What happens if I increase the size of the boat by 30% than the intented size

Discussion in 'Boat Design' started by abrahamg, Apr 13, 2005.

  1. abrahamg
    Joined: Apr 2005
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    Location: Cochin

    abrahamg New Member

    Hi everyone


    Can anyone tell me what happens if i increase the size of the sailboat by 30% for construction than it is intented for as stated in the design ???
    ( Basicly I intent to add 30% to all dimentions, including the frame thickness)

    Also please tell me how make a wooden mast or to find out the radius for a given mast and to put the sail groove in a wooden mast


    Any input will be greatly appriciated

    Abraham
     
  2. Thunderhead19
    Joined: Sep 2003
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    Thunderhead19 Senior Member

    I believe that this is a very bad idea, because the resultant effects on stability, resistance and the resulting forces on mast steps and decks doesn't change in simple proportion. You could be horrified at the outcome unless you crunch the numbers.
     
  3. jfblouin
    Joined: Sep 2004
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    jfblouin Senior Member

    When you change lenght by 30%, you change area by 69% and volume by 120% so your old boat of 30 feet and 6000 pounds displacement look 39 feet long and 13200 pounds displacement after a 30% upgrade. Like Thunderhaed16 said, all parameters while be change, you need to redesign the boat.
     
  4. abrahamg
    Joined: Apr 2005
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    Location: Cochin

    abrahamg New Member

    Thanks buddies.... I was just about to do that.. I changed the berths and the galley and the stowage and was thinking that's it, I got a bigger boat with more volume and cruising capacity.... Guess I have to start all over again....
     
  5. mackid068
    Joined: Feb 2005
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    mackid068 Semi-Newbie Posts Often

    Yeah, I guess you do. ;)
     
  6. FAST FRED
    Joined: Oct 2002
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    FAST FRED Senior Member

    Most times it works just fine , IF you crunch the numbers properly.

    It will take loads more than a 30% increase in balast , and sail area.

    You Might get away with only a 30% larger engine , as many sail boats are way overpowered to start with.

    FAST FRED
     

  7. chandler
    Joined: Mar 2004
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    chandler Senior Member

    Francis Kinney has a law of similitude. It deals with changing dimensions in designs. Maybe take a look at it in Skenes elements of yacht design. An excellent book anyway.
    He worked for Sparkman and Stephens as well as Rhodes so I think he may know what he's writing about.
     
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