Lines Plan

Discussion in 'Boat Design' started by builtinpieces, Oct 25, 2009.

  1. builtinpieces
    Joined: Oct 2009
    Posts: 1
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Gulf coast

    builtinpieces New Member

    I'm looking to create a lines drawing for a ship. I chose a deck area, LBP, beam, depth, draft, and calculated the area for 10 sections, waterplane areas, prismatic coefficient, and other coefficients. Can anyone point me in the right direction as to how to approach the line drawing?

    I also need to create a table of offsets. Which I assume I do after I finish the line drawings and then just read the numbers from the drawing.
  2. jehardiman
    Joined: Aug 2004
    Posts: 3,411
    Likes: 809, Points: 113, Legacy Rep: 2040
    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    I start with a volume (displacement) to length curve for the speed-length ratio I want/am given (these can be looked up in a good NA text). This gives a the station areas and a midship section within beam and draft restrictions based upon standard types (cargo, combatant, speedboat, sail boat, etc.). You seem to have some of these already, so work them all up.

    The LWL to speed places the midship location, then I put in a few waterlines, diagonals (and or bilge radii) and a profile to cover the "cargo" block buildup (ie container hold stacks, cargo holds, staterooms, weapons, engine room and machinery spaces, etc.).

    Then the cross-checking of stations/waterlines/diagonals to the displacement-length curve goes through a few cycles as I put in some control points (design waterline, deck edge, turn of the bilge, etc) for each station and begin my weights. Cycle and repeat until structure, decks, weights, powering, and prime mover are pretty settled. Then I finialize the shell and do a clean lines plan. After the lines plan is finished and all the limits (tonnage, length, beam, etc) are met, then I pull the offsets off.

    Of course, a lot of that work today depends on how you are developing the drawing, by hand to be digitized or directly on the computer. Sometimes you need to work with (or around) any drafting program you are using. FWIW, I have not yet found a CAD program I like for developing a lines plan from scratch.
    bajansailor likes this.
  3. zeroname
    Joined: Oct 2008
    Posts: 276
    Likes: 5, Points: 0, Legacy Rep: 90
    Location: Europe

    zeroname Naval Architect

    well explained jehardiman,
    first calculate the principal particular from basis ship or formulas according to the type of your vessel.
    you may take this book as reference
    Ship Design and Performance for Masters and Mates by Dr C.B. Barrass

    then if u want to draw lines manually in autocad , use series 60 or some standard serios to produce offset table, then using the offset table draw your lines.

    or, if u just need to produce a lines following your selected particulars , and you can use maxsurf academic or fastship or Free!ship for this purpose.

Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.