How to dimension a sailing catamaran?

Discussion in 'Multihulls' started by terhohalme, Apr 27, 2008.

  1. terhohalme
    Joined: Jun 2003
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    terhohalme BEng Boat Technology

    Hi all,

    Couldn't find this kind of document from literature or net. I had to do it myself. I also modified catamaran parameters to mach the document.

    There can be mistakes and misspelling, I'd like to get some feedback.

    Have fun

    Terho
     

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    2 people like this.
  2. nero
    Joined: Aug 2003
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    nero Senior Member

    Wow! ... and Thank you!

    Wish this had been published 4 years ago! You will become the guru of catamaran design when this .pdf gets know and refined.
     
  3. catsketcher
    Joined: Mar 2006
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    catsketcher Senior Member

    Thank you

    Hello

    I just spent half an hour playing with your spreadsheet. I really like it. I did want to do something like this myself but never did. It is very simple to be able to fiddle around with dimensions to be able to get the characteristics you want. It is very impressive.

    Is there anything I can do my end to help. I can spell pretty well. Would you like me to go through and fix the spelling up? Anything else?

    cheers

    Phil Thompson
     
  4. terhohalme
    Joined: Jun 2003
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    terhohalme BEng Boat Technology

    Thanks Phil

    send you a personal message

    Terho
     
  5. JCD
    Joined: Jul 2006
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    JCD Follow the Bubbles!

    Hello Terho,

    Outstanding. If there is anything at all that I can help with...just ask.
    Excellent work! Funtime is here.:D

    J:cool:
     
  6. terhohalme
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    terhohalme BEng Boat Technology

    New version of catamaran parametric study

    Hi all,

    Redefined catamaran parametric study. Now, there is included a calculation of design righting moment for rig design.

    Terho

    ps. Redefining of document is on going...
     

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  7. JCD
    Joined: Jul 2006
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    JCD Follow the Bubbles!

    Hello Terho,

    I want to thank you again for your contribution. It has helped me with quite a bit and it has further reinforced my effort to continue to work hard on the TR27B.

    I'm attaching the spreadsheet so that you can see the results of the actual dimensions of the TR27B in your spread. There were some places where she may have done better and didn't meet certain accepted values, but she still met the Category B requirements. She is at her lightest displacement. I did it in heavy also, but that just brought the SF higher to 24000+. I gotta tell you that the results were really close. The displacement was off by less than a cubic foot (60#'s).

    Again, excellent work, and if you need a bodyguard when the NA's and NE's go after you for revealing all their secrets, let me know.:D

    J:cool:
     

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  8. terhohalme
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    terhohalme BEng Boat Technology

    Don't believe that. The world is full of good books of physics, still the majority of educated people don't understand it. The physicists can have their job.

    The only way to increase knowledge is to share it. I think this is one of the secrets of science too. Our greedy businessmen just think they can have it all to make profit for themselves.
     
  9. Spiv
    Joined: Jun 2007
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    Spiv Ancient Mariner

    Great work Terho, I've made a few aesthetic changes, hope I get your endorsement...:)
     

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  10. catsketcher
    Joined: Mar 2006
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    catsketcher Senior Member

    A few thoughts

    I love this thing. I did do something much simpler for an engineering problem I had. This is great. With my small cats I have a bit of an issue with stability. Using a program to fiddle is much better than me with a calculator.

    I have included a few remarks with the attached Jpeg

    BTW - this is a software question but how can I look at the code behind the cells?

    cheers

    Phil
     
  11. catsketcher
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    catsketcher Senior Member

    Jpeg

    Here is the Jpeg
     

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  12. terhohalme
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    terhohalme BEng Boat Technology

    BM's are metacentric heights (in metres) from the center of bouyancy to metacenter.

    You can take of protection of the table, there is no secrets, all the formulas are puplished earlier.

    Use the newer version...
     
  13. JCD
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    JCD Follow the Bubbles!

    Hello Terho,

    Well amen to that. I don't care how much trouble I go through...I share openly.

    The spread really seems to be taking off. I'm really glad to see that. It makes everything soooo much easier.

    J:cool:
     
  14. terhohalme
    Joined: Jun 2003
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    Location: Kotka, Finland

    terhohalme BEng Boat Technology

    Hi All,

    Made some corrections and refining. Moments and windspeeds should be now clearer. There is also an imperial version of excel spreadsheet for those not familiar with metric physics.

    Terho
     

    Attached Files:

    1 person likes this.

  15. Fanie
    Joined: Oct 2007
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    Fanie Fanie

    Hi Terho,

    Best I've seen in a while... great stuff :cool: From now on you're my best friend :D and best friends help each other, right :rolleyes:

    I have roughly compared my cat to your cryteria, it comes close to the nearest lamp pole, result of long late nights ;) reading reading reading.

    Very nice and thank you !
     
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