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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.  

MountainCat

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About MountainCat

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  • Location
    Colorado
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    A-cats, Windsurfing, Skiing and Trail Running.
  1. Lars Guck won the last three races on a modified Nacra A3 with custom foils built by himself beating Strubles boat with DNA Foils. It would be great to get details and photos of Lar's foils and rig set up. A US manufacturer of competitive A -class foils will be a boon to sailors like myself looking to convert an older boat. Anyone?
  2. No evidence at all. I didn't see any pictures or hear of anybody lifting their rudders up in light weather because they had the cassettes. It is problematic for a number of reasons. First, iot doesn't take much more wind for you to need the rudders fully down, so you need to be 100% confident that you are not going to see a change in wind strength. In reality, if races are sailed in the class minimum wind, you would not choose to lift your rudders. Doing it during the race would give up a fair amount of ground. I really don't see it as an issue. I am interested in why you prefer L foils. I am sure Exploder will sell you them if you want swing ones, but I am not sure why you would buy the Exploder L's when their T's are proven to be faster. It is probably true that the L's are slightly easier to foil with in marginal stuff, but their advantage is in such a narrow wind band that it really isn't worth going with it. I have just spoken to the last person I wanted to check in with before writing anything, so will now try to write a round up from the worlds based on what 4 different sailors have said to me, although the picture is slightly blurred because they don't 100% agree! L foils can be molded in one piece so in theory they should be cheaper with less assembly and finishing labor involved. L foils are easier to protect with a continuous padded sock. In theory, L foils should be faster because they have 2X the aspect ratio having 1 foil tip rather than 2. Of course speed on the course trumps all. I have also heard mentioned that L's are more prone to breakage because of greater asymmetric loading.
  3. I have been trying to tell people for ages that converted boats can be just as fast as purpose built boats. Stevie Brewin did all his training for the worlds on a converted DNA. In addition, his converted Nikita was a weapon. He has won events in converted boats. Thanks Simon for your thorough update. I actually prefer L swing rudders. They seem to be rare. Are there any available commercially? My concern is that in light winds the cassette rudders can reduce wetted surface and may have substantial advantage over swing rudders. Has there been any evidence for that?
  4. What about Mast Flex? Hundreds of A-cat owners (including me) have non-foiling a-cats we are are debating whether to upgrade or eventually replace. The foiling Nikita gives us hope that curved board DNAs, Flyers, Nacras and other carbon A-cats can be successfully upgraded to foiling. It is hard to know the optimal upgrade path. It would be great to hear about the relative success of the latest tech development from the Worlds such as: 1. L cassette rudders versus T swing rudders in light winds? 2. Effectiveness of the short straight traveler in light winds? 3. Thoughts on optimal board and rudder rake? 4. Optimal mast flex with the flatter, tramp seal foiling sails; Bendy masts or a bit stiffer now? Anyone?
  5. MISSED OPPORTUNITY Spectating at the Americas Cup Park was terrible (I was there) with only the bottom third of the course visible and standing crowds at the pier edge with most unable to see clearly because of people standing in front of them.. Why wasn't the 9,000 seat amphitheater positioned to provide good viewing of the race course as well as serving as the concert venue? Oh yes, that would have required smart planning and foresight, apparently both in short supply.
  6. Thank you Dan and the rest of you all for your thoughtful replies on my proposal for a Planing Optimized IC (PO-IC). I don't expect to convince anyone here that it's a better design. I am hoping my boat will be positive proof. I merely want to vet the idea to confirm it's not totally wacky and a waste of time. It seems that at least a few of you think the PO-IC might be fast in specific conditions. Maybe 14 - 20 knots and flat water? In high winds, I think the biggest risk is too much pounding in waves, but I won't know for sure until I try it. The early posts remark how noisy Steve Clark's Josie design was in the waves. For light winds I will make a big effort to optimize the shape for minimum wetted surface and wave making when heeled at 30 degrees. When heeled at 30 degrees, I cannot avoid the hull shape from being quite asymmetric. I am not sure how to think about that. One advantage of the PO-IC is that it will be considerably more stable than other designs with the wide flat sections aft. Not much help though, if it's always too slow. I admit that the semi-displacement narrow designs including and similar to the Chris Maas designs may be very close to optimum for the now existing IC rule; but I am willing to spend some time and effort to see if my ideas have any merit. Already your posts and feedback have me considering several improvements to further optimize the PO-IC design. I think it may be especially important to avoid any bottom curve in the stern flat sections to keep the downward suction force to a minimum. (No sucky time.) I am thinking that I will concentrate all of the bottom curve in the forward 40% of the boat where the cross-sections are curved. In my board sailing, I have compared side by side rockered tail sailboards to straight tail sailboards. The difference is a night and day; the straight tails are very noticeably more low drag and faster while the rockered tail boards are slow to plane and draggy but very easy to turn. I don't think my PO-IC will be "horrifically" slow in light winds if it is properly designed and sailed heeled up on its chine. I think it will be just a small bit slower than other IC's. I am pretty confident my PO-IC will be quite a bit faster than either the foiling moth or the formula boards in 3 to 7 knots due to its longer water line length. FWIW both of these classes with worse light air performance (assumed) than my PO-IC have chosen to sacrifice their light air performance and concentrate exclusively on medium and heavy wind performance. If I am not mistaken, most remarkably, the foiling moths were first dominant in regattas with mixed boat styles and variable wind speeds. Maybe someone with more experience can comment? I don't consider the build risky. If the PO-IC doesn't work satisfactorily, I will just cut off the bottom stern half and fabricate a new one with some curve in the bottom cross-sections. The alternative would be to add sail area and triple the plank length and try to set speed records! ;-) I will try to post my design in the coming weeks. As of now, the design is pretty rough and only in 2D. This is a great discussion by everyone here. I am learning a lot about hull design. Thank you all. M-Cat
  7. I am not convinced that an IC hull optimized for early planning would not be fast in most conditions. Yellow Pages/Macquarie Innovation and the Vestas Sailrocket both use planing hull shapes in their hull pods to achieve speeds over 47 knots; so the high speed potential of planing hulls is certainly there. Formula sailboards are similar in size, weight, sail area and typical expected sailing conditions to new rules ICs. Comparing the sail to weight ratio of a Formula Experience sailboard to a new rules IC with a 75kg helm we get: FE Big Rig: 11.0 m2/ 75 + 15 kg = 0.122 m2/kg FE Small Rig: 7.8 m2/ 75 + 15 kg = 0.087 m2/kg New Rules IC: 10.0 m2/ 75 + 50 kg = 0.080 m2/kg So the IC appears to be in a similar power to weight range at least in high winds when the FE uses the small rig. Another way to look at this data is to observe that the IC is underpowered in light winds and could use a larger light wind sail plan! Of course the comparison above is apples to oranges. The Formula board is likely more efficient than an IC in the following number of ways: Canted rig Sleeved mast Bottom of sail closed off with an effective end plate Single foil with size and shape optimized for wind speed The majority of weight is isolated from hull wave shock by the sailors legs My questions are as follows: Are these Formula board advantages so great that their optimized hull shape has no application to a new rules IC design? Are there no hull shape ideas that can adopted from the optimized Formula board design to IC's? The fastest Formula boards have settled on an optimized design with a width of 1000 mm, a dead flat tail section out to hard chines, little to no tail rocker and sometimes with a cutaway step within 300 mm of the tail. IC's have one advantage over Formula boards in that they have no concern for rocker and rail shapes that facilitate sailor initiated turns by leaning. Formula board bottom shape shown above. Formula boards seem to have a very narrow semi-planing wind range. They go from displacement mode at about 6 knots wind speed to what seems to be a fully planing mode at about 9 knots wind speed. The velocity change through the transition is rather amazing as the board speed can go from about 4k up to as high as 16k with a wind increase from 6k to 9k. The speed transition to "planing speeds" is often assisted by the sailor pumping the sail. The large change in board speed over a relatively small change in wind speed seems to me to be evidence that the board is making a clear "break from one regime to another." Has any one tried building an IC with a Formula sailboard type stern? That is: dead flat cross-sections out to the hard chine and a straight keel at the stern (no rocker). Of course such a design would have a much greater wetted surface and would be slow in low winds just as Formula boards are. Low wind speeds <7k might be accommodated in such an IC design by heeling the IC 30 degrees to leeward in light winds to reduce wetted surface in a similar fashion to how inland scows are sailed. I don't see any reason why an IC optimized for early planing can't fully plane in 9k of wind with the right (bigger) light air rig. My IC designs to date for my upcoming build all feature dead flat cross-sections out to hard chines at the stern, stern widths between 900 and 1000 mm and no rocker or keel curvature in the aft half. What do you think are the chances that such a design might be fast? M-Cat
  8. I found this thread by searching on "planing hull shape sailing anarchy," I was hoping to find information for use in my planned design and build of an A-class cat. As I read through the posts from the beginning my thoughts evolved as follows: 1. I might find something in this thread useful to my A-class cat design. 2. IC's are very odd boats. 3. I am disappointed not to find more discussion about planing hulls. 4. I am amazed by how much the photos of pointy DC's resemble both skeeter ice boats and miniature speed record proas based on the full sized Crossbow I and Slingshot. 5. These DC's are an interesting class. 6. These DC sailors are an amazingly helpful and friendly bunch. (unusual on SA) 7. DC's are amazingly fast for their size and sail area. 8. DC's are much simpler to build than A-class cats. 9. I might build a DC as practice for my upcoming A-class build. 10. This thread has lots of great technical information. 11. I start to design a DC. 12. I print my design and build a paper model at 1/16th scale. 13. I design 2 more DC's and build 2 more paper models. 14. I am definitely going to build a DC. 15. I might try to charter an IC to race this summer in at least one regatta. 16. I'm spending way too much time reading DC posts and researching IC's. 17. DC's are easier to store than A-class cats. 18. DC's are easier to transport than A-class cats. 19. DC's are cheaper to build than A-class cats. 20. I've become addicted to reading DC posts. 21. I don't think I'll build an A-class cat. By now you can probably tell that I've had way too much IC Kool-Aid. By the way, thank you all for your great posts! Oh yes, back to reality. Where can I find the US IC regatta schedule for 2012 and how can I go about chartering a boat for one of them? Just one more IC nut case, Teejay