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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.  

Doug Halsey

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Everything posted by Doug Halsey

  1. 2018 moth worlds - bermuda (march 25 - april 1st)

    Some preliminary racing in Florida a couple of weeks ago... http://usmothclass.com/2018-us-nationals-recap-struble-wins/
  2. Moth Foiler & Back bone issue

    Phil: I know that Chris Rashley had a serious issue with his back just prior to the 2015 Worlds, but was still able to compete & place very near the top. Do you know more precisely what his injury involved and what he had to do to cope with it?
  3. Super foiled configuration

    Here's another moderately successful attempt with bow mounted foils. Gary Seaman (who also sailed sailboards in California) won a speed-trial against the D-Cat Beowulf in about 1972. That was in fairly light conditions (but still foiling). The boat was quite a handful when it blew harder though.
  4. EC2018 Thread

    CCock & DeSea aren't shown as having made CP2 yet. They didn't skip it, did they?
  5. EC2018 Thread

    WaterTribe: https://www.facebook.com/groups/440773022707818/
  6. Everglades Challenge 2018

    https://www.facebook.com/groups/440773022707818/ http://www.watertribe.com/Default.aspx
  7. Can we save Portsmouth handicap racing?

    Like this? (Figure from Ian Ward)
  8. SuperFoiler Grand Prix 2018

    So far, they're not entered. https://www.regattatoolbox.com/entryList?eventID=WYEX9X6zFL
  9. C-Class Little Cup news

    That's pretty funny! I do happen to be a retired aero engineer with some CFD experience (not that it makes any difference). I'm not sure why Erwan was admonishing me to pay attention to your posts; I thought we were saying essentially the same thing.
  10. C-Class Little Cup news

    Are you sure you're computing the speeds correctly? Your saying "Sum of all drags = driving force (@ constant speed)" makes me doubt it, since the aero & hydro drags act in very different directions & cannot be simply added. I also think you would need something more powerful than a hand-held calculator to do the calculations. Even the relatively simple VPP's that I've written require several hundred lines of code.
  11. Moths in Annapolis/DC

    Maybe you could ask at one of these sites, or directly email the officers:
  12. Wing Sail Design

    Thom: I don't think that max lift is the desired condition very much of the time (even assuming that the boat isn't overpowered). As you mentioned, it doesn't give max thrust (except for apparent wind angles of 90°). At smaller apparent wind angles, I think a lift coefficient somewhat larger than the value for max lift/drag, but smaller than max lift, would be the aim. The attached figure illustrates how a solid wing can be better than a soft rig in that range. It was taken from a paper by Sam Bradfield, analyzing the results of the last Little AC won by a soft sail. http://vm2330.sgvps.net/~syrftest/images/library/20160306205859.pdf The solid wings of that era had simpler hinged-flaps, so the newer wings with slotted flaps should have an even greater advantage.
  13. 14' Stunt S9 Foiling Cat

    This is also just a guess: If the boat is allowed to slow down too much prior to the gybe, the apparent wind angle can change quite a bit. Having more twist ensures that at least part of the sail will be trimmed properly, in that case. Of course, it's better to maintain as much speed as possible during the gybe to keep the apparent wind forward. If that is done, the boom does not come across violently; it's more like a tack in light-air.
  14. Wing Sail Design

    I think you can download AMO's paper for free here, but you have to sign up 1st: https://www.scribd.com/document/81116884/High-Lift-Aerodynamics
  15. Wing Sail Design

    Here's a link to the Scherer article: http://mararchief.tudelft.nl/file/39710/
  16. Wing Sail Design

    I think the max-camber location is probably less important in a multielement wing, at least partly because the boundary layer gets to start fresh at the leading edge of each element. The best starting point for understanding the theory is probably still AMO Smith's 1975 Wright Brothers lecture. I couldn't find a link to a free download (yet), but this more recent reference summarizes part of it: http://www.dept.aoe.vt.edu/~mason/Mason_f/HiLiftPresPt1.pdf Some interesting experimental data for models of actual C-Cat wings were published by Otto Scherer in Marine Technology. I'm also still looking for a link for that.
  17. Foils

    I'm getting one of these:
  18. Moth Developement

    Since you're asking about older Moth designs, you might be interested in this: http://www.mothboat.com/ Nothing much about scows though, since there weren't many of them in the US.
  19. Origin of VMG as terminology

    Apparently Einstein was a big fan of his too, calling him "the greatest mind in American history," according to this biography: https://www.aps.org/programs/outreach/history/historicsites/gibbs.cfm
  20. Moth - adding bladder to tramp

    I think that learning to sail the Moth is difficult enough without adding to it by going without the bladders. Apparently, even some big names in the Moth World agree with me. Chris Rashley describes them as "absolutely critical" in this link https://www.youtube.com/watch?v=m4OWY1MgZIU And Nathan Outteridge praises them in this one: https://www.youtube.com/watch?v=FlQi0Vxh1-w
  21. Foiling Moth Setup

    I'm sure you've found several helpful videos. Here's a good one (even though it's over a year old) showing one of the more complicated setups. You don't necessarily need all the same gizmos, but it might help you understand more of what's going on.
  22. Astus Upwind

    Dashware doesn't have to take such a long time. If you start your video with a short segment showing the GPS time from your cellphone, the sync step takes almost no time at all. And if you only overlay the data on short segments of the video that you want to include in your edited version, that doesn't take long either. Here's one of many short clips I've made to help evaluate gybing technique on my Moth (Note: this is not me; it's someone who knows what he's doing).
  23. VPP for dinghies and skiffs

    GPS Action Replay gives an estimate of the TWA. Of course, its accuracy depends on having a big enough sample of data points & how steady the wind actually was.
  24. A-Class North American Championship by San Diego Yacht Club

    Granted, it's hard to say what the most important factors were, but it may not be a coincidence that the only 2 DNA F1's in the fleet finished 1st & 2nd. The attention to detail in the platform aerodynamics is very impressive. In contrast, the 3rd place Exploder was at a bit of a disadvantage, having torn his lower tramps on the 1st day & was sailing most of the series without them. But who can say how big a factor that might have been? And what about the narrower square-tops on the F1's? (See the blue boat in the earlier post by Lost in Translation)
  25. A-Class North American Championship by San Diego Yacht Club

    Just so this thread isn't left hanging, here are the final results: https://sdyc.org/assets/results/results17/a-cat-na-res.htm