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      Abbreviated rules   07/28/2017

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WetnWild

A Cat Worlds Sopot

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Any one know anything about what's likely to happen? Who will win? Will Estevie beat Mischa or will Bundy beat them both. What new gear is likely to turn up? Will there be any half clever ideas to try and get around the measurement rules? Will the measurer be smart enough to catch them?

Come on tell us your secrets. 

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Hahaha. Good luck. There are some new developments out there, I will let others spill the beans.

My bet is on the following:

1) Mischa

2) Stevie

3) Bundy

4) Jacek Noetzel

5) Tymoteusz Bendyk

It's possible Jacek and Tymoteusz will slip in front of Bundy and maybe even Stevie as they have been training extensively at the Worlds venue.

Mischa is without a doubt the favorite to win. No one goes into the gold fleet at a F18 worlds and strings together 6 bullets in 7 races with a drop score of 2 unless you are super human. This will carry over to the A-Cat most likely. If Glenn Ashby showed up he could give Mischa a run for his money. Maybe Stevie has what it takes with his latest gear developments and extensive practice time. I'm dropping Bundy down a little bit as his coaching obligations mean less practice time than the others.

The things I am most curious about:

1) What foils are the top teams on? Z18's? Z20's? Will these replace the Z10's in the production boats? Will these fit in the same slots as the Z10's???

2) What rudder setup are the top guys running? I'm asking for super details like winglet AOA to the nearest 0.1°, rudder rake (measured with a batten), rudder toe in, AND distance from transom to back of the rudder.

3) Rig and sail developments. I think think this is where the biggest gains have been made in the off season...

If someone can shoot detailed video of the boat rigging that would be super helpful. Only Stevie thus far has shared his under tramp rigging guide!

Oh, and video footage of gybes and tacks is always helpful!!

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Ill go there, but wont to get close to the front. That flying stuff is rather easy, but very delicate to get going stable & fast at the same time. And Im not there, actually pretty far away:- ( But itll be cool anyway, always fun to see how fast the frontrunners has gotten.

Some dutch, polish or australian will probably win.. no clue, a lot of moving parts on the fastest boats

Rather interesting developments on rigs, seems like some will show up with jibs, and the exploder-gang has shown a kind of wingmast. Foils are changing as well. 

 

And a lot of different shapes of foils, so almost useless to get measurements on other than identical designs!

 

Best

Lars

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7 hours ago, samc99us said:

Hahaha. Good luck. There are some new developments out there, I will let others spill the beans.

My bet is on the following:

1) Mischa

2) Stevie

3) Bundy

4) Jacek Noetzel

5) Tymoteusz Bendyk

It's possible Jacek and Tymoteusz will slip in front of Bundy and maybe even Stevie as they have been training extensively at the Worlds venue.

I hear that Bundy sailed against the Poles at the venue and was a little slower downwind (losing a few boat lengths over the length of the leg) but he was 150-200 metres faster per leg upwind. That was with his conventional tall rig. Stevie has been using a short rig here in Oz and is telling people that it is quicker, but who knows if it is a game of bluff. He went to the Queensland State titles, won by miles and then tried telling people that the short rig was slow! Some bought it, others didn't.

Quote

Mischa is without a doubt the favorite to win. No one goes into the gold fleet at a F18 worlds and strings together 6 bullets in 7 races with a drop score of 2 unless you are super human. This will carry over to the A-Cat most likely. If Glenn Ashby showed up he could give Mischa a run for his money. Maybe Stevie has what it takes with his latest gear developments and extensive practice time. I'm dropping Bundy down a little bit as his coaching obligations mean less practice time than the others.

I hear different from you. I suspect that nobody has done as much sailing as Stevie and Bundy who would be pretty even on their sailing time. They have trained together pretty solidly and when Stevie couldn't sail during the week, Bundy has been out with others. 

 

Quote

What foils are the top teams on? Z18's? Z20's? Will these replace the Z10's in the production boats? Will these fit in the same slots as the Z10's??? 

I have been told that the development boards are designed to go straight into the Z10 slots. I heard mixed things about Z20's. I believe the new production board will be known as the Z22. How many there will be for the worlds i am not sure.I also hear that rudders are more important than the main foils with new winglets that can be retro fitted to existing foils.

Quote

 

Rig and sail developments. I think think this is where the biggest gains have been made in the off season...

 

I think the biggest gains will have been made with technique. The Brewin tall rig hasn't changed since the last worlds, because Stevie and his group think it is right. If they sail with the short rig, that will be interesting, but as mentioned above, Bundy is said to have hammered the top Poles with effectively the same rig as he used last worlds. I have to assume that as they are all Exploder works riders, they would have been using the same foils, so the difference had to be technique. I suspect this is why they have been so quiet about what they have achieved. By not saying anything, they haven't given the "opposition" any clue as to what is a good or bad speed to aim at. There have been a couple of comments by others on social media. that give a clue. One suggested they were upwind foiling at over 18 knots and sailing higher than a non foiling boat at the last Nationals and while I have no idea of the speed, I agree that once they were up and foiling, they were going higher. The others who were upwind foiling were lower, with the same gear, so that was technique. The one of the guys close to them posted something about Stevie doing 21 knots upwind but I have no idea whether that was a peak speed and at what angle.

A few weeks ago 2 of the top Vic guys went up to train with Stevie and Bundy. They said that they had moved it to a whole new level. I have no idea who will win because I have no idea what everybody has been doing, but I think we will be surprised by how far the game has moved over the last year.

7 hours ago, lars75k said:

the exploder-gang has shown a kind of wingmast

I saw that on Facebook yesterday as well, but I believe it is an old mast that isn't very quick

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Spoke to Bags a bit yesterday.  I didn't realise the A's had moved to measuring after racing had started.  You'd want to be pretty sure your boat measures if doing anything "fancy" because it would be a shame to get disqualified after getting a good result.

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1 hour ago, SCARECROW said:

Spoke to Bags a bit yesterday.  I didn't realise the A's had moved to measuring after racing had started.  You'd want to be pretty sure your boat measures if doing anything "fancy" because it would be a shame to get disqualified after getting a good result.

Not exactly Scarecrow. Maybe you were imbibing too deeply in his renowned hospitality during the conversation. Rookie mistake. 

Mad always in the past all skippers are required to turn up at the event with a valid measurement certificate. Prior to Medemblik a measurement verification process of some aspects of the full measurement was done. Certainly not a full measure. The process done at Medemblik will be the same this time where a number of boats will be verified after each session on the water. 

You are correct though that I would expect the IJ to take a dim view of those found to not meet the measurement rules. 

A note setting out the expectations is on the IACA website. 

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I'm freaking itching to see Sandro's new rig on the boat.

I love how he's gone about the boat design, and those new sails of his look seriously cool.

No more ducking through the triangle? Will he be able to just go behind the whole main? 

Sexy AF Higher aspect main could be really nice coupled with that tiny jib (god I hope he's end plated the jib too, that thing will be so sexy).

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The biggest risk for people and measurement is the differing levels of competence of measurers. It seems to me that some don't know or understand the rules. Look at Thilo Keller's board system that one measurer thought was legal. I hope I have this correct, but it seems to me that a measurer shouldn't be interpreting rules but in this case, that's what happened. If I ever come up with some smart new rule work around, I would want it checked out by the technical committee and I wouldn't expect a measurer to make a call on it.

The interesting thing will be if something new arrives that pushes the rules and the tec committee haven't seen it. I hope nobody has the event ruined by having their brainchild deemed out of class after a local measurer has given it the all clear.

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33 minutes ago, Dazz said:

Really keen to see how these look run up a mast!  

image001.png

Looks very old school. Not decksweeper and a lot of luff round with straightish leech. 

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11 minutes ago, SCARECROW said:

Or is it the ultimate deck sweeper?

Don't think so with that clew position. 

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On 22 July 2017 at 4:13 PM, WetnWild said:

Jethro Tull 

Sorry wrong quote...

2 hours ago, Dazz said:

Really keen to see how these look run up a mast!  

image001.png

Red

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4 hours ago, SCARECROW said:

So has Thilo's system been deemed a no go?

 

That's what I was told but I haven't seen anything that confirms it. If it is legal, forget everything we know about what an A is. All you need is a bit of shock cord to hold something in place while it is measured and then you can use sailing loads to move it out of the measured dimension. How about a system to increase beam? I think it can be done.

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2 hours ago, Sonofabitch said:

Sorry wrong quote...

Red

Very subtle Sonofa. I like your style. 

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16 hours ago, A Class Sailor said:

I hear that Bundy sailed against the Poles at the venue and was a little slower downwind (losing a few boat lengths over the length of the leg) but he was 150-200 metres faster per leg upwind. That was with his conventional tall rig. Stevie has been using a short rig here in Oz and is telling people that it is quicker, but who knows if it is a game of bluff. He went to the Queensland State titles, won by miles and then tried telling people that the short rig was slow! Some bought it, others didn't.

I hear different from you. I suspect that nobody has done as much sailing as Stevie and Bundy who would be pretty even on their sailing time. They have trained together pretty solidly and when Stevie couldn't sail during the week, Bundy has been out with others. 

 

I have been told that the development boards are designed to go straight into the Z10 slots. I heard mixed things about Z20's. I believe the new production board will be known as the Z22. How many there will be for the worlds i am not sure.I also hear that rudders are more important than the main foils with new winglets that can be retro fitted to existing foils.

I think the biggest gains will have been made with technique. The Brewin tall rig hasn't changed since the last worlds, because Stevie and his group think it is right. If they sail with the short rig, that will be interesting, but as mentioned above, Bundy is said to have hammered the top Poles with effectively the same rig as he used last worlds. I have to assume that as they are all Exploder works riders, they would have been using the same foils, so the difference had to be technique. I suspect this is why they have been so quiet about what they have achieved. By not saying anything, they haven't given the "opposition" any clue as to what is a good or bad speed to aim at. There have been a couple of comments by others on social media. that give a clue. One suggested they were upwind foiling at over 18 knots and sailing higher than a non foiling boat at the last Nationals and while I have no idea of the speed, I agree that once they were up and foiling, they were going higher. The others who were upwind foiling were lower, with the same gear, so that was technique. The one of the guys close to them posted something about Stevie doing 21 knots upwind but I have no idea whether that was a peak speed and at what angle.

A few weeks ago 2 of the top Vic guys went up to train with Stevie and Bundy. They said that they had moved it to a whole new level. I have no idea who will win because I have no idea what everybody has been doing, but I think we will be surprised by how far the game has moved over the last year.

I saw that on Facebook yesterday as well, but I believe it is an old mast that isn't very quick

We don't know how much sailing time Mischa has. I suspect it is quite a lot. The DNA camp are usually awfully quiet before a worlds...

I hear differently from you on the latest production board number, but I also haven't heard anything about how the new boards are going! I do agree that the winglets do matter some, various iterations of those floating around and I have no idea what is fast and what isn't. It's also tough to even know what you have! Mine are from late 2016 and I know there have been some iterations since then.

On the rigs, I've heard mixed things. I suspect in over 15 kts of breeze the shorter rig will be faster, but its also a developmental item as the tall rig has had a lot of effort put into it over the years. Those red sails don't appear to be decksweepers but I'm thinking that tradeoff might be worth it as the jib is easier to use and going to bring additional power down low and at wider apparent wind angles than the uni rig, but of course that may hurt upwind. It also adds complexity and weight to the boat that may not be worth it. There is also rumor of some different rigs, soft wing sails, maybe even a hard wing sail...

I do believe the biggest gains are in technique, especially with upwind foiling at play. It could be a whole different level for the top guys at this worlds.

 

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12 minutes ago, samc99us said:

We don't know how much sailing time Mischa has. I suspect it is quite a lot. The DNA camp are usually awfully quiet before a worlds...

I hear differently from you on the latest production board number, but I also haven't heard anything about how the new boards are going! I do agree that the winglets do matter some, various iterations of those floating around and I have no idea what is fast and what isn't. It's also tough to even know what you have! Mine are from late 2016 and I know there have been some iterations since then.

On the rigs, I've heard mixed things. I suspect in over 15 kts of breeze the shorter rig will be faster, but its also a developmental item as the tall rig has had a lot of effort put into it over the years. Those red sails don't appear to be decksweepers but I'm thinking that tradeoff might be worth it as the jib is easier to use and going to bring additional power down low and at wider apparent wind angles than the uni rig, but of course that may hurt upwind. It also adds complexity and weight to the boat that may not be worth it. There is also rumor of some different rigs, soft wing sails, maybe even a hard wing sail...

I do believe the biggest gains are in technique, especially with upwind foiling at play. It could be a whole different level for the top guys at this worlds.

 

Tend to agree. I think one of the good sailors will win with nothing particularly radical. 

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I don't see how a jib will be better on an A. My first concern is that the good guys keep telling me that the secret of fast foiling is constant sheet movement. You need to keep the boat dead flat and that it takes a lot more sheet movement than you think it would. The very few videos of the top boys leave me wondering how the hell I can ever move that amount of sheet on an ongoing basis through a race. Maybe I am making a bad assumption, but i suspect that the jib is left cleated which means that the main is doing all the work when sheeting in and out, leading to the slot changing all the time. The issue will be worse upwind than downwind. Because the jib stays constant, the feel on the helm will change as you sheet the main in and out, something that doesn't seem to me to be desirable when foiling. Changes in rudder loading is what i believe causes death wobbles.

Upwind, I see a jib as limiting height. If the reports are correct and the top guys are sailing higher than normal when foiling fast, which is what it looked like at the Australian Nationals, then surely a jib will limit it. Using mast rotation allows for a better angle of attack of the main when pointing high, but with a jib, you are fighting luff sag all the time, because I can see no way you will get good luff tension on an A. None if the existing boats are built for that. If the shape is right for 15 knots, it will be way too flat for lighter winds.

Downwind, we are not going fast enough to have the jib in tight like upwind, so there are leach control issues of an eased jib and if the sail isn't sheeted right, all it does is increase drag.As speeds change going downwind, the sheeting of the jib needs to be changed. Think about a gybe, where speeds drop and you need to accelerate. I guess you are down to single figures, and get back up on the foils moving from, say 12 knots to 22-24 knots or maybe faster. Even an average sailor like me knows you do ease the sail big time to get up, ease again to keep it flat as the apparent builds and then you pull away to the right course while sheeting on to flatten the whole rig off. I have no idea how you would do all of that with a jib as well. Then you get a lull and you need to head up to stop the boat coming in on top of you coupled with a big ease at the right moment to reduce loads on the foils, something i am bad enough at doing without having a jib to worry about.

I can see how on the right boat, a jib with a crew might be good but on a foiling single hander, I think it is a liability.

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14 hours ago, SCARECROW said:

So has Thilo's system been deemed a no go?

 

It has to be. the boat must conform to the rules at all times when racing, the compliance check is an extra formality thrown in by the NOR. All anyone has to do is protest him and prove on balance of probabilities that the boards were outside the required dimension while racing. Since he has said this is what happens, that should not be too hard.

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The trick with his system is you could get the advantage of the reduced lift from the windward board and still have it measure.  The problem is when you chase extra lift from the leeward foil as well.

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29 minutes ago, SCARECROW said:

The trick with his system is you could get the advantage of the reduced lift from the windward board and still have it measure.  The problem is when you chase extra lift from the leeward foil as well.

I don't see his system as working like that. The real point of his set up is that the boards are in a legal position when measured and that water pressure moves the leeward board into a position that breaches the 750mm rule. The windward board simply sits at the legal position and therefore is no different than what every other boat has which, IMO, means that it's not reduced lift from the windward board but increased lift for the leeward board that is the benefit. Whether that allows you to change the design of the board is another matter, but if both boards are in a legal position, he doesn't have enough lift to foil. His system is simply an attempt to cheat the rules.

I am also not convinced that reducing lift in the windward board is a good thing, at least with current styles of board. When we first started foiling some had systems that allowed different amounts of lift for the 2 boards by changing the AoA independently. everybody removed the system because they found they didn't foil as well with it. I have also found that if you have the windward board up a bit by mistake (there seems to be a theme here - I make lots of mistakes :D), it stops you foiling. 

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Will definitely be fun to see what Sopot has in store. Mischa has recenlty posted pics of carbon dust at Holland Composites, the Scheurer team has shown a lot of innovation this summer with the G7 and its beam forward design that looks really good upwind, the eXploder group continues to pump out more prototypes than anyone else and has really benefitted from working with Gonzalo Redondo over the last year +, and the AUS sailors continue to pursue boomless boats that are optimized for never coming off the wire.  Thilo / AST has something in the flip flop boards but they must remain 8.1 rule compliant.  

Some random thoughts:

  • If someone makes a jib work, I think it will have to be like the Swift Solo with simultaneous jib / main trim.  While I see some benefits of a jib, I don't ever want to deal with rigging one on the A and the complexity of sailing with it.  
  • At some point, the winning factor is going to be the maneuvers and not the straight line speed.  How soon that becomes the case is anyone's guess, but as the boats approach limits on stable speed, getting to foiling jibes and tacks or at least high speed maneuvers is an important factor. 
  • Getting more of the foiling force from the leeward board is a good thing as long as the foil can support it.  Our traditional boards could not really work that well alone.  They needed the other side too.  Thilo's solution provides much more lift from the leeward side but cannot violate the class rules.
  • It's amazing to think about the apparent wind speeds the rigs are seeing now.  We used to go upwind at 10 to 13 knots or so and now with foiling can see 18+.  It's amazing to see how rigs are still working and I continue to believe flat and twisty shapes or lower profile / center of effort shapes are the way to go.  

 

 

 

 

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18 hours ago, WetnWild said:

Don't think so with that clew position. 

Look at the width of it, I think it'd the same height as normal, doesn't go all the way to the back beam, with enough room for him to go behind entirely.... (That's how it looks to me)

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4 minutes ago, Lost in Translation said:

Will definitely be fun to see what Sopot has in store. Mischa has recenlty posted pics of carbon dust at Holland Composites, the Scheurer team has shown a lot of innovation this summer with the G7 and its beam forward design that looks really good upwind, the eXploder group continues to pump out more prototypes than anyone else and has really benefitted from working with Gonzalo Redondo over the last year +, and the AUS sailors continue to pursue boomless boats that are optimized for never coming off the wire.  Thilo / AST has something in the flip flop boards but they must remain 8.1 rule compliant.  

 

Interesting summary. I am confused by your comment about the AUS sailors pursuing boomless sails that are optimised for never coming off the wire. Where did you get that from? They are optimised for all round sailing. Are you simply referring to the fact that all the systems can be reached from out on the wire? If so, that's nothing other than common sense.

Quote

 

Some random thoughts:

  • If someone makes a jib work, I think it will have to be like the Swift Solo with simultaneous jib / main trim.  While I see some benefits of a jib, I don't ever want to deal with rigging one on the A and the complexity of sailing with it.  Do you think there might be a difference because of the speeds involved with foiling?
  • At some point, the winning factor is going to be the maneuvers and not the straight line speed.  How soon that becomes the case is anyone's guess, but as the boats approach limits on stable speed, getting to foiling jibes and tacks or at least high speed maneuvers is an important factor. What do you mean by stable speeds? Whatever that is, I think tacking and gybing are very important now, but it isn't going to be the winning factor because all the top people will be as good as each other at the corner turning. Look at the Moths. All the top guys foil tack and gybe and mistakes are very rare but very costly. I can't ever see it as a winning factor, just a losing one!
  • Getting more of the foiling force from the leeward board is a good thing as long as the foil can support it.  Our traditional boards could not really work that well alone.  They needed the other side too.  Thilo's solution provides much more lift from the leeward side but cannot violate the class rules. It will be interesting to see what happens with this in the future. I don't think it's going to be a factor this time around
  • It's amazing to think about the apparent wind speeds the rigs are seeing now.  We used to go upwind at 10 to 13 knots or so and now with foiling can see 18+.  It's amazing to see how rigs are still working and I continue to believe flat and twisty shapes or lower profile / center of effort shapes are the way to go. 


I agree with your "low profile/ centre of effort shape comment, but I think the flat and twisty is incorrect. Somebody who knows a lot more than me tried explaining this yesterday. With decksweepers, going flat low down does not work, or at least wastes a key benefit. Look at what both Mischa and Stevie have done with their sails. They are far fuller than you would expect low down. If you have the fullness and power low down, you can spill more from up top. Moths need flatter sails than A's, because they use their rigs life a barn door to control power and as you ease the sail off the centreline, you need a flatter sail. Because our sails stay closer to the centreline, they need to be fuller. Then this is where it gets confusing.  I read Chris Rashley's guide and he says you need to ease the traveller down about 100mm to foil upwind, while I am told by others you must not ease the traveller at all. You want the top of the sail to blade out, but the bottom to have a straight leach. This is how to gain height. I have no idea how they do it, but I am told that the faster Stevie goes, the harder he pulls in the sail and the more closed he has the leach. It has been suggested that Stevie and Bundy are pointing higher than a standard boat when they are at their top speed foiling upwind and it looked to me like they were no lower at the nationals, although I was a long way back. From what i could see, their sails did not look twisted at all and I suspect the tight leach is how they get their height.

Downwind, I personally find twist destabilises the boat and that I am better off with a tighter leach. I have no idea if it is right, but I find it far easier to have the traveller lower and a tighter sheet than the traveller higher and lost of twist. Again, I am told that once up to speed, you need to pull on the mainsheet as hard as possible to reduce twist and flatten the sail because if you are too eased, it is too full and you limit the speed. This is where I am personally in real trouble, because I need to keep the sail eased in order to keep the boat flat, but it seems that I am 3-5 knots off the downwind speeds of the good guys. I just cannot figure out how to get any quicker!

From what I saw at the nationals and the stories from those who sailed the Queensland State titles and other rumours, I think there is a good chance that 18+ knots is now an under estimate of upwind performance. I am looking forward to the worlds and hope they have some sort of tracking so we will know for sure, but I am hoping to see the top guys going over 20 knots upwind, otherwise there has been a fair amount of hype with no substance. I suspect that conditions will be a major factor.

My big hope is that the improvements made by the top guys aren't just in speed but also the boats have become easier to make go fast. At the moment, there seems to be too big a gap between the top guys and everybody else. I used to like finishing on the same leg as the winners, while now I hope to be on the same lap. While I keep saying the boats aren't too hard to sail, it would be nice if they were a little easier!

 Not long to wait and we will start getting news from Poland!

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20 minutes ago, darth reapius said:

Look at the width of it, I think it'd the same height as normal, doesn't go all the way to the back beam, with enough room for him to go behind entirely.... (That's how it looks to me)

That's not the issue I see. If that is a deck sweeper, how do you get enough separation between the clew and the traveller to take into account the differing mainsheet tension you need as the wind changes. Surely you need the clew something like 200mm up in the air in lighter winds for it to end up being close to the traveller when pulled down to the maximum after downhaul is applied. I am not convinced it will be a decksweeper as we know it. The question is how close to the tramp does it have to be to get the benefit? It looks like it will have a boom and it will be interesting to see how that is rigged.

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1 minute ago, A Class Sailor said:

That's not the issue I see. If that is a deck sweeper, how do you get enough separation between the clew and the traveller to take into account the differing mainsheet tension you need as the wind changes. Surely you need the clew something like 200mm up in the air in lighter winds for it to end up being close to the traveller when pulled down to the maximum after downhaul is applied. I am not convinced it will be a decksweeper as we know it. The question is how close to the tramp does it have to be to get the benefit? It looks like it will have a boom and it will be interesting to see how that is rigged.

It's very hard to know, boom under the tramp (between the skins)?

He's just fucking with all of us?
He things decksweepers don't work?! Who knows, gotta see it rigged, which is what I'm keen for.

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^ A picture of the sails on a boat is worth a hundred of them on the floor, but then we won't be able to speculate and talk shit any more!:D

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20 minutes ago, A Class Sailor said:

^ A picture of the sails on a boat is worth a hundred of them on the floor, but then we won't be able to speculate and talk shit any more!:D

+1000

and about six months ago I was sailing with one of the top group in a club race. He was using a much modified ex Takapuna Exploder. Got 10 second GPS average of 21 knots at good upwind height. Flat water and wind speed of about 15.  So the speeds are right up. I think the gains will be in who can make it work the best in rougher water and who consistently turns the corners best. 

It will be the best sailors. There's no magic bullet equipment to make an average sailor win the Worlds. 

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1 hour ago, Sonofabitch said:

Ahh, but the best sailors tend to turn an ordinary idea into a majic bullet.

If Stevie wins using a short rig, will you cut your mast down?

I'm pretty sure I have something suitable in the shed but I'm a bit far away to check. But I'm an ordinary sailor so would make no difference  

But fuck that I'll be aiming to win the 2018 Classic Division of the Worlds at Hervey Bay.

 

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11 minutes ago, Sonofabitch said:

You're getting ahead of yourself WnW. Who will win Classic at Sopot and how far up gold fleet will they land?

DougietheGun has been practicing in short fat A class and crowd funding this campaign. He will win in Sopot with c boards 17th in gold. He,s a demon in classics. Never did transition well from foiling ns14s

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56 minutes ago, Sonofabitch said:

You're getting ahead of yourself WnW. Who will win Classic at Sopot and how far up gold fleet will they land?

Keep up Abitch. The Worlds Classic concept will be voted on by national presidents at Sopot and if successful run for the first time at Hervey Bay. Even you could participate if you get rid of all that stupid gear that ACS keeps going on about. Decksweepers, sealed tramps, short travellers, funny shaped boards and silly little heads. Come on you know you can do it. 

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45 minutes ago, Sonofagun said:

DougietheGun has been practicing in short fat A class and crowd funding this campaign. He will win in Sopot with c boards 17th in gold. He,s a demon in classics. Never did transition well from foiling ns14s

Agun have you been supping deeply from the cup that pleases again. Been round enjoying Bags hospitality again perhaps. Do you even remember who you are  

As we all know Dougie the Gun has retired from sailing. He bought a Taipan.

 

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6 hours ago, WetnWild said:

.......... all that stupid gear that ACS keeps going on about. Decksweepers, sealed tramps, short travellers, funny shaped boards and silly little heads. 

Now we are getting somewhere! 

Short traveller = auto capsize device. Prevents you from sitting still between races as you can't get the sail out far enough. Stupid as

Decksweeper = Phsio's friend. My back is completely stuffed trying to get through that stupid small gap in the sail

Funny shaped boards = hole maker for the sail. Pull them up from the leeward side and the angle goes straight through the sail. Don't ask how I know!

Sealed tramps = The one good idea of the whole era! I hated the gap between the inner edge of the hull and the tramp. Rope just want to slip down that gap and drag through the water and whenever you put a shackle, screw or bolt down on the boat, it promptly falls between the gap never to be seen again.

So lets forget Classic vs foiling and go for Comfort vs Torture. If the top guys want to keep hurting themselves, fine, but give us old fools a chance of not needing a wheelchair after every sail.

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7 hours ago, A Class Sailor said:

Now we are getting somewhere! 

Short traveller = auto capsize device. Prevents you from sitting still between races as you can't get the sail out far enough. Stupid as

Decksweeper = Phsio's friend. My back is completely stuffed trying to get through that stupid small gap in the sail

Funny shaped boards = hole maker for the sail. Pull them up from the leeward side and the angle goes straight through the sail. Don't ask how I know!

Sealed tramps = The one good idea of the whole era! I hated the gap between the inner edge of the hull and the tramp. Rope just want to slip down that gap and drag through the water and whenever you put a shackle, screw or bolt down on the boat, it promptly falls between the gap never to be seen again.

So lets forget Classic vs foiling and go for Comfort vs Torture. If the top guys want to keep hurting themselves, fine, but give us old fools a chance of not needing a wheelchair after every sail.

Ah ACS you've finally seen the light. If God had meant us silly old fat fools to fly she wouldn't have given us Rule 8. May your hulls never leave the water my son. The DL award is yours. 

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16 minutes ago, WetnWild said:

Ah ACS you've finally seen the light. If God had meant us silly old fat fools to fly she wouldn't have given us Rule 8. May your hulls never leave the water my son. The DL award is yours. 

Maybe the benches he used to design for his foilers are a good idea after all. Nicely padded, with arm rests. Maybe even like a Chesterfield....:ph34r:

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Lol.

So what about the rumor floating about regarding on the fly adjustable rudder winglets? I thought Stevie and Bundy removed these or didn't find them particularly helpful at the last worlds???

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2 hours ago, samc99us said:

Lol.

So what about the rumor floating about regarding on the fly adjustable rudder winglets? I thought Stevie and Bundy removed these or didn't find them particularly helpful at the last worlds???

Yeah I've seen similar being used since then. Also Landy has been trying an hydraulic damper on the rudder to soften the wiggle. 

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1 hour ago, WetnWild said:

Also Landy has been trying an hydraulic damper on the rudder to soften the wiggle. 

Won't work, gliders binned that idea some 3 or 4 decades ago. Never quite haven't understood why foilers are not going to T Tail configurations like aircraft where most of the rudder is fixed and only 40% of the surface moves. The foil is then mounted correctly just in front of the upright which is mounted in a fixed position giving max strength for lightness with a fully balance rear blade which doesn't have the power to create the problems a conventional rudder has.

I guess A Class Sailor will chime in here and say how its all been done before and it wasn't a success as low speed handling was poor, but has it ever been used on a modern foiler ?

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24 minutes ago, Waynemarlow said:

Won't work, gliders binned that idea some 3 or 4 decades ago. Never quite haven't understood why foilers are not going to T Tail configurations like aircraft where most of the rudder is fixed and only 40% of the surface moves. The foil is then mounted correctly just in front of the upright which is mounted in a fixed position giving max strength for lightness with a fully balance rear blade which doesn't have the power to create the problems a conventional rudder has.

I guess A Class Sailor will chime in here and say how its all been done before and it wasn't a success as low speed handling was poor, but has it ever been used on a modern foiler ?

Landy thought it worked quite well but maybe you are more credentialed than he.......

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Yeah especially as its used elsewhere on modern aircraft control systems: https://www.nasa.gov/centers/dryden/pdf/88699main_H-2425.pdf

Further, glider control surfaces are typically balanced to counter flight loads and make the stick more neutral. By definition they are aero damped. No such thing exists on a foiler. I think a lightly damped rudder control system would work quite well on an Exploder or DNA. We have a method that effectively does this but isn't as smooth or predictable as a hydraulic damper. Its noticeable when its not in effect.

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5 hours ago, WetnWild said:

Also Landy has been trying an hydraulic damper on the rudder to soften the wiggle. 

I don't think that the primary role of hydraulic part was to act as a dampener although there might have been a secondary effect. It wasn't actually attached to the rudder but instead, it was part of his adjustable rudder AoA system and was in place of shock cord in order to push the system back. It attached to a lever arm that moved the gudgeon in and out. I personally don't think that placing a dampener on the gudgeon is going to stop death wobbles. The Moths do it by wrapping shock cord around the tiller and down to the transom which has an added benefit of self centering, but I believe some have tried it on the A and it didn't work. 

7 hours ago, samc99us said:

So what about the rumor floating about regarding on the fly adjustable rudder winglets? I thought Stevie and Bundy removed these or didn't find them particularly helpful at the last worlds???

Bundy used a system at the last worlds and i believe that Exploder have had a few attempts at making systems but nothing seems to have worked so far. The issue is how useful it will be. The way it was explained to me is that on the Moth, they cannot change the  AoA of the main foil and that the wand is what changes it. Because it has a narrow operating range, you adjust the rudder winglet to pitch the boat and keep the main foil in range for the speed and conditions. With the A, we adjust the AoA of he main foil to the conditions and therefore adjusting the rudder foils isn't as important. It has been suggested that the big advantage will be to dial in lift in marginal foiling conditions to get up and running because lifting the transom seems to be the big issue. The word is that Exploder have sorted the lack of lift by making bigger winglets and these make light wind foiling easier and foiling more stable in general, but to date, this has only been tested by the top guys who are good at early foiling anyway, so it might all be relative.

I personally hope we don't need to go with adjustable rudder systems, because the boats are getting complex enough anyway. there is a direct relationship between rudder winglet AoA and the main foil AoA. If we start playing with the rudders, we then have to get the main foils right for any given rudder setting. It just seems like another thing I will get wrong that will make foiling harder! I want the boats to become easier to set up and sail. One thing I did hear is that Stevie never adjusts the rake of his boards once he has them set for the conditions, using the same setting upwind and downwind. I hope that is right because that is one less thing to change at the marks.

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On 8/8/2017 at 6:03 PM, SCARECROW said:

So has Thilo's system been deemed a no go?

 

It seems there has been a big thing going on behind the scenes. Today we got the final answer.

http://www.a-cat.org/?q=node%2F1039

I am sure in this case it is OK to post the key points

Quote

 

The foil system presented in the facebook video (https://m.facebook.com/story.php?story_fbid=855820077927862&id=216203388556204&_rdr) at foiling week by Thilo Keller/AST has caused many questions about legality. The Technical Committee was asked to look into it, and a unanimous Technical Committee found that the foil concept of Thilo Kellers "AC nano" didn't comply with the A-Cat Class rules.

The case was appealed by Thilo Keller/AST and taken to the highest authority, World Sailing, for a rule interpretation.

The following interpretation to the A-Class Catamaran Class Rules has been made to be effective 10th August 2017:

CURRENT RULE:

8.1 No part of each hull or hull appendages below the waterline shall be less than 0.75 meters from the centerline.

INTERPRETATION:

The distance between any point of the daggerboard to its closest point on the centreplane of the boat shall be measured through the full range of motion (i.e. extension/retraction, cant and rake) permitted by the daggerboard case configuration and without taking into account the daggerboard deformation produced by forces expected during its normal use while racing. 

 

So common sense seems to have prevailed. I still find it extraordinary that somebody could think that holding a board in one place by shock cord for measurement purposes and allowing it to move to an "illegal" position when sailing would be OK, but then again, I guess I get carried away sometimes with my convictions and Thilo had put a lot of time and effort into the idea. I hope it doesn't kill off his long held enthusiasm for the class and for development, because he has been one of the people who has always pushed the boundaries which is what development classes need.

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5 hours ago, A Class Sailor said:

It seems there has been a big thing going on behind the scenes. Today we got the final answer.

http://www.a-cat.org/?q=node%2F1039

I am sure in this case it is OK to post the key points

So common sense seems to have prevailed. I still find it extraordinary that somebody could think that holding a board in one place by shock cord for measurement purposes and allowing it to move to an "illegal" position when sailing would be OK, but then again, I guess I get carried away sometimes with my convictions and Thilo had put a lot of time and effort into the idea. I hope it doesn't kill off his long held enthusiasm for the class and for development, because he has been one of the people who has always pushed the boundaries which is what development classes need.

The structures of our class have once again served us well and come up with the obvious answer. 

Agree with your hope for the future. 

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5 hours ago, A Class Sailor said:

I don't think that the primary role of hydraulic part was to act as a dampener although there might have been a secondary effect. It wasn't actually attached to the rudder but instead, it was part of his adjustable rudder AoA system and was in place of shock cord in order to push the system back. It attached to a lever arm that moved the gudgeon in and out. I personally don't think that placing a dampener on the gudgeon is going to stop death wobbles. The Moths do it by wrapping shock cord around the tiller and down to the transom which has an added benefit of self centering, but I believe some have tried it on the A and it didn't work. 

Bundy used a system at the last worlds and i believe that Exploder have had a few attempts at making systems but nothing seems to have worked so far. The issue is how useful it will be. The way it was explained to me is that on the Moth, they cannot change the  AoA of the main foil and that the wand is what changes it. Because it has a narrow operating range, you adjust the rudder winglet to pitch the boat and keep the main foil in range for the speed and conditions. With the A, we adjust the AoA of he main foil to the conditions and therefore adjusting the rudder foils isn't as important. It has been suggested that the big advantage will be to dial in lift in marginal foiling conditions to get up and running because lifting the transom seems to be the big issue. The word is that Exploder have sorted the lack of lift by making bigger winglets and these make light wind foiling easier and foiling more stable in general, but to date, this has only been tested by the top guys who are good at early foiling anyway, so it might all be relative.

I personally hope we don't need to go with adjustable rudder systems, because the boats are getting complex enough anyway. there is a direct relationship between rudder winglet AoA and the main foil AoA. If we start playing with the rudders, we then have to get the main foils right for any given rudder setting. It just seems like another thing I will get wrong that will make foiling harder! I want the boats to become easier to set up and sail. One thing I did hear is that Stevie never adjusts the rake of his boards once he has them set for the conditions, using the same setting upwind and downwind. I hope that is right because that is one less thing to change at the marks.

I was chatting with Landy on the beach about his rudder system. He said it was about stabilising the wobble. He doesn't usually bullshit to me. 

The rest of your stuff makes sense. 

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5 minutes ago, WetnWild said:

I was chatting with Landy on the beach about his rudder system. He said it was about stabilising the wobble. He doesn't usually bullshit to me. 

The rest of your stuff makes sense. 

I know that Landy would never bullshit anybody, never mind you!:D Here is a picture I took of what we are talking about.

IMG_3641small.jpg.15947c147f335a208dfa77237496d842.jpg

I had assumed that the little hydraulic device was simply something to act against the pull of the purchase and to push the system back when the rope is eased. I can see how it would take wobble out of the system, but i am still a bit unsure how it would stop death wobbles which come from the bottom of the rudder and which are felt through the tiller. I don't see how the gudgeon moves when you have death wobbles and therefore how that would stop them. Landy is a lot smarter than me, so I guess I am missing something.

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40 minutes ago, A Class Sailor said:

I know that Landy would never bullshit anybody, never mind you!:D Here is a picture I took of what we are talking about.

IMG_3641small.jpg.15947c147f335a208dfa77237496d842.jpg

I had assumed that the little hydraulic device was simply something to act against the pull of the purchase and to push the system back when the rope is eased. I can see how it would take wobble out of the system, but i am still a bit unsure how it would stop death wobbles which come from the bottom of the rudder and which are felt through the tiller. I don't see how the gudgeon moves when you have death wobbles and therefore how that would stop them. Landy is a lot smarter than me, so I guess I am missing something.

Good photo ACS. I have one somewhere but can never figure out how to upload from my iPhone. Always too big. 

That looks like the version from the Nats. It was slightly modified at Qld. Moved to the box in line with the pintle. He confirmed your comments that not much needed to be regularly changed once on the water. This was just an easier way to set up on the water rather than over the back with s spanner!

we are probably talking about different things with the wobble. I meant just limiting the speed of steering which can lead to a lot of other issues if you oversteer. The death wobble itself is a whole other world of pain as I'm sure you know. Can be caused by s lot of things I guess. Weed, alignment slightly loose figment etc. 

sort my upload problem and I'll bring you lots of Sopot pictures!

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1 minute ago, WetnWild said:

sort my upload problem and I'll bring you lots of Sopot pictures!

Pictures would be great, but a few comments would be even better. I think we will all want to know whether people try short rigs. What has Mischa been working on in the workshop for the last few weeks. Has anybody come up with anything really radical. Most important, who is fast and if possible, how fast is fast. I hope there is some form of tracking, although I suspect that will mean i don't go to bed for a week!

Sorry, can't help with the photo problem. That photo was sent to me by somebody else and I don't know how to make the picture smaller:(

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5 hours ago, A Class Sailor said:

I had assumed that the little hydraulic device was simply something to act against the pull of the purchase and to push the system back when the rope is eased. I can see how it would take wobble out of the system, but i am still a bit unsure how it would stop death wobbles which come from the bottom of the rudder and which are felt through the tiller. I don't see how the gudgeon moves when you have death wobbles and therefore how that would stop them. Landy is a lot smarter than me, so I guess I am missing something.

Umm am I missing something here, the hydraulic device is not a damper at all in this situation, it is a hydraulic spring which just sets the AoA, yes it has a damping motion to ensure the expansion rate of the spring is controlled, nothing more than that. In fact these spring have damping in only one direction, outwards, most of you will be familiar with these on your car rear boot door.

It will have no impact at all on the so called Death Wobble which in fact is occurring from the very reason why light aircraft and gliders abandoned all flying tail plane surfaces. For you dis believers have a read of  https://en.wikipedia.org/wiki/Pilot-induced_oscillation

Sam you should know better than to quote an F18 all flying tail plane as an example, its designed to be totally out of control all of the time, for better maneuverability at high speeds.  But that fly by wire input and control to the all flying surface is by controlled by computer which operates 1000's times faster than any human can. Without that the aircraft would crash every time.

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4 hours ago, WetnWild said:

sort my upload problem and I'll bring you lots of Sopot pictures!

Set up a Dropbox account and download the pictures to that first. Then simply link your post to the drop box.

I'm not sure which phone you have but almost certainly somewhere in the picture settings there will be an option to lower the quality of the pictures. Low quality will allow you to upload them direct.

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3 hours ago, Dazz said:

The uptip mainsail reminds me of my windsurfing sails! 

shorty.jpg

Please don't mention that word Dazz - Likely to attract comment from an undesirable!

Landy has benn building such sails as standard for A's for about 4 years. Not quite as exaggerated though. Wind tunnel testing showed less drag if the sail tip was slightly above the mast section. I use it on my Tri sails but don't have any performance comparisons. 

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1 hour ago, Waynemarlow said:

Set up a Dropbox account and download the pictures to that first. Then simply link your post to the drop box.

I'm not sure which phone you have but almost certainly somewhere in the picture settings there will be an option to lower the quality of the pictures. Low quality will allow you to upload them direct.

iPhone 6 and photos are in ICloud. Can't see any option to change size. 

Dont understand Dropbox. I thought it was what the King used when required from high up in his castle. 

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1 hour ago, Waynemarlow said:

Umm am I missing something here, the hydraulic device is not a damper at all in this situation, it is a hydraulic spring which just sets the AoA, yes it has a damping motion to ensure the expansion rate of the spring is controlled, nothing more than that. In fact these spring have damping in only one direction, outwards, most of you will be familiar with these on your car rear boot door.

It will have no impact at all on the so called Death Wobble which in fact is occurring from the very reason why light aircraft and gliders abandoned all flying tail plane surfaces. For you dis believers have a read of  https://en.wikipedia.org/wiki/Pilot-induced_oscillation

Sam you should know better than to quote an F18 all flying tail plane as an example, its designed to be totally out of control all of the time, for better maneuverability at high speeds.  But that fly by wire input and control to the all flying surface is by controlled by computer which operates 1000's times faster than any human can. Without that the aircraft would crash every time.

That was the early version in the photo Wayne. Later it was attached to the box above the pintle. Been discarded now though I think as it was months ago. I'll look at Sopot. 

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1 minute ago, Erwankerauzen said:

Any available workpaper regarding the drag test above mentionned ?

Thanks in advance

 

 

Sorry Landy just told me it was done in the F1 spoiler wind tunnel by Scheurer as they had a family connection working their spoilers. 

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Scheurer has done some of the best testing out there. If they have a top rider on their platform I think it will be a hard boat to beat, very well optimized for foiling with most of Thilos full foiling A-cat ideas incorporated.

WetNWild, I really want as many photos from Sopot as possible as they keep the brain churning more than a few words. Here is one app that reduces photo size: http://www.idownloadblog.com/2014/02/22/how-to-reduce-pictures-file-size-on-iphone/. Another trick is to email yourself the photos from your phone and then use the "small" option when hitting send.

 

 

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2 hours ago, Waynemarlow said:

Umm am I missing something here, the hydraulic device is not a damper at all in this situation, it is a hydraulic spring which just sets the AoA, yes it has a damping motion to ensure the expansion rate of the spring is controlled, nothing more than that. In fact these spring have damping in only one direction, outwards, most of you will be familiar with these on your car rear boot door.

It will have no impact at all on the so called Death Wobble which in fact is occurring from the very reason why light aircraft and gliders abandoned all flying tail plane surfaces. For you dis believers have a read of  https://en.wikipedia.org/wiki/Pilot-induced_oscillation

Sam you should know better than to quote an F18 all flying tail plane as an example, its designed to be totally out of control all of the time, for better maneuverability at high speeds.  But that fly by wire input and control to the all flying surface is by controlled by computer which operates 1000's times faster than any human can. Without that the aircraft would crash every time.

Wayne,

   That was simply an example, I am aware of the fly by wire control system in an F18. In the aircraft world, there are advantages and disadvantages to all moving control surfaces, elevator being the most common of course. I have designed and flown both. I prefer the fixed stab with moveable elevator surface but this is a bit lower in efficiency (we are talking a few percent at best) and has a smaller C.G range than an all moving stab. Plenty of GA aircraft have all moving stabs and they aren't falling out of the sky-lots of Piper Cherokees and Cessna 177's still flying. The key is properly balancing the surface so as to avoid flutter and linkage overload. They are more sensitive to getting right than the hinged control surface setup, and slop is the enemy of these surfaces which I suspect is one reason they have been killed off in modern glider design. The other is high speed flutter, the L/D of a modern performance glider is pretty astounding, as is the minimum sink rate, which generally means the goal is to get from thermal 1 to thermal 2 as fast as possible, i.e a high Vne is a requirement, and that is easier met with a fixed stab/elevator combo than an all moving stab in a GA aircraft. The Boeing 737 series uses an all moving stab in conjunction with a hinged elevator; the computer adjusts the moveable stab to account for the aircraft weight and balance and the pilot flies the elevator. 

Death wobble: your comments pretty clearly states that you haven't sailed a foiling A yet, as this is NOT the same thing as pilot induced oscillation! PIO certainly can occur on a sailboat, more so on a foiling boat, but less so in the yaw axis than in pitch in my experience (incorrectly timing the waves and your body position, leading to c.g induced pitch oscillations that would ordinarily be damped by the winglets). The death wobble being discussed is more like flutter, and can occur anytime the rudder setup isn't bone tight. Would a fixed rudder with moveable trim tab help this? Maybe. My take is if it was worthwhile, Groupama C would have done it, the AC boats would have done it, someone would have done it on an A-cat. I don't think its worthwhile as upwind and on the start line the all moving rudder is crucial.

-Sam

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Sam,

The only foiler I have sailed is the S9, where the rudder controls definitely could get into the PIO induced situation, typically just as you transitioned out onto the wire. I'm sure as you gained experience you could learn to keep things better under control and indeed I ended up locking the stick down on the boat deck just as you swung out. As it sped up though you could feel the rudder wanting to get into that wobble from PIO and it was interesting to watch the first timers on the boat, do just that. Indeed almost every beach cat I have sailed will do that at higher speeds, its not just unique to the foilers.

If you are saying that flutter is coming into the situation then that's a different thing altogether. What symptoms are you talking about as I have only ever seen flutter on my F16 which had T foils on at about 20 + knots where you would start to get a hummm and then you could visibly see the whole board begin to get a bit of a high pitched oscillation in it. But it was never bad enough to really worry about as mid twenties was top whack.

My guess if you are genuinely getting flutter then I would expect cavitation of the foil from the oscillations and even delamination and or destruction of the boards such is the density of the water compared to air.

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1 hour ago, WetnWild said:

Please don't mention that word Dazz - Likely to attract comment from an undesirable!

Landy has benn building such sails as standard for A's for about 4 years. Not quite as exaggerated though. Wind tunnel testing showed less drag if the sail tip was slightly above the mast section. I use it on my Tri sails but don't have any performance comparisons. 

 

IMG_0088.PNG

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39 minutes ago, Waynemarlow said:

Sam,

The only foiler I have sailed is the S9, where the rudder controls definitely could get into the PIO induced situation, typically just as you transitioned out onto the wire. I'm sure as you gained experience you could learn to keep things better under control and indeed I ended up locking the stick down on the boat deck just as you swung out. As it sped up though you could feel the rudder wanting to get into that wobble from PIO and it was interesting to watch the first timers on the boat, do just that. Indeed almost every beach cat I have sailed will do that at higher speeds, its not just unique to the foilers.

If you are saying that flutter is coming into the situation then that's a different thing altogether. What symptoms are you talking about as I have only ever seen flutter on my F16 which had T foils on at about 20 + knots where you would start to get a hummm and then you could visibly see the whole board begin to get a bit of a high pitched oscillation in it. But it was never bad enough to really worry about as mid twenties was top whack.

My guess if you are genuinely getting flutter then I would expect cavitation of the foil from the oscillations and even delamination and or destruction of the boards such is the density of the water compared to air.

That is time on the boat. Not disagreeing that it could perhaps be better, but a readily available solution running a trim tab AND retaining the rudder kick up doesn't exist AFAIK. The best thing to do is tighten up your steering! Important on a floater, critical on a foiler.

There is definitely high frequency oscillation at high speed (above your 20 kt barrier) IF things aren't locked down AND you get weed on the rudder blade. Otherwise it is fine. No foil self destruction is happening-I think the problem is a bit overblown but it is important to eliminate play and it might help to install a bungee on the tiller crossbar.

How is the training at the worlds venue going?

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2 hours ago, samc99us said:

Scheurer has done some of the best testing out there. If they have a top rider on their platform I think it will be a hard boat to beat, very well optimized for foiling with most of Thilos full foiling A-cat ideas incorporated.

WetNWild, I really want as many photos from Sopot as possible as they keep the brain churning more than a few words. Here is one app that reduces photo size: http://www.idownloadblog.com/2014/02/22/how-to-reduce-pictures-file-size-on-iphone/. Another trick is to email yourself the photos from your phone and then use the "small" option when hitting send.

 

 

Thanks good tips. I'll do what I can. 

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@samc99us @Charlie P Mayer - rudder wobble is starting to be a concern for me past 15kt speed now that I can get my Whisper to go right :-) -- mostly my transition to the wire is ok, but even when solid on the wire, gusts and lulls mean leaning out / pulling in body weight. It is tricky to avoid wobbles.

In fact, the wobbles I am getting are manageable, but I am looking ahead past 15kt; and thinking of dampening with strong bungees. Perhaps a V-shaped dyneema line + a short stretch of very strong bungee; all anchored at the fulcrum of the V, on the middle of the rear crossbar.

I've seen such dampeners on Moths. Are any in use on A-Cats? 

Such a setup is not adaptive/conditional on speed (as such systems are on modern airplanes). I don't know of any practical way to make it so. At least, it'll put a damper on regular tack/gybe maneuvering, be a PITA(rm) in lower wind conditions, and perhaps a safety concern if the helm goes over...

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Martin, if you are getting wobbles that early, I wonder if your rudders are overbalanced.  

I know Sam has been playing with reducing balance to improve tracking and I don't think has found a happy medium on this setting alone but it works very well for me.  By positioning the rudder blade a little aft in its tiller housing, the the balance on the rudder is reduced and the boat is more stable on the foils. I have been very happy with my A set up and feel the boat tracks very well at 20+ knots of boat speed.  It is relatively forgiving to foil at various upwind and downwind angles.  

One of the key things to think about though in all steering issues is not steering.  It is trimming.  Trimming should be the large majority of your adjustment while foiling.  You may already be going this and I apologize if it is obvious, but it's amazing how much better a foiling cat goes when it isn't having to turn up and down all the time.  The rudders just need to track and occasionally make adjustments after the sail trim first responds to gusts or lulls.

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If you are getting death wobbles at that speed, there is something wrong with the set up and I think it is unlikely to be to do with balance. The first thing to check is for  is any slack in the system. There can be no movement at all in the stocks. How do you tighten the boards in the stocks? On the A, there are 2 clamps on the dagger style stocks and you cannot move the blade once licked. On my conventional pivoting rudders, I struggle to get them up and down they are so tight. The slightest movement will set off death wobbles. Also, the slightest wear in the gudgeons is  hugely magnified.

i have not seen or heard of anybody using shock cord like the Moths. I am not sure how you would do it on a cat. On the Exploders. The rudder is bolted down onto the pint Les and you can control wobbles by tightening the nut.

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A little bit of local content from Sopot... https://drive.google.com/file/d/0B2RejMpWWHRiR0wwZDN6WWxyQTg/view?usp=drivesdk 

I hope the link works:) Should be more detailed interviews and techy boat bits to come. The players are starting to arrive and new boats are coming in from the Exploder factory every day. A solid storm blew through last night and tested the marquis and the beach ground supports.

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Hi Martin!  I've been using tape and pieces of rubber hose on my old cats to eliminate slop for many years.  Prindle 15 used a very short piece of rubber hose between the casting and the hull to pre-load the mechanism.  All of them got a turn or two of electrician's tape between the pin and the casting.  The S9 rudder mechanism is much tighter than those old cats, but I still added a round of tape on the pins - most of it peeled off when I mounted the castings, but there no slack at all.  When we first started the rudder foils would try to rotate forward at speed, which would create too much rudder lift.  We added a very short piece of rubber hose inside the bottom casting to act as a pre-load bumper on the rudder.  Now the factory locking mechanism pushes against the rubber bumper and voila!  No more surprises at 20 knots.  John and Jonathan were a treasure of information in this area.  Apparently the Phantom gets quite violent if there is any rudder slop.  When you come pick up the crunched S9 I'll show you what we did.  Do you ever get ventilation on the rudders?

Anyway, eliminate any slop (check the bolts) and proper tuning should get rid of the wobblies.

Charlie

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10 hours ago, paularsen1 said:

A little bit of local content from Sopot... https://drive.google.com/file/d/0B2RejMpWWHRiR0wwZDN6WWxyQTg/view?usp=drivesdk 

I hope the link works:) Should be more detailed interviews and techy boat bits to come. The players are starting to arrive and new boats are coming in from the Exploder factory every day. A solid storm blew through last night and tested the marquis and the beach ground supports.

Fantastic video! Can't wait to see more!!!!

It definitely sounds like the conditions will play a factor for most of the fleet, probably more so than the tech?

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First few pictures beginning to show up on Facebook and the like catsailngnews.com has a picture of a new Exploder with a DNA style solid tramp. The tramp looks great but I don't like the way the traveller sticks out above the tramp or the full length curved track. There can also be no under tramp mainsheet system. While the aero advantage of the traveller and mainsheet below the tramp probably won't make a difference to sailors like me, it has to be better. I have been told that the under tramp mainsheet runs better as well because you have 2:1 at the back and 5:1 under the tramp all of which has less friction than the 10:1 systems people have been using, I also found out that people are running 2 auto ratchets with the under tramp system. 1 is in the flip flop block that comes out of the tramp and the other is under the tramp itself. It seems that this is better for easing the sail as the ratchet never grabs when easing sheet.

Now i want to know about rigs! Will anybody risk going short? How short is short? Will there be a jib? Please can somebody help!!!!

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4 hours ago, A Class Sailor said:

First few pictures beginning to show up on Facebook and the like catsailngnews.com has a picture of a new Exploder with a DNA style solid tramp. The tramp looks great but I don't like the way the traveller sticks out above the tramp or the full length curved track. There can also be no under tramp mainsheet system. While the aero advantage of the traveller and mainsheet below the tramp probably won't make a difference to sailors like me, it has to be better. I have been told that the under tramp mainsheet runs better as well because you have 2:1 at the back and 5:1 under the tramp all of which has less friction than the 10:1 systems people have been using, I also found out that people are running 2 auto ratchets with the under tramp system. 1 is in the flip flop block that comes out of the tramp and the other is under the tramp itself. It seems that this is better for easing the sail as the ratchet never grabs when easing sheet.

Now i want to know about rigs! Will anybody risk going short? How short is short? Will there be a jib? Please can somebody help!!!!

Be patient grasshopper. The bullshit stops when the flag drops. 

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On 8/11/2017 at 9:37 PM, Lost in Translation said:

Martin, if you are getting wobbles that early, I wonder if your rudders are overbalanced.  

I know Sam has been playing with reducing balance to improve tracking and I don't think has found a happy medium on this setting alone but it works very well for me.  By positioning the rudder blade a little aft in its tiller housing, the the balance on the rudder is reduced and the boat is more stable on the foils. I have been very happy with my A set up and feel the boat tracks very well at 20+ knots of boat speed.  It is relatively forgiving to foil at various upwind and downwind angles.  

One of the key things to think about though in all steering issues is not steering.  It is trimming.  Trimming should be the large majority of your adjustment while foiling.  You may already be going this and I apologize if it is obvious, but it's amazing how much better a foiling cat goes when it isn't having to turn up and down all the time.  The rudders just need to track and occasionally make adjustments after the sail trim first responds to gusts or lulls.

Can you guys talk a little more about death wobbles, what they are, how they start, how to kill them, looseness in the system vs. balance problems that create them, etc.?

LIT, when you say " By positioning the rudder blade a little aft in its tiller housing, the the balance on the rudder is reduced and the boat is more stable on the foils" - are you pushing the top of the rudder aft or the bottom of the rudder aft?

I've had the wobbles and I've seen the rubber tiller tiebar ends vibrating once the wobbles started! I've just slowed the boat down until they go away. I've also worked really hard to get my rudders tight in the stocks but maybe I haven't done enough.

I've seen that some people are eliminating the rubber tiller tie bar ends which seems like a good idea to me. Photos of that would be nice. I was thinking of having a one end threaded so I could throw the rod for setting the rudders parallel.

Other thoughts?

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Death wobbles....... even the slightest amount of play in the rudder stock is multiplied greatly at the bottom of the rudder. You need to get the boat up in the air so yoy can have the rudders down and then you push and pull them from every conceivable direction looking for any play at all. On my boat, when I tried to check for sideways movement in the stock, there was none but when I grabbed the blade at the front and back and tried twisting it, I found the front had a bit of play in the stock. With conventional pivoting rudders, it should be a struggle to push the rudder blades down and to get them up. You also need to check for the slightest play in the gudgeons and pintles usually caused by wear. You can drill out gudeons and insert bushes if you can find the bushes. I learnt a new way of fixing that recently from the Hobie sailors. Cut up Coke cans to create really thin shims that can be pushed down between pintle and gudeon. The metal is so think you can cut it with conventional scissors. You cut a piece the same depth as the gudgeon and enough to go half way around the pin. Curve it a little to start it off and push with something like pliers. Quick and very cheap.

I don't have a picture of the Exploder tiller bar fittings but they are just a pin sticking up from the tiller on the stock. You then need a hole in the tiller bar. Exploder have nice tiller bar end fittings that slip inside the end of the tiller bar with a pre-drilled hole. They slide in far enough that by adjusting how far into the tiller they go, you can play with the toe in.

I believe you can dial out some of the death wobbles by playing with how much the rudders tuck under the boat, but I am told that only really applies at high speeds. For most of us, the real issue is play in the system.

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42 minutes ago, A Class Sailor said:

Death wobbles....... even the slightest amount of play in the rudder stock is multiplied greatly at the bottom of the rudder. You need to get the boat up in the air so yoy can have the rudders down and then you push and pull them from every conceivable direction looking for any play at all. On my boat, when I tried to check for sideways movement in the stock, there was none but when I grabbed the blade at the front and back and tried twisting it, I found the front had a bit of play in the stock. With conventional pivoting rudders, it should be a struggle to push the rudder blades down and to get them up. You also need to check for the slightest play in the gudgeons and pintles usually caused by wear. You can drill out gudeons and insert bushes if you can find the bushes. I learnt a new way of fixing that recently from the Hobie sailors. Cut up Coke cans to create really thin shims that can be pushed down between pintle and gudeon. The metal is so think you can cut it with conventional scissors. You cut a piece the same depth as the gudgeon and enough to go half way around the pin. Curve it a little to start it off and push with something like pliers. Quick and very cheap.

I don't have a picture of the Exploder tiller bar fittings but they are just a pin sticking up from the tiller on the stock. You then need a hole in the tiller bar. Exploder have nice tiller bar end fittings that slip inside the end of the tiller bar with a pre-drilled hole. They slide in far enough that by adjusting how far into the tiller they go, you can play with the toe in.

I believe you can dial out some of the death wobbles by playing with how much the rudders tuck under the boat, but I am told that only really applies at high speeds. For most of us, the real issue is play in the system.

I have 2015 DNA set up and I've spent a fair bit of time trying to get the rudders to stop rocking fore and aft in the cassette. I've re-potted one half of the cassette with the rudder in it and put epoxy blobs at the four corners of the cassette but I think the only real answer is to re-pot both sides of the cassette to eliminate any rocking movement. Otherwise its just a moving target. Also once they are locked in then I need to make sure the AOA at the bottom is the same. It takes time to figure out how to get it all right.

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It’s going to be an interesting regatta.

And always fun to discuss all the technical stuff, but it somehow reminds me of the triathletes discussing which swimming pants are fastest;- )

It does mean something (sometimes a lot), but it is a sailing regatta, and the important thing how people sail and setup their boats. The technology differences amongst the first 10-15 boats will be notable, but I don’t think it will decide who's winning. Maybe, we will know next Friday.

And weather forecast predicts good condition - a week out is not that predictable, but at least there is no sign of way too little or too much wind. And it won’t get too hot, that’s good, I hate sailing in +20 celsius.

sopot.JPG

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Lars,

  It looks like pretty good sailing conditions! Who is fast in the training group? Anyone consistently foiling upwind? I agree that how people sail makes the biggest difference but I've also come to realize that boat setup, tuning, and sail selection really do matter. Foil setup in particular is very important to stable foiling, and certain sails are better in breeze when foiling (namely those developed by top foilers).

Can't wait to see how the regatta progresses!!!

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There's been some great notes on rudders and the wobbles; I didn't want to stem the flow, nor distract more from the actual thread topic. 

Thank you all for the wobbles notes. In my case, the wobbles are all pilot-induced; sailing singlehanded on a 2-up cat, slightly overpowered, without a mainsheet cleat, sheeting in involved bringing the sheet to the tiller extension hand. As I got tired, my steering got slightly jittery when I was grabbing the mainsheet. My rudders are rock-solid in their stocks, as far as I can tell :-)

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Martin

Nobody uses a cleat on an A and yes, you have to learn to steer straight at all times. The issue is simple. When up on foils, you have little rudder in the water and you are travelling fast, which mean there is little resistance to steering input and the boat reacts fast to any input. One tip is to look for ways to dampen down the whole system. Moths use shock cord over the tiller attached down to the boat.. Try to find a way to do something similar with your boat.

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