Learning scantling, step 0: design flow

Discussion in 'Boat Design' started by magwas, Jan 2, 2010.

  1. magwas
    Joined: Oct 2009
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    magwas Senior Member

    Now a step back. It seems my first step was based on some misunderstanding.
    It is told to me that I need a General Arrangement plan to start scantling. I figured out (with some help) the requirements of a general arrangement plan (one which should accompany a boat ready to build, see the first step), and saw that there are items (like railings, navigational light locations, deck machinery, liferaft) which I would think should come later. Also it seems that general arrangement plan (which would be the base for scantling) should show size of items (which could be sized in the scantling process), like keel, rudder, mast, windows, etc.

    Thanks for SamSam for hint to the right directon.
    It is Stephen M. Hollisters "The Design Spiral for Computer-Aided Boat Design"
    See also http://www.boatdesign.net/forums/boat-design/design-spiral-where-start-building-boat-28580.html

    Now I think that the heated comments were due to two main reasons:
    1. I started the process somewhere in the middle, giving the impression I don't have a clue what is involved. Well, I don't. This is why I am asking.
    2. Some thought that I want to learn this whole thing in 5 minutes without effort. I assure you I know it is impossible. I am well aware that this will take lot of time, and I am prepared to start tens of forum threads about one small issue each.

    Some have recommended books to learn from. Thank you for it, I am sure they are great books. But for me it is important to rely only freely available information, and where there is not enough information available for free, to pop them into sunshine. I do not ask you to agree with me in my "quest to free information" :) , and more recommendations for paper books are welcome. But please be understanding when I ask about things which might be written in some paper books, but I won't read them there. I need Your insight.

    The Spiral describes the process like:
    Step 1. The Design Statement. - Define the purpose of the boat and quantify and list the major design attributes in decreasing order of importance. Include a measure of merit for the vessel, if needed.

    Step 2. The Conceptual Design Phase. - This step determines whether the boat described in the design statement is feasible and how you will have to modify the stated goals in the design statement to achieve a successful boat design. Principal dimensions, general arrangements, major weights items, and powering options are chosen and concept drawings are produced. This information is often included in a design proposal which is submitted to a prospective client. This step is often done on speculation in the hopes that the client will select the design for construction.

    Step 3 The Preliminary Design Phase. - This step determines the details of exactly how the boat will implement the results from the conceptual design process. The hull shape is finalized and more exact calculations are performed, including stability, performance, and structural calculations.

    Step 4. The Detailed Design Phase. - This step is concerned with producing the "deliverables" of the design project: a faired set of lines, a table of offsets, arrangement drawings, structural drawings, construction details, and specifications.

    As I understand it, 2-4 of the above steps all go throught the phases below:
    - Hull definition
    - Hydrostatics
    - Weights
    - Powering
    - Stability
    - Structures
    - Arrangements

    Based on the above, it seems that I will have general arrangement plan, but at first it would not be as detailed as the final one, and it will evolve by thinking through the phases above.

    Well, I think this entry is not much about questions, but just to record what I have figured out. I do have questions about details, but I will ask them when they are applicable. I plan to proceed with the design statement, and after that hull definition and hydrostatic in the conceptual step.
    The ever to be asked question still remains, however: is there any conceptual problem or misunderstanding of some detail in the above?
    (And please do not tell me that I will not be able to design a boat in two easy steps in five minutes. I know that.)

    See http://www.boatdesign.net/forums/boat-design/learning-scantling-design-statement-30778.html for design statement
    Last edited: Jan 2, 2010
  2. TeddyDiver
    Joined: Dec 2007
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    TeddyDiver Gollywobbler

    Just curious.. but what's your #1 , the design statement..
  3. magwas
    Joined: Oct 2009
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    magwas Senior Member

    I am working on it right now.

  4. Tad
    Joined: Mar 2002
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    Location: Flattop Islands

    Tad Boat Designer

    In your list of phases.....I presume that's the design spiral?......The most important thing is BUDGET......that rules every other decision.
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