Wood for Birdsmouth mast

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  • 26 Jul 2019 13:17
    Reply # 7798027 on 7571097

    This is an article I wrote on building my mast. I used recycled Oregon otherwise known as Douglas Fir. The process is comparatively easy though there is a good bit of work in it. There were a few knots in the timber but as long as they are not loose or checked, or too many it should be okay.

    Birdsmouth mast construction


  • 17 Jul 2019 11:52
    Reply # 7783786 on 7571097

    Thank you all for all the advice. However plans have been put on hold for a while. My younger brother got a year long contract in Dublin and needed some cheap accommodation. We sailed Rougette down to Dun Laoghaire last week. So I am boatless for a year. I shall hopefully use this time to look into all the ways I might acquire a mast.


    michael

  • 09 Jul 2019 22:43
    Reply # 7771310 on 7571097

    Hi Michael,

    Annie Hill very kindly mentioned me (in Perth) and also Dan Johnson (Ullapool). We are sometimes known as Mast Partners - Dan on the build side and me on the wood procurement and milling side. I didn't realise that you are in Scotland. Very much within coo-ee as Annie puts it!

    I've cut two masts on my mill for Dan, who was carrying out conversions to two boats recently. One was simply 8 sides and tapered, solid, at about 30' if I recall rightly, and we cut it up the middle having shaped it to 8 sides and tapered so that Dan could hollow it out and glue it back together. The other was used solid and, as it was a bit smaller, Dan took it 4 sided with the taper cut.

    Last year we converted our Cornish Crabber pilot cutter ANNIE (29'6") to a JR with great effect. She's been based in Crinan for about 35 years. Our mast we made out of locally-grown and air-dried Douglas fir, laminated and solid. One day I might hollow it out, or build one in the birds-mouth method but the one we have seems good for our 6.5 ton centreboarder. The weight is absolutely not an issue.

    You've already had good advice here regarding  timber quality. Anyway I would be happy to discuss timber etc if you want to get in touch.

    Pol.

  • 14 Jun 2019 08:24
    Reply # 7579153 on 7571097

     Staved timber mast

    Hi Michael

    I have built 24 staved timber mast out straight Oregon planks 50 mm thick

    The mast has been in use for 10 years. Each mast took me 3 month to build.

    In JRA Magazine 66 page 10 I have shown, how it could be done

  • 13 Jun 2019 14:28
    Reply # 7577372 on 7571097
    Anonymous member (Administrator)

    Frankly, Michael,
    I think it will cost you a lot more in work to build a mast from staves. Besides, the grown mast should be shaped (at least to 8-sided) and then cut in half and dug out, while the trunk is still raw. This speeds up the drying process to a few months and prevents plitting.

    Unless you already have the new junksail, the maststep and partners ready, then sailing with a JR this summer is out of the question.

    If you plan and do your homework properly, you will be ready for take-off in May, next year.

    Good luck!

    Arne


    Last modified: 13 Jun 2019 20:31 | Anonymous member (Administrator)
  • 13 Jun 2019 11:38
    Reply # 7577068 on 7571097

    Thanks for all the replies, most grateful. My hopes for a very cheap mast seem to have been dashed. 

    Annie I did not know that about my local junkies so maybe I will contact them.

    I believe using a grown mast would involve many months waiting for 

    it to dry out and then shaping it. The birdsmouth method would give me a mast very quickly.

    If I had sufficient funds I would call ALC to find out what they would

    charge for a 10m tapered column delivered to Ardoran Marine, Leargs by 

    Oban but am afraid to ask.

    About the PT wood. Before I raised the question I did do a search on the web and the 

    consensus seem to be that as long as the wood was given sufficient time to dry

    it would be ok for gluing. The treatment adds moisture to the wood and it is this 

    which causes the problem with gluing.

    I also had a crazy thought that I could fill the core of the hollow mast with

    closed cell foam to give it more structural integrity.

    Anyway I will go away and think some more.


    Michael

  • 13 Jun 2019 09:19
    Reply # 7576995 on 7571097
    Hey, Michael, are you a lucky man?  You live within coo-ee of Pol Bergius, who has his own sawmill and Dan Johnson, who makes wooden masts.  And they both own junks.  I suspect if the three of you get together, you could come up with a plan.
  • 13 Jun 2019 09:13
    Reply # 7576994 on 7571097
    Anonymous member (Administrator)

    There is an exception to the clear grain timber rule: There may well be some knots in masts, either solid or dug out, made directly from a trunk of wood. These knots stand at right angle to the surface and do no harm.

    Besides, if boats only could be built from clear, knot-free timber, then there would not have been any boatbuilding in my country, which there certainly has been, and still is.

    What I admire most with local wooden-boat builders (apart from their skills with their axe), is their ability to ‘read’ the wood and make sure the knots are placed so they do no harm (no knots at the plank’s edge, for instance).

    That said, I agree that the originally shown ‘fence planks’ didn’t look good for masts, with the knots all over the planks and in awkward positions.

    Arne


  • 12 Jun 2019 21:37
    Reply # 7575797 on 7571097

    As the others have said you certainly want clear grain good quality timber for a mast, and really for any other boat construction. It does not necessarily need to be an exotic timber. My recently sold junk rig yacht 'Footprints' had a timber mast, (staved), constructed from straight grain Pine which is our standard plantation grown building timber here in New Zealand. At 21 years that mast is still in excellent condition.

    It is often surprising what you can find in a local area. I had this dilemma when looking for framing timber for the catamaran I am building. All the exotic framing suitable timbers were very expensive and not available locally. In the end I found a local timber mill who specialise in a timber we call Macrocarpa, but which is actually Montery Cypress. I was able to purchase all my framing timber for a very reasonable price as straight grain clears. The only downside was that they were shorter lengths so for stringers I have had to scarf together to get longer lengths. But you can become proficient at scarfing pretty quickly.

    Last modified: 12 Jun 2019 21:49 | Anonymous member
  • 12 Jun 2019 15:49
    Reply # 7574315 on 7571097

    I've only tried to epoxy pressure treated wood once, and it did not hold well.  I really wouldn't do it on a mast.

    To echo David, though, the problem with the wood you have indicated is that the quality is way below what you want.  Knots in the wood, depending on location and orientation can reduce the piece's strength to almost zero.  Clear straight grain is the way to go.  

    That said, I have had some luck with the general big-box stores like Lowes or Home Depot.  You buy carefully selected large width and length 2x8, 2x10, or 2x12s, and rip the outer sides off, which can give you straight grain quarter sawn Douglas fir. If you flip them end for end, you can mitigate out some of the imperfections. You throw away the middle piece, which is nearly always flat cut.

    But I wouldn't do that for a mast, though, either.  Dimensional lumber like that is usually kiln dried and has all sorts of internal stresses that make themselves known six months after assembly in the form of twists and bends.

    You want to make friends with your local sawmill.  Explain what you're looking for, and how you want to use it.  They are usually helpful and knowledgeable.  Sometimes they are real scoundrels, too, so do your homework.

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