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Thread: Strip planking and bulkhead insertion

  1. #1
    Join Date
    Oct 2019
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    Bath, UK
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    Default Strip planking and bulkhead insertion

    I've read a few strip-plank build logs now. As far as I recall, they have all built temporary frames on a stillage, planked over them, rolled the hull over and then inserted the bulkheads. Why don't builders replace the temporary frames with the bulkheads and plank directly on them? As far as I can see, the advantages are large:

    • No temporary frames to cut out.
    • It's a lot easier to fair in a bulkhead before the planks are on than to shape a bulkhead to be a close fit in the finished hull.
    • No clamping required during planking - the planks can be fixed directly to the bulkheads (eg with Raptor polymer brads that can just be left in place).
    • The hull is considerably stiffer when it is turned over.


    Even if there are not enough bulkheads in the design to completely replace the temporary frames, you can still replace some of them and gain the same advantages to varying degrees. As far as I can tell, the only downside is that once you've turned the hull over, all the bulkheads are in place and restrict access for installing the interior. Is that enough to offset the advantages?

    Some designs are not amenable to it, of course, notably ones that don't have (many) planar, full-width bulkheads. But it is mentioned as a good option in Dave Gerr's The Elements of Boat Strength.

    For designs that support it, why isn't it done this way?

  2. #2
    Join Date
    Jan 2017
    Location
    Manitoba, Canada
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    Default Re: Strip planking and bulkhead insertion

    Sometimes it is done this way. Years ago I built Elver, a Steve Redmond design; it is built upright by strip-planking directly on the bulkheads. There were no temporary frames as I recall.

    However, strip-planked hulls require a lot of interior scraping and sanding to get the inside of the hull smooth, and this is much easier to do properly without frames or bulkheads in place.

    Ken

  3. #3
    Join Date
    Oct 2019
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    Bath, UK
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    Default Re: Strip planking and bulkhead insertion

    Quote Originally Posted by Hull Speed View Post
    Sometimes it is done this way. Years ago I built Elver, a Steve Redmond design; it is built upright by strip-planking directly on the bulkheads. There were no temporary frames as I recall.

    However, strip-planked hulls require a lot of interior scraping and sanding to get the inside of the hull smooth, and this is much easier to do properly without frames or bulkheads in place.

    Ken
    If you were building her again, would you do it this way again?

  4. #4
    Join Date
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    Default Re: Strip planking and bulkhead insertion

    Many designs do. One of the main reasons for no internal framing is so a hull can be glassed inside before fitting out, if the design is for inside and external sheathing, otherwise im all for as many bulkheads fitted as possible during the planking process.

  5. #5
    Join Date
    Jan 2017
    Location
    Manitoba, Canada
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    Default Re: Strip planking and bulkhead insertion

    Well, that's the way an Elver is built; to do otherwise would require major re-thinking of the build sequence.

    But if I had the option I suppose I would use temporary frames, so I could do a better job on the interior hull than I did on the Elver. Yes, it would be tricky to fit the bulkheads into the hull, but that's part of the fun of boatbuilding - learning the techniques.

  6. #6
    Join Date
    Aug 2010
    Location
    Rockland Maine USA and Woodbridge, Suffolk, England
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    395

    Default Re: Strip planking and bulkhead insertion

    All my designs are built on permanent frames and bulkheads. That was the way we built wood-epoxy yachts of all sizes professionally over the years. If you are careful to remove any excess epoxy from the interior as you go, cleaning up is not usually a big deal. Tongue-&-groove strip planking (often called called "Speedstrip" in the UK) does a better job and makes a cleaner interior than either square-edge or cove-&-bead and is also just as easy as cove-&-bead to machine yourself.

    The only exception (to tongue-&-groove being superior to cove-and-bead) is when you have a reverse curve hull, rather than a modern canoe body. In way of the reverse curve, T&G will leave slightly open seams on the inside to be filled with thickened epoxy, whereas cove-&-bead likely will not.

    I have to say that all the hulls I have been responsible for building, and all my designs, are not simple strip-planked - the strips are just the inner skin to be followed by diagonal veneers or structural biaxial glass. And none of them have any requirement for glass clothing the interior.

    Cheers -- George
    To be truly free to live, one must be free to think and speak.

    A C Grayling

  7. #7
    Join Date
    Mar 2008
    Location
    Hulls Cove, ME
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    458

    Default Re: Strip planking and bulkhead insertion

    I built mine as you described; a combination of permanent bulkheads and temporary frames,strip-planked and cold-molded. Mark Smaalders’s designed Kahuna.

    http://forum.woodenboat.com/showthre...ar#post2077519
    Last edited by scottmacc; 10-01-2019 at 07:32 PM.

  8. #8
    Join Date
    Jan 2009
    Location
    northwestern Wisconsin
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    4,679

    Default Re: Strip planking and bulkhead insertion

    On my Alaska, the bulkheads did not go all the way to the sheer, but stopped at thwart height. I'd have had to extend them to build on, and then trim them later. Didn't seem to make a lot of sense. So, temporary molds it was, as shown in the plans.

    Tom
    You don't have to be prepared as long as you're willing to suffer the consequences.

    www.tompamperin.com

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