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    • UnderDawg

      A Few Simple Rules   05/22/2017

      Sailing Anarchy is a very lightly moderated site. This is by design, to afford a more free atmosphere for discussion. There are plenty of sailing forums you can go to where swearing isn't allowed, confrontation is squelched and, and you can have a moderator finger-wag at you for your attitude. SA tries to avoid that and allow for more adult behavior without moderators editing your posts and whacking knuckles with rulers. We don't have a long list of published "thou shalt nots" either, and this is by design. Too many absolute rules paints us into too many corners. So check the Terms of Service - there IS language there about certain types of behavior that is not permitted. We interpret that lightly and permit a lot of latitude, but we DO reserve the right to take action when something is too extreme to tolerate (too racist, graphic, violent, misogynistic, etc.). Yes, that is subjective, but it allows us discretion. Avoiding a laundry list of rules allows for freedom; don't abuse it. However there ARE a few basic rules that will earn you a suspension, and apparently a brief refresher is in order. 1) Allegations of pedophilia - there is no tolerance for this. So if you make allegations, jokes, innuendo or suggestions about child molestation, child pornography, abuse or inappropriate behavior with minors etc. about someone on this board you will get a time out. This is pretty much automatic; this behavior can have real world effect and is not acceptable. Obviously the subject is not banned when discussion of it is apropos, e.g. talking about an item in the news for instance. But allegations or references directed at or about another poster is verboten. 2) Outing people - providing real world identifiable information about users on the forums who prefer to remain anonymous. Yes, some of us post with our real names - not a problem to use them. However many do NOT, and if you find out someone's name keep it to yourself, first or last. This also goes for other identifying information too - employer information etc. You don't need too many pieces of data to figure out who someone really is these days. Depending on severity you might get anything from a scolding to a suspension - so don't do it. I know it can be confusing sometimes for newcomers, as SA has been around almost twenty years and there are some people that throw their real names around and their current Display Name may not match the name they have out in the public. But if in doubt, you don't want to accidentally out some one so use caution, even if it's a personal friend of yours in real life. 3) Posting While Suspended - If you've earned a timeout (these are fairly rare and hard to get), please observe the suspension. If you create a new account (a "Sock Puppet") and return to the forums to post with it before your suspension is up you WILL get more time added to your original suspension and lose your Socks. This behavior may result a permanent ban, since it shows you have zero respect for the few rules we have and the moderating team that is tasked with supporting them. Check the Terms of Service you agreed to; they apply to the individual agreeing, not the account you created, so don't try to Sea Lawyer us if you get caught. Just don't do it. Those are the three that will almost certainly get you into some trouble. IF YOU SEE SOMEONE DO ONE OF THESE THINGS, please do the following: Refrain from quoting the offending text, it makes the thread cleanup a pain in the rear Press the Report button; it is by far the best way to notify Admins as we will get e-mails. Calling out for Admins in the middle of threads, sending us PM's, etc. - there is no guarantee we will get those in a timely fashion. There are multiple Moderators in multiple time zones around the world, and anyone one of us can handle the Report and all of us will be notified about it. But if you PM one Mod directly and he's off line, the problem will get dealt with much more slowly. Other behaviors that you might want to think twice before doing include: Intentionally disrupting threads and discussions repeatedly. Off topic/content free trolling in threads to disrupt dialog Stalking users around the forums with the intent to disrupt content and discussion Repeated posting of overly graphic or scatological porn content. There are plenty web sites for you to get your freak on, don't do it here. And a brief note to Newbies... No, we will not ban people or censor them for dropping F-bombs on you, using foul language, etc. so please don't report it when one of our members gives you a greeting you may find shocking. We do our best not to censor content here and playing swearword police is not in our job descriptions. Sailing Anarchy is more like a bar than a classroom, so handle it like you would meeting someone a little coarse - don't look for the teacher. Thanks.
    • B.J. Porter

      Moderation Team Change   06/16/2017

      After fifteen years of volunteer moderation at SA, I will no longer be part of the moderation team. The decision to step aside is mine, and has been some time in the works but we did not wish to announce it in advance for a number of reasons. It's been fun, but I need my time back for other purposes now. The Underdawg admin account will not be monitored until further notice, as I will be relinquishing control of it along with my administrative privileges. Zapata will continue on as a moderator, and any concerns or issues can be directed to that account or to the Editor until further notice. Anyone interested in helping moderate the forums should reach out to Scot by sending a PM to the Editor account. Please note that I am not leaving the community, I am merely stepping aside from Admin responsibilities and privileges on the site.

Doug Halsey

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Everything posted by Doug Halsey

  1. I find it pretty strange that you're using the past tense & referring to Moths as "ancient foilers." The class is doing just fine in many parts of the world, and the boats & foils continue to evolve. Nevertheless, I'm curious about Gacking too. I know it has been done in the Moths, but I wonder how common it ever was & whether its use has diminished as the best sailor's ability to do foiling tacks has improved. It would be pretty incredible to see one of the AC teams pull it off though!
  2. The SpeedPuck (like the other Velocitek products) stores a file that can be downloaded to a computer & analyzed in software like GPS Action Replay to display the boat's performance. If Tom would make at least one of the Astus's files public, that would help a lot in evaluating his speed claims.
  3. When I tried to get insurance from BoatUS for my Moth (3 years ago) , they told me they wouldn't insure any boats with hydrofoils. Try Gowrie Group.
  4. Sorry about that! I know the 14's are great boats & I'm glad to be wrong in this case.
  5. I don't think you'll come across many I14's in San Diego, but we've got an active & growing bunch of Moths at Mission Bay YC. Currently ~8 Mach2's & several older BladeRiders. 6 mph would be a very light-air day; more typically around 10mph or more in the afternoons. Enough for >20knot boatspeeds most days. Lots of fun! And rotating masts & other innovations are definitely allowed.
  6. You don't have to consider cant angles & leeway to find examples where having a slight V can be advantageous. It's an established fact (backed by both experiments & numerical calculations) that the induced-drag efficiency factor improves as the angle of V increases. At higher speeds, the increased wetted area & possibly sooner tendency to cavitate make the V foils have more drag. But at lower speeds, the induced drag becomes more dominant, often resulting in smaller total drag. So, it's not really surprising that the light-air foils might have more of a V shape.
  7. From the Racecourse description: "Please note: Racecourse orientation and length may vary based on wind direction & strength." So you can bet we'll see some shorter courses in lighter winds. My question is whether there is any minimum length for the course?
  8. And might some of them already be prepared to do that?
  9. Since the helmsmen can control the foil incidence, shouldn't they be able to help avoid this situation in the future by learning to reduce the AOA whenever they round up?
  10. I'm not sure exactly what the research shows, but you only mention generating more lift. So, what about conditions where the boat is fully powered up & they need to trim to minimize drag?
  11. +1000!
  12. I do appreciate your comments & was just making a lame attempt at a joke. I'm not really as grumpy an old man as I sometimes seem.
  13. I think Estevie Norman must be another name for Steve Brewin, but WetnWild is also telling us he's part of the same inner circle.
  14. I doubt if these diagrams are the results of any calculations. They show the magnitudes of the forces to be the same for the upper and lower wing sections, giving an exaggerated picture of the importance of the tip. In reality, the upper forces should be smaller, by an amount that depends strongly on the wing's planform & twist distribution (as well as other details of the shape).
  15. When I 1st read this, I thought you were just misspelling "Okoume" & was surprised you could find it at a big-box place. But a little Googling showed me I was wrong & there actually is something called "Okuma." Can you tell me how they compare?
  16. Those are all too slow to stay on the foils, aren't they?
  17. When I click on that link, I get my videos again & it gives the following as the url: https://www.youtube.com/my_videos?o=U They must have folders with the same names several places, making it tricky to know the right one to paste into your posts. I don't entirely understand it either.
  18. I watched the 1st video & was especially interested in the portion after about 5:15, when the boat is on starboard tack & you can see the wake from the forward foil sweeping aft & sometimes impinging on the aft foil. At times some spray from the rudder/aft foil is visible above the crossbeam, but it doesn't seem to correlate with when the forward wake hits the rudder. Are you aware of any effects from this kind of thing? I was going to let you know that I've made some crude attempts to get videos of the same phenomenon on my Moth, but I see from the 2nd link that you already know that. It's interesting to read about your experiences with the S9 & to watch the videos. It looks like you're having lots of fun!
  19. Since the very concept of hull speed is all about wave drag, zero wave drag implies no hull speed (or perhaps infinite hull speed). Exactly! Instead of "extraordinary," maybe I should have said "impossible", "absurd", or something stronger. But I don't think Amati wants to hear it. I do want to hear it. But FWIW I was one of those unfortunates who couldn't replicate the Millikan Oil Drop experiment and paid for it. So when I say, as I did, that models are an opinion, I actually meant it. Granted, my argument was an appeal to authority, while yours seems to be 'it's just a pile of shit.' Which is basically what self appointed enforcers were doing with the Oil Drop Experiment. Resistance isn't all wave related. I think skin friction is resistance too? Am I wrong in thinking that waves are a result of a hull (in this case) displacing water at a speed? And waves exist because of the gravity interface between water and the atmosphere? Different hull shapes create diffferent waves, and different resistance- if that is the case, it seems a little arrogant to proclaim a truth that something is true based only on supposition. Hypersonic flow does exist. Large Boats do plane I think your assertion is a very practical one based on current knowledge. But if I was willing to actually build a model, and try it out based on what I have at hand, other that your impatience with my apparent stupidity, why the condescension? I'm not denying physics- I'm trying to understand physics in a more personal way. I'm sorry if I came across as arrogant & condescending. I only intended to point out a couple of matters that I thought were well-established (not my personal suppositions). In any case, we shouldn't let that distract from the more interesting questions concerning proas, and I hope your experiments will help shed some light on them.
  20. Since the very concept of hull speed is all about wave drag, zero wave drag implies no hull speed (or perhaps infinite hull speed). Exactly! Instead of "extraordinary," maybe I should have said "impossible", "absurd", or something stronger. But I don't think Amati wants to hear it.
  21. You've probably heard the expression "Extraordinary claims demand extraordinary proof." It would be pretty extraordinary if someone could design a hull with zero wave drag at its hull speed. What's the extraordinary proof? That the code developer used to work at Boeing? That your boat could sail with a keel that he designed? That you built a cool boat? I don't think so!
  22. Your software indicates zero wave resistance at hull speed??? And you aren't skeptical about that??? I figgered that Dave made an assumption about supersonic flow around a bluff body, but Joseph Norwood did that same thing in his book about fast sailboats- especially trimaran outriggers at higher Froud (sp?) numbers. So skeptical me builds a 16' by 36" hull with the Vacanti modelling software (hey, it's what I have), and the wave propagation was going down a bit (by eye at least) at higher speeds. I don't know what to make of it. I'm skeptical of assumptions in mathematical constructs, but pressure field activity, mathematically, is beyond me. In my own defense, I keep reading masters theses about where modelling logic can spin it's web, but it's still a new discipline, and does represent an opinion, in a very sophisticated sense. E. B. White might agree? Any analogy between supersonic airflow and waves in water is only superficial & there's no reason to think it might be useful for any sailboat calculations. There are other codes available that solve the actual equations of interest (the Michlet code, for example) . But regardless of what code you use, a result like zero wave resistance should make you wonder what went wrong.
  23. Your software indicates zero wave resistance at hull speed??? And you aren't skeptical about that???
  24. The original Emma Hamilton certainly was a work of art!