, I hit the beam, my shin it sees hit the strap which is where I got my nice big laceration, through a 5mm wet suit. suffice to say I had some considerable bruising here and there too for good measure.

I was surprised to find myself conscious at that point, sort of smeared over the front beam. I was still hooked on, so I couldn't just let go and drop under the boat. So I wanted to get up on top of the trampoline, but I am very cautious about applying any kind of non-design load to the carbon strap under the beam, as a failure of the strap would mean an instant "boat taco" and a complete destruction of the boat. I also was trying to get my legs out of the water as I didn't want the boat to trip over my legs in the water, and pitch pole on my head after having got through the worst of the wipeout with the initial impact. So I was madly kind of walking backwards in the water. What you don't see in the video is me looking over my shoulder at the rapidly approaching rocky shore, that the boat is bearing away to, thinking, "great, it's going to hit the rocks at 10 plus knots THEN pitch-pole on top of me". So then I am looking for Fredo, waiting for him to head the boat up into the wind to stop it when I finally realize, "Oh Geeze, Fredo has left the building". I determine this when I see is bright orange hat some 200 M behind the boat. Eventually the tender pulls along side, the guys grab the forestay and we pull her up into the wind like a horse.

So, moral of the story is you don't have to completely reconfigure the boat to meet some safety goal (Go sail lasers if that is your concern), you just need a bigger f-ing hook to hold you in your position when experiencing high-G moments, which was of course installed later that day.

Now we are foiling, I make a point of not sitting or half trapping directly behind the trailing edge of the foil that is pulled up to windward, it's the most dangerous thing in the area, or directly behind the standing rigging for that matter. I'm either on the tramp, inboard, where I can shoot straight forward into the piss if required, or out on the wire completely, with the newly improved and upgraded hold back hook on, so then I can just crumple a bit on the rail, and not hit things in anger. Plus, the PBO rigging is a lot nicer to run into than the old piano wire shrouds and forestays.

And we all appreciate you were courteous enough to have good footage of the entire event, and now play-by-play to top it off.

Seriously, glad you did not hurt yourself, or the boat, worse.

GybeSet · October 11, 2013

You can get stable fast flight from inclined (dihedral) surface piercing foils. The lift off speed can be very low and top speed very high. 2D section shapes are very important. Upwind performance is phenomenal when its set up right. Brett Burvill and I sorted this out on the Windrush Moth back in 2000. The boat at the 2000 worlds had some control issues and after the worlds we worked them out by adding rudder elevator adjustment and vertical tips on the front foils and implemented similar ideas on Spitfire. However the Moth class killed that line of development and forced the central T foil arrangement. We did try a T foil off each wing bar in the early days and felt that the surface piercing arrangement was better, lower takeoff speed, higher top speed, simpler, more robust, no moving parts. There is some loss of righting moment as the boat rises.

Was off your rocker ever tried with just the lee T foil in the water and the windward one pulled up? Also the report I read on Off Your Rocker mentioned NACA 4 digit airfoils (from memory), there are other (probably better for that application) foil sections, were any others tried?

Does anyone know or want to divulge what 2D hydrofoil sections are being used on the various boats?

Piv, if you don't have the Steve Killing C Class analysis e-mail me-it's too large to post here. Won't work in a PM.

====

Do you think that the surface piering foil configuation-given the same level of development-could be faster than the bi-foil arrangement on a Moth?

Piv just letting you know someones knocking on your front door

hope you have the lights turned off

Foghorn77 · October 11, 2013

Oh shit hook size is definitely an acceptable weight trade-off.

MR.CLEAN · October 11, 2013

got a pic of the bent hook, mag?

sorry, the straight hook?

piv · October 11, 2013

GybeSet and Doug, I Read that Killing Paper a few years ago if its the one I am thinking of. Really good stuff. It would be great to see similar papers from all the current C cat designers.

When I was in uni I read a thesis of some work done on the cunningham C and the tripple element wing and I saw it packed up at the yacht club, awesome boat, at that time I think it was Yellow Pages. The thesis is in the RMIT library, I didnt keep a copy of it. There was another one done on a sit in sailing hydrofoil and then I did mine on high speed sailboards. The Yellow Pages was good stuff, but superceded by Cogito. It would be great if there was an online repository for open research on this stuff, maybe there is. Anyone know? Maybe we could set up a drop box or something and authors could put their papers in it. Ive got my own collection of pdfs and papers and books, probably like everyone else here. There was a great book I got out from our local library about 30 years ago when I was a kid, I cant remember the name of it or the author but it was full of sailing hydrofoils like Williwaw and the first Mayfly I think and the Nigg Flying fish boats???. That made me think sailing hydrofoils were "normal", so I was never scared to give them a go. Fortunately there are some great innovators in WA like Brett Burvill, Garth and John Illet and Glen Oldfield amongst others. There is a C here at the Nedlands yacht club, just enough to keep the dream alive.

blunted · October 11, 2013

Followed by, "Oh this is gonna hurt". My hands came up automatically as you can see in the video and whammo, I hit the beam, my shin it sees hit the strap which is where I got my nice big laceration, through a 5mm wet suit. suffice to say I had some considerable bruising here and there too for good measure.

Seriously, glad you did not hurt yourself, or the boat, worse.

Ahhhhhh.......It's only a flesh wound.

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