Is this a Catamaran or a Quasi-Catamaran?

Discussion in 'Boat Design' started by SmallLight, Aug 24, 2025.

  1. SmallLight
    Joined: Aug 2025
    Posts: 21
    Likes: 9, Points: 3
    Location: Ontario

    SmallLight Junior Member

    Hello,

    I came across this boat, the “Catfish”, which is described as a catamaran.
    My intuition is that the design will have good initial stability, but is really more of a monohull.
    Is this a good design, or neither fish nor fowl?

    [​IMG]
     
  2. baeckmo
    Joined: Jun 2009
    Posts: 1,864
    Likes: 890, Points: 113, Legacy Rep: 1165
    Location: Sweden

    baeckmo Hydrodynamics

    .....a monohull barge. A catamaran has a tunnel with an open water surface between its two hulls, and that makes a difference in behaviour.
     
    BMcF likes this.
  3. SmallLight
    Joined: Aug 2025
    Posts: 21
    Likes: 9, Points: 3
    Location: Ontario

    SmallLight Junior Member

    Thank you.

    What are the tradeoffs of this sort of hull versus a Jon boat with the same dimensions?
     
  4. clmanges
    Joined: Jul 2008
    Posts: 608
    Likes: 161, Points: 43, Legacy Rep: 32
    Location: Ohio

    clmanges Senior Member

    Fixed it for ya. Text options lack strikethrough.

    My impression is that some tinsmith was trying to emulate a RIB hull and quit before he finished the ends. And what's with the stitch-welds? I assume those are supposed to be reinforcement plates, but I think they're an invitation to disaster; any stress between the two pieces is going to focus on the ends of those stitches and try to unstitch them.

    [​IMG]
     
  5. SmallLight
    Joined: Aug 2025
    Posts: 21
    Likes: 9, Points: 3
    Location: Ontario

    SmallLight Junior Member

    Thank you for the delightful correction!

    I agree - the design seems to reflect intuition rather than careful analysis. When someone thinks they have solved a hull problem with a simple-to-produce, ‘proprietary’ solution, they probably haven’t.
     
  6. kapnD
    Joined: Jan 2003
    Posts: 1,539
    Likes: 558, Points: 113, Legacy Rep: 40
    Location: hawaii, usa

    kapnD Senior Member

    If pushed fast enough, it will function as a catamaran, but only practical in really smooth water.
    It’s basically an overcomplicated Jonboat.
     
    clmanges likes this.
  7. Ike
    Joined: Apr 2006
    Posts: 2,731
    Likes: 511, Points: 113, Legacy Rep: 1669
    Location: Washington State

    Ike Senior Member

    There is a simple solution to your question. The definition of a monohull is simply, sitting at rest in the water with a normal load (people,gear, engines, etc), it makes only one footprint . If you draw a waterline around the boat, and it's just one continuous water line, it's monohull. If you have two separate footprints it's a multihull.

    I doubt very much this boat would make two footrpints even on a plane.
     
    BMcF likes this.

  • 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.