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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.  

MultiThom

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About MultiThom

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    tpdavis@yahoo.com

Profile Information

  • Location
    Benicia, CA
  • Interests
    Trimaran sailing. Currently own a Triak and have a SeaRail 19 ordered
  1. I enjoyed reading this. A technical questions...how did you decide on the shape and length and twist on those ama foils and how do you actually construct them...doesn't look easy. When I looked at the F101 stuff, it struck me funny that the design boat size and performance level was about the same as Corsair Pulse 600-with a lot less of a learning curve to sail it (and more payload).
  2. That's right. It is just a sheave with attachments at the ends. I can make it for myself for under a $100. What's interesting is that it can convert ANY continuous line furler into a top down furler (look at the costs of those, they run $2K). But, the guys who've posted before have a point...how many folks need to go deeper downwind than they already do with their asymspins that have the furling line stitched into the luff? Frankly, most folks aren't experienced enough to know that something like this would help. I figure about a 20 degree difference in gybing. I need it because I need to keep in the shallows against a 3 kt current and that means gybing every 100 yards or so.
  3. It's not the carbs, it's the gas (at least here in CA). The regulators require so much junk in the fuel that it gums up a naturally aspirated machine. I've taken to stopping the gas flow to the carb and letting the engine idle until it dies...works for me. OBTW, check your gas cap vent...my engine does that routinely (run 10 min then die)...won't relight until I open the gas cap.
  4. The rating folks for this race (Leech Lake Regatta) assigned the SeaRail 19 a D-PN (PY) of 63. The racer who sailed it is Bob Bilger who is a very experienced sailor, so, at least in capable hands, the SeaRail 19 can do well with a PY of 63. The race conditions were BN 1 on day 1; BN 3 on day 2 and BN 2 on day 3.
  5. That's the same sort of argument folks used to convince themselves that the pig cars GM was making in the 60s were the best you could do. Then Toy and Dat came across the ocean. Everything got better once there was competition. Cars now last more than 3 years...cars get better mileage...Now folks have moved most of their multihull production to China and VietNam...do you think that Harken and Ronstan will survive if China decides to get into the market for marine hardware? They might, but not by charging a boat buck for a 50 buck part. You see it already in less expensive snap shackles. 15 years ago I had to pay 50 bucks for something I get now on eBay for 15. I'm just kvetchin' that simple bearing races surrounded by aluminum or stainless is easy to produce and need not cost a boat buck.
  6. OK, good one. Not everyone is upset spending boat bucks for things that cost pocket change...I get it. But it irks me.
  7. No, I wouldn't charge that much because it isn't really a low-volume part if they marketed it correctly. Also, I would point out (as I just did) that you can MAKE YOUR OWN very cheaply. Nobody owes me nuthin' but marine hardware costs more than it should--we are getting ripped off. This particular piece would take about a half hour to design using CAD and could (don't know that it does) use most of the pieces from a single line furler which they retail for $100 or so. Probably costs $50 to make or less.
  8. I've gone out of my way to learn alternatives to high priced marine stuff. But sometimes there are things that just irk me. 15 years ago I needed a top down roller furling spinnaker. At that time, only Roll-Gen made them and they were way overkill for my F242. So, I figured out what I'd need by reverse engineering what I saw in their promotional video. Step one was a continuous line furler--OK, Facnor made one I could afford. Step 2 was an anti-torque line. Gotta say, that took some doing but I finally ended up sheathing some poly line in plastic tubing--it wasn't the most flexible, but it did the job. Step 3 was something to keep the tack steady while allowing the antitorque line to twist. Basically it is just a ball bearing sheave with eye's attached to the axle. I made it from a bicycle wheel hub and welded eyes to the axle. Here it is, 15 years later and there are still no reasonably priced parts to convert a continuous line furler to a top down furler (item 3 above). The parts exist...in fact Ronstan RS220060 would do the job nicely...wanna guess how much they want for something that is just a sheave? $1120. Like I said in the title, we are getting ripped off if it goes on a boat.
  9. Boat (not mine-mine is near Mecca today on a container ship) participated in a race over the weekend and finished well. Attached is a photo showing its finish. At first, it looks just like a becalmed lake, well zoom in and you can see the rest of the fleet. So, we know the SR can deal with light breeze.
  10. Sorry you had such a crummy weekend. Do you really need 5 hp? I know the boat weighs a ton (literally), but if you lake sail and don't need to get anywhere fast, it'll probably need less than 5. I like my Honda 2.3 (air cooled so you don't have to flush after each sail). It has its issues (like no reverse and the vent cap doesn't vent very well); but starts right up every time which is what I need it to do. I have heard good things, as well, about the propane outboards.
  11. I am curious as to how the twist is derived. Is it just vector sums? So in the windward case, the boatspeed is 13kt, the windspeed is 13kt coming from 45 TWA (FAST BOAT!). SO the AWA is 22.5 and AWS is 24. Assume that's top of mast. SO bottom of mast is seeing same boatspeed, but TWS of 10.2 (80% of top of mast-assuming you believe the folks who design wind turbines) and AWA is 19.6...so twist needed is 22.5-19.6 or 2.9 degrees...did I do that right?
  12. We sailed the weta in those conditions most of the time. If you are solo put the sheets in the most forward hole until you feel safe with it; if you have crew, we used the back holes with impunity. The boat owner went out often single handed in that and higher wind...full wetsuit. He didn't use the big downwind sail, though, with wind above 20. If you are going to be single handing often in big wind, you might consider getting a reef put into the mainsail.
  13. Absolutely true. If you want an exercise machine for the water, get a mirage drive kayak. If you want to sail, though...
  14. I went ahead and calculated the % wind seen at different heights along a 40 ft (12 meter) mast using the normal air value of Hellmann's constant. At the base of the mainsail you'll see 80% of the wind seen at 10meters and 102% at the top of the mast. So in 10 m/s true wind (about 20 kts) at 10 meters above the boat, you see 8 m/s (16 kts) at the boom and 20+ kts at the very tip top. Those are the TWS...you'll actually see the vector sum of boatspeed plus TWS on the angle of attack. In stable air the differences will be more pronounced (Hellmann's constant would be 0.27 instead of 0.1). Very unstable air would be even less at 0.06. Which is pretty much what FrankB said, the more turbulent the breeze, the less twist you need.
  15. You know he didn't actually measure the windspeeds to create those graphs, right? When I saw that in his book I wondered why there were 4 different lines for each condition; then I figured he was just illustrating what it might look like. We do know today, though, that there are methods to approximate true behavior for engineering needs. I found it interesting that wind gradient is considered in wind turbine design which leads one to believe that there is need for adjust twist for modern tall masts, but that wikipedia article I mentioned above also says there is a reduced wind gradient over water as compared to over land. You might want to use the equation it provides and check your twist calcs under different stability conditions over water...just for fun. https://en.wikipedia.org/wiki/Wind_gradient It also introduces an additional term of air stability which I think we've all experienced...some days the wind is "all over the place" with vortices and eddies in 3D; some days you can pretty much count on a steady breeze. I've never sailed as fast as you guys...at most I reached 18 kts downwind and occasionally 15 to weather. Never considered twist and when I built mainsails or jibs for my boats, I normally did not create twist as part of the design-mostly because I didn't race much in laminar winds. Funny though, the sails all did have twist simply because the fabric tension transmitted through the mainsheet went through the leach (My sails were not square tops) and the differences in drag through the height.