Interesting Info to Share

Hey guys, just wanted to share some really interesting info Our local cat guru, Scott M, had just conducted an interview with Greg Goodall last weekend when he passed through Singapore.

We'd been experimenting with some new settings he had provided using 2 boat pacing for the last few weeks and the interview is somewhat of a consolidation of what we had also discovered for ourselves. The interview can be seen here

http://boatsbikesboards.wordpress.com/

I think the interview is especially interesting for anyone sailing a boat with the full F16 width and the aluminium masts that comes with the AHPC boats.

Interesting times ahead <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Good read.

Thanks for the tip.

Now all we need is a Singapore association, and let the interesting times begin.

Push and prod "ckuang" and Alice Lim to get a Singapore Association going.

And the Singapore F16s will racing at a local regatta over the next few weekends, linky here: www.westerncircuit.com

Due to unforseen circumstances and all sorts of other things, I will either be on the TP52 or sailing demonstration races.

Hey Taipanfc, not sailing your new boat? Darn, was hoping to see it out on the water. Am really curious to see what it looks like. saw the hulls at RM already and they boats are really really well finished.

Looking forward to the weekend of racing.

Was told by the committee the cat fleet didn't want us racing with you guys. Bit strange I thought, maybe scared <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" /> But will be out there tomorrow morning having a blast before doing training on the TP if you want a look see.

Ah I see. Yes, i heard talk about that. Haha, but they way some of the sailors in the cat fleet sail, are you sure you want to put your brand spanking new boat on the line with us? <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" /> Even I'm planning delayed starts for the next few weekends. The last time I tried going for it I managed to get a hole punched in my A from a barging taipan.

for Blade sailors, there's a new post up n the blog about a new blade being tested out. This blade has modified beams and running a goodall F16 sail instead of the standard configuration.

You replaced the stock rudders and rudderstock with Viper rudders and (alu) stocks ?

That suprises me, from the look I had in 2007 these Viper components were most certainly not superior.

Beams, yes.



Well, that Ullman rig that was on it was not exactly a winner. I have experienced myself the difference between the Ullman and Ashby or Glaser sails and it was quite noticeable. That Ullman rig is a passed station for at least 1.5 years now in my opinion. A real pitty as Ullman should really have been able to design a good suit of sails, but ...




I think the hybrid Blade and Taipan are subject to the same behaviour. You have to start steering the boat down BEFORE the gust or wave hits the boat under spinnaker, not after or during them. Many sailors seem to forget this dictum. Of course, this can be "corrected" by putting heaps of volume in the bows but beyond some point only at the expense of something else. Having said this I personally think there is some room in the hybrid Blade for additional bow height and therefor a little more volume. I think the Aussie Blade has gotten the distribution just right as indeed the Viper seem to have. I overheard some designers comment on this topic during the 2007 Global Challenge and the consensus seemed to be that mostly bow height was important here and much less overall volume. The hulls of the Viper are very tall and the Aussie Blade are taller as well. Taipan is modestly tall but has almost no volume there and the VWM Blade is halveway between these. Still, with proper technique this difference can be corrected quite well. And the proper technique is to start steering down before the gust hits, accellerate the turn during the gust and start head-up when the gust starts winding down. Again, this makes quite a difference and should also be employed on the Viper and Aussie Blade for maximum performance.


One more suggestion. Move that rotation arm from underneath the boom to above the trampoline. No drawbacks worth mentioning and you'll increase the perceiped space on the trampoline significantly. Less eyepoking during fast 2-up gybes. Stitch some small strips of cloth on the trampoline in an arc like fashion and you'll have your mast rotation measurement for quick resetting.

Good luck nice to hear about these experiments ! Anxious for more.

Wouter

Rudders replaced as the original McKenzie ones had heaps of problems. Can't remember exact details, but the locking mechanism was stuffed and I think they were cracking.

If they are still using the original Blade mast, then there is a big hole at the bottom of the mast where the original spanner was. Either bad installation or bad design, but the bolts really ripped up a big hole on either side of the mast so this is the only alternative. Much prefer the desk sweeper, a lot less friction and prefer rotation to be independent from mainsheet tension.

Wouldn't mind seeing a high aspect board on this boat rather than the fat Taipan boards.

Are you saying they put Taipan boards in agent orange and the described Blade (or is it the same boat)?

Both Agent Orange and the Hybrid use Taipan c/boards. Can see it in the pics in the link ckuang put in the first post.

Also have to congratulate ckuang on 3 bullets on the first weekend of Western Circuit. Certainly doing very well jumping from the A to the Viper.

Ohhh, you guys still had the McKenzie ones, those were indeed a load of crap. The first (prototype)set for testing was alright but for the full order he delivered what can only be described as junk.

I too broke one of them in 2 minutes of sailing; a few years back. I wouldn't want to have a set of those if I got them for free ! Nobody in the F16 class is ever going to do business with him again. The class and Blade builders got burned there. Luckily only 4 boats ever got fitted with those. I'm amazed the hybrid Blade was still fitted with these. The others have scrapped these years ago.





There is ? I haven't seen that with the Blades overhere.




Became standard to the design from early the 2007 onwards. Still, I'm amazed at how well the low aspect boards seem to do in comparison.

Wouter

Actually, this dependents on how you define the Taipan boards.

I can't speak for agent orange, but the hybrid and other Blades delivered with the low aspect daggerboards all use a longer daggerboard then the Taipan but of the same general shape. It differs in some other details as well, but not enough to be obviously different.

And indeed congratulations to Ckuang !

Wouter

I have dealt with McKenzie for quite a while and if the boards are specced correctly, then they are really good. Had a set for the Taipan, and for that they were built a bit differently (as requested) and never had any problem over 3 yrs. Got a set for the A, and these are a lot lighter but you need to be careful in certain cases otherwise they will snap, eg do a big round up in windy conditions and not ease the main first into it.

In relation to spanner, as I said either design flaw or bad installation. I was rather shocked how bad it was, but it was at a stage that hard to tell the initial reason why.

And yes, the Blade c/boards are an inch or 2 deeper, and those boards are still quite good. But comment was on a Viper/Capricorn style deep high aspect board.

Awww, thanks for the well wishes guys. It really was a fun race with the downwind legs becoming gybing duels between all the 3 vipers. It's amazing how close in speed these boats are. I must say the F16 viper is probably one of the very best boats i have ever owned. I really "get" the design and understand why the boat behaves the way it does. Although there are still some mysteries I'm trying to find the answers to though.

Just to clarify some doubts about the hybrid blade, the mast is the new ahpc section and not the original section which came with the blade. I believe the original one had the mast rotation moved from tramp level to the boom level because it had corroded badly.

On the hybrid blade, the only thing original is just the hulls, everything else are parts taken from a viper. As far as viper rudder casing goes, yes, i did try to find out of there were carbon casings in the works, unfortunately, when I inquired via the local dealers, apparently the answer was a negative and ahpc has no plans to offer carbon casings for the viper as of now. Of course, at the level we sail at in Singapore, I don't think carbon anything is going to make a difference. None of us here are headed off to the olympics anytime soon. I just wanted to find out because I just wanted to pimp out my boat, you kinda like the sailing equivalent of the MTV show, "Pimp my ride" haha

I like the mast rotation a la A class style as well where it is just above the tramp. I'm not too sure what the benefit is of having it just below the boom. Less clutter perhaps?

And yes, the Mackenzie rudders were apparently awful on the F16. all the blades snapped on the early boats like agent orange and a F16 taipan, which is really too bad because the carbon casing etc looked really awesome.

I'm really looking forward to getting a chance to have a blade vs viper fight on the water. BTW, I had no idea that the Australian bade hull has more volume than the American made blade hull. Is that true?

With respect to the McKenzies; I wonder why you guys never replaced them with the AHPC Carbon stocks (as delivered for the Taipan 4.9's) as they are very good indeed. The cast alu Viper Stocks are heavy in my opinion and present no real advantage over bend alu tube stocks that are significantly lighter. The guy building these is near to me (10 km away max) and I was surprised to hear his quotes on these. These bend tube stocks appear to be the best alternative to carbon stocks; both in weight and cost. Fellow F16 owners at my club have been using these for two years now and no issues with them. These stocks also allow the rudders to be rotated upwards by more then 180 degrees see picture.






Yes. however the more important difference is in the freeboard. The Aussie Blade hull has a higher freeboard and the bows themselves are taller as well. This while keeping largely the same overall appearance. I think the sterns are a little more narrow as well. Basically, the Aussie Blade is an evolution to the American Blade driven by the experience gained on the first model models (both timber homebuilds and series production). Ohh, before I forget the Aussie Blade has different beams as well; although these beams are offered to anyone wanting to use them.

Having said all this, when the two boats when head to head at both the 2007 and 2008 F16 global challenge the skippers sailing them were extremely close in performance. Although the comments were that the Aussie Blade handled the heavy seastate better under spi. Upwind was anyones game. Same with respect to the Viper F16 sailed by Greg in the later days. In direct comparison there was surprisingly little difference even when one boat handled certain conditions more comfortably then the other.

Personally I put this down to the engines (rigs) being so well limited by the class rules as to be identical in all intents and purposes. Of course at these events we only had sails made by proper and highly regarded sailmakers. Glaser, Ashby and Landenberger. The Aussie Blade was carrying a more experimental sail and I don't really know where to place that for lack of other data.

Wouter

Would it be possible to make these bent tube stocks at home, if it is not a proprietary design does anyone have any good photos's of these stocks.

Gareth

Grob yes you can make them at home, but you'll need a little practice.

1. Scribe a circle on some 25mm ply (your tube will spring a little so go 10-15mm small than the required inner diam.

2. create a clamp and bending lever as shown.

3. clamp in some suitable tube (20 or 25mm).

4. Rotate lever in one single slow movement, going beyond 180 degrees..

4. and repeat for 4 similar parts then cut to length and join with either welds or rivets..

Wouter

The Viper at the 2008 GC only just started one race.

Not sensible to use it's performance from 2008

Scooby,

I wasn't refering to the Viper but the Aussie Blade.

Wouter

OK, Sorry.

Photo attached.

Thickness of rudder blade determines what size extrusion to use. My blades are 18mm.

I use 19.05mm OD Hollow square, 1.83mm wall thickness, corner radius 1.57mm. Alloy is 6060, T5 and can be purchased anodised.

A cardboard template is good for getting the bend angle correct.

Bottom gudgeon is a solid piece of aluminium cut to shape.

Modified Blade looks good, some interesting racing in Singapore.

Darryn
Mozzie
1782

Darryn, Chris,

Thanks for the pictures and diagrams.

Gareth

I can't speak for other nations around the world but the alloy 6060-T6 (a better version then 6060-T5) is quickly become THE standard alloy for any profiles. Bascially this means that when you go down to a local hardware shop overhere that the standard alu profiles are of this alloy. The older standards of 6063-T4 and T5 are being replaced and we are the better for it. 6060-T6 has a 0.2% yield stress of 160 MPa and get therefor stand up to 60% higher stresses before sustaining a permanent bend. This is good if your rudder stock takes some abuse from time to time but it also measn you have to excert more force to permanently bend it yourself. Just as a comparison steel typically has yield stress limits in teh range of 300-750 MPa. So it should not be too difficult to bend these alu profiles.

Often the standard sections are not anodised but unless your stock are permanently submerged in salt water they don't need to be either. Especially not for your first try. You'll get several years of surface out of these just the same.

Wouter

Simon - I have to disagree with you there.

The Viper at Zandvoort was derived from well established Capricorn f18 platform & foils with the rig & sail plan taken from years of knowledge from AHPC's involvement with Tiapan 4.9's here in Aus.

The viper sailed 2 races at Zandvoort & was on the pace from the start as was expected.

Our Blade was hindered by the fact our mainsail had never seen a mast before the event & we paid the price. Hence a luff round alteration during the regatta in time for the long distance race. The change made us more competitive, but still room for improvement.

talking about rigs and sails, was just wondering if there was any chance the F16 website could be updated with a list of available sail makers for the F16 class? So far my experience has been with Goodall sails, but i'm also really interested to find out the difference between all the sail makers.

Out of interest, does anyone run mixed set of sails? ie ashby main, goodall jib and GP spin, stuff like that? how do you guys find what the right comb is and tune your rigs for the different interactions between the different sails? Reason i'm asking is because i was thinking of experimenting with a kite that is flatter than the current goodall kite (i'm really happy with the current one, just want to experiment) and was wondering if you guys have any good sail makers for flat kites to recommend?

I think we need some more volunteers to work the website for the class. The PR group has already made significant improvements especially with the multiple languages, but there can always be done more.

With respect to sails. I think a good number of F16 boats sail with mixed sails. Most often the jib and mainsail are of the same maker and the spi is of another. But I haven't been able to find recurring theme in these mixed setups. Most Ashby sails owners have a spi from another as Ashby is/was not yet comfortable with selling a spi of his own design. However, all sailmakers have gone through a period of F16 sail development and results from the past may not have any bearing on what can be expected from future purchases.

From personal experience, the Landenberger spinnaker appears rather flat and with a straight leech, much more then my 2003 Goodall spi.

Wouter

We love new contents for the website! Everything from creative writing to tech stuff like flat kites etc. Just get in touch with me or the PR group to have it published (Gary "twicebitten", MarkP, Gill, Kathleen).

For downwind work the spi is critical. I would be happy with any good "upwind" main while going downwind.
For upwind, I have had good results mixing different sails. The best jib we ever used on the Tornado was from Landenberger (normal luff length). This fitted well with our homemade/FCA main. The interactino between selftacking jib and mainsail is not critical (yet) in my opinion, unless you are optimizing your sails and rig for a special event with known weather conditions. Even then the best of the best make the wrong calls sometimes. Like going to China with special sails for light winds.. I guess what I am trying to say is that the performance gain available is so small that it is not worth investing time and money there unless you are very, very skilled in the full game.

hey Rolf, let me see what i can do from the Singapore side. Maybe Scott M and I can start generating some articles etc for the site. If you want to PM me an address i'd be happy to send u a cd of some F16 sailing here in singapore. or perhaps if you have a ftp site or something.

I think short of an national association, this is what we in Singapore can do for the F16 association. Unfortunately, I don't think we'll be able to find anyone who wants to set up an association. In tightly legislated Singapore, there is a massive amount of protocol, paper work and accounting once an association is set up. I doubt the fees from a F16 association in singapore would even be able to pay the certified accountant for the annual reports.

But thanks so much for the info. I'll look into the landenberger kites

I'm on my third F16 kite which is a Grant Piggott, the previous 2 being Ullman and Landenberger. As much as I like the Landy from my personal experience I find the GP faster. Now all I've got to do is learn to sail in the upright position as this is faster still <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" /> At present advertising space is best left on the tramp. Well that's what my friends tell me <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Mark,

I did wonder if that picture would appear....


I agree that the GP sails kite is quicker. When Grant and I were talking about building it we decided that flat would be faster overall (but harder to trim consistantly, but we decided that the trade-off was worth it). I'm still learning how it works properly and I think it will be very halyard tension critical. Too little in big winds and it does not set, too much in light stuff and the leach twists away and the luff will not set at all.

I'm still fiddling with Battens in my GP mainsail. More info when I have worked it out but so far I am sailing with a lot ofd tension in the top 4 battens to support the leach as the downhaul comes on.

So everyone is voting for the GP kite? anyone have experience with the goodall spin vs the GP? it's kinda interesting that in last weekend's race, we were running a newer goodall kite that seemed a little flatter than the older goodall kites and the boat with the flatter seemed to go better downwind, so i was wondering what happens if i got an even flatter kite than my current goodall.
Wouter, what do you feel is the difference between the landeberger kite and the goodall kite? was the flatter kite faster for you?

If you have money to burn, try contacting Gran Segel in Malmø - Sweden. They revolutionized the Tornado spis in 2002 when they supplied Martin and Kristian with their design before the worlds in Marthas Vineyard. The same spi have been the class standard since and did very well in China this year. They will be happy to make a F16 kite based on their Tornado and F18 experience. Contact Claes Hirseman at claes at gransegel.se and talk with him about your boat and what kind of conditions and sailing you do.

A flatter kite is faster becouse it have less drag, if we simplify a bit. On a boat like the Tornado and F16 which both have power to burn this makes them faster (in my opinion). But you will reach a point where the VMG dont increase anymore as you make the kite flatter (ref: the US teams kite in China). Kite design is not easy, there are a lot of variables there.

That is also interesting info.
How do other sports, clubs, ect get around the red tape ?

Tony, with regards to sports clubs/associations etc in Singapore, they either tend to be National associations ie Singapore Sailing, or if they are country club, sailing clubs etc, they tend to be registered as private companies. I know in Australia you guys have like the 16ft skiff club and lots of really small clubs and associations. it doesn't happen here. Oh yeah and many of these clubs that are registered as private companies require less red tape. Associations, ie in the case of F16 association here in Singapore, are supposed to be non profit and thus the government keeps a pretty close eye to make sure that is stays a non profit and the money is being used correctly etc. I was suggesting to the local F16 dealers here that our F16 association could be registered as a private company to bypass the red tape but i'm not sure how the international association would take to that.

Have you asked?

Wasn't there also some clause that allowed F16 sailors to become members of the international F16 organisation directly in such instances. I mean when very strickt local rules or insufficient local size of the fleet prevented the creation of the local organisation ?

Will be more difficult to arrange for a major F16 event in such a situation but at some point you have got to weight tho pro's against the con's.

This may also be a way around the issues.

Wouter

I agree with you Rolf & believe one of the variables is having enough shape in the kite to start with....its a balancing act.

I also believe the gransegal kite are a smoother shape than most other T kites because they have many more panels in the luff of the sail.....hence controlling the shape better.

FYI - a aussie comparison of costs in 2004 was $2,200 for a gransegal kite & $1,350 for most other locally made kites. Big difference.

Marcus,

I suppose that price was for a Tornado kite?

Next kites we do we will have to try something like that. More panels in the luff, glued construction (I'll never forget stitching the yellow spi! What a mess with seamstick in my Pfaff and not enought time before we had to leave for the regatta!), flatter shape, design the entry for about 45degs and add a bit of twist to the shape. With our three identical boats we should be in an ideeal position for testing the shapes. That is, when they are finished..

Ckuang had another great race on Sat. He and Scotty McCook were a long way ahead of the rest of the fleet, but managed to beat Scotty by a minute. Scotty is quick, and Kuang has only recently jumped from the A to the Viper. Good to watch the 2 sail downwind. Both had different techniques which was interesting to watch.

Hey TaipanFC, nah, I think your downwind was a lot more interesting than mine. Didn't know you had to go so far forward on a foiling moth but you looked really really fast. My next singlehanded boat will probably be a moth rather than an A class unless they start to allow foiling A classes <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

As far as my downwind technique, can't say there's much to it right now. I'm stil trying to figure out the secret of downwind on the viper. much easier to figure the boat on the upwind, but down, not so sure. Tried playing the sheet downwind this weekend and found that by letting the mainsheet off a bit it really helped to power up the rig some. couldn't really see the benefit of playing it like crazy like they did on the tornado finals race but maybe need more testing.

This weekend should be great. Back to windward leewards again. Much easier than passage races and easier to compare speed etc.

Still trying to figure out the secret to really really great downwind speed.

funny thing is viper is so precise as a boat that even a few millimetres here and there on the downhaul, rotation, outhaul, etc, seem to make a huge difference to the boat so finding the exact right combi is really hard but definitely for the guy that can pin it down, the speed is amazing.

You are getting the right idea for downwind. It is almost like going wild downwind on the A, constantly working the main in conjunction with your steeting. Working the main is to help keep the drive forward in the kite and being able to work deeper and keep the apparant forward. Keeping the main cleated the whole time means you raise the windward hull too much and lose the ability to drive lower faster.

Have to stay forward on the moth as you need to keep your weight over the foils. Back too much means you increase the Angle of Attack and the bow lifts too much and the whole thing ventilates and decides to dive underwater quicker than a submarine. Lot more to think about for sure, but that was the fourth weekend sailing it, so getting better for sure.

hmm interesting info on the moth. But doesn't the moth have some trim tabs on the rudder to compensate if your weight is too far back? In that case, how come they dont make the racks further forward? Sorry if this is goin OT on the thread, but seeing the moth just flowing through the fleet of boats was very beautiful.

Foil on the rudder is manual and the angle is adjusted by twisting the tiller extension. Lot quicker to react by moving your body, plus with 30kg boat and me being 70kg, my weight is a big part of the boat on the water. Still learning about these foils and angles etc. Lot to think about for sure.

I can't say that I agree here.

Wouter

Wow, you agreed with me!

Thanks I made a typo : can => can't


I've found that my Taipan F16 sails plenty fast and deep with my main cleated; it is just that you have to get your steering right. Meaning to bear-off/head-up before the gust hits/leaves. Besides this is the only way to do it when solo under spinnaker.

But even 2-up we seem to get the best downwind speed by going deep with sufficiently good speed with a cleated main.

So basically, I think that assuming their is correllation between cleated main and deepness that it is at most and very weak correllation. In most instances too weak for most F16 sailors out there to justify them forgetting about leaving the main cleated.

Wouter

To say you cant agree with someone is not the political/social approach to take. <img src="http://www.catsailor.com/forums/images/graemlins/smirk.gif" alt="" />

Rather I think you should state your experience is otherwise.

I personally have a different view to your Wouter. I believe the boat is less "choked" when the helm has the ability to ease the traveller a little with bear aways & then back to near centre when chasing the "grove" again. But obviously this is difficult to do when sailing 1 up. <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" />

So Wouter, do you actually sail? Your comment really shows a lack of experience in some ways. I agree with Marcus, working the main means it gets less choked. And one of the other posters in another thread quoted something similar from the current F16 GC winner John Pierce in respect that the sails don't know which way you are going unless you trim them in the correct manner.

he sure does sail!

I found out on Sunday that he was in the REM race, didn't see him though..

Wow, I stand corrected. But pics?

how did you go in the rem race?

Pics or it didnt happen <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />
http://www.rbossink.nl/nam2008.html
Results: http://www.wvz.vuurwerk.nl/uitslagnam2008.html
Here he is at the briefing somewhere:

there he is.....looking the wrong way mind you!!! <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" /> <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Sort of like spot Wally/Waldo isn't it? Thanks for your help Marcus! <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" /> Bonus points if we can spot Macca?

Halveway in the F20 and F18 fleet (25th out of 47); about the same as last year when I was solo, but this time the proper F18 crews were about.

I sailed as crew on a F16 owned by a fellow club member. We are quite pleased with this result. We have only sailed 5 times together (incl. these days) this whole season and this is about all of the sailing either of us did the whole year. We expected to do worse because of it, especially since the beam reach under spinnaker of the first 15 km really doesn't favour the F16.

We also started on sunday but we had to retire in the first race due to a dislocated shoulder of my skipper; no fun I can tell you. I had to climb over him to reach the tiller and mainsheet to prevent the boat from capsizing and gave him some additional hurt that way. I figured that going over was worse in this situation then causing him some more pain. Now you also know the reason behind the DNF, DNS and DNS for the second day. I have got to admit though I've rarely seen a guy so though and pain tolerant as my skipper; he never blamed me for making the least bad choice in a bad situation.

I see Macca did really well in final results. Still doesn't mean a darn thing when its comes to engineering though.


With respect to the other comment; if you hull raises to high under spinnaker then you have turned down too late. You can correct this of course by letting out some mainsheet but you can also learn to spot the gust sooner and take quicker steering action. For any solo F16 sailor this skill is an absolute must for lack of manipulators at the ends of your arms. I found the same skill really helps when 2-up requiring much less mainsheet sheeting. Result same downwind speed and depth but achieved by a different path way this time with the main cleated. Hence my earlier disagreement.

Wouter

Ummm, were we talking about engineering here (and specifically in this thread)? It is a cat sailing forum for those with interest in cat sailing.

But everytime my race results are investigated on the forums the next stage is always a stab at my public comments in the engineering field. This time I thought it smart to pre-empt this.

I have always said that I'm not a top cat racer as I have never aspired to be such a person. My claim to fame is engineering. Having said that, I'm not a bad cat sailor either; I still seem to reach mid fleet status in a serious fleet without doing any amount of training or making nearly sufficient hours on the water (especially this year; less then 10 hours before the NAM-REM). More often then not I use old or homebuild equipment as well.

That will be it from me.

Wouter

So why so few times sailing this year then Wouter? If you have the passion, you make the time, its possible. Specially when in Summer in Northern Europe it is daylight for so long and sailing is possible long into the evening. I know I certainly make the time to go sailing.

What is your point?

I have sailed just three times this summer, and I am about as dedicated as they come to high performance catamaran sailing. When you go at Wouter like that, you hit others as well. This eternal bickering gets tiresome, from all parties.

Rolf, gotta remember, no tone on the internet. Your interpretation a lot different from my intention. My question was of interest, not of attack.

Didn't we cover this a few months ago ?

I'm completing a research assignment with respect to very large scale wind turbines remember ?

The kind that are placed off-shore in windparks like these :




Working on the control flaps to increase fatigue life of blades and bearings by counteracting the aerodynamic disturbances; called the Smart Rotor Concept.





Although you have to ignore the flaps near the root of the rotor blade, these are pretty useless and have been disgarded a long time ago. The two flaps near the end are still in the project.


This project is consuming large portions of my energy and time. 6 more months to go. Simply put I got other things on my mind.

Still, I don't see myself get much better at racing cats though. I'm not really interested in putting in the time and effort to reach the top; Besides the level of cat racing in the EU is pretty high so reaching the top requires a considerable amount of time and effort. I'm also gethering the years so to speak. The time for dreams in the direction of top sport has passed for me; I expect to mainly sail and race recreationally and I can do that well enough with the skills I have now. The future belongs to the younger sailors among us; from now on I simply want to enjoy myself.

Wouter

Thanks for clearing that up. I reacted like I did becouse those "rounds in the past" is bad both for the class, PR wise, and the crowd here at Catsailor.
I have not sailed this summer becouse I dont have a boat, and the only cat available is certainly not high performance. Suits me well as I have been able to think a lot about my sailing and do some stuff around the home. The "great wall of Molde" is what Marcus have taken to calling my summer project.. <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" /> Lost 8 Kgs in the progress and almost got my handstand as well. Next year I certainly hope to be able to sail a lot more, like 3-5 days a week). There is sunlight until 2300 in summer, and it dont ever go really dark.

Marcus,

Don't you increase the drag by opening the main, when bearing away? And don't you loose pressure by doing it also?

Gill

I am not Marcus, but I'll have a go anyway as I am stuck in front of the computer.

1: Drag and force are not linearly proportional to each other over sails.
2: We must try to make the sails produce as much power for as little drag as possible, in the direction we want to go.

By opening the main you decrease the drag, and direct the force generated more in the direction you want to go, in my opinion.
More pressure is not always to the good if what it do is generate more drag and a force in the "wrong" direction.

Perhaps Marcus has some better way of explaining, or a better point of view <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

I agree you need to easy the mainsail a little when bearing off.....

Consider.

1, Gust hits, you accerate
2, As you accelerate you sheet in a little and the hull lifts (you may or may not sheet in)
3, As the hull lifts, you bear off, what happens to the apparent wind? It heads aft and so you need to sheet off a little.

I just sail a F16 solo downwind with enough mainsheet tension to protect the mast. However, I find it better/easier with enough wind to keep the windward hull flying higher than usual, it looks better in the photo's for starters and the other reason is because (and I'm sure to be corrected) I feel that it produces more buoyancy in the leeward bow! To me it feels as if I've changed a displacement hull into a plaining hull by the heel of the boat.
Fire away...........I also capsize (occasionally)
I'll probably answer the sail, drag question the day before I hang up my harness which I hope wont be for a long time <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Hey everyone, just wanted to let you guys know there is more updates on the website at

http://boatsbikesboards.wordpress.com

on the latest prebend settings for the Viper.

We're really going towards a much more powered up rig on this boat as the width of the boat and the power of the downhaul seems to allow us to do that and still sail within a really wide range of conditions. Greg has also been moving towards a much more powered up setting for his viper.

Gill, with regards to opening up the main with the kite up, I can't really explain the aerodynamic forces, however, over the weekend, we experimented with opening up the main and easing the spin off about an arm's length while bearing off downwind (once the hull was already flying and there was a good bit of apparent wind) and we found that we could bear off and go deeper for a longer time before having to head back up to generate more apparent wind.

I actually found that by easing the main at the right time helped to power up the rig and keep our hull flying downwind. Hope this helps.

So what kind of reduction of fatigue are you looking at? And this increases the life by how much (guessing still estimation)?

Would those flaps do anything for us at the rear edge of our mainsail <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

Exactly what I would suggest doing.

My area of responsibility lies in the control flap actuator design (using Shape Memory Alloys); other people are looking at the effects of fatigue reduction. Additionally, the right controller has a large impact on the achieved results; this is the job of yet another person. We are a group of people who at this time are specializing in our respective area's. Last year a setup was placed in the low speed windtunnel and even with a very simple PID controller the smoothing effect was quite dramatic. There is a movie available that shows the before and after, but as all within this project it has not been cleared for publication without authorisation. Same with respect to the data we have achieved.

Basically what I'm trying to say to you here is that theoretically the effect can be quite significant as supported by initial real life tests in much simplified (windtunnel) tests, HOWEVER, there are some serious issues to be solved in the area of the flap actuators and the also the multivariable controller. When the later is not implemented correctly then the system can actually increase the loads and reduce fatigue life. In my case I need to boost as very inexpensive and simple SMA actuator to much higher speed and accuracy; this to avoid installing any expensive and complex hydraulics or pneumatic systems.

The data you are looking for is sadly not available yet with sufficient accuracy as that would require a real-life test setup comparable to the turbines being installed now. We are still some ways from that.

My reply has to suffice at this; both to limits in what we know now and agreements of confidentiallity.

I'm sorry,

Wouter

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

This is the kind of information, while generaly correct, can get you in trouble or at least make you slower if not used properly.

Keep in mind that if you want to sail fast down wind you are trying to maintain a constant apparent wind. In which case the main sail trim will not need to vary.

The biggest mistake I see with new spin drivers, is that they head up until the hull rises, then bear off til it comes back down. This technique almost always results in over stearing and huge fluctuations in your speed. On the 16 if your hull comes up without a noticable increase in speed your weight distribution and or trim are not correct. On the 16 you need to move your weight around a lot. The acceleration is what you are trying to achieve, not the lifting of a hull.

Also be very aware that buy easing the sheet or traveler in conjunction with bearing off in a gust, you open up the sail and present a big flat area of sail dirrectly in front of the wind 8.5 meters up in the air. This is the perfect recipe for stuffing the bows in every big gust.

Thanks Wouter. One of the funds I work for does a lot of wind investment in Asia so interesting to hear of new tech. Lot of stuff coming out of India and China for sure.

And I second that !

Wouter

Well, certainly 2 schools of thought here. I sailed Taipan 4.9s sloop rigged and A-Classes. Going wild downwind is standard behaviour. Means you have to work hard to keep the apparant forward. Moving to kites I found it easy to cleat and forget the main initially. But after a while (and with a gd crew) played the main similar to the T49 and A and found good increases in speed. Especially in conditions where there isn't enough wind for the crew to be out on the trap.

Probably all down to the technique of how you steer and react to the gusts.

I do not agree that you are trying to maintain constant apparent wind. You are trying to go as fast as possible and as deep as possible. As you accelerate the first thing that happens is that the apparent wind moves forward, thus you need to (maybe) sheet IN. If the hull rises (it may not) you then need to eaither let some sheet off, or bear off. IF you bear off, the apparent wind moves aft, thus you may need to sheet out, but as you bear off, you may continue to accelerate and so you may NOT need to sheet out.

What we are trying to do is stay at max speed and also drive down on any gusts which allow you to sail DEEPER and FASTER.

IF I had 3 hands I would hold the tiller, play the kite and play the mainsail downwind. As I only have 2 hands I have to compromise and so I cannot play the mainsail down wind very much and so it has to be cleated.

Your comment



is not how I see it. When I've been sailing 2 up (Hurricane 5.9) and the bows dive in, the quickest way to get the bows out was to easy a few inches of mainsheet - this opens up the top of the mainsail and dumps a little bit of power just where the most torque on the bows is coming from. This is what I think Bundy was doing in the onboard video from the medal race at the ollies, ease the mainsheet to pop the bows out of each wave they went into.

This is actually the core of the discussion really :




I would say this sentence is imcomplete as


.... thus you need to (maybe) sheet IN or BARE-OFF

As the latter moves the apparent wind back to the original angle for which the sails were trimmed, avoiding any need to adjust the sheet tension.

Basically you can keep the apparent wind angle to the mainsail constant by changing the course of the boat and indeed sheeting the spi. That way you can optimize the performance while having only two controls in your hand instead of three. Of course when doublehanding your have 2 times more hands and can do more. Personally I only played the mainsheet traveller when 2-up to cut-off a rapid rising of the hull when I was too late steering.

Wouter

You could write 5 books on how to do this. Nothing is ever straight forward, at least technique witten in a single sentence. I have seen a lot of new guys (myself included) get distracted by procedures like playing the main down wind.

FASTER is the goal. The DEEPER part only comes from bering off in order to maintain a more constant apparent wind. My take on this is that the proper technique for maintaining you weight placement, and your steering are by far the more important functions for going fast. Playing the main sheet is a very fine adjustment (so you keep your back stay pressure at a min) and while, if done correctly, will help, is way down on the list of skills to master.



This is OK --BUT -- The typical reaction by the driver in a gust is to bear off. This moves the apparent wind back, add the nose diving and the boat slowing down and it goes back more. Let out you sail top and you are going swimming. Note Bundy was maintaining a forward apparent wind, and by easing his sheet and letting off some top he was doing as you say, but this was only sucessful, becuase he had forward apparent and he did not attempt to bear off.

Even if some or even most get it wrong the first times around (or until somebody takes them onboard and shows them), I think it is important to share advanced ideas and techniques. Knowing there are better ways to do it is very valuable when trying to improve. All new techniques takes time on the boat to get right, but getting this kind of impulses and feedback on our forum is part of what makes our F16 class so good in my eyes.

Wouter, your sentence is incomplete <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />

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

Matt,

There are many theories & none of them necessarily right or wrong & each sailor does need to explore their limits.

Maybe experiences are best shared.....

Why dont you share what occurance caused your big nosedives in the first two windy races at the Zandvoort GC races where your transoms were pointing at the sky.? <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />

I'll never forget one of John Pierce's quotes;
'The mainsail doesn't know that you're going downwind'
Think about it.......it makes a lot of sense considering the amount of apparent wind which can be generated when sailing a F16 sensibly.

Thanks Marcus. <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" /> My multiple swimming experieces at Zandvoort were exactly why I was posting to this thread. I'm light and if I twist off the main in a gust where the apparent wind goes aft, it is not possible for me to save it, generaly making my crew very unhappy.

I know there are a lot of techniques for each person and boat set up that will all work, and I did not mean to make it sound different. Just adding my caution from some big wind bad expereinces.

M

Hey Matt, what was the windspeed at Zandvoort? The reason I'm asking is that i just also wanted to put in a disclaimer about my experiments with the main and kite.

We found on the Viper that the "get the apparent wind going, bear off, ease kite and mainsail and drive lower but keep hull flying technique" good up till about 13-14knots of wind speed. Once the wind speed hits about 15 knots, the viper becomes a whole different animal altogether. Our experience with the viper in about 15 knts with the kite up is that the boat starts to plane just like one of those high performance dinghy and we don't really sail it like a conventional cat anymore. Every time a gust hits, the boat just keeps accelerating like on a skiff and the nose has no inclination at all to dive, as such we just focused more on keeping the boat flat and on a plane rather than going for depth and flying the hull as the loss of speed and distance of the boat coming off a plane and getting it back on was just too great.

To achieve this we focused more on playing the sheets of both the main and spin than trying to steer the boat down for distance. I'm not sure if this is the same for a blade hull as we seem to have more flat section than the blade hull but certainly different wind speeds also seem to require different technique.

Perhaps other Viper sailors or perhaps a F18 capricorn sailor might be able to chime in and explain what I'm talking about because i know the concept of a planing cat is still a little odd in some ways. Or maybe i'm just imagining things <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

Ckuang,

I think an even more important disclaimer next to wind would be waves. The wind speeds at Zandvoort where around 19 knots, waves betwee 90 and 110 cm.

The waves made if very difficult to accelerate and keep speed -> apparent wind changed constantly and big gusts hit you from the back.

On the Blade you really need to get the hull flying in bigger winds to my opinion (just not sure yet on how to generate enough wind without steering to high). If you fly a hull you just can't stuff the bow anymore in gusts. If you sail it flat, you stuff the bows easily when bearing off.

Gill

Spin picture

In my experience the technique for sailing with the spinaker is different for singlehanded and 2 up.

One thing that remains the same though is that you steer the boat for max VMG then trim the sails accordingly.

In non hull flying conditions this is about 'feel' and the only way to get this is with experience

For hull flying conditions it is a bit easier,

For single handed, sit on the windard hull set the traveller in the middle, then set the main so that the top leeward tell tail is flying most of the time (80% will do)then cleat it and forget it it, a bit of experience will tell you where to put it, but don't fiddle with it just sail the boat with the rudder and spinaker.

Then steer and play the kite to keep the hull up. Keep the steering small as the rudders act like brakes, let the hull fly up and down quite a lot so that you can avoid big rudder movement.

Since the steering is the most important (you cannot loose the tiller) and you must hold the spinaker sheet in your other hand you can do no more.

For double handing it's much easier, position the crew between the lower hull and trapezing, moving them up as the wind increses, 2 extra hands means the helm can play the main as well as steer, just use one armfull of sheet to smooth out the steering, (steering is slow so try to do the minimum) the crew can also smooth out the gusts by moving a small amount in response to gusts and lulls, every so often look up and check that the leeward top tell tails are still streaming, it's better to be under sheeted than over sheeted.

Remember though the speed comes from the steering in all conditions KEEP THE RUDDERS AS STILL AS YOU CAN!!

Sounds like my experiences John.

I would just add, that the last thing you want to be doing is playing the main sheet when you are on the edge <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" />. If you ease too much main the flow in the head will stay or become attached as you bare away causing the bows to drive down. When you are on the edge you want the head of the main to stall as you bare away so it depowers. This is why cleating the main works. Playing main is only for when you are looking for power. <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />

hey guys, much more experimenting over the weekend with sailing the viper downwind with the kite up in a local regatta with about 10 cats on the water, 8 of which were in the F16 configuration. 1 other taipan4.9 and one nacra inter 17

Scott McCook our local cat guru has added a whole lot of updates on downwind sailing and mast rotation for anyone who's interested. The blog can be found here

http://boatsbikesboards.wordpress.com