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

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

  1. spartans_78
    Joined: Mar 2011
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    spartans_78 Junior Member

    Hello there.

    I am new to this site and new to boat building.

    I am attempting to build my first boat----out of cardboard!

    Yes you heard right, cardboard.

    I am entering a Cardboard Boat Regatta in April. I am opting for the "unlimited class" which means I will have a propulsion system, instead of oars, or paddles.

    I am going for an old-style hydro look. She will be a flat bottom, as building a tunnel was a bit much, I thought for my first time.

    I wanted to show you some initial photos to get some feedback from some of you experts!

    Tell me what you think! Offer suggestions, criticism or whatever...

    Thanks,

    Stevo.
     

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  2. spartans_78
    Joined: Mar 2011
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    spartans_78 Junior Member

    Hey there.

    One question for you guys.

    How can I ensure that I have enough hull surface to make sure I don't sink!

    My hull is 24 inches across the transom and 84 inches bow to stern.. The height of the hull at the highest point is 12 inches and it tapers down to 2 inches in the front. I have attached two tapering sponsons to the side that measure 12 x 6 at the back and 2 x 2 at the front.

    Thanks,

    Stevo.
     
  3. ancient kayaker
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    ancient kayaker aka Terry Haines

    The density of (fresh) water is 62.4 lb/cu ft; multiply that by the hull area and divide that into the total weight to get the draft.

    My concern would be for stability; I suggest you make a small wooden mockup and weight it with coins until its center of gravity is were you expect yours to be, and see if it floats without being flipped by small waves.
     
  4. gonzo
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    gonzo Senior Member

    What are the rules? The last cardboard race I competed on didn't allow any waterproofing.
     
  5. Angélique
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    Angélique aka Angel (only by name)

    The 'Tread' -also named- 'Q-factor' is far too big...
    Good luck with the project!

    Cheers,
    Angel
     
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  6. Poida
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    Poida Senior Member

    The question is Angel will the boat stay afloat long enough to sustain an injury from repetative pedalling?
     
  7. rwatson
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    rwatson Senior Member

    Your main hull will displace about 380 kilos, the sponsons about 40 kilos each ( 2.2 kilos per pound )

    The sponsons will do very little for bouyancy then, they may help stability.
    Hope you dont have to go very fast.

    Tape them together with lots of plastic packing tape - thats will keep the water away for a while.
     
  8. Angélique
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    Angélique aka Angel (only by name)

    Hi Poida,

    What's your contribution to this thread about Stevo's boat . . ? ? ;)

    See the question: ‘‘Tell me what you think! Offer suggestions, criticism or whatever...’’

    So please post your ideas that will make this boat better . . . :)

    Cheers,
    Angel
     
  9. spartans_78
    Joined: Mar 2011
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    spartans_78 Junior Member

    Thanks to you all for replying.

    I have never done this type of thing before, so I hope I have planned it well enough. It is at least to my best ability.

    The rules state I can use liquid nails as an adhesive. I also plan on using wood glue for my lamination's. I will use the liquid nails at every seam and open edge for sure. They also allow duct tape, but I am going to stay away from that, I think. I am going to go with masking tape and Kraft paper soaked with glue for my tape. I think it will mold better and be smoother when it is dry. I will also be allowed to use any one-part polyurethane paint I like. I am going with bright red as I am naming her "Miss Bud".

    Angelique, I was concerned about the width of the pedals at first, but this "race" isn't a long one. There will be a qualifying race, then a heat race, then a final race. It will be around the wave pool at Hurricane Harbor, so I don't think fatigue will be a factor too badly. I did make it as narrow as possible, given what I had to work with. Thanks.

    Turkey Dancer, I never thought about mocking one, I just went for it. I am now going to incorporate a top "roll" if you will at the top edge of the gunwhale. If I do drought a lot of water, I am hoping the addition will be enough to give me the extra buoyancy needed. If nothing else, it will give the sides more strength...

    I will keep you posted as I go, for those who are interested.

    Thanks again!

    Stevo.
     
  10. Poida
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    Poida Senior Member

    Angel I apologise if making a comment on your post you considered rude as discussing each other's posts has been an interesting feature of this forum for many years. I am sorry and I will never comment on your posts again.

    Criticisms, I didn't see the point in critisizing what looks like has already been done, I don't know the rules and I consider that asking for help was too late in this case.

    Poida
     
  11. rwatson
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    rwatson Senior Member

    Spartan - over the last 12 months, there has been a lot of discussion on pedal powered boats -

    eg http://www.boatdesign.net/forums/boat-design/pedal-powered-boats-23345.html

    Rick Willoughby is the most experienced developer of pedal power, and I have seen his 'machines' in action personally. They were performing around the 14 knot mark


    I think you will find that your prop, and your hull design is not going to produce very fast results, based on my limited understanding and experience.

    If its not too late, you really need a long thin hull, and a very long thin propellor.

    I may be at least worthwhile reviewing some of the old discussions, to get an idea on how at least how to optimise your propellor if the hull is too far developed to change.
     
  12. messabout
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    messabout Senior Member

    Take RWatsons advice. The hydro design will be of litle use for your purpose. You can not produce enough human power to plane the hydo and if not planing, a hydro is a piglet. Do go for a long slender monohull boat and you will ultimately go faster.
     
  13. Submarine Tom

    Submarine Tom Previous Member

    What are the rules?

    When is the event?

    What is the gear ratio in your drive?

    How strong/big are you?

    What is the history of past entrants?

    What is the envelope of possible sea states during the race.

    -Tom
     
  14. Angélique
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    Angélique aka Angel (only by name)

    No human powered hydroplanes, but here some pictures of human powered hydrofoils. Pictures where taken at the Human Powered Vehicles World Chamionships 1995 in Lelystad Holland (I was there).

    [​IMG]

    [​IMG]

    [​IMG]

    The red one is Af Chapman II from Sweden, the white one is Haarlem Shuffle from Holland (far as I remember the Af Chapman II is from the late 1980's).

    ---------------------------------------------------------------------------------------------------------------------------

    But they are not from cardboard and can't be build within budget of this project I guess..

    So I think a slender monohull and to try to optimise the prop is good advice here. Maybe a model aeroplane prop would work... I've seen modified ones from alloy at low rev's on fast human powered boats..

    Poida, you took my post far too serious, please pay atention to the 'wink' and 'smiley', they set the tone how the post was intended to be.

    Good luck!
    Angel
     

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  15. spartans_78
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    spartans_78 Junior Member

    Thanks

    Angelique, very cool pictures of those hydrofoils!

    Submarine Tom. The races are in a little over a month. The rules are simple, use imagination, cardboard, glue and polyurethane paint to make one of two types of boats. Either a paddle-or-oar powered boat, or a mechanically powerd boat. Most of the entires will be the paddle/oar type. I thought that type a little boring for me, so I went with a mechanical type.

    My gear ratio is 1:4 so for each pedal rev, my prop will rotate 4 times. I am 6'3" and weigh 210#. Most of the ther entrants in this class have utilized twin pontoons and a bike frame with a paddle wheel. I have seen one with an airplane prop that I thought would be way too small to work. I wish I could have seen then go, but I had to leave before those boats went out.

    There will be up to 4 boats going out at a time in the wave pool of a water park, so the water should be fairly smooth.

    Messabout. I realoze I will never be able to get the boat on plane, but I have always liked the design of a hydroplane. I have wanted to build an actual hydroplane, so I have been kicking this idea in my head for about 30 years. I have altered the design a lot to do it out of cardboard, so this is a big unknown. Like I tell my freinds, this will be either an epic faliure, or ultimate genius! Either way, it will be fun and taht's what it is all about. Half of this "competition" is about looks and appearance, so Maybe I can get an award for best in show... Who knows?

    RWatson. Thanks for the link to the pedal powered discussions. Very interesting stuff, indeed. I am pretty much stuck with the design I already have started... That's OK, though. I will let you all know how it works out. When you speak of a long, slender hull I imagine you are referring to the 20-25 foot mark. For this deal, it simply wouldn't work. The place we are doing this is too confined. So, I went with 7 feet. I am pretty much limited to the size of the cardboard sheets I am working with. They are 75 x 110, so in my mind, i had to stay within 7 or 8 feet. I am also working on little to no budget on this project, so I have been scrounging to come up with the gearbox (out of a junked lawn mower) and prop (off of a boat that ran over some rocks and broke the splines and bent the blades).

    Again, Thanks to all for replying! This is going to be fun, for sure.

    Stevo.
     
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