info on cat. conversion to two Sm. canoes / kayaks ?

Discussion in 'Multihulls' started by junkman, Dec 4, 2009.

  1. junkman
    Joined: Nov 2009
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    junkman Junior Member

    I'm playing with the idea of a catamaran that can be dismantled . The two floats placed beside one another and bolted down on top the frame that holds them together, (in the water) and then car topped. The other part is to make the two floats wide enough to use as two individual canoes or kayaks or the like, with out making them to bulky and slow for cat sailing.

    The purpose is to have fun with a little efficiency but focus on versatility.
    Some where between a rabbit and a turtle. I assume I'm the very first guy that has come up with this idea .... ha ! :D

    Any related threads or sites would be greatly appreciated.

    Thanks in advance,
     
  2. BWD
    Joined: Aug 2006
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    BWD Senior Member

    nothing new under the sun, they say, but good luck with your "Trabble."
    Some stuff to check for ideas/issues of interest if you haven't already:
    http://homepages.paradise.net.nz/garyd/
    and this blog for a start:
    http://sailnaway.blogspot.com/searc...-max=2007-01-01T00:00:00-05:00&max-results=20
    NCSU guys that made 2 dierking outriggers and operated them sometimes as a cat (at east once, anyway).
    Can also be done with kayaks.
    Maybe you should also look at Chris Ostlind's website, several things there might be compatible with your idea:
    http://www.lunadadesign.com
    Have fun.
     
  3. bill broome
    Joined: Jul 2008
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    bill broome Senior Member

    look into sailing canoes. there's two kinds really: canoe with a small sail, for fun and a bit of help with paddling is easy to organize. then there's the serious kind with a bigger rig and a hiking plank. this is basically a small
    trimaran without those sissy ayas.

    two canoe catamarans are possible, but they are flat bottomed and will slap in a chop. a big double kayak has a better shape for sailing, i'd try a tahitian sailing canoe plan first:

    it just needs a cross platform at the mast foot, where the crew keeps the boat upright by moving in and out on the windward side. put a very small aya on one side to keep the boat up when tacking. both sides if you prefer less drama. big drawback is pretty much need two crew.
     
  4. catsketcher
    Joined: Mar 2006
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    catsketcher Senior Member

    Go proa

    The cat will be slow and have insufficient buoyancy or the kayaks won't be stable enough to sit in and too high. Look up Gary Dierking and look at his outrigger canoes. Good for paddling and for sailing
     
  5. hoytedow
    Joined: Sep 2009
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    hoytedow Wood Butcher

    The first boat I ever built was just such a boat. Each hull was 1' x 2' x 8' with 2 2" x 4" x 6' beams holding the hulls together. Each beam was connected to the hulls with 4 5" bolts with 3/8" wing nuts and washers for a total of 8 bolts and wingnuts to connect the whole assembly together. I ran the boat on the Hillsborough River with a 5 hp Sears outboard for three years until I built my second boat. It was strong and faster than it looked, with room for 2 on board in good comfort. It was also because of the wide beam very stable and I could easily dive and re-enter the boat. Beam 6' length 8' hard chines to gunwale 1' draft 2 to 3" depending on load
     
  6. muddin redneck
    Joined: Jun 2009
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    muddin redneck DO IT IN THE MUD!!!

    Double Canoes For A Cat

    here are a few pics i found just the other day that i thought were just plain cool and used them as my computer background. it may give yoiu an idea on how to make you boat. the boat could be widened if you wanted to. hope this helps
     

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  7. junkman
    Joined: Nov 2009
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    junkman Junior Member

    Looks simple enough to build two p-redesigned hulls and mate them. If I can find a shape that lends itself to both needs. It look as the shapes will want to be low and wide- slow and choppy or high and narrow-difficult to row and balance. Perhaps not a rabbit or turtle, a "platypus".
    Ill look at all and see what comes of it. I'm not in a hurry as it will be about a year before I can hit water on the west coast. Something like a kayak sounds interesting but figure Tahitians have been at it some time, hull shape any way. Ill check out the sites Thanks Guys. for the information.
     
  8. dstgean
    Joined: Aug 2006
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    dstgean Senior Member

    I have been having fun with outriggers with just the sort of thing you are thinking of. Gary's Tamanu is great as an outrigger canoe and I used it paired with a Hobie 18 rig as a big comfortable cat in last year's Texas 200. It can be done and I think the idea has been around for several thousand years.

    Another related idea is the boat built for the expedition around OZ. Two kayaks specifically designed to mate as a catamaran.

    Most of these fatter hulls will be limited in speed. OTOH, the skinny hulls demand an outrigger which means setup time.

    http://wikiproa.pbworks.com/Two-Dierking-Tamanu-Canoes
    http://wikiproa.pbworks.com/Texas-200-report

    Dan
     
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  9. Chris Ostlind

    Chris Ostlind Previous Member

    That will certainly work and it will provide a boat that has very shallow draft (provided you don't bite into the apple of overloading the bugger) From a technical perspective (and it will only apply if you want to get this design thing down to a gnats butt of accuracy) is that two individual hulls that close together will have some crazy wake cramming between the hulls which will add to the total drag of the boat.

    For slower speeds and really thin water expeditions, this is a good idea. You could unhook one of the canoe hulls when you reach a point where the double cat thing is just too wide to negotiate the waterways and go even further into the Heart of Darkness. ;-)

    Fabulous picture scrounging, muddin man.
     
  10. Chris Ostlind

    Chris Ostlind Previous Member


    When it comes to adventure and exploration, versatility wins everytime above specialized craft. No matter where you go, there will always be a circumstance that will stop a specialized form and a well thought-out versatile boat will just keep on chugging.


    Yes, there are all sorts of so-called design no-no's for a boat of this type. What matters in the end, is that you wind-up with a boat that can do all the stuff you'd like... as long as you recognize and accept, the stuff that a more dialed-in specific design could have done much better for a given need.

    In short, don't complain when a dedicated catamaran smokes you under sail and don't say a word when a full tilt flats skiff blows you out in really shallow water. Instead, challenge both of their specific design functions with a boat that can operate well in all of those areas so that you can comfortably do your thing wherever you may need to go.

    Keep it as light as possible while being strong enough to not break every time you take it out. Boats like this thrive on low weight. As Colin Chapman, the famous designer of Formula 1 cars and the Lotus automobile brand, once uttered... "Simplicate and add lightness".
     

  11. junkman
    Joined: Nov 2009
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    junkman Junior Member

    Your photography is nice and legible,very good job on that and your building progress. As I'm browsing these boats I find that I would really benefit from building bigger than Id planed.

    Me thinks any thing one dose should be a multiple design unless one truly needs specifics and should not escape the mind, a light boat would be ultimate. (speaking as a boat novice)
    I didn't think of adding flotation to single hull, when separating the Cat , but this would allow one to make the hulls very tall yet still get to use as canoe and such........nice.
    Ive been looking for some shape in between but have the jitters going back and fourth. I had thought of making something like the Lars, http://www.duckworksbbs.com/plans/jim/larsboat/index.htm maybe adding some height and beefing it up. Ive changed my mind again!
    As for sail power if you haven't visited this site, very interesting http://www.garryhoyt.com/id36.html I wonder if this could work with a double hull. Looks very innovative check out the 360 turn around!. Good Video.
     
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