Planing Trimarans

Discussion in 'Multihulls' started by Doug Lord, Sep 30, 2006.

  1. Raggi_Thor
    Joined: Jan 2004
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    Location: Trondheim, NORWAY

    Raggi_Thor Nav.arch/Designer/Builder

    Yeah :)
    Anyway, I have been more on telemarktalk.com than on boatdesign.net since the snow arrived in October, and now after eight months of skiing, I see that this discussion is on the same place as it was before the winter..
    I guess I didn't miss any important facts :8

    To cut the knot or make the egg stand, why not just say that it isn't either or?
     
  2. Raggi_Thor
    Joined: Jan 2004
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    Location: Trondheim, NORWAY

    Raggi_Thor Nav.arch/Designer/Builder

    Actually it will be four years when the snow starts falling again in September..
    (since 09.30.2006 )
     
  3. Chris Ostlind

    Chris Ostlind Previous Member


    I had no idea you were a tele skier, Raggi. This winter in Utah, we've had some of the best snow in many seasons for Randonneur outings. Just beautiful huge piles of dry, light powder.

    The bad thing was the repeat avalanche issues all season which took four back country skiers away... one not found until this spring because he didn't have a beacon when his group went out. A sad, but regular, event as some never learn.

    As to the egg metaphor... I only wish, but it seems to cycle around mostly because of boordom by one person and it resurfaces from time to time with nothing substantive to support that individual's offerings. Oh, well...
     
  4. cavalier mk2
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    cavalier mk2 Senior Member

    Ah, snow bound and cabin fever, that explains a lot. Quick and silly rebuttal to the points selected earlier. Math can show the force needed to raise the main hull out of the water , dynamic lift/planing would show as the main hull rising to the surface sooner. It will be different for every design, do your own homework! Being nasty so people toss information your way is a poor way to learn about design. The model suggestion is for those who want to test ideas, again do your own homework, I don't need a planing main hull proven to me. On planing double ended hulls find a copy of Skene's Elements of Yacht Design to verify the following, "There is a shape, however, which is double ended and will plane without squatting. It is a V-bottom planing powerboat in which the chines are brought around, in the same surface as each side of the V, to a point on the stern.....fore and aft lines run out horizontally, as though to the usual transom stern, instead of curving upward as on a whaleboat." No need of appendages. In reading your other comments about planing with both amas out of the water I realize you are trying to place me in the "if the main hull planes it is a planing trimaran" camp which I'm not. My point about different kinds of hulls being used for different aspects of a design was clearly made and I don't say a planing main hull makes a planing boat but a boat with a planing main hull! I don't have a Nacra but I have sailed a Hobie 16 which didn't plane, in fact in a gust the compression can send the hulls under water. I'm sure though a planing cat could be made by connecting a couple of Lasers........If you've been on this topic for 4 years it might be a good change for you to get a little closer to the coast where we sail year round ;)
     
    1 person likes this.
  5. Chris Ostlind

    Chris Ostlind Previous Member

    Cav-Man

    The proof of your claims is not incumbent upon me to produce. You suggested that towed models would reveal the truths and I suggested that you prove it. Real simple. If you think it's important, then you take it upon yourself to make those proofs known. It's not my Yob, Man.

    As to the homework needed to arrive at the figures for when a trimaran hull lifts, or is being levered to the surface by the mechanical configuration of its form.... Done that, many times over and know the process well at this point. What isn't obvious is the understanding you fail to exhibit and that, my friend, is all on you as to getting up to speed. There are tons of resources available, lots of kind folks who are willing to help and all you have to do is generate the energy needed to make your discoveries.

    As to the double ended craft that planes with the aid of planing surfaces, such as the well-respected, Bartender design... well, you made the claim, so go right ahead and make the proofs. I tried to help you with the struggle by showing images of the Bartender and how it comes together for the purpose so claimed, but apparently that wasn't good enough for you. So, how about you produce the photos of the boat you have in mind. We'd all love to have our IQ's lifted by your knowledge base and I, personally, would like to see such a craft. You said it, so you prove it. Again, it's not my responsibility to take care of your claims.

    As to the statement, "My point about different kinds of hulls being used for different aspects of a design was clearly made and I don't say a planing main hull makes a planing boat but a boat with a planing main hull!"

    Great, Cav, perhaps you are finally getting it. One problem with that when it comes to a trimaran that does not have the typical and well documented attributes of what is accepted as a planing hull... If you want to make the claims, then it's all on you when it comes to actually proving it. So far, all you have done is talk about it. You haven't demonstrated that the hull has any of the attributes and you certainly have not shown that the lift is coming from the mechanical leverage of the leeward ama in the water.

    Now, perhaps you wish to argue that the leverage, as suggested, is insufficient to raise the main hull up and onto the surface in what looks like a planing function. If that is so, prove it. Give us some real data and not just talk. Basically, show us the numbers.

    It boils down to this, Cav... You seem to think that the main hull of these mentioned trimarans can get to the surface all on its own without being jacked-up there by the immersed fulcrum of the leeward ama. You mentioned model testing to make these proofs, as if models can be called forth as precise arguments in the discussion. I would direct you to this recently posted interview on another thread in which one of the leading hydrodynamicists in the boating word today talks about the efficacy of models as proof sources: http://catsailingnews.blogspot.com/2010/05/cs-interview-martin-fischer.html

    Take a moment, if you will, to digest what he is saying. Look at the body of work he has done over the last several years. Now, let us all know, with a straight face, that you can give us precisely accurate data that shows what you would like us to believe. Still, if you want to roll with the, "pull a model boat around and it will show you if it can plane" theory, then by all means, knock yourself out and prove it to us. You made the argument, you make the proofs. I have nothing to do with that bit, Cav and it's all on you if you think it is valid.

    Some posts back, both Paul B and myself suggested that you could very easily, well, maybe not so "easily", but still... you can prove that an F-Boat can plane by: Simply dropping the amas, sticking racks on that dude, chuffing-on a large number of performance dinghy guys and go out and give it a go. See, for real, if the hull can plane, all by itself under sail and do get it on video. That will show you if the boat needs to be levered-up, or if it can get there on its own. I suggest that it won't.

    This same thing holds true for your trimaran. That's a perfect test vehicle if there ever was one, since you have total control of the beast and can quickly get it ready to make its solo planing debut. What do you say, Cav? Wanna put your boat to the test for all to see. Heck, if you get it ready, I'll even fly up to wherever it is you are located and shoot the video for you. Nothing like a broadcast quality HD video clip to show us that you know of what you speak.


    Lastly... and I do mean lastly. Just what is it about wanting to live in the mahogany halls of planing boats that is so compelling when even the average trimaran is still ridiculously fast compared to any average monohull on the water? Isn't it good enough for you that you have to float goofy claims out there that you have a "planing main hull"? Isn't this kinda like putting a personalized, carbon fiber, body-hugging, wannabe F1 racing seat in your V6 Honda Accord with the rest of the interior stuff still intact? Come on, man, quit trying so hard to be something that doesn't matter anyway and just go sail the boat.

    Sheesh.
     
  6. cavalier mk2
    Joined: Mar 2010
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    cavalier mk2 Senior Member

    Ah the stress of the high seas of Utah is starting to show....Skene's is a fine source for those that can read a book. I don't drive a honda and your overwrought responses are beyond civil. Your assumptions about me are laughable, you would do yourself a far better turn if you actually refrained from attacking someone who's experience you know nothing about. You are doing yourself many disservices, after all who wants a design from that hothead from "Looney Deluded Design" in that sailing mecca of the ski slopes of Utah? Grow up sport, if you are going to pose, behave like a professional. Learn from the responses from the successful designers who use this site because they have mastered the social skills of public relations you so desperately need. This thread is a turkey and a fine lesson to me to watch out for topics that are the pet peeves of a nut :) Have a nice day !
     
  7. Gary Baigent
    Joined: Jul 2005
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    Gary Baigent Senior Member

    cavalier mk 2, you're floundering in a quagmire of ignorance and sustained afloat only by an inflated ego.
    By the way, I've done thousands of miles on a Hedley Nicol trimaran like yours, (although probably a faster version because the owner was an excellent sailor and continually tuned the craft) .... and that boat, the whole boat mark you, not the levered up vaka dreamland stuff, travelling at its highest speed offwind, NEVER planed.
     
  8. Doug Lord
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    Doug Lord Flight Ready

    ==================
    Wow! Gary you are so great! But a discussion with you is like sticking ones hand into a charcoal fire. And about as productive. Thanks for your experienced,technical insight! What a great designer/sailor!
     
  9. Gary Baigent
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    Gary Baigent Senior Member

    Stick to your wacho fantasyland Doug, like a comic drawing with a dialogue bubble crammed full of mathematical figures leading to a damp squid of a firecracker. Everyone here awaits with bated breath for a real, full sized, touch-with- hands boat to emerge from your said bubble inflation.
     
  10. cavalier mk2
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    cavalier mk2 Senior Member

    Actually the boat sails really well, I'm sorry you had problems getting yours up to speed Gary. Perhaps you need some PR lessons too? Here's one for you ax grinding kids to have fun with- Do you use displacement or planing skis in the mountains? For the mountain boat guys a fun dual purpose skiff is one that can also be used as a toboggan . We had fun with one a year the snow level got down to sea level but you hill people have more of a market. Have fun in the sandbox kids, Ostracizing Ostlind will be happy to know he has a posse ;)
     
  11. Doug Lord
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    Doug Lord Flight Ready

    =============================
    Ouch!(1) I've never seen such technical brilliance.....
     
    Last edited: May 24, 2010
  12. Raggi_Thor
    Joined: Jan 2004
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    Location: Trondheim, NORWAY

    Raggi_Thor Nav.arch/Designer/Builder

    I'm out of here, lets go skiing in the spring corn :)
     
  13. Raggi_Thor
    Joined: Jan 2004
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    Location: Trondheim, NORWAY

    Raggi_Thor Nav.arch/Designer/Builder

    Just a short message to Chris, sorry to hijack, but one post more or less doesn't really harm this thread ( :) )

    We had a nice and cold winter with quite a lot of snow, had our last tours and turns in the local woods here at May 16, but right now it's extraordinary dangerous up in the mountains due to extremely fast melting. Avalanches have been a mixture of water, snow, sand, rocks and mud:

    http://www.newsinenglish.no/2010/05/17/avalanche-kills-two-two-others-missing/

    and

    "Slush avalanches on almost level ground!"

    Google translation:
    http://translate.google.com/transla...ondelag/oppdal/article1484683.ece&sl=no&tl=en

    [​IMG]
     
  14. Gary Baigent
    Joined: Jul 2005
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    Gary Baigent Senior Member

    I'm a kiwi, mate, from Auckland, not Utah or wherever ... where we sail, (and Aucklanders aren't too bad at sailing and know about getting boats up to speed), no skiing or fluffing around in boxes on snow here- although I did once see snow flakes one winter sailing back from Waiheke, but normally, we don't get it here.
    However I do know about snow, being born in South Island and spent a lot of time in the mountains, hunting and mountaineering. Your point is ......?
     

  15. Chris Ostlind

    Chris Ostlind Previous Member

    Gosh, Raggi, what a vista.

    I can only imagine how that region looks in full winter coat and ready for clean, first turns.

    The avalanches are a dangerous aspect of the terrain. I hope the slushy rips end soon and you guys can hike with a degree of freedom.
     
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