What do you think - entering a Cardboard Boat Regatta unlimited class

Discussion in 'Boat Design' started by spartans_78, Mar 17, 2011.

  1. rwatson
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    rwatson Senior Member

    We all have to live with limitations. Just a quick note before the race - every foot you add to the boat will provide a lot more speed.

    You dont have to go 20ft - you could perhaps do two 'pods' under the hydro hull ( bit like a catamaran hull using two canoelike hulls) . 12 ft would make a huge difference in top speed, 16ft even more. Even if you could just do simple V section hulls - it would help.

    Ricks props were about 12 inches long, two bladed, and were hand built. The lawmower blade idea isnt as strange as you might think. Good luck
     
  2. Poida
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    Poida Senior Member

    This looks like a novelty race rather than one where you want to win.
    If that is the case the design is excellent although you have no chance of winning.

    If you wanted to win, you could strap a couple of compressed air cylinders each side. At the word GO! you wrench open the valves.
    You will at least have a 0.1% chance of winning and 99.9% chance of the cylinders crossing the finishing line without you.

    If the rules do not stipulate that all of the craft must cross the finishing line, you may have a win via a loophole.

    To remain within the rules you may have to fill the cylinders with a pedal powered compressor.

    If you use oxygen cylinders, the cardboard will ingnite at a much lower temperature, and I believe that crossing the finishing line engulfed in a ball of flame is the way to go.

    Have fun.
     
  3. ancient kayaker
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    ancient kayaker aka Terry Haines

    Some highly original concepts there Poida! May Angels forgive you ...

    Stevo, from what I have seen of these races merely finishing is considered to be an achievement . That being the case, it probably pays to put most of your effort into durability rather than speed. Of course, that's might be a bit prosaic for some folk.
     
    Last edited: Mar 20, 2011
  4. Angélique
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    Angélique aka Angel (only by name)

    Seeing the info so far I think to get the best chances for finishing and also improving speed is to dump the non-planing-hydroplane-hull and make twin slender pontoons and fit the drive unit and seat in between.. make it a recumbent type of course and sit just above the water, drive unit also as low as possible between the hulls...

    But the hydroplane type is Stevo's love baby and fun is also a goal here.. so like always, first thing to do is to set priorities.. which still can be done . . :)

    Good luck!
    Angel
     
  5. ancient kayaker
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    ancient kayaker aka Terry Haines

    - 'sides, he can always add an outboard later ...
     
  6. Angélique
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    Angélique aka Angel (only by name)

    Oh yes, like the many times posted pictures here...

    [​IMG] - [​IMG]

    First one is everywhere over this forum, last one is linked to the source (one of them)..

    Cheers,
    Angel
     
  7. spartans_78
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    spartans_78 Junior Member

    Once again, nice posts by all, even you, Poida. I wonder why all the negativity, though? :)

    I have been toying with the idea of adding a couple of small rocket engines into my sponsons... I have a friend that works in the aerospace industry and he has access to some.... If I time it right, I should be able to make the turn and then light the candle on the last straight before the finish....


    Angelique, I still may add a couple of V's to the bottom of the hull. It may give me just enough lift to get the flat portion out of the water far enough to reduce drag. At the very least, it will add strength to the bottom.... I just don't want to copy everyone else out there with the pontoon idea. I am sitting in a recumbent position, though. At the very least, I hope she looks good. I am taking the vain skier's approach on this one. Sometimes it's better to LOOK good on the slopes, than actually be a good skier!

    I have been wondering, what makes the airplane prop so much better than a boat prop? Is it the lack of high rpm that can be produced by pedal power? I am no engineer by any means ( as you can tell from my design apparently) but since the pitch of the boat prop is so much larger, I would think would lead to moving more water... At any rate, the wave pool just isn't deep enough for me to even consider it....

    Thanks again all!

    Stevo.
     
  8. ancient kayaker
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    ancient kayaker aka Terry Haines

    Well, Stevo, we like to tell it like it is: or in this case like it might become :)

    With enough rocket power the boat’s tendency to sink would be offset considerably :eek:

    Don’t overdo the Vee’s: if you add too much buoyancy low down you will compromise stability. Think of it as a pendulum with the weight at the center of gravity supported by a virtual pivot at the center of buoyancy. If the CoB is below the CoG it will try to invert. You’ll like get a more technical answer - this is hardly a rigorous treatment :cool:


    It’s lack of power; like a bicycle the less power you have the lower gear you must chose. Low gear = prop with low pitch. Since the blades are also moving slowly they need to be long to get enough “grip” on the water, else they will just stir it. Also a narrow blade has less surface drag. Narrow blade, low pitch, large diameter = aircraft type prop. Again, you’ll like get more technical answers ...

    BTW we are all assuming here that the waves will be turned off in the wave pool ;)

    ... but you will also get a lot of good wishes including mine. We treasure the ideas from folk who are trying to do something different (and difficult) no matter from how far out :!:
     
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  9. spartans_78
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    spartans_78 Junior Member

    Nice! I like the feedback and easy to understand explanations!

    No waves in the pool, for sure! Last year several boats didn't need the waves to end any chances of even starting the race. I hope my contraption isn't one in the running for fastest to sink 2011!

    I will be working on it some more this evening, so hope to be able to post a few more pictures showing more progress....

    Stevo.
     
  10. ancient kayaker
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    ancient kayaker aka Terry Haines

    :idea: don't forget to have someone there with a video camera when you light up ... :)
     
  11. Submarine Tom

    Submarine Tom Previous Member

    Good stuff. Great fun. Enjoy.

    Generally, a person can create about 200 - 300 watts for 0.5 - 2 minutes, or, 100 - 140 watts for an hour or two.

    So, about 1/4 of a Hp at the prop after transmission losses. You can probably work out the rest.

    For the vessel: lots of glue and cardboard where appropriate.

    Good luck!

    -Tom
     
  12. spartans_78
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    spartans_78 Junior Member

    Ha ha, Dances with Turkeys.... I never video ANYTHING after lighting up!

    Submarine Tom, so you figure I am only good for 1/4 horsepower? I have no idea, but I like the way you got there. I figured I would get a prop as big as possible, so this one actually came off of an old 115 Evinrude that some poor guy ran over a sand bar, or some other low water area. Do you think it will be hard for me to turn this? Like I mentioned in a previous post my ratio is 1:4, so considering the light weight and low draught of water, I should move fairly well, right?

    I don't know any more. The best thing for me to do is, just not worry about it and GO FOR IT!

    This speculation has been fun. Thanks to all for your contributions!

    See you on the water!

    Stevo.
     
  13. George T Thornton Jr
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    George T Thornton Jr New Member

    What I want to know is, where can I get these same components for my project?
     
  14. Angélique
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    Angélique aka Angel (only by name)

    Hi George, welcome to the forum :)

    ‘‘ What I want to know is, where can I get these same components for my project ? ’’

    The same components as what, there were 27 posts before you about components on this thread, could you be a bit more specific about what you're looking for ?

    Also some info about your project would help to get a meaningful reply, cause advice on what you need and where to get it depends on what you want to build.

    Good luck with the project !
     
    Last edited: Jun 28, 2017

  15. George T Thornton Jr
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    George T Thornton Jr New Member

    I want to know where to get the parts shown, where the guy was building a cardboard boat. Peddles, gearbox, driveshaft and propeller.
     
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