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Thread: Leeboard questions (foil shapes, etc)

  1. #1
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    Default Leeboard questions (foil shapes, etc)

    There is plenty of leeboard info I have gleaned from this site and other spots on the web. I am interested in getting a consensus from those already using them. I plan to make mine soon, utilizing a single leeboard on a removable thwart. I would like to use a shape and style similar to Solway Dory's. I believe theirs is 48" or so. Is making it from hardwood versus ply worth the extra time and expense? Also, I've read differing accounts as to thickness, anywhere from 1/2" to 1" thick. The only drawing I've found of a foil shape is the symmetrical ACA rig found here: http://www.enter.net/~skimmer/building/aca_rig.pdf
    That board is 54" long (36" in water), 9" wide, and 15/16" wide. Does that setup seem optimum?

    As to the removeable thwart, does it make sense to try to locate the center of my sail area in such a way I can mount the leeboard thwart over the canoe center thwart? Here is my canoe: http://www.indianrivercanoemfg.com/Eagle.htm The picture masks the fact that the thwart is smack in the middle of the canoe at its widest point.

  2. #2
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    Plywood is not the best option. It is not the cheap option if you have to buy a full sheet.
    Plywood is not as strong as solid wood as half the grain is running across the board and has little strength. I would even make the board out of softwood rather than plywood.
    SD leeboards are made of Ash and are 7/8 inch thick by 8inch wide and a little over 4ft in length. We use a typical hydrofoil section, and use templates to check that we have achieved the correct shape. Many people who have a go at making their own do not bother with a template and end up with a board that is too thick at the front and back, usually because it is a lot of work to remove all the wood that is not the board so they call it a day when they get fed up with planing.
    Which section you go with is probably less important than making sure that you accurately copy the shape.

  3. #3
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    Quote Originally Posted by DaveS View Post
    Plywood is not the best option. It is not the cheap option if you have to buy a full sheet.
    Plywood is not as strong as solid wood as half the grain is running across the board and has little strength. I would even make the board out of softwood rather than plywood.
    SD leeboards are made of Ash and are 7/8 inch thick by 8inch wide and a little over 4ft in length. We use a typical hydrofoil section, and use templates to check that we have achieved the correct shape. Many people who have a go at making their own do not bother with a template and end up with a board that is too thick at the front and back, usually because it is a lot of work to remove all the wood that is not the board so they call it a day when they get fed up with planing.
    Which section you go with is probably less important than making sure that you accurately copy the shape.
    Thanks for this info. I am lucky enough to have a carpenter friend with a power planer. I had not thought about using a template. I will make one. Thanks for confirming the size and construction for me.

  4. #4
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    At SD we are considering offering our leeboard in kit form.
    It would be an Ash blank that we have machined to the correct thickness, with a leading edge and trailing edge taper machined onto it. This removes 95% of the wood acurately and would only need the nose planing and the steps between the tapers fairing in. I could supply a template for the profile, and one for the cross section. We like the idea of people making their own gear as that is where we started ourselves, but it is nice to see people doing it really well. Do you think this is something that people could be intersted in. If it proved worthwhile we could offer other gear in this form as well.(although postage to Florida might prove prohibative)

  5. #5
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    Quote Originally Posted by DaveS View Post
    although postage to Florida might prove prohibative)
    LOL. If you were shipping damn great lengths of ash, even postage WITHIN Florida could be prohibitive: it's ~550 miles from Fort Zachary Taylor State Park (Key West) to Fort Clinch State Park on the Georgia border - about the same as from your workshop to Paris! Shame though, as we've both noticed considerable interest in your sailing canoes, rigs and accessories from that side of the pond.

    I like the idea of stuff being available in kit form though: canoe sailing and tinkering with stiff seem to go together, really

    Ps. Kit rudder? More complicated... but could be done!

  6. #6
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    Its ironic really but the Ash we are using at the moment is American White Ash, as is most of the Ash for sale in the UK.
    I think the side mounted rudder would work in kit form. We have spent a bit of time recently simplyfying it and removing some of the expensive stainless hardware as well as making it lift up and down remotely.

  7. #7
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    I think kit form could be attractive. As always, some are more price conscious than others, while another sub-group just likes making things. Do you have an idea of what the kit would retail at?

    All the best,
    Ian

  8. #8
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    Quote Originally Posted by idc View Post
    I think kit form could be attractive. As always, some are more price conscious than others, while another sub-group just likes making things. Do you have an idea of what the kit would retail at?

    All the best,
    Ian

    Excellent point, and my thoughts exactly. I admire your gear, and would love to just swipe the visa and take delivery. UPS is my friend! Unfortunately, at this point in time funds are critically low for me, and it is do it yourself or do without. Admittedly, the kit would appeal to me even if I could afford to purchase outright. With the majority of the planing done, final finishing would be enjoyable.

    Did you sell plans for foils at one time? A plan with template and instruction would be of great interest to both the die hard do it yourselfer as well as the working poor among us. As you mentioned, the cost between hardwood and plywood is small considering the results, and I do enjoy quality work. Yours is a proven and tested design. Kits for leeboard and rudder would be great and likely appeal to many...
    Last edited by lvacgar; 12th-April-2011 at 01:17 AM.

  9. #9
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    We think the leeboard kit would be around 40.
    The previous owner of SD , John Bull, used to sell plans but we do not anymore. If you think there is sufficient interest we could put a set of drawings on the website for free. I would have to see if we could make the template print to scale (i am not very computer literate) but it would be nice to see people doing good copies of our gear. I often see people copy something from a photo but get the scale etc. all wrong. If it doesnt appear in the next few weeks give me a nudge to remind me to get on with it.

  10. #10
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    Quote Originally Posted by DaveS View Post
    We think the leeboard kit would be around 40.
    The previous owner of SD , John Bull, used to sell plans but we do not anymore. If you think there is sufficient interest we could put a set of drawings on the website for free. I would have to see if we could make the template print to scale (i am not very computer literate) but it would be nice to see people doing good copies of our gear. I often see people copy something from a photo but get the scale etc. all wrong. If it doesnt appear in the next few weeks give me a nudge to remind me to get on with it.
    That kit price is 1/2 your retail, and is a great buy. How steep are shipping and any incidental fees to the US? Your offer to post drawings is most generous. I don't know that you'd have to make a scale template. From a simple drawing with critical dimensions listed we could do that. I was thinking of using the ACA drawing of the NACA 0009 foil they recommend. I do love the profile of your leeboard though, and if you are willing to share the dimensions I would whittle away with all due credit to the designer!

  11. #11

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    For a sailing canoe leeboard you don't really need the kind of strength that a sailing dinghy would require IMHO. A perfectly adequate board can be made from spruce; slice it up into half-a-dozen strips and epoxy them back together so they have vertical grain, with the odd numbers flipped. Then plane and shape. There are lots of exotic profiles with claims of excellence but a NACA 4-digit foil like NACA-0010 is as good as any and can be found at http://www.ppart.de/aerodynamics/profiles/NACA4.html. It will be more durable if the leading edge is hardwood, maple dowelling does a good job.
    Last edited by Ancient Kayaker; 13th-April-2011 at 03:32 AM.
    Terry Haines

    Boats are like rabbits: you can have one or many, but not two - A. Onassis

  12. #12
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    Minor technical point on templates: an A4 PDF should print out the same for most folk.

    The passport office do a "locked" PDF to give you a fixed sized template for passport photos: it's not rocket science... and between us I'm pretty sure we could overcome such issues!

  13. #13
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    Quote Originally Posted by Ancient Kayaker View Post
    For a sailing canoe leeboard you don't really need the kind of strength that a sailing dinghy would require IMHO. A perfectly adequate board can be made from spruce; slice it up into half-a-dozen strips and epoxy them back together so they have vertical grain, with the odd numbers flipped. Then plane and shape. There are lots of exotic profiles with claims of excellence but a NACA 4-digit foil like NACA-0010 is as good as any and can be found at http://www.ppart.de/aerodynamics/profiles/NACA4.html. It will be more durable if the leading edge is hardwood, maple dowelling does a good job.

    Thanks Terry for that. I'm trying to scrounge up some free hardwood scraps but spruce is cheap here. A dowel or hardwood 1x2 for a leading edge and off we go...

  14. #14

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    Most hardware store-bought wood is slash cut which means the grain viewed at the end of the plank runs across the width rather than vertically between the faces, so cut it into strips a little wider than the thickness of the board and stack them vertically to get the ideal grain orientation - the wood is more stable like that - also saturate the end-grain with varnish/paint/epoxy to prevent splitting.
    Terry Haines

    Boats are like rabbits: you can have one or many, but not two - A. Onassis

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