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Thread: Old drawing abbreviation mystery

  1. #1
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    Default Old drawing abbreviation mystery

    I have a set of professional drawings for a 1938 boat. The bottom frames show the dimensions as: SID. 7/8”, MLD. 1 1/2”
    It’s pretty clear that they refer to thickness and height, but what do those abbreviations stand for?
    Thanks
    Bill Foster

  2. #2
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    Default Re: Old drawing abbreviation mystery

    perhaps "sided" and "molded" which would indicate direction of measurement.

  3. #3
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    Default Re: Old drawing abbreviation mystery

    Sided and moulded.For example, a frame might be 1 1/2" sided and 1 3/4" moulded which means that the parallel faces are 1 1/2" apart and the curved (or moulded) faces are 1 3/4" apart.

  4. #4
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    Default Re: Old drawing abbreviation mystery

    ^or to put it another way, sided is the thickness of the slab that you saw the frames from.
    Or the width of the lamination that you stack up to laminate a frame, seven 1/4'' lams giving 1 3/4 moulding.
    It really is quite difficult to build an ugly wooden boat.

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  5. #5
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    Default Re: Old drawing abbreviation mystery

    Definitely "sided" and "molded", but if those numbers are correct the designations are reversed unless the frames are sawn from grown stock. It would be practically impossible to bend 7/8 x 1 1/2 stock against the 1 1/2 dimension against the hull or ribband. 7/8 x 1 1/2 stock is not unusual 7/8 bent against the hull form, molded, 1 1/2 the fore and aft dimension, holding it's siding. My take.

  6. #6
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    Default Re: Old drawing abbreviation mystery

    Quote Originally Posted by Thad View Post
    Definitely "sided" and "molded", but if those numbers are correct the designations are reversed unless the frames are sawn from grown stock. It would be practically impossible to bend 7/8 x 1 1/2 stock against the 1 1/2 dimension against the hull or ribband. 7/8 x 1 1/2 stock is not unusual 7/8 bent against the hull form, molded, 1 1/2 the fore and aft dimension, holding it's siding. My take.
    If they are the ''bottom frames'' they may be the floors linking steamed timbers.
    It really is quite difficult to build an ugly wooden boat.

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  7. #7
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    Default Re: Old drawing abbreviation mystery

    Atkin boat by chance? I believe he commonly used sided to mean the slab planed thickness and molded to mean the curved or other dimension, rather than the convention regarding tangent vs normal to the hull. Don't have any drawings near me to confirm.

    Edit- you reference bottom frames, is this a hard chine or flat bottom boat? Dimensions would make sense.

  8. #8
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    Default Re: Old drawing abbreviation mystery

    Quote Originally Posted by J.Madison View Post
    Atkin boat by chance? I believe he commonly used sided to mean the slab planed thickness and molded to mean the curved or other dimension, rather than the convention regarding tangent vs normal to the hull. Don't have any drawings near me to confirm.

    Edit- you reference bottom frames, is this a hard chine or flat bottom boat? Dimensions would make sense.
    That won't work, and I don't believe it is conventional. That would mean that every frame would have to be sawn out of differing thickness stock. If the boat is round bowed or in a fantail counter, you use cant frames to prevent the frame section becoming to extreme.
    It really is quite difficult to build an ugly wooden boat.

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  9. #9
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    Default Re: Old drawing abbreviation mystery

    Thanks to everyone for the helpful replies. Using your suggestions I was able to find a number of historical references to both “siding” and “mould” dimensions, specifically in reference to boat frames. Siding is clearly the fore/aft dimension and Mould(ing) refers to the tangential perpendicular to the arc of the hull) dimension.
    The drawings are for the early Lightning (Sparkman & Stevens). The dimensions I gave are correct for the bottom frames of that boat which are sawn or, more recently, laminated.

    Thanks again.

  10. #10
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    Default Re: Old drawing abbreviation mystery

    Thanks for the clarification. Not surprised that Olin was correct.

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