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      Abbreviated rules   07/28/2017

      Underdawg did an excellent job of explaining the rules.  Here's the simplified version: Don't insinuate Pedo.  Warning and or timeout for a first offense.  PermaFlick for any subsequent offenses Don't out members.  See above for penalties.  Caveat:  if you have ever used your own real name or personal information here on the forums since, like, ever - it doesn't count and you are fair game. If you see spam posts, report it to the mods.  We do not hang out in every thread 24/7 If you see any of the above, report it to the mods by hitting the Report button in the offending post.   We do not take action for foul language, off-subject content, or abusive behavior unless it escalates to persistent stalking.  There may be times that we might warn someone or flick someone for something particularly egregious.  There is no standard, we will know it when we see it.  If you continually report things that do not fall into rules #1 or 2 above, you may very well get a timeout yourself for annoying the Mods with repeated whining.  Use your best judgement. Warnings, timeouts, suspensions and flicks are arbitrary and capricious.  Deal with it.  Welcome to anarchy.   If you are a newbie, there are unwritten rules to adhere to.  They will be explained to you soon enough.  

Erwankerauzen

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About Erwankerauzen

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  1. Moth Developement

    Thank you very much Phil, Happy week-end and fair winds. Best regards. Erwan
  2. C-Class Little Cup news

    Hi, Re-reading this thread I wanted to notice how the above-mentionned remark can be information-rich: It provides me with a great explanation, regarding the discrepancies I systematicaly exhibits, as soon as I compute A-Class figures with datas reported on forums or from "parking conversations": 1-From righting moment, apparent wind velocity & wind angle + rig aspect ratio, it is possible to get a rough idea of the driving force , using only a basic hand computer( Mine is HP 12-C from 1983) 2-On the other hand we can compute all drags (aero+hydro), using well recognized proxy equations and coefficients. So if everything would be correct, we should be able to "reconcilate" the figures and get: 3- Sum of all drags = driving force (@ constant speed) But to actually reconciliate these figures, I have to "cook" the friction coefficients to their lower theorical values , same for platform aero drag....crew drag on trapeze and so on.. But if actual boat velocities were slightly lower, so would be the drags (more than proportionnaly) , and would fit pretty well the computation of the driving force. A SAILING ANARCHY thread could be dedicated to build polar curves for hitec boats (C-Class, A-Class Moth..GC32...) and be could be helpful for the whole community... with a dedicated moderator and his... dedicated Excel Spreadsheet.... Happy week-end everybody Erwan
  3. Moth Developement

    I am looking for average dimensions in order to compute the righting moment when the boat is foiling. As the boat heels to windward, I need the the distance between the foil and the gooseneck or the sail foot; Does nt matter that much. Good proxies would be perfect,; it is not about 1 or 2 cm. I will be travelling for the next days and be back saturday. Best regards Erwan
  4. Moth Developement

    Hi Moth Sailors, If somebody could provide me with a simple figure I would be very happy. I have no Mach2 near home at the moment, and I would like to know the vertical distance between the horizontal "wing" of the main foil and the sail foot or boom gooseneck, in sailing conditions or maximum cunningham tension. Thanks in advance Erwan
  5. Moth decksweeper and lowered mast stumps

    Phil S Thanks for these interesting comments, I am not a Moth sailor yet, but I am very interested with the Moth developments. So regarding the end plate effect; Intuitively, I though it was most effective where there is the biggest pressure difference between windward and leeward sides of the sail: so in the front part near leading edge. But it seems my intuition is wrong, Have you any extra comments to help me understand Thank in advance Erwan
  6. C-Class Little Cup news

    You are perfectly right WetSnail, but I made the bet that as the C-Class are a little faster than the 18/20 feet boats, and as lift is proportional to Velocity squared, I guess that 10% in extra speed would translate in + 21% extra lift for the same foil (both lateral & vertical lift). Regards E
  7. C-Class Little Cup news

    Smart comment Sam, Displacements with 2 men crew are similar for Nacra 20 =Phantom=C-Class, so it seems logical they could share similar foils even if righting moments are different. Just like for gennakers, which are not usefull because C-Cat are quickly overpowered by her huge apparent wind, since they have foils, 2/3 elements wingsails might be a too big engine for these apparent winds. That is why when it comes to wingsail for cat foiler, I would look for single element wing which aims primarily to minimize all drags. Happy week end EK
  8. C-Class Little Cup news

    Thanks Sam for taking time to write this long post and feeding the ongoing debate. A C-Cat wing is around 40 feet long and 60 kg heavy, so it requires special care. for a 17 kg 14 sqm soft wing for instance, a stainless hinge as provided by Greg Goodall for decades could make it for one person rigging. I mentionned vinylester to illustrate that concentration of stress and strain on one little piece (main crossbeam) could "ultimatly" allow low tech for the hulls whitout giving up stiffness. The leading edge of this large mast is smartly designed, unfortunatly, I am afraid that its inability to twist, would offset other advantage, especially downwind. Cheers
  9. C-Class Little Cup news

    You are right on every points, But a wing is not always a 2/3 elements wing like for C-Cat, it can be a single element wing/soft sail with a morphing section, as we do not need huge HP in the section, because we have high apparent wind The weight of the main tube for a wing like the one designed/Build for an A-Cat 10 years ago/ 7 m long/ was around 4.1 kg.(Thanks to HALL SPARS) The wing should be as crash proof as existing rigs, otherwise no future, I agree. But is easier to achieve with a morphing structure, which is flexible in many points, than with stiff symetrical wing sections arrangements. I feel confident a clever guy will suss out a solution if there is some significant performance pick up to be expected. Cheers
  10. C-Class Little Cup news

    Well said Sam, You should add, that the main advantage of a wingsail are not only in the aero issue. A wing does not need a pulley block on the rear beam so: 1-Foiling tacks and gybes should be easier. 2-No more stress on the rear beam with the pulley block and long leech requiring high load to be flat enought(=little twist) for apparent wind when foiling windward. 3-Moving some area in front of the mast rotation axis, allow to move the foil accordingly and it increases the wheel base and narrow the high load area of the platform between foils / front cross-beam/ shrouds /lateral stays. It should be reasonnable to expect new generation A-Cat with removeable cross-beams from the hull. (After all, GroupamaC was not a one piece boat, and she seemed stiff enough to foil with a reasonnable stability in many wind/sea conditions.) ............and a splitted wing in order to be able to pack a bunch of boats in a 20 feet container and minimize carbon footprint for transport, as this issue will come sooner or later. Overall these new A-Cat generation will be made of a strong main cross-beam which will bear most of the big loads of the (foils + mast foot + lateral stays) so the use of the best technology will be concentrated on a "little" part of the platform instead on the whole platform, while hulls could require only basic technologies as an A-Cat hull has enough inertia to address the front stays' loads at the bows and rudder winglets' lift at the back with fiberglass/foam sandwidch/vinylester. So a wing could lead to cheaper boats could it ? In order not to be off topic, I could have presented this point differently: Can GroupamaC be a benchmark for the future of the A-Cat ? Cheers
  11. C-Class Little Cup news

    Pierre Jean, Do you know if, as you did with Fred Eaton, the groupama team has been open to share their design ? That would be a great step toward another bright future, for instance. When I was at Falmouth in september 2013, the only team which locked its door to maintain confidentiality on their boat, was GroupamaC, So they did not meet exactly the "Open Source" spirit which was among the traditional values of the Little Cup. For sure Cammas brought the cup to a new level, but as he had to comply with his sponsor requirements, he was managing a business more than attending to a sailing competition. If he refused to give his useless wing to ETNZ after the capsize in the cup, it is probably because Groupama has no interest in developing its insurance business in Kiwiland. So as you can see the LAC has changed a little bit. I met Remi for the first time in 1986 when he was trying to work for Le Maout and his Formula 40. Next time you have time for a beer in Paris let me know by PM. Best Regards EK
  12. Foils

    NorthSea Junkie, On your video, you pull the cunnigham when the boat is on the beach with the wind probably coming from the front , then you turn the boat around 90° and pull it to the water , so it seems wind and waves are not in the same direction allowing you to gain speed before to have to climb the waves. Just like A-Cat Sailor, Iwould not be especially afraid to sail my A-Cat in this venue. IMHO, the issue is not to take off from the beach, it would be probably more challenging to come back on the beach with a "fragile" boat like a A-Cat or "fragile" devices like T foils at the bottom of your rudder blades. To land safely my former A-Cat in these sea conditions, I used to turn the boat in front of the waves, lift and secured very well the rudders in the up position, put the main sail traveller in the appropriate position to have the sail foot aligned with the wind while the bows are facing the waves, then I went on the windward hull in front of the front cross beam, it helps lifting sterns a little bit above the water and I let the waves bring me back to the beach in reverse mode (the sterns first). The issue is you get a free shampoo for each wave, but more important the line or system which secure the rudders in up position must be very reliable because when you are going backwards to the beach in the waves, you cannot go back at the transom to raise again your rudders. Main sail traveller position is important to help you to maintain the bows in front of the waves . Hope it can help Best regards EK
  13. Foils

    Thank you Mr Clark for bringing a more Cartesian rational analysis of the winglets Thank you too Team GBR with your I14 experience, both help a lot to have a better understanding. Northsea Junkie, you should not be discouraged: In order to start from the beach in breaking waves with T foils at the bottom of the rudder blades , you might have to change the package including the rudder casing with vertical movement instead of pivoting movement for the rudde blades. Depend also where the wind is coming from, and the waves size, sometimes it is possible to walk in the water until deep enought for the rudders down, push the bow downwind, jump on the windward hull and lock the windward rudder first, get some clearance from the beach and waves before to tack and lock down the second one. In this case you can use winglets at the bottom with the same casing and rudder blades it is probably the cheapest solution to prevent pitchpoling. As precised by Mr Clark with winglets at the bottom, the windward one remains in the water when flying a hull while it is not the case if positioned higher on the blade. In addition, if the Prindle 15 paltform twists a little bit under rig loads the windward one might have the bigger effect. Best regards EK
  14. Foiling Monohull - what would it look like?

    At 40 knts boat speed in 25 knts TWS The apparent wind speed when sailing windward @ 40 knts would be around 60 knts So Mates, you must hold firmly your Sailing Anarchy caps (model Hill Billy is my prefered one)
  15. Foils

    Pat, I think A-Class Sailor means that if the winglets are not at the bottom tip of the rudder blades, they will not increase the effective aspect ratio relative to the geometric aspect ratio with the same efficiency. AFAI Understood the Bieker effect: Even with the winglet at the bottom of the rudder blade like for International 14 skiff*, the low pressure at the top of the winglet (positive AoA and hence lifting force oriented upward), combined with the change in pressure under the hull, due to the stern wave (we are talking about monohull planing dinghies), contribute to a lower hull drag. I guess , at least for I14, the winglet has a multiple role: 1-Provides positive lift in most normal sailing conditions. 2-Contributes to a lower stern drag in the same normal conditions 3-Prevent nose diving as soon as the boat starts to pitch with a negative AoA * Not sure, but for I14, I think the winglet span is not that different from stern width To be sure we should post something on the SA dinghie forum, and ask skiff's specialists. Cheers