Scaleing

Discussion in 'Boat Design' started by jjoftheusa, Feb 13, 2007.

  1. RANCHI OTTO
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    RANCHI OTTO Naval Architect

    Ranchi was never with his father on a lake when kid....your image is beautiful!

    When kid I went to fish with my father but in salt water and .....from a pier!
     
  2. Raggi_Thor
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    Raggi_Thor Nav.arch/Designer/Builder

    Ranch, I actually use 1 for all kinds of water :)
    That gives me a safety margin in saltwater, boats ussually grow heavier than we think.
     
  3. Raggi_Thor
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    Raggi_Thor Nav.arch/Designer/Builder

    I suppose you thing G is 9.8 also?
    OK, that's it :)
     
  4. RANCHI OTTO
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    RANCHI OTTO Naval Architect

    g = 9.81 depending where you are...

    1026 depending where you are too due to the salinity of water....

    1 depending on the purity of water...

    all is relative in this world......
     
  5. RANCHI OTTO
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    RANCHI OTTO Naval Architect

    For you I suppose g not G is 9.80665 m/s^2 at sea level lat. 45.5°......
     
  6. RatliffFranklin

    RatliffFranklin Previous Member

    Scaling

    Let's take 1/10th scale to keep the math simple

    1/10th width x 1/10th length x 1/10th depth = 1/1000th weight

    So let's say you have a model that's 3 feet long and weighs 4 pounds.

    At 1/10th scale that model would represent a boat 30 feet long weighing 4,000 pounds.
     
  7. Quicksilver
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    Quicksilver Junior Member

    thank you for the replies. Another question though, is 4000lbs reasonable for a boat that large? I don't know how much the Villain IV weighed, but it had 454's. http://powerboatlistings.com/view/2116. Mine sits in the water a bit low too
     
  8. RatliffFranklin

    RatliffFranklin Previous Member

    Weight

    Whether 4,000 pounds is reasonable depends less on the hull and more on the type and number of engines.
     
  9. RANCHI OTTO
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    RANCHI OTTO Naval Architect

    The displacement for the CHAPARRAL VILLAIN IV is according to tech. description in a spanish web of 3'500 kg (7'716 lbs) equipped with 2 x 365 hp.

    I don't know if this figure is for fully loaded, half load or empty....
     
  10. Quicksilver
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    Quicksilver Junior Member

    huh, see this is why I asked, 7lbs would be one heavy model, it would take a lot of power to get it out of the hole, I try putting 7lbs in the hull and see what the waterline looks like. I'm not really serious about getting the boat scale or anything, just interested in the subject.

    perhaps I'll try putting about 3/4 of a gallon of water in a jug in the empty hull, that would add up to around 7lbs. There's 3ft of snow on the ground, but luckily I have my trusty Rubbermaid test tank.
     
  11. Raggi_Thor
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    Raggi_Thor Nav.arch/Designer/Builder

    Isn't your scale 1:12?
    Then 7.716 lbs / 12^3 = 4.47 lbs
     
  12. RatliffFranklin

    RatliffFranklin Previous Member

    Scaling

    In that case a proper representation at 1/10th scale would be 7.7 lbs with .720 horsepower
     
  13. jim lee
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    jim lee Senior Member

    Well in my case, yes there is!

    My J/35. I just LOVE the boat. It was perfect in every way possible.. (IMHO) Until I had three kids. More room would be nice..

    Every larger boat I've seen is full of interior. Bathrooms, bedrooms, powder rooms, etc etc.. I just want a bigger J/35! Something can pack more kiddies and food into. And, I want it to sail like a J/35 should. 45' or so feet long?

    Is this possible? Would a scaled up J/35 still sail like a J/35? And how could "Sail Like a J/35" be measured?

    Many thanks in advance!

    -jim lee
     
  14. Raggi_Thor
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    Raggi_Thor Nav.arch/Designer/Builder


  15. jim lee
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    jim lee Senior Member

    Naw, I don't like the other J-boats. Too full O' junk inside.

    -jim lee
     
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