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Thread: Making a birdsmouth catboat mast

  1. #36
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    Default Re: Making a birdsmouth catboat mast

    Anyone handling a load of lumber soon realizes that there's a difference in density between different planks of the same species. With this in mind I weighed each stave, then divided the weight by the length in feet. The result is a weight per running foot, the number written on the end of each plank. As is obvious, there is a significant range, the densest being almost half again as heavy as the lightest.

    The idea here is to use the heavier pieces in the bottom of the mast and the lightest in the top. When making up the eight staves pieces will be chosen from the pile according to their position in the mast.



    Last edited by Jim Ledger; 07-20-2017 at 07:06 AM.

  2. #37
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    Default

    Ok now you've clearly put far too much forethought into this!
    No adversary is worse than bad advice.

  3. #38
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    Default Re: Making a birdsmouth catboat mast

    Fir responds well to climb cutting with router or shaper; depending on grain sometimes it is necessary and as you say to be undertaken with caution. Where did you order that mast stock with the built-in taper? / Jim

  4. #39
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    Default Re: Making a birdsmouth catboat mast

    Quote Originally Posted by P.L.Lenihan View Post
    Good Morning Mr.Ledger,


    Great to see you able to tackle so many interesting boat bits despite the weather. Has me longing for my dearly departed bow shed like there's no tomorrow!

    You may have to get yourself an antipodean translation dictionary when dealing Gary. Recall, he is the one who not all that long ago made light of his mast with this brilliant pose:


    What some would call heavy, he would probably call light.He's tiger in disguise, he is and not easily dissuaded from manly tasks!

    I hope your mast comes out to a manageable weight.....but not too light,mind you, as I've read how cats like some heft way up front like that....something to do with gentle motions and loose vectors,if I recall.




    Cheers!



    Peter
    Not wishing to belittle my achievement in the eyes of others, I will point out the 44 gal drums at each end that it rested on.
    I was concerned about the weight and how it would affect the trim of the boat being so far forward. I can say the effect is not as far as I can tell when under sail, noticeable. Redwing as actually quite stiff once heeled to the upper chine.
    It really is a great way to make a relatively light hollow timber mast.
    The definition of stupid has got to be the belief that more guns will negate the bloodshed done with guns.

  5. #40
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    Default Re: Making a birdsmouth catboat mast

    How many bird's mouth masts have you made previously? I would only think of some of these details AFTER the mast was finished. I'm in the process of building a little one (18') right now. Hurry up so I can see what I need to think about.

  6. #41
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    Default Re: Making a birdsmouth catboat mast

    Quote Originally Posted by dktyson View Post
    How many bird's mouth masts have you made previously? I would only think of some of these details AFTER the mast was finished. I'm in the process of building a little one (18') right now. Hurry up so I can see what I need to think about.
    This my first go at a making a birdsmouth mast. Don't wait on me because I won't be able to glue up until the warmer temperatures arrive. Good Luck and don't forget to post some pictures!

  7. #42
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    Default Re: Making a birdsmouth catboat mast

    You grow more and more trustworthy with each passing day.....

  8. #43
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    Default Re: Making a birdsmouth catboat mast

    Quote Originally Posted by Jim Ledger View Post
    This my first go at a making a birdsmouth mast. Don't wait on me because I won't be able to glue up until the warmer temperatures arrive. Good Luck and don't forget to post some pictures!
    ok Jim, I'll just have to wing it. I have been posting some preliminary pics on my humble thread.

  9. #44
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    Default Re: Making a birdsmouth catboat mast

    Quote Originally Posted by dktyson View Post
    ok Jim, I'll just have to wing it. I have been posting some preliminary pics on my humble thread.
    Have a look at this link and you will find a couple of other very helpful articles on Duckworks as well.
    http://www.duckworksmagazine.com/04/...outh/index.cfm
    When it comes to working out the specs for your spar that site is worth it's weight in gold.
    The definition of stupid has got to be the belief that more guns will negate the bloodshed done with guns.

  10. #45
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    Default Re: Making a birdsmouth catboat mast

    Quote Originally Posted by dktyson View Post
    ok Jim, I'll just have to wing it. I have been posting some preliminary pics on my humble thread.
    Have you been following John Hartmann's thread A Ilur in Vermont? He's doing small birdsmouth masts right now and is going into quite a lot of detail.
    I was born on a wooden boat that I built myself.

  11. #46
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    Default Re: Making a birdsmouth catboat mast

    Quote Originally Posted by Rich Jones View Post
    Have you been following John Hartmann's thread A Ilur in Vermont? He's doing small birdsmouth masts right now and is going into quite a lot of detail.
    Heading over there now...

  12. #47
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    Default Re: Making a birdsmouth catboat mast

    There will be roughly twenty scarf joints to be made to join the stave parts end to end, forty ends. The scarfs will be roughed out with an adze, cleaned up with a slick and finished off with a hand plane.

    Here's a video of the roughing out process...


  13. #48
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    Default Re: Making a birdsmouth catboat mast

    Hi Mr.Ledger,

    It is difficult to imagine a better way to be greeted, upon waking up, then to see the past meeting the present in this fine video demonstration of an adze in use.

    A few questions,if I may.

    1) Is the far end secured some way to the shop floor to prevent the stave from getting kicked forward with each throw of the adze?

    2) Would securing the stave somehow, near its' worked on end, keep it from hopping around with each throw of the adze?

    3) Being able to sight the scarf line accurately would appear to suggest a bent over working postion, the use of a mirror or you've better eyes than I. Which is it?

    4) When you say the adze is rather sharp, is it sharpened to a fine chisel edge,micro bevel and all or is it sharpened like your big slick shown in a previous video?


    After the third viewing of the video, it occurred to me how perhaps it is somehow better to have the stave loose so that it may precisely move around somewhat to thwart a mis-aligned throw of the adze instead of wreaking havoc on the surface. Just ideal thinking, pre-coffee uptake.


    Thanks for taking the time to video document this interesting and useful application of an adze.





    Cheers!



    Peter
    Do it,do it,do it,do it,do it,do it,do it,now!
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    This boat was built with ten thumbs.No fingers were harmed in anyway.

  14. #49
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    Default Re: Making a birdsmouth catboat mast

    That was so interesting, even my one year-old son wanted to watch.

    It looks like great cardio exercise.
    There's the plan, then there's what actually happens.

    Ben Sebens, RN

  15. #50
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    Default Re: Making a birdsmouth catboat mast

    Excellent.

    Same muscles as pulling a bull rake? Close?

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  16. #51
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    Default Re: Making a birdsmouth catboat mast

    Wow! I own an adze and can use it but I settled for a router and jig.
    The definition of stupid has got to be the belief that more guns will negate the bloodshed done with guns.

  17. #52
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    Default Re: Making a birdsmouth catboat mast

    Being slack I'd do two half depth cuts with my 7 1/4'' Makita . Very neat Mr Ledger !
    '' You ain't gonna learn what you don't want to know. ''
    Grateful Dead

  18. #53
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    Default Re: Making a birdsmouth catboat mast

    There are eight staves, each comprised of at least three pieces. Each piece has an inside and outside, as well as a top and bottom and a place in the glued up stave. The chance of a mix-up is high. To mitigate the possibility of error I'm using a simple system of markings on the face of each piece.

    The photo below shows two of the marks. The top one translates to the outside face of stave #2, third section up, with the points pointing to the top of the mast. The other is the second piece up in #4 stave. If the staves are assembled in proper order there should be no joints within two feet of each other anywhere. Adjacent joints are spaced further apart while close joints occur on opposite sides of the mast..



    Last edited by Jim Ledger; 07-20-2017 at 07:08 AM.

  19. #54
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    Default Re: Making a birdsmouth catboat mast

    As I glue up the scarf joints I'm using a piece if heavy aluminum square tubing to align the birdsmouth notches across the joint. After clamping the joint the tubing is removed.





    Last edited by Jim Ledger; 07-20-2017 at 07:09 AM.

  20. #55
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    Default Re: Making a birdsmouth catboat mast

    Quote Originally Posted by Jim Ledger View Post
    As I glue up the scarf joints I'm using a piece if heavy aluminum square tubing to align the birdsmouth notches across the joint. After clamping the joint the tubing is removed.



    I can just imagine you in bed at 2 a.m., laying there thinking up ways to make things simplier and less prone to problems!
    I was born on a wooden boat that I built myself.

  21. #56
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    Default Re: Making a birdsmouth catboat mast

    Quote Originally Posted by Rich Jones View Post
    I can just imagine you in bed at 2 a.m., laying there thinking up ways to make things simplier and less prone to problems!
    More likely find me eating a bowl of Corn Flakes while reading a Far Side collection.

    Here are three staves during a glue-up. The weather has been unusually mild for the past couple of days. Most of the scarfs have been cut and about half have been glued up.



    Last edited by Jim Ledger; 07-20-2017 at 07:10 AM.

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    Default Re: Making a birdsmouth catboat mast

    You may want to explore those pitch pockets a bit, to determine extent. That fir looks nice Jim; got any room inside the mast for some aluminum foil? / Jim

  23. #58
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    Default Re: Making a birdsmouth catboat mast

    Quote Originally Posted by chas View Post
    You may want to explore those pitch pockets a bit, to determine extent. That fir looks nice Jim; got any room inside the mast for some aluminum foil? / Jim
    Would the aluminum foil inside the mast be some sort of radar reflector? What other purpose?
    I was born on a wooden boat that I built myself.

  24. #59
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    Default Re: Making a birdsmouth catboat mast

    Sorry Rich, I didn't explain that well. Somewhere I read about foil in a hollow mast serving to highlight your wooden boat on a radar screen; seemed to make sense although I recall some discussion as to its effectiveness. / Jim

  25. #60
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    Default Re: Making a birdsmouth catboat mast


    Would the aluminum foil inside the mast be some sort of radar reflector? What other purpose?
    The WBF's very own, dearly departed late and great Chuck "Paladin" Phillips had much to say on this subject.


    http://forum.woodenboat.com/showthre...nside-the-mast
    http://forum.woodenboat.com/archive/...p/t-18410.html
    http://forum.woodenboat.com/archive/.../t-113943.html
    http://forum.woodenboat.com/showthre...AR-Regulations
    http://forum.woodenboat.com/archive/...p/t-42873.html

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  26. #61
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    Default Re: Making a birdsmouth catboat mast

    Simply brilliant Sir Jim. The range of skills you attempt to master knows no bounds. Kudos.
    If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.
    -Henry David Thoreau-

  27. #62
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    Default Re: Making a birdsmouth catboat mast

    Quote Originally Posted by Jim Ledger View Post
    There will be roughly twenty scarf joints to be made to join the stave parts end to end, forty ends. The scarfs will be roughed out with an adze, cleaned up with a slick and finished off with a hand plane.

    Here's a video of the roughing out process...
    Just catching up on threads up here in B&R, this one in particular: Nice work Jim! I remember hearing the proper way to learn using an adze like that is to have steel caps and a double layer of old olive oil tins opened up and used as shin guards as mistakes can be quite messy.

    Did you have a mirror off to the side so you could see the line you were cutting to?
    Jarndyce and Jarndyce

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  28. #63
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    Default Re: Making a birdsmouth catboat mast

    Quote Originally Posted by chas View Post
    You may want to explore those pitch pockets a bit, to determine extent. That fir looks nice Jim; got any room inside the mast for some aluminum foil? / Jim
    Thanks, Jim. The pitch pockets were both few in number and shallow, nothing a little thickened epoxy won't cure should one dare to show up on the finished surface. There will be plenty of room for foil, I just have to determine the best way to contain it , maybe a couple of onion bags filled with strips tacked in fairly high up.

    Here are a two staves being glued full length...




    Last edited by Jim Ledger; 07-20-2017 at 07:11 AM.

  29. #64
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    Default Re: Making a birdsmouth catboat mast

    Quote Originally Posted by Duncan Gibbs View Post
    Just catching up on threads up here in B&R, this one in particular: Nice work Jim! I remember hearing the proper way to learn using an adze like that is to have steel caps and a double layer of old olive oil tins opened up and used as shin guards as mistakes can be quite messy.

    Did you have a mirror off to the side so you could see the line you were cutting to?
    An adze mistake would be messy, Duncan, which is why you don't want to try it in sneakers. Also, no mirrors were used in the production of the video, an occasional glance at the side was all that was needed.

    I'll admit that the adze work was a bit of grandstanding. I have power planes that would have done the job faster, unless you count the sweeping up. I like using the adze, though, and take advantage of all the opportunities I get to get in some practice. There was a marked improvement in my technique over the course of cutting the forty-odd scarf ends, the video being about halfway in. The aim improves which allows cutting with more assurance and authority. The pacing slows which allows heavier strokes with less effort. I can't imagine how good someone would get with proper instruction and a lifetime of practice. We'll never know.

    A glued-up scarf showing optimal squeeze-out, visible all along the joint, but not too much.



    Last edited by Jim Ledger; 07-20-2017 at 07:12 AM.

  30. #65
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    Default Re: Making a birdsmouth catboat mast

    Quote Originally Posted by Sailor View Post
    Simply brilliant Sir Jim. The range of skills you attempt to master knows no bounds. Kudos.
    Nah, not really, one time I was brilliant...now not so much.





    So, you've milled the lumber, glued up the staves, the next step is to cut the staves to the correct taper.

    We have three control diameters given in the plans, deck level... 8 1/2", up where the gaff jaws bear when the sail is hoisted all the way... 7 5/8", and the top of the mast at 3 1/2". It's goint to be a straight line from the deck to the hoisted gaff jaws, a straight taper. From there to the top is a nice fair curve.

    It's good to do a layout of the mast in shortened form. If you draw the height of the mast at, say, 3"=1', while keeping the width full size, you will have a handy reference. The taper of the mast can be drawn on this foreshortened view, which will give you the diameter at any point, should you need to know it.

    Maybe you've drawn out the staves in cross section, or even done them in Autocad or some such. It's a fine excercise, but put them aside. In order to plot the varying widths of the staves the absolute best way is to use slices of the actual milled stock. As shown in the photo, slices can be cut on a chop saw, their length cut against a stop. By trimming the actual stock very accurate widths can be determined. Drawing full-size will put you in the ballpark, but small differences in thickness or the birdsmouth not coming to a sharp point will throw the numbers off.




    Last edited by Jim Ledger; 07-20-2017 at 07:12 AM.

  31. #66
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    Default Re: Making a birdsmouth catboat mast

    That looks like a great way to find the size of any solid plugs. Are you planning any non-hollow sections?
    No adversary is worse than bad advice.

  32. #67
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    Default Re: Making a birdsmouth catboat mast

    Quote Originally Posted by Figment View Post
    That looks like a great way to find the size of any solid plugs.
    You can see that very thing here: http://forum.woodenboat.com/showthre...19#post3671719

  33. #68
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    Default Re: Making a birdsmouth catboat mast

    I've thought till now that these birdsmouth masts were only viable in small boats - and haven't bothered to read about them before opening this thread. A very interesting thread - where I also see some fairly large masts in progress and finished. Impressive products in every way.


    So, now I have a question about replacing the solid wood mast I now have in my 22sq.m. with a stiffer, lighter birdsmouth mast. Is a 40ft mast with an even taper from about 5 inches at the foot to about a 3 inch diameter at the top a reasonable project in a birdsmouth? I'm thinking 8 sides for the convienence.
    The original mast was a solid, laminated spar. I broke that and made a solid, unlaminated sitka pine replacement which was 6in at base originally, but has dried to about 5.5 in and is too willowy. It would be a good project if this birdsmouth technique could give something similar to the original in weight and stiffness. What do you knowledgeable guys say to that?

    Whether yea or nay, this has been an interesting read.

  34. #69
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    Default Re: Making a birdsmouth catboat mast

    I haven't checked all of the linked references, so this may have been mentioned previously. Earlier there was a comment about the size of the spar. I went back and looked at Lucky Luke's account of his massive spar making project. I don't do the linking thing, but Luke's project can be found by searching Building 72'schooner in Viet Nam
    Post #1380 Starts - “ it is noteveryday that a 35cm. diameter, 700 kg. mast is made (and to follow will be37cm. and over 800 kg!), here are some photos of making the foremast!”


  35. #70
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    Default Re: Making a birdsmouth catboat mast

    Last edited by kc8pql; 01-17-2014 at 02:18 PM.

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