Pedal Powered Boats

Discussion in 'Boat Design' started by Guest625101138, Jul 14, 2008.

  1. tom melon
    Joined: Aug 2022
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    tom melon Junior Member

    at the moment I don’t have requirements, I’m just feeling the edges of what’s possible before I go any further.

    I got the gearbox cheap on eBay, not super set on using it. I had an idea of using it for a tandem boat, but that’s down the line

    If I was going to settle on a requirement now, I’d say it has to be better than my kayak, otherwise I would just take that out on the water and the project is worthless.
     
  2. portacruise
    Joined: Jun 2009
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    portacruise Senior Member

    Even with the best and most optimistic setup, it will not be better than your kayak in every way, you'll be riding different animal. One way to find this out is to rent one where they're available, at a water place. That's what I did a few times during holiday, and that's how I found out pedal boats were not for my particular type of excursions and interests. But, there's nothing else in the world that is capable of fitting my particular requirements compared to what I have, guess I'm sort of persnickety, haha!

    Good luck!
     
  3. tom melon
    Joined: Aug 2022
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    tom melon Junior Member

    It doesn’t need to be better in every way it’s obviously a different type of water craft. I don’t think we need to get caught up in semantics.

    by better I mean I can go further and faster than I could with a paddle. I am already a cyclist, tandem and recumbent rider. I’m already well suited to long days on the pedals.
     
  4. BlueBell
    Joined: May 2017
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    BlueBell . . . _ _ _ . . . _ _ _

    Are you planning, or considering, kayak style paddling while pedalling?
    It's nice to have options and better for you to have variety in your exercise.
     
  5. tom melon
    Joined: Aug 2022
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    tom melon Junior Member

    Regardless of the boat type I’d take a paddle for security, in case there’s a problem with the drive, and I can imagine it would useful sometimes for manuovering.

    I like the idea of kayak style pedal boat, but I’m not sure how effective that would be. Feel like there will be too much drag and the layout won’t suit a recumbent pedal drive. Are there any examples out there?
     
  6. kerosene
    Joined: Jul 2006
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    kerosene Senior Member

    Tom have you checked Rick’s boats on this thread? They are recumbent, very efficient but not exactly kayak style being very long with outriggers.

    java prop is bit hard to find (reliable download link that is) and it is but cumbersome to use but not that hard with some patience and stubbornness and once you get hang of it you can easily check ballpark efficiencies of different prop setups. I think Rick’s 8:1 must be pretty good. I recall from my tests that with human power range (200W +-) 400-500rpm at prop was giving the best compromise. Naturally with much larger prop lower rpm would do but plenty of reasons why it would be impractical.
     
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  7. jehardiman
    Joined: Aug 2004
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    jehardiman Senior Member

    Yep, a 24 t0 36 in wheel is ideal, except for fabrication, beaching, and transportation (i.e. all the other stuff about building and using a HPV). We got away with them because they were very close to the human powered submarines' diameter.
     
  8. tom melon
    Joined: Aug 2022
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    tom melon Junior Member

    yes I have been through the whole thread some time ago and been in contact with Rick who was very helpful.

    I would just do a copy of Ricks boats, but they are too long for me to transport, and I’m not really trying to set records. I’d like more practical boat that I could spend the day in comfortably, but still push along a decent speed. Problem is I will loose speed with a shorter wider kayak style craft, and at what point is it better to just paddle. I have also considered a small cat.

    I’d be concerned with grounding a large 24” prop on the shallows, which is going to somewhat of a problem with any prop.
     
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  9. portacruise
    Joined: Jun 2009
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    portacruise Senior Member

    There are some ways to solve the grounding problem when a much smaller prop is used. Here's video of the basic principle of the most common way.



    Of course it may not work at speed shown using 24 " props / low rpm and the generally low power Reservoir available with HPB. But that is the basic principle used in my one man boats to travel in extended thin waters down to 4", where paddles don't work very well.
     
  10. tom melon
    Joined: Aug 2022
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    Location: UK

    tom melon Junior Member

    I was thinking of using ricks flexible shaft, and lifting it out when necessary. Obviously that depends of the shape of the hull.
     
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  11. portacruise
    Joined: Jun 2009
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    portacruise Senior Member

    Yes, I met Rick on another forum and it took some time convincing him that the principal of an unsupported flexible shaft would work #47 link below. Rick went on to develop the idea and use it in the first boat that Greg used for the 24-hour distance / speed record #59, beat the kayak paddling record at that time, as I recall.

    Prop Shaft Systems. https://www.boatdesign.net/threads/prop-shaft-systems.24636/page-4#post-286133

    Posts number 53 and 54 have videos that I sent Rick...
     
    Last edited: Feb 25, 2023
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  12. Tiny Turnip
    Joined: Mar 2008
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    Tiny Turnip Senior Member

    Rick was hugely helpful to me when I did my pedal catamaran conversion, and I'm still considering either rebuilding the cat, but lighter, or as near as I can get to one of Ricks boats, but with the hull in two parts, bolted together. Is that not something you could consider?

    Its not so complicated to use your 2:1 gearbox, and add gearing on the output shaft to achieve 6:1 and a smaller (16"-20") prop.

    And depending on your drive arrangement - a skeg to protect the prop, or lift it out and paddle in the shallows - all work for me.
     
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  13. tom melon
    Joined: Aug 2022
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    Location: UK

    tom melon Junior Member

    that’s actually a great idea, why not have the boat in two parts and somehow join them together. Do you have any idea of the best way to do this?

    do you have some pics of your cat? I’d like to see how you did it.

    Im not sure I totally understand what you mean by adding gearing to the output shaft. Do you mean using bike gears like Ricks boats or some other method? I think ultimately i will have to gear up the gearbox, I think a large slow prop is going to be a problem.
     
  14. Tiny Turnip
    Joined: Mar 2008
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    Tiny Turnip Senior Member

    Gary Dierking, who is a member here, (garydierking) has some really sweet designs for simple 3 plank beach proas which simply bolt together.

    my approach would be to have a well and just bolt through two beefed up bulkheads with some rubber washers. You could get more complex.

    My boat was based on an old Dart 18 catamaran, with seacycle drives and recumbent bike seats. I've been extremely happy with it, but it is heavy, and the Dart hulls slice into the beach making it tough to move out of the water. I'd rebuild in the same format, possibly with two part hulls, in 3 plank plywood, which should be lighter and easier to slide up the beach. Here's the boat:



    Yes, just like Ricks - I think for speed and efficiency they would be hard to improve on. You would want to consider a simple way of tensioning the chain, and a thrust bearing, but the losses would be minimal.
     

    Attached Files:

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  15. Tiny Turnip
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    Location: Huddersfield, UK

    Tiny Turnip Senior Member

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