Construction boat design Russian South America

Discussion in 'Wooden Boat Building and Restoration' started by Javier Salas, Dec 16, 2019.

  1. Javier Salas
    Joined: Dec 2019
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    Location: VENEZUELA

    Javier Salas Junior Member

    Hello everyone, I live in South America and I started to build a Russian design boat, in truth what I have done is just a notebook, preparing to continue with the work and studying the drawings in CAD, I observe that when measuring in alignment does not match with the horizontal measurement, example: in the first one it tells me that it is 300 mm and the second one is 254 mm, this puts me in doubt of what measurement I should use, note the horizontal measurement in the plane in JPG is similar to that of the cad 254 mm; please who can advise me on this question, thanks.
     
  2. bajansailor
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    bajansailor Marine Surveyor

    Welcome to the Forum Javier.
    Can you post any photos of the drawings showing your areas of concern?
    254 mm sounds like a metric equivalent of a dimension originally in inches (ie 10 inches).
     
  3. Javier Salas
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    Javier Salas Junior Member

    The measurements differ from cad to jpg image
     

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  4. bajansailor
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    bajansailor Marine Surveyor

    254 mm appears to be the height of the chine at this station.
    Are you saying that on another drawing the dimension is given as 300 mm?
    Do you have a lines plan or body plan or offset table that you can refer to, to see if this vertical dimension is in agreement?
     
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  5. Javier Salas
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    Javier Salas Junior Member

    The measurements in the image are different from those of the cad
     

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  6. BlueBell
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    BlueBell Ahhhhh...

    254^2 + 176^2 = 309
    64516 + 30976 = 95492

    Using Pythagoras Theory I get 309 versus 300 as shown.
    Close...

    I see you're measuring centre to centre.
     
  7. bajansailor
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    bajansailor Marine Surveyor

    I think I can see where the difference is - the 300 mm measurement is a diagonal measurement along the hull from the keel to the chine, whereas the 254 mm measurement is the vertical height of the chine above the baseline.
    The horizontal component of the triangle (ie the measurement sideways from the keel to the chine location) should be approx 160 mm (?).
     
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  8. BlueBell
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    BlueBell Ahhhhh...

    160 mm works with Pythagoras formula.
    Javier, is that an error on the drawing or plan?
     
  9. Javier Salas
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    Javier Salas Junior Member

    I don't understand Pythagoras very much, what I want to know in what format I make the cuts, with the image or the cad
     
  10. BlueBell
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    BlueBell Ahhhhh...

    Google it, it's good stuff.
    I'm sorry I can't be of further help.
     
  11. TANSL
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    TANSL Senior Member

  12. bajansailor
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    bajansailor Marine Surveyor

    I think that BOTH measurements (300 and 254) are correct for where they are indicated.
    Re Pythagoras, the equation is x.x = y.y + z.z
    Or in words, the square of the hypotenuse of a right angled triangle is equal to the sum of the squares of the other two sides.

    So we have (300 x 300) = (254 x 254) +(160 x 160)
    (approximately - I have 'rounded off' the 300).

    Note that the 300 dimension is from the side of the keel, NOT the hull centreline.
    The 'half width' of the keel is 15 mm; if we subtract this from the 176 mm shown, we get 161 mm - close enough to my calculated 160 mm.
     
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  13. Javier Salas
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    Javier Salas Junior Member

    I don't know but, I imagine it could be because of the missing sections because of the cutting angles
     
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  14. DGreenwood
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    DGreenwood Senior Member

    Javier. If your are able to use CAD to draw, try this.
    Draw a line horizontally through the lower point extending it out 200
    Next do the same with the upper point.
    Now take a dimension vertically between these lines.
    It will be 254.
    I think this will help you understand where the 300 comes from.
     

  15. Javier Salas
    Joined: Dec 2019
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    Location: VENEZUELA

    Javier Salas Junior Member

    Hello everyone, the general community of the forum is appreciated with all my heart, they were very kind with their collaboration, I already resolved the dilemma and I am happy to continue with my life project, thanks to the answers of the dear friends of the forum I resolved the doubt; Dear Javier: There is no contradiction between the two drawings, the jpg and the CAD. The measure of 254 is the VERTICAL distance from the spine to the horizontal baseline that passes through the keel. The measure of 301 is the distance between those two points but measured diagonally, measured on the hull panel. I hope I have clarified the problem. Both drawings are correct and say the same.
     
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