Self-Righting Catamarans

Discussion in 'Stability' started by kvsgkvng, Mar 11, 2012.

  1. kvsgkvng
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    kvsgkvng Senior Member

    Self-Righting Catamarans

    I am trying to gather any information on a possibility to have a self-righting catamaran. I am considering any system or devices, which would bring a catamaran to its normal position. One of obvious devices comes to mind almost immediately: a voluminous buoy on top of all recreational Hobby-Cats. This will prevent this catamaran to go “turtle.” It is up to the crew to right it after that. It doesn’t look good to me though. Then I was thinking about a device with compressed CO2 cartridge(s) triggered by an emergency. It would blow up a balloon on top of the mast, which is under water. In normal conditions, a simple and almost invisible packed balloon could be hidden in the top of any mast. It would be triggered automatically by an inclinometer. It looks OK to me.

    I wonder if there are devices/systems/designs or combination of those out there which would allow to right a capsized catamaran on its own?

    Would it be wonderful to have a catamaran with all advantages of a multi-hull and the righting ability of a mono-hull?

    Regards.
     
  2. Alik
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    Alik Senior Member

    There are some methods and ideas described in Norwood's book...
     
  3. gonzo
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    gonzo Senior Member

    A balloon on the mast head will keep the catamaran from turning turtle, but will not right it. Also, unless you have a large supply of CO2 and a way to deflate it, it is a one time use only. There have been several ballasted catamarans built and they work. However, they defeat the advantages of the multihull, which are shallow draft and low displacement.
     
  4. HakimKlunker
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    HakimKlunker Andreas der Juengere

    A self righting cat is something like a submarine made of polystyrene sheets....
    The secret is not so much technology, but simply good seamanship.
    First of all (I would say): don't capsize a cat - and all else is not needed.
     
  5. upchurchmr
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    upchurchmr Senior Member

    You need to look into the AYRS library for the Ruiz method of righting. It might have been mentioned in the Norwood book. Multihulls magazine (US) had an extensive pictoral of righting tests.

    Gonzo hit the nail on the head.
     
  6. Alik
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    Alik Senior Member

    Or just build a cat that can be sailed upside down! Remember Serenity cats??
    :D
     
  7. Richard Woods
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    Richard Woods Woods Designs

    The day I started working with Derek Kelsall in 1979 he tested a selfrighting 35ft catamaran in a lake. You can check with him for the details, but basically when upside down the bows were allowed to flood, thus sinking them.

    The cabin was relatively large and so kept the boat well afloat. The boat would then rotate itself vertically until it was at about 130deg (so the bows were under water, but the boat had righted itself)

    Then it was "simply" a matter of pumping the water out

    I made a model for a Southampton Boat Show which I demonstrated endlessly to fascinated passerbys.

    It did work, but the boat, particularly the interior, was severely compromised to achieve the selfrighting. I saw it 30 years later in the Caribbean. Still compromised and still upright.

    I think instead of trying to make a multihull self right it would be better to try and make monohulls (power and sail) unsinkable. A bigger market and it would save more lives

    Yet although the technology exists (inflatable bags or built in foam compartments) no one is actually interested in having a safer boat.

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  8. kvsgkvng
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    kvsgkvng Senior Member

    I have an idea for a fully self riting catamaran. I am confident it will work, however I would prefer to first try to patent it. I am itching to publish it, but I had previous experience to publish something else and now it is being used all over the world and I got $50 bucks in donations :(

    The inflatable baloon is certainly is one time deal. It is an emergency procedure and it is meant to be used once. A simple car inflatable bag technology could be used. I think several hundred bucks justify a lease for life. Instead of CO2 a compressor with dry cells could be used as well as a redundancy measure. And I keep my mouth shut about the rest.

    The above is all technicality of a one method to go "turtle." However it will not right the hull back to normal.

    What is "AYRS library for the Ruiz method of righting?"
     
  9. kvsgkvng
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    kvsgkvng Senior Member

    As usual, asked a question, did a search and got this patent. Not insulting anyone I would not use this device.

    What I plan would not use any other means except standard rigging on a cat. I think I should patent it, if contraptions like those shown below get patented...

    Does anyone know a decent patent lawer? Not a shark, not a cruck, I am willing to share, but not be robbed.
     

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    Last edited: Mar 11, 2012
  10. gonzo
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    gonzo Senior Member

    You give your location as *. It is difficult to give you a lawyer reference unless we know where you live.
     
  11. upchurchmr
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    upchurchmr Senior Member

    Sorry, go to this link http://www.ayrs.org/ayrslist.htm I have no idea which publication might have the Ruis recovery method, perhaps you could get in touch with them and get some help. This is a group of amateur designers who experimented with a lot of ideas. I was familiar with them in the 70's.

    Actually Richard Woods description of the recovery method Kelsell used sounds identical.

     
  12. JRD
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    JRD Senior Member

    Well, for the most part they are not sharks and crooks.... but will most likely drive a new Porshe... maybe a Ferrari! (if you can't figure out how these are paid for, don't read any further)

    Depending on your location, it may cost more to get a patent claim accepted and pay the annuities than to build your boat... even with the CO2 baloon attached.
    If you want real protection, you pay for the best attourney you can afford, sports car and all. A patent will only protect you if its claims are technically and legally comprehensive and all encompassing, and in many countries..... Every piece of prior art found in the area of your claim will diminish the scope of your protection, in some cases to the point where it only prevents an exact copy, if even that.
    The cost is in the research requried to find this out, every discovery and change will come with an invoice.

    My advice, for what its worth, unless you have a viable business plan to market your idea and make a return on investment, or you are made of money.... just build the boat and go sailing.
     
  13. gonzo
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    gonzo Senior Member

    The patent will only protect you if you have enough money to pay an attorney to go to court for you too.
     
  14. Fanie
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    Fanie Fanie

    I have seen a tri that can be righted by winching the down stay shorter. It also had a flotation device in the mast end, this could perhaps be inflated with a tilt switch.

    Best of course is never to capsize in the first place.
     

  15. HakimKlunker
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    HakimKlunker Andreas der Juengere

    Gentlemen,
    Until now I have not seen any self righting idea in this thread.
    Does the term not mean that a boat returns to upright position by itself? The moment you operate a device, or apply a method: it is not longer self righting in my opinion.
    Or would anyone say that i.e. a'Laser' is self righting?
     
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