Locating Chain Plates

Discussion in 'Boat Design' started by Bomber, Jan 19, 2010.

  1. Bomber
    Joined: Jan 2010
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    Location: Nicaragua

    Bomber NicaFun.com

    I have purchased an older 51 foot Catamaran that had never been fully completed. It is a sailboat design, however it has never been rigged. The boat was used a little bit as a motor boat, and has now been on the hard for 8 years. Without the original plans/design, how can I determine;
    1. The proper location for the chain plates?
    2. The correct number of stays and chain plates?
    3. Also, does anyone have any thoughts on the drawbacks of using a shorter mast than what is common for this length boat. Besides loss of speed of course.
    4. Any thoughts on rigging her with a kite? I've seen some boats doing this!

    The boat is located in Nicaragua, where supplies are very limited, and I have found a mast and rigging that I can buy, but it is 48 feet long. It seems that Cats in the 50 foot range use masts of 65 to 70 feet. I do realize that this is a huge project and also one that has me "over my head" a bit, but I do think fitting this boat is possible. I just worry about major structural damage/failure if I put the shrouds in the wrong location.

    Thanks for your time.
  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    You need someone that can understand the structural stresses and balance of a rig. That is an onsite job. A shorter mast will give you less speed, but for cruising it shouldn't be a major problem. 48 feet is a bit short, but you could rig it as a cutter to increase sail area
  3. Bomber
    Joined: Jan 2010
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    Location: Nicaragua

    Bomber NicaFun.com

    Since the boat is in Nicaragua, it makes it challenging to get parts, supplies, and qualified inspection or design instruction. Know anyone that is qualified and wants to go to Nicaragua?
  4. mcollins07
    Joined: Jan 2006
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    Location: Texas

    mcollins07 Senior Member


    Are you considering a spinnaker or a kitesail such as at kiteship.com ?
    What have you seen? I'm very interested in kite-sails myself.

    if you go with the kite-sail then a mast is not required. A short un-stayed mast might be helpful with deployment, but probably not necessary. Seems to me the shrouds would get in the way of a kite-sail.

    ~ Michael
  5. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    I may, but not before a month. Do you have any photos?
  6. Steve W
    Joined: Jul 2004
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    Location: Duluth, Minnesota

    Steve W Senior Member

    I agree with gonzo,if you can post some photos someone here may be able to recognize the design and then maybe you can contact the original designer which would of course be the preffered first choice. If that dosnt work out i may be able to come down and do the design and structural work for you,im in Minnesota and i hear Nicuragua is quite nice this time of year.Pm me if you like. A shorter rig may or may not be suitable depending on the boat as the section may be too small also.

  7. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Bomber, you need a designer or NA to draw up a rig for you. Don't even think about the kite idea. It's cute, but not especially practical. Nicaraqua will have skilled NA's available, you'll need to hire one.
  8. Kaluvic
    Joined: Jan 2010
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    Location: Yemen and Lebanon

    Kaluvic New guy

    If you do try and wing it your self...remember that the stresses on the rigging (stays and chain plates and tangs) of a cat will be greater than on a comparable sized mono since it won’t heel and dump air like a mono.
  9. Manie B
    Joined: Sep 2006
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    Manie B Senior Member

    Bomber here is REALLY GOOD ADVICE

    take note :idea:
    1 person likes this.

  10. naval ark
    Joined: Mar 2006
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    Location: U.K.

    naval ark Member

    +1 for Bomber, Manie B, Kaluvic, etc.

    You need a proper yacht designer (qualified naval architect) and a structural engineer that understands the construction material of the boat. You may find this in the same person.

    It is imperative to put a correctly sized rig in the right place, and once it's there you do not want it to fall off... or break the boat. Hence my suggestion above.
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