Estimated displacement

Discussion in 'Boat Design' started by makobuilders, Apr 7, 2016.

  1. makobuilders
    Joined: Feb 2009
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    Location: Seattle, WA

    makobuilders Member

    Is there an accurate way to estimate the the displacement (at DWL) of a monohull trawler with the following dimensions?

    Length overall 13.85 m
    Beam 5.00 m
    Draft 2.00 m
    Gross tonnage 30.0 t
     
  2. Jamie Kennedy
    Joined: Jun 2015
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    Location: Saint John New Brunswick

    Jamie Kennedy Senior Member

    Use the block coefficient, whatever is typical for a monohull trawler. You may also have to account for overhang in length and beam, if any is typical for a monohull trawler.
     
  3. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    If the Gross Tonnage is defined as the total weight of the boat, that is the displacement. Otherwise, you could get a rough estimate with the waterline width and length, draft of hull (not including skegs) and the type of hull shape.
     
  4. TANSL
    Joined: Sep 2011
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    Location: Spain

    TANSL Senior Member

    No, Gross Tonnage is not the total weight of the boat.
    Could you give more details of this new method?. Is so, as you describe it, or is there any missing element to consider?

    Makobuilders, perhaps the attachment will be helpful.
     

    Attached Files:


  5. makobuilders
    Joined: Feb 2009
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    Location: Seattle, WA

    makobuilders Member

    In this case tonnage is definitely a measure of volume. I don't have the actual block coefficient, but using a comparable one the boat calculates to a displacement of 52 long-tons. Close enough, thanks.
     
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