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Thread: Lofting and forms

  1. Default Lofting and forms

    Ok , this has probably been asked before but cant find where, I am starting a cedar strip long term project and I am using this prep time to learn the black magic of "lofting" because I want to live the whole deal , my question is do you think the offsets in canoe craft book are the same as the plans would be ,, call me paranoid but I wouldn't want to risc building from an example only table of spells because the company would obviously prefer you to buy the plan ? Wouldn't blame them that's business but then I wouldn't get a chance to enjoy lofting lol ?
    what do you think ?

  2. #2
    Join Date
    May 2007
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    Deepest darkest Wales
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    3,881

    Default

    It's the traditional way of doing the job.

    The caveat is that the offsets may not be accurate - any shortcomings should become apparent in the lofting process - a fair line takes precedence.
    This post may vanish at any moment.

  3. #3
    Join Date
    Mar 2008
    Location
    Dumbarton
    Posts
    2,608

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    Use the offsets to draw the lines plan.
    Start with grids for stations waterlines and buttocks and mark the offsets on for each curve, and then use a flexible batten to draw the curve through the marks - the batten needs to be flexible enough to follow a smooth curve, but stiff enough that it won't pass through any marks not on the smooth curve. Normally start with body plan then waterlines then buttocks, and if really fussy diagonals. Lift the points for subsequent plans from the previous one and if a point is not fair look at which way to move it and then update each plan until you get something fair on all views. Some boats may deliberately have hollow sections which can make fairing more challenging.
    When you are happy, translate to full scale from your body plan, this will give you a final check on the fairness of the line before you cut each frame.

    If offsets are computer generated, it is not usnusual for rounding accuracy to produce some points that are not on the original fair line so it is usually worth doing some fairing if working from offsets however reliable they should be.

    How hard can it be?

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