Trimaran Design Concept with longer foils than the main hull

Discussion in 'Multihulls' started by boradicus, Jun 3, 2013.

  1. Ad Hoc
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    Ad Hoc Naval Architect

    boradicus

    You took the words out of my mouth :)

    You need to understand that looking at one design is not the ”rule” that defines how they must all be as such. Any design is designed to satisfy an SOR..or a Statement of Requirements. In simple language what is you’re aiming at?

    Speed, cost, number of cabins, cost etc etc …everyone one of these inputs, and more, affects the design and how the finished design performs.

    Any weight limitation comes about from the clients or designs, SOR. The weight effects the speed, but more importantly it dictates the hull size. If you wanted a palatial vessel with marble heads, 50mm thick solid wood veneers a Jacuzzi etc etc..all this adds weight. If your cost, or budget is fixed, then this invariably will dictate the length, to a degree; since cost x length is a pretty linear relationship for “small” vessels. But if all the weight of the items you want (your SOR) ends up being say XXX tonne but your budget or the length, means the length cannot support the weight, your choices are either to extend the length or increase the buoyancy (shape).

    If you extend the length, your costs go up…if you increase the buoyancy, the drag goes up she ends up slower..and so on.

    If they are light, then the draft, for its length, can be minimal.

    The VCG affects many things, and many things can affect the VCG too, thus you need to decide what type of boat will satisfy your SOR. That design will or should, ensure the aforementioned in the design are addressed, by the designer.
     
  2. boradicus
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    boradicus Senior Member

    Dangerous Designs???


    Thank you, Richard! I am still pondering what you mean by dangerous designers, and not pursuing the designs like unto Wild Thing. Did either designer completely abandon this idea, and if so was it for safety reasons? If it was for safety reasons, as a designer could you be specific as to what those dangers are in particular, or is it more along the lines of speculative caution that you would admonish against pursuing a similarly designed vessel.

    Please keep in mind that I am also quite new to boat designing in addition to being new to the forum. I would not even call myself a designer, because in truth I am here to learn so that I can design one day!

    This forum is great because it seems to be a place where we can discuss ideas rather freely and learn at the same time from the experience of others on the forum and through helping each other think through the stages of designing. I don't even feel worthy to be here, but I am so glad for the warm reception I have had! :)

    As far as the purpose of the vessel, I am thinking in experimental terms - in other words, as opposed to thinking along the lines of how a client would present an idea to a designer, I am asking myself the question, "what can be done with this?" And from thinking this way, it is my ambition to learn more about what design entails, and why certain things ought to be done, and why other things ought not to be done, if that makes any sense!

    Thanks again for all the feedback! I really appreciate it! I think I did list a few of the design parameters in my initial post, but as I said I am open about things. The initial idea was to be able to have a smaller sized boat actually capable of larger sized craft sea-faring - does that help at all? Thanks!
     
  3. boradicus
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    boradicus Senior Member

    Okay, I guess I did not post this initially like I thought I had- sorry guys. This is the basic reason for wanting the larger amas:

    Thanks, again, everyone! :)
     
  4. boradicus
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    boradicus Senior Member


    Ad Hoc, thank you for the informative response. I would like very much to learn how to design. Would you have any texts that you would recommend from your own training that would be helpful for me to read? Thanks again, and thank you for answering each of my questions.
     
  5. Gary Baigent
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    Gary Baigent Senior Member

    The longer float concept is still very much around, has not been abandoned, look for example at the huge Oracle Deed of Gift Americas Cup winning trimaran, or the altered and lengthened ORMA 60 trimarans from France.
    You also have the opposite, smaller floats (meaning lighter platforms) but with lifting foils like past world record speed holder Hydroptere.
    There are ways and many ways to skin a cat. Fashion also plays a part.
    Reading between lines about boat you would maybe prefer; check out the Buccaneer 24 threads on boatdesign.net. Can build it yourself, is fast, safe, light, carries three people.
     
  6. Ad Hoc
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    Ad Hoc Naval Architect

    It really depends upon how much you want to learn and what level of maths you can consume and if you have the time & patience too. There is a significant amount to learn, if you wish to dive in as such.

    There are several threads related to such, like here:
    http://www.boatdesign.net/forums/education/recomend-naval-architecture-textbook-29145.html
     
  7. Richard Woods
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    Richard Woods Woods Designs

    Where did I say "dangerous designers"?

    What I meant was, if an experienced designer tries a new idea and then doesn't draw a whole new range of designs based on that idea it might mean they decided it was not worth doing

    Richard Woods
     
  8. boradicus
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    boradicus Senior Member

    Missions!

    Cool & thanks! Warwick mentioned that perhaps I should inquire with you about the design you are working on that has long amas. I like the idea of the Buccaneer and Sid quite a bit. But I am also trying to soak as much information in as I can - like a sponge - so I can learn about designing too. I like building, but a lot of the fun comes in with the design and then knowing that what you build actually had something to do with what came out of your own imagination :D! Over a year ago, I design and build my own portable vocal recording booth/studio, and earlier this year I finished making my own Wing Tsun Dummy and an electric slide guitar! Now I am working on finishing writing, arranging, and recording songs for a CD that I hope can help fund drilling water wells for a Christian community in Africa. My church is helping, and some of my friends are helping to record. One of my dreams from long ago was to be a missionary by boat. Originally, before even the boat idea occurred to me, I had this dream to travel the world and play guitar / music with as many different people and cultures as I could! I had newly become Christian, and I think I just wanted to share the love of music with everyone - I wasn't really going to church then, but something had happened that had changed my life! Later, God told me to go to a certain country, and although I didn't go (I should have - maybe my faith wasn't strong enough to just pick up and go - but I heard the story of a pastor that was called that same year to the same place and he just went) The Lord grew in me a heart for doing missionary work. I have yet to go on mission, but I have done bible studies with people online from different countries, and He did call me to go somewhere else in 2007. I don't want to go into the details of it all but let's say that I believe that the fulfillment of His calling in my life is in the process of being worked out now. Anyway, yes - back as early as 2002 I came up with the idea of being a missionary with a sail boat, and in fact one of my pastors and his wife were missionaries (although I didn't know it at the time that I was first called) and they traveled a lot by boat in a small island community as well. They also had a bible college, but they went out into different communities.

    Anyway, I am excited to be here :)!!!!!!!
     
  9. boradicus
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    boradicus Senior Member

    Misread word probably!

    Sorry Richard, I must have misread something somehow! I thought it was in your post, but it could be that I possibly miss-scanned the page being a bit tired and saw the word dangerous somewhere in another window - who knows - but thanks for clarifying your post :)
     
  10. redreuben
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    redreuben redreuben

    "cursor to paper or pencil to screen."

    Richard Woods of Woods Designs

    www.sailingcatamarans.com[/QUOTE]

    Let me guess....... Windows ?

    Too funny.
     
  11. boradicus
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    boradicus Senior Member

    Ad Hoc,

    I really appreciate that! I have been looking through the book area, but it actually makes a difference when someone to whom you are speaking can make a positive recommendation or point you in the the direction of a recommendation.

    ~

    To Richard:

    Richard, after somehow seeing the word dangerous I was thinking in terms of the abandoned design ideas of which you spoke, and I remember reading on Amazon.com how in this review by Mr. White, who was in fact the author of the book on multi-hull design in question, that Mr. White was reiterating how important it was to have sufficient clearance for the section that connects the two hulls (I don't precisely know what you would actually call that section being that it is a catamaran). That made me wonder if that would apply to trimaran designs where the amas are long. In other words, on a mono hull, your gunwales are going to be sufficiently high in proportion to LOA of the vessel, such that length comes into play as a seaworthiness factor when facing larger seas. For both a catamaran and a trimaran of equivalent hull lengths, this factor would seem to be relatively consistent as well. However, you did seem to admonish about changing the hull design and having a good reason for doing so, and I am wondering if in fact having longer amas is not sufficient for correspondingly larger seas; the height of the gunwales would seem to play a significant role as well.

    What are your thoughts? And please forgive my misreading your post earlier - I have not really had sufficient sleep and that probably has something to do with misreading things.

    Thanks! :)
     
  12. redreuben
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    redreuben redreuben

    Borad,
    It all comes back to the intention of the design, increasing gunnel hight will quickly add volume which will give you more sail carrying power but also more windage and a much harder ride.
    Compare Sid to a Horstman. What is the purpose of the boat ?
     
  13. boradicus
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    boradicus Senior Member

    Red - the main purpose for the particular design strategy is to turn a minimalistic hull into a vessel capable of handling proportionally larger seas. In the specific case I am proposing, using a 10M for the amas would, I believe, tend to be the recommended entry level LOA for seafaring vessels. I decided to work with probably the toughest example first - open seas - although it is the concept that I think is interesting and possibly useable for coastal cruising down to beach camping, etc. I think the concept begins to lose its value when you get down to anything without a cabin. Thanks for the feedback and the helpful response! I will look into a Horstman, and as Gary B. already knows, I am a huge fan of Sid.
     
  14. Gary Baigent
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    Gary Baigent Senior Member

    Boradicus, you're a religious man - in that case better not listen to me ... because I'm from the other dark side, a going-to-hell-for-sure atheist.
    However in the past multihullers have been accused of being religious zealots ... so you'll fit okay in that company.
    In terms of educational good books (no pun), Jim Brown's "The Case for the Cruising Trimaran" and Derek Harvey's "Multihulls for Cruising and Racing" are essential reading. Also Robert Harris's "Racing and Cruising trimarans" although an early publication, everything he says is still relevant. There are numbers of others of course, but those are good bibles.
     

  15. Ad Hoc
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    Ad Hoc Naval Architect

    Finally, some common ground. See you when I get there :p
     
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