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Thread: JIM, an 18 foot canoe yawl.

  1. #36
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    Default Re: JIM, an 18 foot canoe yawl.

    Woah! Let's not get too excited over this!

  2. #37
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    Default Re: JIM, an 18 foot canoe yawl.

    OK I'm hardly an old timer just a backyard hack but I'll throw my spiling batten into the ring and say having done it both ways compass spiling is quicker, accurate (just make sure you remove previous marks) less wasteful and more satisfying but hey as they say whatever floats your boat.

    Just a note on the truss method 1" or so ply battens instead of wood work better as they conform to the hull shape easier.

    Cheers
    Mike
    Last edited by m2c1Iw; 07-29-2012 at 07:56 PM.

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    Default Re: JIM, an 18 foot canoe yawl.

    Quote Originally Posted by Terry Haines View Post
    Woah! Let's not get too excited over this!
    Ain't nothin' more important to get excited about than how best to spile a plank.

  4. #39
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    Default Re: JIM, an 18 foot canoe yawl.

    Quote Originally Posted by TerryLL View Post
    Ain't nothin' more important to get excited about than how best to spile a plank.
    While we're waiting for Peter to catch up, we could also argue about cutting the planks- jigsaw or skilsaw. Can't use a router with my cardboard templates.

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    Default Re: JIM, an 18 foot canoe yawl.

    Quote Originally Posted by jim_cricket View Post
    While we're waiting for Peter to catch up, we could also argue about cutting the planks- jigsaw or skilsaw. Can't use a router with my cardboard templates.
    No debate needed. Skilsaw with fine tooth narrow-kerf blade set shallow. I think this thread may be drifting.

  6. #41
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    Default Re: JIM, an 18 foot canoe yawl.

    Quote Originally Posted by m2c1Iw View Post
    OK I'm hardly an old timer just a backyard hack but I'll throw my spiling batten into the ring and say having done it both ways compass spiling is quicker, accurate (just make sure you remove previous marks) less wasteful and more satisfying but hey as they say whatever floats your boat.

    Just a note on the truss method 1" or so ply battens instead of wood work better as they conform to the hull shape easier.

    Cheers
    Mike
    Peter? Are you paying attention?
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  7. #42
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    Default Re: JIM, an 18 foot canoe yawl.

    I know spiling works ! There's really no argument, I guess I just like the aesthetics of the truss.... we'll see how it goes when that job arrives but Jim says planking is a little way off. I'm just about to rip the laminates for my stem and stern post inners .
    '' You ain't gonna learn what you don't want to know. ''
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  8. #43
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    Default Re: JIM, an 18 foot canoe yawl.

    I guess I just like the aesthetics of the truss....
    In that case I'll not have a bad word spoken about black skivvies!
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  9. #44
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    Default Re: JIM, an 18 foot canoe yawl.

    Only a Victorian would wear a black skivvy!

    Oi Peter, you sneaky bugger! There I was in blissful ignorance waitng for your thread to start and here it is already! It's great! Good luck with the build, the design looks really nice (although it now looks like we're going to have a plague of sprits up there in the deep North!). I like the little trusses method too - it just eliminates so much of the room for error. I'd go with the air stapler though.

    Rick

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    Default Re: JIM, an 18 foot canoe yawl.

    I'm ready to start planking, so this is an interesting discussion. Spiling a good plank I mean, no opinion on black skivvies.

  11. #46
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    Default Re: JIM, an 18 foot canoe yawl.

    One wasted afternoon , well not totally wasted , I now have a great pile of sawdust and a lot of neat firewood starter and have learned how not to do something! I ripped out all the laminates for the stern post inner and the stem inner . All at around 1/8" x 2 1/4" but they really don't like the bend. Admittedly it's a hard one and my stack of oregon is dry 20 years .




    I dug out Iain Oughtred's excellent book from under of layer of sawdust and discovered that he suggests a layered futtock method as his first choice ! Duh ! That's the way it will go now, 3 layers of 17mm.
    '' You ain't gonna learn what you don't want to know. ''
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  12. #47
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    Default Re: JIM, an 18 foot canoe yawl.

    There's no doubt that regular spiling with a compass or tick stick is a great method. But, it seems to me, for those of us who aren't doing it all that often, it's a little prone to error. Those who do it a lot make almost unconscious allowances for their own particular ways of manipulating the various bits and pieces, and certainly get very good at it, but the rest of us need to make a few errors before we can adapt to our own patterns of behaviour. So, for me, it's worth the extra effort to form up a truss-pattern which can then be placed exactly where the plank is going, adjusted accordingly, and then copied with the plank. If I were to use the traditional method, I'd be making up a test piece anyway, and that would use more material. There's no need for me to save time with planking, and using a few extra sheets of plywood or mdf to get the planking just right is a reasonable price to pay, I think.

    Rick

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    Default Re: JIM, an 18 foot canoe yawl.

    Peter, those strips shouldn't have cracked like that. You can wet them, wrap them in black plastic and leave them in the sun for a couple of hours to soften them. Then use a former to wrap them around that mould. The former is a strap of flexible steel with a handle at either end. Then with the former holding the strips around the mould, clamp them. Let it all dry and then use the former again when you do your gluing.

    Or use layered futtocks ..... I'm looking forward to finding out what a layered futtock is.

    Rick

  14. #49
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    Default Re: JIM, an 18 foot canoe yawl.

    A layered futtock is basically a sawn frame, the layers overlapped in different places and glued instead of bolts, I'd go three layers. I could persevere and steam them or wet them but the amount of glue I'd be using has become apparent too ! Layers it is .

    Layers.jpg

    Layered sternpost.jpg
    Last edited by PeterSibley; 04-03-2018 at 01:28 AM.
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    Default Re: JIM, an 18 foot canoe yawl.

    One of my great favourites:



    Rick

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    Default Re: JIM, an 18 foot canoe yawl.

    Quote Originally Posted by RFNK View Post
    There's no doubt that regular spiling with a compass or tick stick is a great method. But, it seems to me, for those of us who aren't doing it all that often, it's a little prone to error. Those who do it a lot make almost unconscious allowances for their own particular ways of manipulating the various bits and pieces, and certainly get very good at it, but the rest of us need to make a few errors before we can adapt to our own patterns of behaviour. So, for me, it's worth the extra effort to form up a truss-pattern which can then be placed exactly where the plank is going, adjusted accordingly, and then copied with the plank. If I were to use the traditional method, I'd be making up a test piece anyway, and that would use more material. There's no need for me to save time with planking, and using a few extra sheets of plywood or mdf to get the planking just right is a reasonable price to pay, I think.

    Rick

    But where is the room for error in this?



    I'm not sure I like the idea of splitting the stem and stern posts down the middle even with epoxy as the glue.

    I'f'n you're going to all this trouble with these truss skivvy things, I'd look at today's experiences as a really good excuse to go out and build me steamin' box!
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  17. #52
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    Default Re: JIM, an 18 foot canoe yawl.

    Argue with St Iain of Oughtred.
    '' You ain't gonna learn what you don't want to know. ''
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    Default Re: JIM, an 18 foot canoe yawl.

    Quote Originally Posted by Duncan Gibbs View Post
    But where is the room for error in this?
    All around. Trussed me.

    Rick

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    Default Re: JIM, an 18 foot canoe yawl.

    Quote Originally Posted by RFNK View Post
    All around. Trussed me.

    Rick
    Pay the man !
    '' You ain't gonna learn what you don't want to know. ''
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  20. #55
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    Default Re: JIM, an 18 foot canoe yawl.

    Quote Originally Posted by PeterSibley View Post
    Argue with St Iain of Oughtred.

    It's all those black skivvies I wore as a youth: I'm a natural born iconoclast. In fact I'm wearing three of the things right now!

    Quote Originally Posted by RFNK View Post
    All around. Trussed me.
    I was once presented with twice five number of puns in order to see which ones would make me laugh. No pun in ten did.
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  21. #56
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    Default Re: JIM, an 18 foot canoe yawl.

    Trust you chose a suitable expletive from the boat builders dictionary after the lams broke actually that would have been from the list titled mild as it's only a minor set back.
    Interesting the inner ones look like they took the bend OK from different stock I spose. I'd have another go perhaps use an outer form or more clamps wet the lams down first and select from straight grain flat sawn, should work.
    Or make that steam box now as the skivied one suggests.

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    Default Re: JIM, an 18 foot canoe yawl.

    I was once presented with twice five number of puns in order to see which ones would make me laugh. No pun in ten did.
    That's not very punny at all

    Rick

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    Default Re: JIM, an 18 foot canoe yawl.

    Quote Originally Posted by Duncan Gibbs View Post
    But where is the room for error in this?

    The spiling batten used with either a compass or spiling block will allow you to transfer the exact shape of the plank onto the plank stock. But, it's not idiot proof. If the spiling batten is a lot more flexible than the plank stock it can sag inward between molds, throwing off all the points when laid out flat. It's also very important to avoid any edge set when tacking on the batten, as that edge set will disappear once the batten is laid out flat, throwing off all the points.

    The possibility that little errors can creep into the process is the principal reason to cut the plank a bit oversize and do a trial fit. Geoff Kerr recommends cutting wide of the mark by a good 12mm in his WB articles on the Caledonia Yawl, and then testing the fit. When I planked up my CY, having that extra meat at the plank edges saved my grits more than once.

    The trussed template method looks like it will produce a perfect pattern, but it's also susceptible to errors caused by edge set and flexibility. Cutting the plank a bit oversize and doing a trial fit is a lot easier than throwing away a plank and starting over.

  24. #59
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    Default Re: JIM, an 18 foot canoe yawl.

    Quote Originally Posted by PeterSibley View Post
    .




    I dug out Iain Oughtred's excellent book from under of layer of sawdust and discovered that he suggests a layered futtock method as his first choice ! Duh ! That's the way it will go now, 3 layers of 17mm.
    Peter ,

    Don't do it, don't do it. A glued-up plywood stem is just so amateurish. Yes it's easy, sufficiently strong and stiff, quick, and cheap. But this boat deserves better.

    Just take those DF lams and lay them out flat on a towel. Put another towel on top and pour on the boiling water. In 15 minutes those lams will bend around that form with nary a complaint. Clamp them there overnight, unclamp in the morning. Truss up each one with some string so they hold their shape and let them dry for a day or two. Then back on the form with a decent layer of thickened epoxy. With that many lams you'll have a very stiff stem worthy of your effort.

  25. #60
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    Default Re: JIM, an 18 foot canoe yawl.

    You also probably need to use more clamps applied as you round that corner with some cawls the width of the wood under them. They broke right there and they appear to be unsupported unless you removed the clamps from there.

  26. #61
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    Default Re: JIM, an 18 foot canoe yawl.

    Quote Originally Posted by TerryLL View Post
    Peter ,

    Don't do it, don't do it. A glued-up plywood stem is just so amateurish. Yes it's easy, sufficiently strong and stiff, quick, and cheap. But this boat deserves better.

    Just take those DF lams and lay them out flat on a towel. Put another towel on top and pour on the boiling water. In 15 minutes those lams will bend around that form with nary a complaint. Clamp them there overnight, unclamp in the morning. Truss up each one with some string so they hold their shape and let them dry for a day or two. Then back on the form with a decent layer of thickened epoxy. With that many lams you'll have a very stiff stem worthy of your effort.
    I don't know that he was talking about plywood for the futtock style layup. It works pretty well in solid wood, and is a little quicker and doesn't make as much sawdust as laminating. The downside is changing grain direction on either half of the stem (or frame). John Gardner was a proponent of this method of laminating. Its certainly a good way to do dory frames and stems.

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    Default Re: JIM, an 18 foot canoe yawl.

    I don't see a problem at all with a stem glued up with solid wood. Iain shows a couple of methods in his book. Cut from solid wood in the traditional way - just epoxy glued at the joint that would otherwise be mechanically fastened, or glued up from staggered pieces like Crickets futtocks as discussed.

    I chose to do the laminated way more for the best use of the material I had rather than the additional strength, it's not like them stems will be standing there all on their own. I would do them based on the best use of the material.

  28. #63
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    Default Re: JIM, an 18 foot canoe yawl.

    [QUOTE=Vernon;3486498]...Cut from solid wood in the traditional way - just epoxy glued at the joint that would otherwise be mechanically fastened, or glued up from staggered pieces like Crickets futtocks as discussed.

    A lot depends on the particular design of the stem. I'm not sure of the molded depth of Jim's stem, but it sometimes makes more sense to laminate. It does look like Jim has a very tight radius at the forefoot, though. Tighter by a lot than Oughtred's DE's, and similar to the Matinicus stem. In my case, I used the solid construction like Vernon mentions, but the molded depth is quite large, and the timbers are beefy. Any of these methods will produce a strong stem. On the Matinicus, the outer stem (apron) was laminated, but it doesn't wrap around the forefoot. This setup really consists of stem and knee.


    This is the lofting of stem and sternpost.


    and this how the parts were bolted together.

    Cricket

  29. #64
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    Default Re: JIM, an 18 foot canoe yawl.

    Since you've gone to so much trouble with the laminations & mold you might as well give it one more try. As has been noted before the inner (darker) lams bent fine and two of the lighter colored lams are OK too.

    There are several possible causes. The broken lams may have separated from the others at the point of max bend so the bend in them became sharper. Or perhaps one broke at first and the force on it was transfered to the others which then followed suit. Also, it looks like the grain in the broken lams runs off the edge.

    Try again but this time apply clamps or bindings as you bend the lams around the mold. Take care to cut with the grain, you can split a piece off the plank to establish the grain direction if it is hard to see, and arrange for the straightest grain to be at the sharpest bend.

    Air-dried wood bends easiest but I find I can bend kiln-dried wood 1/8" thick around a 6" bend radius, with a little surface moisture applied a half-hour or so before, provided I take it slowly to allow the wood time to accommodate the bend. I use a water-based glue like Titebond III since it tolerates the moisture, and the glue edges get sealed by epoxy when the planks are attached. The moisture discourages splitting at the surface which leads to a full break. Heat is helpful for bending wood.

  30. #65
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    Default Re: JIM, an 18 foot canoe yawl.

    You could pre-bend the thin laminations using dry heat. Instrument makers use dry heat with a bending iron. The bending iron could be something available for sale to luthiers or you can make one up with a short length of pipe and a torch. Pre-bend the laminations to as close to the final curve as you reasonably can and bend them the rest of the way as you lay up the lamination.

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    Default Re: JIM, an 18 foot canoe yawl.

    Quote Originally Posted by jim_cricket View Post
    I don't know that he was talking about plywood for the futtock style layup. It works pretty well in solid wood, and is a little quicker and doesn't make as much sawdust as laminating. The downside is changing grain direction on either half of the stem (or frame). John Gardner was a proponent of this method of laminating. Its certainly a good way to do dory frames and stems.
    I kinda flew off the handle there, thinking in terms of a plywood stem only. So let me offer a more balances opinion.

    A stem made up of layered futtocks in solid wood is quite acceptable, and I did it that way myself on my first build. Dealing with the changing grain direction is a real nuisance when it comes time to bevel. Yes, Sir Iain offers that method using solid wood, so there'll be no objection from me. Be sure to remove any temporary fasteners as early as possible or you'll curse the heavens trying to get them out after the epoxy is fully set. Yup, made that mistake also.

  32. #67
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    Default Re: JIM, an 18 foot canoe yawl.

    Quote Originally Posted by TerryLL View Post
    . . . Be sure to remove any temporary fasteners as early as possible or you'll curse the heavens trying to get them out after the epoxy is fully set. Yup, made that mistake also.
    Sage advice indeed! I used thin nails to hold a laminated outer stem in place. Thinking the epoxy couldn't get much of a grip on the nails and would hardly be stronger than the steel I didn't bother to remove the nails for a couple of days. even though they were not in deep half the nails twisted off when I tried to remove them. Should have got them out at the epoxy's plastic stage. I have since been told heating them with a soldering iron would have released them . . .

  33. #68
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    Default Re: JIM, an 18 foot canoe yawl.

    Quote Originally Posted by TerryLL View Post
    Peter ,

    Don't do it, don't do it. A glued-up plywood stem is just so amateurish. Yes it's easy, sufficiently strong and stiff, quick, and cheap. But this boat deserves better.

    Just take those DF lams and lay them out flat on a towel. Put another towel on top and pour on the boiling water. In 15 minutes those lams will bend around that form with nary a complaint. Clamp them there overnight, unclamp in the morning. Truss up each one with some string so they hold their shape and let them dry for a day or two. Then back on the form with a decent layer of thickened epoxy. With that many lams you'll have a very stiff stem worthy of your effort.
    I'm not talking about using plywood Terry .... I'm sure I didn't say that . I have lots of good timber here, mountains actually . I was a bit disappointed that 1/8" laminates broke so looked up IO's plywood boat building book and there was his suggestion , a built up stem as his first option, laminations second .

    I'll have another look tomorrow as today is all day driving. Thanks for the boiling water suggestion .We'll see how it goes but right now a multi layer lamination from flat timber meets standards.
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    Default Re: JIM, an 18 foot canoe yawl.

    Aren't you done yet? You've had a whole week to build this thing already.

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    Default Re: JIM, an 18 foot canoe yawl.

    Quote Originally Posted by PeterSibley View Post
    I'm not talking about using plywood Terry .... I'm sure I didn't say that .
    Peter ,

    No you didn't mention plywood for the stem. It's not the first time I've shot off a reply before carefully reading the post, and probably not the last. My sincere apologies.

    Terry

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