1) Are hulls same shape in a Cat 2) hull spacing

Discussion in 'Boat Design' started by Will, May 4, 2004.

  1. Will
    Joined: May 2004
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Florida

    Will New Member

    I'm thinking about building a catamaran... either power or sail.

    My question is... are the two hull's identical in shape?

    This would allow me to build only one mold.

    ALSO - is distance apart important? I'm guessing that the eddies and currents from the bow cutting thru the water would make it important to have some minimum distance between hulls for best performance.

    Thanks for any help.

    Will
     
  2. sorenfdk
    Joined: Feb 2002
    Posts: 511
    Likes: 27, Points: 28, Legacy Rep: 394
    Location: Denmark

    sorenfdk Yacht Designer

    The two hulls are not necessarily the same shape, but most are.

    The distance between the hulls is important, especially for a sailing cat. Larger distance = more stability, smaller distance = more resistance. But the distance can also be too large and make tacking difficult.

    Anyway - before you can begin building, you'll of course need a design. If you buy one, these problems have probably been solved by the designer. If you want to do the design yourself, there are a LOT more things to consider, so I would suggest you find all the relevant litterature you can, and start reading.
     
  3. Tim Bard
    Joined: Apr 2004
    Posts: 6
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Saudi Arabia /Australia

    Tim Bard Junior Member

    Look at Compu-Craft for plans >>> ccplans.com

    Col Clifford has a lot of designs and ~50 years experience.

    He is a very clever designer

    Tim
     
  4. sorenfdk
    Joined: Feb 2002
    Posts: 511
    Likes: 27, Points: 28, Legacy Rep: 394
    Location: Denmark

    sorenfdk Yacht Designer

    Oops - I forgot something!

    Most sailing cats have symmetrical hulls, BUT most powercats have asymmetrical hulls!
     
  5. Will
    Joined: May 2004
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Florida

    Will New Member

    Gee, I wonder why powercats have asymmetrical hulls and Sailing Cat's don't ?

    I thought many of the Sailing Cats were also being sold as Power Cats... just by leaving the mast off... but what do I know :)

    thanks for any additional comments - Will
     
  6. SailDesign
    Joined: Jan 2003
    Posts: 1,964
    Likes: 114, Points: 73, Legacy Rep: 650
    Location: Jamestown, RI, USA

    SailDesign Old Phart! Stay upwind..

    Distance between the hulls also affects drag - bigger distance, less drag. However, bigger distance also = more structure needed for cross-beams, etc. You pays your money and takes your choice :)

    Steve
     
  7. guest

    guest Guest

    No one mentioned, the seperation distance of a sailing cat is the big factor for speed. THe cat can take huge sail area because the cg when loading a hull is way outboard. A hobie 16 has asymetric hulls, and I've heard it allows the boat to perform without a centerboard, a lead I have not investigated. Most hulls separation distances are limited by the 8 or 8.5 foot max trailering width mandated by the DOT.
     

  8. guest

    guest Guest

    also, wrt some power cats, I have heard that assymetric shape has been used to lift water to a raised engine, like a tunnel hull allows a raised engine on flats boats. One usage.
     
Loading...
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.