• Announcements

    • 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.

svendson

Members
  • Content count

    237
  • Joined

  • Last visited

About svendson

  • Rank
    Anarchist
  1. Thanks Laurent!!
  2. For safey, we have Gerber River Shorty's on our PFDs and in the cockpit. Don't find folders to be adequate for emergency situations. Also like that the sheath has no moving parts or springs to rust. Thus far have had zero issues with knife retention in the sheath, despite having it mounted handle down on my left side for easy right handed access. Price is quite reasonable at about 40 bucks. One of 4 knives has a couple small rust spots after 4 years of use, otherwise all good. For rope work I use craft knives or ceramics and just chuck when dull. Would love to get a Boye, just haven't managed to get past the eye watering price.
  3. A smooth lee side isn't necessarily the be all and end all of wing mast trim. This is the approach advocated by, among others, Tom Speer in his paper (from 1993 as far as I can tell) "Aerodynamics Of Teardrop Wingmasts" and was based on the assumption that eliminating the leeward side separation bubble would yield the best performance. Mr. Speer has more recently (2015) updated his philosophy, concluding that optimum L/D is more relevant to sailboat performance than maximum outright lift. http://www.boatdesign.net/forums/hydrodynamics-aerodynamics/sail-aerodynamics-457-42.html#post746097 http://www.boatdesign.net/forums/hydrodynamics-aerodynamics/sail-aerodynamics-457-43.html#post746622 Under-rotating a teardrop mast can be a good thing, compared to rotating it to the point where the lee side forms a smooth contour. It's common for there to be a large separation bubble behind the mast on the windward side. When the mast is under rotated, you can get a modest separation bubble on both sides. The two smaller bubbles can have less drag than the one large one. For each angle of attack or lift coefficient, there is a mast rotation that produces the minimum profile drag. It's only in the neighborhood of 6 - 7 degrees angle of attack that the smooth lee side profile (blue curve) has the best performance. Less mast rotation is needed at lower lift, and at the highest lift the mast needs to be over-rotated from the smooth lee side condition. I've attached plots of the pressure distribution and boundary layer displacement thickness for each mast rotation, taken at the angle of attack that produces the best lift/drag ratio for that rotation. This isn't exactly the same as the envelope of minimum drags, but it's close. What's interesting is the location of the stagnation point is very similar for all of these cases. It's near the leading edge, a little to the windward side. The extent of the separation bubbles varies quite a bit across the range, so going by telltales on the sail to judge the size of the separation bubbles is not going to be a good guide to trimming the mast. But something that indicates the stagnation point location will be a consistent guide to the best mast rotation.
  4. Goes "like a raped ape" to coin one of the owner's sayings (about his tuned Harley). Between the extremely light weight of this particular boat and the wing, it is possible to sail under glass conditions. Cigarettes then come in handy as the way the smoke drifts is key to getting the wing trim right. Top speed to date is about 23 knots, with a bunch of big farm boys crowded against the aft beam. With the L/D ratio the rig puts out, the water ballast in the stern was an upgrade that was absolutely needed for racing 2 or 3 up in anything over about 12-15 knots. The new float bows don't add a whole lot of volume, but they do shed water much more easily than the original flat deck, making the boat significantly more forgiving to push hard. The usual challenges for these kind of large chord rigs apply when docking or raising/lowering the mast in crosswinds. Not ideal for anchoring either. But, horses for courses, and given how this boat has been used thus far since launch, the wing is absolutely the right rig to have on it. Could have been made lighter with more careful engineering, and even lighter again by doing molds from scratch rather than re-using the XOZ F28 mast molds, but as trackday points out the benefits gained in improved vessel dynamics are hard to quantify while the lead time and cost for the aforementioned improvements are not.
  5. Nice RM! Looking forward to some of your great commentary bringing this edition to life. I can't help but feel that, barring an absolutely perfect weather window, we are going to find out just how far this bigger is better approach to solo multis can be pushed. I just hope no one gets hurt.
  6. This is sailing anarchy. We talk about whatever we like wherever we like. If you want orderly stick to topic no criticism or comparisons you are in the wrong place. Start a raw 30 fan club if you like. I guess you must rein yourself in a fair bit on other online groups and let it all out here because you are being a wee bit of tosser. You can, as you say, do as you will here in SA. So can everyone else. Criticising others for posting whatever they want (such as requests to stay on topic) in the midst of assesrting your right to post whatever you want is about the most embarassing fit of hypocritical nonsense I've seen anyone suffer in quite some time. We get to make the bed we lay in here - if I want flame wars and shit fights I can go to AC anarchy. I come here to find info on a what I think is a cool boat about which info is otherwise scarce on the interwebs, and discuss it. Now, you can continue the shit fight that you have singlehandedly started and ensure that Tony and anyone else associated with this project never comes back here again, just like Doug Lord and Chris O and so many others have done to so many threads before. As you have established, you are totally free to do that. Or you can just chill out, take my post as the tongue in cheek attempt to pull the thread back on topic it was meant to be, and hopefully some more interesting tidbits will continue to drop. You could even make one of those constructive contributions to the discussion at hand I've seen you make elsewhere.
  7. Jeebus, less Seacart and more Grainger in the Grainer Tri thread! I don't care about an extreme demountable trimaran that was launched and died years ago and that I will never consider owning. When I come to this thread I want to read about the first production folding tri I have seen that has high prismatic floats and the mast at around 50% LOA, and which I just may own one day if my wallet makes it that far. So on topic - according to the Airplay FB website, rather interestingly this is a design originally commissioned by Corsair that they then turned their back on in favor what seems to have been a lower capital investment in the Cruze. Which I am actually quite grateful for. I like the vast majority of the features of the Airplay design but as an owner of a recent model Corsair I find their production quality unnacceptable. Not structurally unsound (so far anyways), but I would never consider buying another Corsair product. Hopefully with Hudson behind it, the production quality will be solid. Unfortunately there is only one photo available without paint or finishing, hopefully they will upload some more with close-up detail if the production is really as good as they claim. Has anyone heard any info on pricing? I reckon that is, as usual, going to be the key to the success/failure of these boats.
  8. Depends. If the mainsail takes the correct shape, the distribution of stress within the sail is correct and whether this is achieved by a more or less vertically oriented mainsheet plus boom, or angled mainsheet alone is irrelevant. However, if you tend to extreme oversheeting of the main in the interest of forestay tension, you will pay a higher price with the boomless setup due to a main that is flatter as well as closed in the leech.
  9. How does a trimaran resist capsize from the pressure in the sails? By pushing the leeward ama down into the water. The amas have a much lower heave response amplitude than the main hull, so any action from beam seas is going to tend to throw the boat onto the leeward ama. So yes, the float rudders probably come out of the waves sometimes. But with far less regularity and far less severity than the main hull.
  10. I have the F-22 rudder. Makes no discernable difference to the situation I outlined.
  11. I only have a little F-24 and I sometimes encounter a swell wavelength and size that leaves me with very little mainhull/rudder in the water, even when reefed fairly conservatively. This usually starts to occur when the sea state is getting to the point where I am steering quite aggressively around the worst waves. If I get a set of these inconvenient waves, the 6-8 inches of rudder left in the water after the first one is inadequate to turn the boat in time for the next wave and the boat ends up getting a pretty hard smack. It can handle it, but I wish I had the control to avoid more of those hits. Wouldn't consider it as a refit, but on a new boat, especially one with substantially higher volume floats than my F-24, I would definitely be pretty interested in figuring out a good system for float rudders.
  12. Umm, Sodebo cut both floats off and moved them 80cm forward.
  13. There are some properties of high prismatic hulls, regardless of application, that are fairly well known and accepted. They include: -Lower Cr (wave making drag) at high Froude numbers (high speeds). -Increased longitudinal metacentric height. This mean better longitudinal stability at small pitch angles. As long as the prismatic stays reasonably high (ie one end or the other doesn't get submerged or lifted right out), this is true for larger pitch angles as well. Importantly, the area under the longitudinal stability curve goes up, meaning more energy is required to pitchpole. -Increased pitch and heave damping -Increased heave and pitch accelerations -Increased wetted surface area for a given displacement. The last two points are pretty clearly disadavantages for most kinds of boat. The rest strike me as pretty clear advantages for sailboats, especially for ones of the Super Race variety. And probably most serious racers can and do choose to live with the short, jerky motion of the boat as a tradeoff for the increased performance. Many multihull designers around the world seem to have arrived at the conclusion that a high prismatic ama is worth the trade-offs for a racing boat. More recently, with the French in particular, ama design seem to be working on combining a slight bit of rocker for low wetted surface area at low ama immersion (and thus low heeling moment and low speed) with a high prismatic shape at high immersion for high speed performance. The MOD70 and the Multi50 Fenetrea Cardinal (ex Crepes Wahou 3) are pretty good examples of this latest trend. John Shuttleworth observed from tank testing in a paper from the 80s (available on his website) that the transom stern designs of the French boats carried a drag penalty at all speeds and decided to go with a pintail shape for the Ostar boat he was designing at the time. It has been shown time and again that looking at any one variable that contributes to sailboat performance without considering it as part of the system as a whole can lead to suboptimal design (as Ian himself has highlighted). The pin top elliptic roach mainsails of the late 80s and early 90s are a good example of this. Yes, the elliptic profile has the least induced drag. But, it also has the largest root bending moment for a given lift. And so, on a moment constrained system like a sailboat, it is in fact a shape with more induced drag which is best. Maybe this is what has happened with the pin tail ama, or maybe the majority of the industry has bought the hype of the F40 and Orma 60 eras and worked it's way into a suboptimal corner of the design space. Either way, given the dominant trends that can be observed across the field, I believe it is perfectly reasonably to question of one of the few designers who is bucking the trend on a Super Race boat. The weight of the majority doesn't mean the odd guy out is inherently wrong, but it is natural to wonder why he or she has made the choices she has. To give an ad absurdum type example, if a team showed up to F1, Nascar, or any touring car championship with a 3 wheeler, you would very likely be quite interested in hearing why. As can easily be seen on many of the photos floating around the internet, the F-85SR ama is not a high prismatic shape - although it may well be the highest of any F-boat to date. In particular, it is the rocker and v-section shape in the aft part of the hull that gives the biggest reduction in prismatic coefficient. So, it is also quite reasonable to focus on that bit of the hull which is most obviously bucking the prevailing trends. Of course, adding volume in just the stern would affect the longitudinal balance of the boat and as the F-boats are generally pretty good, this is not terribly desireable. And so we get the explanation from Ian that helps it all make sense - in his opinion there is no acceptable way of putting more volume in the bows. And thus more volume in the stern cannot be offset and the running trim of the boat would be compromised. Ian, I sincerely wish your last post had been your only one on this particular subtopic. It was educational, informative, and addressed the subtopic in a positive and professional manner. As far as not being able to get more volume up forward goes, I hold your opinion in high esteem so I am willing to accept that at face value. A folding, road legal trimaran is sitting in a very highly constrained corner of the design space so I imagine fairly small changes in the SORs would have a large influence on what can be achieved in the final design - sacrificing some interior space for higher prismatic amas for example. I think some of the noise being heard around here could and probably should be interpreted as a very small market demand for quickly folding, single purpose racer done to the well known and respected Farrier quality standards, rather than a criticism of the existing design for which the dual purpose SORs have been made very clear. Given your long standing and well advertised disinterest in single purpose raceboats, it is probably a slightly useless piece of market feedback. But then again, depending one's particular outlook and motivations for sailing, it could be argued that labelling a dual purpose design as a Super Racer is a bit of a misnomer as well.
  14. I got in touch with the Multihulls direct guys about the Farrier options they have - extremely fast, clear, and frank replies every time. Pricing came out pretty much in line with what I estimated self building to cost. I figure that makes sense. They are in a very low cost country, buying in bulk, and I am in a very high cost one, buying at retail. Everything I have learned from previous builders also indicates the you very rarely save much money in the end, you just spread the payment period out over more time. Personally, I suffer from an odd dementia where I would like to build a boat just for the sake of doing it. But, if life keeps getting in the way like it has been the past few years, then I will very likely end up buying from the Multihullsdirect guys when I've saved up enough pennies and get my building fix from something smaller like an F-16 or an A-cat.
  15. Hole. E. Sheeit! Pure boat porn, that is what I am talking about!