Small tacking equal length outrigger/catamaran.

Discussion in 'Multihulls' started by bearflag, Jul 5, 2010.

  1. bearflag
    Joined: May 2010
    Posts: 227
    Likes: 17, Points: 0, Legacy Rep: 195
    Location: Thousand Oaks, California

    bearflag Inventor/Fabricator

    The ultimate plan is to build a 20m-ish sized multihull in either a catamaran or an Equal-L Pro-a or tacking outrigger (can sail as an Atlantic or Pacific) for trans-oceanic travel. Must be livable, but not palatial. It is not intended to be a marina boat. Boat is intended to be sailed short handed at all times (1-2).

    However, I have a few wild-*** ideas about materials, and myself and a few of my associates think it is probably worth building a small, beach-cat sized boat for fun and what not, and to test out the sail plan, geometry, engineering, structure, hullshape, materials etc, before we commit the time and money to something much bigger (even though the big-daddy will most likely use more common, time-tested building methods and materials).

    So the question is, what sized (length) should I build for the prototype/beach cat. The final boat will be pretty low-slung, so for the mockup, an open floorpan will be a pretty close approximation. (the boat won't be an exact scale model, but is more intended to build proficiency and test the important parts)

    The design considerations:
    High L/D ratio.
    Semi-displacement, wave piercing, possible "ram" shaped bow. Lots of volume kept low up front.
    Shallow draft, no keel.
    Near minimum wetted area (alysoidal/circular) submerged hull. (slight rocker bow to stern)
    Hulls are fine up front and at the tail.
    Angled daggerboards
    Equal length (or near) hulls.
    Unequal hull volumes.
    Offset sailplan, sails will be located appx. 2/3ish towards the "thin" hull.
    Stayed rotating mast(s)
    "Thin hull" will have enough buoyancy so that the "fat" hull "could" fly, ie supports total weight of boat + dynamic forces.
    Boat is intended to be more stable than not. Although flying small boats is, fun, performance cruisers are not supposed to capsize. If any hull flies it should be the heavy/fat hull, or both of them, but not the "thin hull" only.
    Trailerable or more ideally roof mountable and put together or folded up in short order. From a beach or whatever.
    My pickup truck is 17 feet long. :)
    Ideally, it would be able to have a tent and or/ some scuba/spearfishing or camping gear for 2 people.
    The ocean is less than 10 miles from my house, so, I am not that worried about putting a boat on a roof if I build a rack for it.
    Will sail the california coast, possibly make trips to catalina etc if it feels seaworthy enough. Possible baja coast, gulf of california, lake powell, or pacific northwest.

    Any ideas/suggestions are welcome, though my main question is what lengths are most ideal for these constraints?

    17 feet, 20 foot, 24 foot etc. Does it need to be bigger?
  2. dstgean
    Joined: Aug 2006
    Posts: 142
    Likes: 5, Points: 0, Legacy Rep: 68
    Location: Chicago Area

    dstgean Senior Member

    length of cat

    17' if you are cartopping, 24 if you are trailering.


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