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Thread: I am making a windvane

  1. #1
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    Default I am making a windvane

    Now, the boat this will go on, is an S2 7.9, which is a fiberglass boat. However, an awful lot of the parts are wood, so I figure that I can post this, here!

    The S2 7.9 has a transom-hung, essentially vertical rudder. There is no skeg. The stock rudder is a kick-up job, but it swivels on a single bolt, which is very substantial. Nonetheless, rudders do snap off, so as documented on this board about 2 years ago, I built a wood core, non-kickup rudder. Here's an S2 7.9 with the stock rudder.



    I'm building the Rudder Head Mount and USD windvane as invented by Jan Alkema. You can read Jan's article about the concept here: http://www.windautopilot.de/docs/alkema/RHM-USD.pdf

    That article is a good read. The late Walt Murray incorporated a USD vane in to his last set of designs. The Mister Vee vane uses a USD vane, and Mister Vee has archived a lot of Walts truly wonderful hand-colored structural drawings like this one.



    So with that in mind, let's get started!

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    Default Re: I am making a windvane

    I'm building this while I'm "Sheltering in Place" here in the SF Bay Area. I'm trying very hard to use stuff I have left over from previous projects, and spending the bare minimum amount of money.

    The first thing I did was glue up the "blanks for the oar carrier and the pendulum oar from that same 2 x 3 redwood that I have access to. There's an empty lot down the street which has this outdoor-grade, "relatively knot free" redwood sitting there. It's been there for YEARS, over a decade, and it dirty but is not rotting. I've liberated a few pieces of it, and used it for things like making an emergency rudder for the Z2, and a new rudder for the Piper One Design.

    So I took some of that redwood and ripped some 1" wide strips together, and edge-glued them with PL Premium Construction adhesive. I love this stuff. When I built the first redwood rudder, the "practice" rudder for the racing rudder I made for the S2 7.9, I glued up some test strips and busted them. The wood ripped up before the joint did. That practice rudder is now an emergency rudder on a Capo 30, that HOPEFULLY will be racing to Hawaii this summer....we'll see what COVID-19 does to the Pacific Cup. Here's the pendulum oar blade "blank" glued up on my garage floor.



    You can also see the oar-carrier off to the left with a couple of clamps on it. The oar is 1" thick, the oar carrier is made from 2" thick redwood, which is the smaller dimension of the redwood I'm using....it's 2 x 3, an honest 2 x 3. The pendulum oar will hang off of the carrier with some dinghy pintles/gudgeons I have in a scrap box of stuff I was give years and years ago.

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    Default Re: I am making a windvane

    Here's the oar carrier....the part at the bottom with the bits set into the main body and not yet sanded. The top part, much the same is what I was going to bolt to the top of the rudder, but in fact I have a piece of aluminum flat stock that I bought a while ago for this very project. Today I'll go get some heavy aluminum L-extrusion and replace that with an epoxy-and through-bolted aluminum one. That will be hugely stronger than the sanded piece I'm showing you here and it might cost all of $12 for the materials...totally worth it. If the experiment works, I'm sure I can use that for the "upgraded" version...IF I "upgrade" at all!

    Last edited by Alan H; 04-02-2020 at 02:55 PM.

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    Default Re: I am making a windvane

    I've spent two evenings shaping the pendulum oar, more-or-less smoothing out the top part to fit the gap in the dinghy pintles. There's a bit more sanding to do. I've shaped the bottom into something like a foil. It's hardly NACA-anything, but the back 1/3rd of the blade is tapered and the front 1/4 is rounded off to something that vaguely resembles an elliptical foil leading edge. Tools were a drawknife (I love my drawknife), a surform plane, my belt sander, and regular old sandpaper.

    Many years ago I built a windvane based on a bunch of Walt Murrays designs. That windvane never worked. The VANE worked, it was the pendulum oar that didn't. I remember motoring out of my marina on my Santana 3030-with the framework temporary bolted/lashed to the back of the boat and the pendulum oar swung out to one side and stayed there, no matter what.. It didn't work at all and I gave up on it.

    I've been thinking about that, and it occurred to me that the oar itself was buoyant. I mean, I made it out of 1x pine. that means that once it's pulled even a little bit out of completely vertical, the buoyancy is going to force it to the surface. That's the exact opposite of what you want, so I'm going to be adding some lead to the bottom of this pendulum oar, to try to pull it back down to vertical, and even things out.
    Last edited by Alan H; 04-02-2020 at 03:27 PM.

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    Default Re: I am making a windvane

    I have some light fiberglass cloth and even about 2 feet x 9 inches of linear carbon fiber around, so I will probably sheath most of the bottom of the underwater part of the oar with some carbon on each side. The carbon will go up to a couple inches above the lower pintle, and down to about 8 inches from the bottom of the oar. That should make it pretty darned stiff. Then the whole oar will get a layer of light 6 oz glass in epoxy.

    for the windvane part, I have some fiberglass tubing, which is leftover from the Highland Games. This stuff is what we use for the weight-over-bar event crossbars. They're actually track and field, high jump crossbars. They get broken a lot in the Games so I "inherit" the busted pieces and use them for various projects. A 10-11 foot length, which is what we use for crossbars, is somewhat flexible, but a 5 foot piece is pretty stiff. IT's a lot like what Mister Vee uses for their windvane posts. It's 1 3/16ths OD.

    To hang the actual air paddle off of the top of that post, I need to make some brackets. So here some stock aluminum from the hardware store that I had lying around, assembled with JB Weld.



    That will get incorporated into a clamping system at the top of the post, which will allow the upper end to be adjusted into the wind. The top of the triangle is where the bracket that carried the wind blade pivot post will go.

    Speaking of the wind blade, I glued one up, last night. Here it is, letting the wood glue set, on the tonneau cover of my truck.


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    Default Re: I am making a windvane

    More to come over the next few days!

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    Default Re: I am making a windvane

    Thank you for the photos, nice build, I always wanted to see the making of one of this devices.

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    Default Re: I am making a windvane

    I just blew up my budget at the metal warehouse and hardware store, on aluminum stock and s.s. nuts, bolts and screws. $14 for the stock, $54 for the s.s. bits and bobs. OUCH

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    Default Re: I am making a windvane

    Hey this looks great! For your transom-hung rudder, I would have opted for a trim-tab self-steering device, but you do you!

    One caution: since you're building your pendulum oar from wood, be very careful that it ends up symmetric. We have a home-built wooden pendulum-style wind vane (it's the Hebridean), and a slightly warped pendulum oar introduced a slight bias in the steering that gave us fits for months. Really kind of miserable to be baby-sitting the self-steering all night on passage.

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    Default Re: I am making a windvane

    I shall watch this with interest.
    ​"Life is under no obligation to give us what we expect." Irrfan Khan. RIP

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    Default Re: I am making a windvane

    The reason I didn't do a trim tab system is that I race this boat on San Francisco Bay A LOT. I didn't want to be hauling around the trim tab for two racing seasons before I head off for the trip where I'll need the windvane. I could build another rudder specifically for that trip, but wow....building a rudder is bluidy lot of work, lots more than this windvane will be! If in fact it doesn't work, I will probably re-purpose it and build a "regular" servo pendulum system using the same vane.

    However, if I was cruising, I'm convinced that the auxiliary rudder with trim tab would be what I'd build.

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    Default Re: I am making a windvane

    Maybe a trim tab could be worked out to be removable when racing.

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    Default Re: I am making a windvane

    Quote Originally Posted by Alan H View Post
    The reason I didn't do a trim tab system is that I race this boat on San Francisco Bay A LOT. I didn't want to be hauling around the trim tab for two racing seasons before I head off for the trip where I'll need the windvane. I could build another rudder specifically for that trip, but wow....building a rudder is bluidy lot of work, lots more than this windvane will be! If in fact it doesn't work, I will probably re-purpose it and build a "regular" servo pendulum system using the same vane.

    However, if I was cruising, I'm convinced that the auxiliary rudder with trim tab would be what I'd build.
    Makes sense to me. I love self-steering devices and can't wait to see how yours works out! Will it have to sit way out aft of the transom-hung rudder? How will you adjust the course setting? We briefly had an Aries (lost overboard on a miserable night... long story), and loved the clicky-click method of adjusting the setting. Two strings to pull: one to adjust to port, one to adjust to starboard. Each click equals 5 degrees of heading.

    The Hebridean had a kind of set-screw mechanism (loosen the set screw, spin the wind vane to the new heading, re-tighten the set screw) that technically works but was tough to adjust on a pitching boat while the vane was swinging about and doing its job.

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    Default Re: I am making a windvane

    Quote Originally Posted by Wesley View Post
    Makes sense to me. I love self-steering devices and can't wait to see how yours works out! Will it have to sit way out aft of the transom-hung rudder? How will you adjust the course setting? We briefly had an Aries (lost overboard on a miserable night... long story), and loved the clicky-click method of adjusting the setting. Two strings to pull: one to adjust to port, one to adjust to starboard. Each click equals 5 degrees of heading.

    The Hebridean had a kind of set-screw mechanism (loosen the set screw, spin the wind vane to the new heading, re-tighten the set screw) that technically works but was tough to adjust on a pitching boat while the vane was swinging about and doing its job.
    So the linkage between the windvane movement and the movement of the pendulum oar will be done by running s.s. bicycle brake cables through teflon-lined, s.s. mountain bike brake housing. This is how the commercially available Auto-Helm device, from Scanmar International works. I like this linkage because it's extremely easy to set up and super easy to repair.

    Auto+Helm+top+of+support+pole.JPG

    Auto+Helm+aux+rudder+and+trim+tab.JPG

    The action of the windvane activates a trim tab. The trim tab on the Auto-Helm is about twice the size of the pendulum oar I have made, so we'll see. Also, I'm a bike mechanic from 'way back so "bike stuff" is familiar to me.

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    Default Re: I am making a windvane

    The wind-paddle mast is lime-green fiberglass tubing. It's essentially the same thing as the fiberglass poles that you find on Pruning saws at the hardware store. It had an Outside Diameter of 1 3/16 inches. So a fiberglass tube of Inside Diameter of 1 1/4 inches will just sleeve over it. I might buy a 2-foot section for $27 plus shipping, or I might wrap the fiberglass tubing I have with a layer of wax paper, and do a few wraps of 6 or 8 ounce cloth around it and make my own tube.

    The fiberglass pole will be affixed to the stern pulpit on centerline. The pendulum oar carrier sits on top of the rudder, there is no framework that sticks out from the transom. The Pendulum oar itself swings back and forth an inch or two behind the trailing edge of the rudder.

    Anyway, I need to make or buy a "sleeve" for the fiberglass pole that serves as the mast for the wind vane. The bracket that hold the pivot rod for the wind vane will be glued to that sleeve. The sleeve will be slit, in the top 6 inches so it can be squeezed tightly over the mast. Two 1/4 bolts and wing nuts will do the tightening.

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    Default Re: I am making a windvane

    OK, today I spent most of the day on the windvane. I did the following...

    1. cut the angles at the top of the wind blade and got a piece of 4-inch glass tape in epoxy folded over the bottom of it.
    2. painted a layer of epoxy on the wind blade, and laid on a 1-inch wide strip of unidirectional carbon fiber on each side for stiffening.
    3. discovered that I had another, longer piece of the lime green fiberglass pole stuff, that I'm using for the mast. Nice...
    4. drilled, cut, glue'd and assembled the main wind blade carrier.
    5. laid out some funky duct tape on the garage floor in the appropriate angle, sort of put everything into alignment, and checked to make sure it will all fit....it will!

    Geomettrycheck.jpg

    Wind Blade Carrier....still life with tools and laundry basket...

    VaneCarrierAssembly1.jpg

    and 6. wrapped the lime green pole stuff in a couple layers of wax paper, and used some leftover lightweight fiberglass cloth to wrap around it, for the moveable part that the wind blade carrier will ride on. Once I got all the cloth on there (3 layers) I wrapped it again in wax paper, and then wound duct tape around the whole thing, really tightly. We'll see how this comes out.

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    Default Re: I am making a windvane

    Except for a nice 45-minute walk with my Missus when the rain let up, I worked on the vane all day, today. Most of this work is cutting out or drilling or gluing little fiddly-bits. SWMBO mentioned that whatever I was making sure had a lot of parts, and she is right.

    So today I took off the fiberglass tube that I made around the green fiberglass pipe that will be the windvane mast. I laid it up yesterday and let it kick off all night. This tube is what the wind vane carrier assembly will be attached to. It needs to fit pretty snugly to the vane mast. Well, the epoxy soaked through the wax paper a little bit, so sadly I had to split the tube to get it off. No big deal, I was going to wrap it with more glass anyway. I was shocked at how well it came out, actually. Anyway, I got it off, cleaned up the mast tube, and wrapped the mast tube with a double layer of cling-wrap...household plastic wrap. That should seal it! Three wraps of wax paper went over that and then I slipped the fiberglass tube I made over that. It got multiple wraps of light fiberglass....scraps I had left over, and the top got several wraps of my last bit of 4-inch glass tape. That is where the clamp that holds the windvane will go.

    That got wrapped up around the outside with 3 wraps of wax paper and then I used tightly wound duct tape to keep everything compressed. This is what it looks like...truly an exciting photograph!

    polewrap.jpg

    It was pretty cool today, down in the 50's for most of the day so I warmed the rod with the heat gun a few times to help with getting the epoxy to set..

    I made a couple more parts...warmed the wind blade a few times with a heat gun to get the epoxy to kick off, and assembled everything on the garage floor. Before I cut the 3/8 aluminum rod that is the axis of rotation of the wind blade, and which the carrier spins on I wanted to make dropdead sure that everything lined up. Jan Alkema and Walt Murray recommend 30 deg. incline with the USD vane. Two other guys who have made them suggest less, more like 15 degrees. Other vanes (not USD) vary from no incline at a;; to almost 40 degrees. I decided on 25 degrees. 90 - 25 = 65. So with the rod that is the axis of rotation of the blade at 65 degrees from the mast, does everything fit together?

    I clamped everything to a piece of wood, used a paint can for a counterbalance, and set it all up. Son of a gun!

    Damn, I'm good!

    Geometrycheck2.jpg
    Attached Images Attached Images
    Last edited by Alan H; 04-05-2020 at 11:45 PM.

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    Default Re: I am making a windvane

    Since it didn't smell like epoxy, being all wrapped up with duct tape 'n all, I put the wrapped vane mast in my study under the ceiling heater vent last night. Today, during a break from work, I pulled off the duct tape and here we are...

    polewrap-pulloff.jpg

    Why did I do this? In fact, why use a fiberglass mast at all? Answer: because I saw that the Mister Vee vane uses a fiberglass mast, and I had it. I know how tough the stuff is, so why not? Anyway, why make the sleeve? Because it's a course-setting system. The whole vane carrier has to rotate on the mast so you can align the course with the prevailing wind, right? Well, that sleeve fits very closely around the mast, enough to not wobble at all, but not so closely that it won't spin easily.

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    Default Re: I am making a windvane

    No pictures today.

    A couple of the wood parts got a first coat of paint.
    I cleaned up the fiberglass sleeve, worked off the wax paper that was stuck to the surface.
    Made a bushing from some weird, semi-soft plastic that actually was part of a bicycle basket system on my wife's bike. I cut pieces and epoxied them together to make a 1 1/4 by 2 inch by 3/8th inch thick bit, which will serve as the lower bearing surface for the vane.

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    Default Re: I am making a windvane

    Alan, it sounds like you've had a fair bit of experience with wind vanes and the bike cable method. Do the cables not cause more friction than other methods? No issues with cables rusting? Does this method still work in very light airs?

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    Default Re: I am making a windvane

    Quote Originally Posted by Small boats rock View Post
    Alan, it sounds like you've had a fair bit of experience with wind vanes and the bike cable method. Do the cables not cause more friction than other methods? No issues with cables rusting? Does this method still work in very light airs?
    These are all good questions, and to answer them, I'm going to point you to a couple of links.

    first...Girl in a Gale. This lass made a copy of the commercially available Auto-Helm windvane, which you can buy from Scanmar International.

    http://www.girlinagale.com/2010/11/c...-steering.html

    If you look closely at the pictures of the Autohelm, you will see that the "cables" are actually a very low-stretch monofilament. They run in a double-layered, waterproot tube. If you read what "Gale Girl" did, she ran heavy fishing line through hydraulic cable, to achieve the same result.



    You ask if the cables will rust. Good question...How about friction inside the housing?

    https://www.jensonusa.com/SRAM-Slick...-Cable-Housing


    Teflon/plastic-lined brake cables.... Shoot some tri-flow down inside the tubing, run the teflon-infused cable through it and these things are ~extremely~ slick. I need two, they're on sale for $29.

    If I'm really spooked and worried about even the stainless steel cable corroding, well...

    https://www.jensonusa.com/SRAM-Slick...-Cable-Housing

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    Default Re: I am making a windvane

    Remember that the linkage sees no more than at most, maybe 20 pounds of force...be generous...30 pounds. A strong person can exert as much as 125 pounds of force on a gripping machine. Crazy-strongmen can crush 200 pounds or more. Most people can crush more like 65-70-80 pounds, so brake cables are MUCH stronger than needed.

    I also happen to have a roll of .105 in. diameter weed-whacker monofilament. I might cut a yard of it, and put a 25 pound weight on it and see how much it stretches. That would be totally corrosion-proof.

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    Default Re: I am making a windvane

    Hey, good idea. I have a roll of that stuff too, wasn't sure what to do with it (other than whack weeds of course). Thanks for the informative links.

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    Default Re: I am making a windvane

    Quote Originally Posted by Small boats rock View Post
    Hey, good idea. I have a roll of that stuff too, wasn't sure what to do with it (other than whack weeds of course). Thanks for the informative links.
    The weed whacker stuff I have is on a rather tight roll, so it's conformed to the roll. I think it would be wise to straighten it...probably by hanging a 5 foot length of it with a 10-20 pound weight on the end, and warming it with a heat gun or hair dryer.. "Warm"...not melt! ....until it's straight. That, or just leave the weight on it for a few days to straighten it out. I've found that I can tie a knot in this stuff and lock it in with superglue. That means you can use an old-skool halyard shackle, drilled at the top at one end.

    It's pretty darned strong. I mean, if I cut a couple of feet of the stuff and get a good grip on it with both hands, I can't pull it apart...break it in a straight line pull. I'm pulling a heck of a lot more than 25-30 pounds, so it's plenty strong enough for the job. I think the question is whether it would kink and break at a hard turn around a bolt/nut lockdown point.
    Last edited by Alan H; 04-09-2020 at 12:24 PM.

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    Default Re: I am making a windvane

    PTFE is a chemical acronym for Teflon. Now, "Teflon" is a trademarked name, I think by DuPont, so other companies who make the stuff, can't call it that. However, PTFE is generally available in the USA, Canada and Europe. It's quite UV resistant, and totally solvent resistant. You can squirt Tri-Flow into it all day long and not hurt it..

    http://www.druflon.com/ptfeprop.html

    PTFE tubing is "relatively" non-compressible, I mean at the loads we're talking about, and "reasonably" flexible.

    https://www.mcmaster.com/ptfe-tubing/sleeving-4/

    So for my weed-whacker monofilament, which is 0.105 diameter, I could get the 0.133 ID stuff, which is 96 cents a foot. I might need ten feet. Hmmmmm. It's tempting to try this, as it would be utterly corrosion-proof and super-slick.

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    Default Re: I am making a windvane

    Today I put the counterweight in the pendulum oar.
    When I made a windvane back around 2006, I tried it out on my Santana 3030. I well remember the day, chugging out of the harbor, with the pendulum oar rammed hard over to one side. I could not ever get it to center. The WINDvane part worked great. It was almost bit-for-bit a version of one of Walk Murrays vanes. However, the pendulum oar just would not work. I finally gave up on it.

    As I was contemplating this windvane, I got to thinking about that issue and it occurred to me that I made the pendulum oar out of 1 x 5 pine. That floats, right? When the oar is straight up and down, the force of the "floating" is straight up. But the moment that pendulum oar moves even a couple of degrees out of exactly vertical, it's going to float to the surface, which means sticking way the heck off, out to the side. How to fix this?

    Well....how about adding some weight to the bottom of the pendulum oar?

    I was out for a walk the other day, and I came across a steel contracters stake, lying in the street. I grabbed it, knowing that I needed both this counterweight and the counterweight on the windvane today I flew by the seat of my pants, and hacksawed out what I thought might be enough weight for the windvane counterweight, from that stake. I eyeballed it, weighed it in my hands and made a vague, wild guess about how much weight might keep the oar more or less neutrally buoyant. I knew that the weight had to be in line with the axis of rotation of the oar. If it was significantly off from that axis, when the oar was out to the side, the weight would tend to make the oar rotate, and keep it working hard on the rudder, even when the course was corrected. So in fact this piece of rod is very close to the axis of rotation, maybe 1/4 inch behind it.

    pendulum-counterweight1.jpg

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    Default Re: I am making a windvane

    There's nothing scientific about this...I didn't measure anything, I just guessed. I figure if it's not right, I'll make another oar.

    Anyway, the piece of steel was wirebrushed to clean it up, and I hit it with a file and sandpaper to really get the rust off. I packed it in there with sawdust/wood dough in epoxy.

    pendulum-counterweight2.jpg

    and then wrapped it with wax paper for a release membrane and clamped it. It won't be perfectly fair when the epoxy kicks off, but it won't be awful, either. Since the whole oar will be wrapped in 8 ounce cloth in epoxy, this steel is well isolated from salt water.

    pendulum-counterweight3.jpg

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    Default Re: I am making a windvane

    Yesterday I sanded the epoxy/wood mix that locks the counterweight inside the pendulum oar, and put on some microballoons/epoxy-spooge to fair it. More progress today; I fiberglassed the pendulum oar. I had a bit of unidirectional carbon fiber left over, and figured I'd use it to stiffen up the oar. Those black strips are not one single piece, though everything below the waterline is one piece. The longest part is about 3 1/2 feet long and overlaps where the counterweight is. Then there are two, approximately 1 foot pieces above that overlapped by a couple inches, to carry the carbon fiber to above where the lower pintle will be. It's not optimal, I'd rather have a continuous piece, but I used what I had and there's substantial overlap..

    The fiberglass is all one piece, 8 ounce stuff.

    FiberglassOar.jpg

    I'm wearing Tyvek forearm protectors, you just can't see 'em. The oar is supported at the ends by deck screws driven into the ends of the oar, and then balanced on the ends of the sawhorses.

    I clamped the trailing edge of the 'glass below the waterline to at least attempt to get a really fine edge on it. There was one spot where the glass just would NOT lie down, so I have an extra layer of wax paper there, and it's smashed flat with clamps and boards. I also compressed the sides of the oar above the waterline just to make sure I got really good bonding.

    FiberglassOarClamped.jpg
    Last edited by Alan H; 04-11-2020 at 08:22 PM.

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    Default Re: I am making a windvane

    Strewth, didn't realise how big the oar is. Certainly adds perspective with you in the picture. Long time ago I owned a navik. The oar was quite small by comparison.

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    Default Re: I am making a windvane

    Quote Originally Posted by Small boats rock View Post
    Strewth, didn't realise how big the oar is. Certainly adds perspective with you in the picture. Long time ago I owned a navik. The oar was quite small by comparison.
    What you see there is 6 feet long and 4 1/2 inches in chord. It'll be 4 inches shorter when I trim it! How did I come up with that? Well, from the top of the rudderhead to water level on my boat is 32 inches. I figured that I wanted about 3 feet of foil in the water. That might be excessive, we'll see! It's certainly more than is needed when the oar is perfectly vertical, but you lose a lot of depth when the oar is cranked out to 45 deg. on one side. Still, I figured, better too long than too short. I can easily take another 4 inches off the bottom if I need to, but not more than that or I'll run into the counterweight.

    After the glass kicks off, I'll be cutting about an inch off the front of the above-water part of the oar to add in some balance.

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    Default Re: I am making a windvane

    Oh. total expenditure for this project so far...$14 for aluminum parts, $54 for a mess of stainless steel hardware, $10 for a block of 3/8 HDPE which I actually might not use, and another $2 for a bolt, lock washers and lock nut I forgot to get the first time.

    Obviously I've bought or been given all this stuff at some point, but that's the DEDICATED expense, so far.

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    Default Re: I am making a windvane

    Quote Originally Posted by Small boats rock View Post
    Strewth, didn't realise how big the oar is. Certainly adds perspective with you in the picture. Long time ago I owned a navik. The oar was quite small by comparison.
    But the oar had its own tab on the back, and most of the length was taken up with SS tube. Naviks are great bits of kit, and i have seen a few home made versions based on the original dimensions that have all worked well.

    Keep going, im not sure the weight would have been needed, but will be interesting to see how it all works out, im thinking you might need more water flow across the blade in terms of speed, than one without weight.

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    Default Re: I am making a windvane

    Quote Originally Posted by skaraborgcraft View Post
    But the oar had its own tab on the back, and most of the length was taken up with SS tube. Naviks are great bits of kit, and i have seen a few home made versions based on the original dimensions that have all worked well.

    Keep going, im not sure the weight would have been needed, but will be interesting to see how it all works out, im thinking you might need more water flow across the blade in terms of speed, than one without weight.
    I notice that Jan Alkema's original drawings pencilled in a much shorter oar, on a long tubular shaft, that's larger in chord. His drawing looks something like a Monitor pendulum oar. However, photographs of his original setup don't look like that, at all.

    Here's a screenshot from Jan's original paper, 2005...

    JanAlkema-USDandRHM.jpg
    This is his "final" version, where most of the structure is done in stainless steel. You can see that the pendulum oar foil is about 4 inches in chord and maybe 2 1/2 feet long. So what I've built is bigger than what Jan made, but not extremely so.

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    Default Re: I am making a windvane

    You can also view this page: https://www.omick.net/adventure/sail...0Steering.html

    I look at his setup and think that it's wildly overbuilt, to control an extremely small rudder, but then his boat had an inboard rudder as well, so....Anyway, they used the system as pictured to cross the Pacific, and you can't really find fault with that!

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    Default Re: I am making a windvane

    I pulled the clamps and wax paper off the rudder today. Hmmm...Most of it was good, but there were a few too many spots where it didn't bond well. The worst was one side where the blade transitions from foil (below the waterline) to rectangular (above the waterline). I got to it while the epoxy was still a little soft so I cut off the flash, slathered fresh epoxy into a few place and clamped it again. There were a few bubbles...not horrible, so they got cut out and got a layer of epoxy with a mess of glass fiber mushed into it. Anyway, It wasn't BAD, it just wasn't quite as pretty as I'd hoped. Anyway, it's still on the sawhorses in the front yard, catalyzing away again, with a mess of wax paper and clamps on it.

    I also taped off part of the wind blade and it got a coat of paint. Some of the flash from the oar, and extra epoxy got re-purposed to further beef up the middle of the fiberglass tube that will hold the actual wind-vane. That thing will be bomb-proof.

    ...and the Mrs & I went for a 21 mile bike ride today after "online" church. That's the first time I've ridden a bicycle for more than about 40-50 minutes in probably a decade and a half, and I didn't die.

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