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Thread: pedal power

  1. #1
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    Default pedal power

    Where does pedal power via transmission to propeller rank in terms of power and efficiency with other forms of human powered boat propulsion, especially compared to rowing with and without a sliding seat?
    Simpler is better, except when complicated looks really cool.

  2. #2
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    Default Re: pedal power

    I study this a lot, I think there's a pedal powered boat in my future, and everything I read points to a pedal prop assembly as being the most powerful with the right ratios and prop.

    Here's some evidence of that, a small person waterskiing behind a pedal powered kayak. You can't do that with oars. Unfortunately Bob Stuart is no longer producing the SpinFin. He sold the business and patterns/molds to a fella who, it appears, has done nothing with it.

    http://www.elmtreedental.com/AR_Pedalkayak.html

    And here's the Spin Fin.

    http://microship.com/bobstuart/spinfin.html

    I am considering hooking pedals to a shaft and prop that tilts up into a kind of a low profile centerboard trunk, a lot like the Dispro Boats. The hull might be a light weight multi chined dory where the sheer plank has been deleted and decks added, like a wide kayak with huge flotation tanks.

    Here's a Dispro (Disappearing propeller) unit,

    http://www.dippy.ca/howpics/device.htm

    And here's a site where you can learn more about a Dispros.

    http://www.dippy.ca/how.htm

    And here's a picture of the dory I would base the hull on.


  3. #3
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    Default Re: pedal power

    I've seen a number of Dispro boats aver the years. Have you seen Paul Gartside's pedal boat. I like his take on the retractable prop with built in skeg for protection. This boat has traveled the length of the Mississippi, then around Florida and up the Intracoastal then all the way to Nova Scotia.

    Blue Skies" is an oddball little boat that we built several years ago with and for our oddball friend Bill Hayward. Bill got hooked by the idea of pedal power after many years of rowing and was looking for a boat to do some long distance cruising. To add to the challenge he needed liveaboard accommodation and the ability to operate on fast flowing rivers and in shallow water without damage to the drive system. A tall order to say the least, but the boat has proved most successful and logged thousands of miles around the waterways of North America. Her lines and specifications are in the plan catalog. She was built canoe fashion, cedar strip over a temporary mold, glassed inside and out. There is a 6 ft. 6 in. sleeping cabin forward; accommodations are extended by a bimini top with side curtains over the cockpit. The drive consists of a bicycle crank turning a shaft through a 6:1 bevel gear running in an oil bath. The shaft is fitted with a universal joint where it exits the hull and the outer shaft is supported by a pivoting skeg that folds up into a trunk in the stern. The skeg extends under the propeller so that on grounding it kicks up without damage. Both skeg and rudder can be hoisted for beaching.
    Pedal Boat "Blue Skies" in shallow water with propeller and rudder raised.Detail of rudder assembly.When the skeg is lowered the propeller operates in clear water below the hull. The 13 in. x 18 in. propeller turns at about 300 RPM, and delivers a sustainable 4 knots.


    Simpler is better, except when complicated looks really cool.

  4. #4
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    Default Re: pedal power

    Yes I've seen that, never seen a Dippy though. I keep coming back to it hoping to find who builds the gearbox. Thanks Paul.

  5. #5
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    Default Re: pedal power

    Bump. Looking for a gearbox myself.

    Would like to get some exercise when the sails are down.

  6. #6
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    Default Re: pedal power

    We have a UK company producing commercial tandem pedal powered canoes.

    http://pedalcraft.co.uk/?page_id=29

  7. #7
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    Default Re: pedal power

    They look nice. Not much detail on the drive system.

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  9. #9
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    Default Re: pedal power

    Here's a mock up of a trunk where the unit can be tilted/lifted clear of the bottom and will kick up if you hit bottom.


  10. #10
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    Default Re: pedal power

    A great sourse including props you can build yourself and a belt drive system that looks lots more efficient that any beveled gear gizmo can be found at WoodenBoat 222, page 62. Or google Philip Thiel.

  11. #11
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    Default Re: pedal power

    Great. Thanks.

  12. #12
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    Default Re: pedal power

    Brian

    This is the pic I was thinking of. Any idea who did this? Looks very custom.

    Last edited by bluedog225; 05-19-2015 at 03:31 PM.

  13. #13
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    Default Re: pedal power



    Last edited by bluedog225; 05-19-2015 at 03:43 PM.

  14. #14
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    Default Re: pedal power

    If you want to do 18 knots on water, you need an airscrew to pedal though. Mark Drela's Decavitator.
    https://www.youtube.com/watch?v=z1lDi6M-u_U
    Sorry if YouTube is playing up- Google Decavitator for details.

  15. #15
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    Default Re: pedal power

    I just want to glide along at 3mph in 6 inches of water.

  16. #16
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    Default Re: pedal power

    With two pedalling, Super Phoenix was slightly faster using a prop, not airscrew. 18.67 knots.
    This link may work:
    https://www.youtube.com/watch?v=RvE6Xd6tgPA

  17. #17
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    Default Re: pedal power

    Quote Originally Posted by bluedog225 View Post
    Brian

    This is the pic I was thinking of. Any idea who did this? Looks very custom.

    That was a picture I took at Beale Park Boat Show a few years back. The builder was peddling down the Thames with the UK HBBR group. Boat was a modified Welsford Walkabout, with a Hobie Drive stern mounted and linkages to connect forward. did look a bit over complicated.

    The Hobie Drive system seems to work very well and people are fitting them to various hulls. Here's a link from the CLC forum

    http://www.clcboats.com/forum/clcfor...ead/30159.html






    Here's the Rutland Pedal Craft



    Brian
    Last edited by keyhavenpotterer; 05-19-2015 at 04:44 PM.

  18. #18
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    Default Re: pedal power

    "I just want to glide along at 3mph in 6 inches of water."

    Then you're going to want either horizontal "counter rotating" (opposing?) fins or an air prop in only 6" of water.

  19. #19
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    Default Re: pedal power

    Yeah.....1-2 feet deep is more realistic.

  20. #20
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    Default Re: pedal power

    Thanks Ian. I pulled the issue and had a look. I'm afraid the pedal drive description is a little high level for me. But I will try to find another writeup now that I know where to look.

  21. #21
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    Default Re: pedal power

    The very most efficient right angle drive is a helical bevel gearbox. P. Thiel's home made version is certainly clever but is much less efficient due to the use of so many components. His home made prop is not even close to efficient, you can get one from Sea-Cycle, cheap. Requires 1:6. He also recommends the Sea-Cycle as shown previously.

    You can get a helical bevel gear box designed specifically for pedal drive boats here;

    http://lampin.com/right-angle-gearbox/

  22. #22
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    Default Re: pedal power

    Come to think about it, if you insist on keeping it cheap you can easily and affordably gear up to 1:6 by sitting sideways in the boat and using 1:6 sprockets, one on the pedals the other on the shaft. Sit just to one side of center and mount the pedals out on the other side a ways to keep your center of gravity midships.

  23. #23
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    Default Re: pedal power

    Gib, Was that Christopher's Dory? That is a nice looking boat.

    Greg Lindberg made a pedal power unit for a kayak using a large model airplane prop.

    These are a collection of largely pedal power links that might provide some food for thought:
    http://www.mission-base.com/pedal-power/pp_index.html
    http://outyourbackdoor.com/article.php?id=624
    http://nativewatercraft.com/features.cfm?id=14
    http://www.waterbike.eu/Articles/

  24. #24
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    Default Re: pedal power

    A decade or so ago SWMBO and I used one of Phil's boats at the CWB on Lake union in Seattle. It had two seacycle units side by side for two-up. The pushing more or less up rather than down was a pain after a while. And I found the seacycle unit a bit fragile and had to repair them once or twice while working in the shop there. And,no, we weren't trying to beat them up. It was a quiet outing for the fun of it. SWMBO and I tried one backing and the other forward would spin the boat on its own center. Fun and perhaps handy at times. Maybe seacycle has improved their engineering. I've no idea. Has anyone else had any problems with those units?
    Last edited by Tom Robb; 05-09-2016 at 04:16 PM. Reason: Speeeling:(

  25. #25
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    Default Re: pedal power

    Gib, have you tried a Hobie "Mirage Drive"? It really is amazing. I have never used an efficient prop drive powered by a bicycle arrangement, so I have nothing to compare it to, but a did use a Hobie kayak recently, and was amazed that I never felt the need to unclip the double-blade paddle.

    We went upstream against 2-3 kts, and circumnavigated a large island in a river. No sweat at all -- and I'm a canoeist, a paddler by long-standing preference.

    The darn thing really works well.

    Dave

  26. #26
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    Default Re: pedal power

    Thanks Gib. That Sea Cycle drive is looking pretty good.

    I will need to take some measurements.

    I am thinking of mounting it midship and extending a flexible stainless shaft about 12 feet.

    That will run it a couple of feet past the stern (or more).

    I recall from some research I did on Willoughby's (sp?) stuff that a prop on the end of a long, free floating, shaft was self tending in that it squatted down and stayed in the water. But it was also flexible enough to bounce over obstacles.

    Something like a long drive Sampan motor shaft.

    What part of the world are you in?

    Tom

  27. #27
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    Default Re: pedal power

    Yes, that is Christopher's dory. He lets me row it from time to time.

    And no, I have never pedaled any pedal powered boats. I'm sure that the Mirage drive is efficient and durable, but for my use, where I will be beaching a lot and also want reverse it's not suitable. I'm watching though, and if I see one around you can bet I'll give it a try, with the owner's permission of course.

    I'm building a boat now specifically for camp cruising using the Sea-Cycle, just came in from the shop for supper in fact. I'm closing in on it, but just like with any other boat, or house, the closer I get to finished the more tiddly the work so it's going slowly. Also, it always seems that the closer I come to finishing a boat, and the more antsy I am to have it done and try it out the more other jobs I get asked to do or just need to do around here.

    Anyway, once it's done I'll post a build thread and get a friend to make a video of it in use. He races kayaks, maybe I'll ask him to race me while his wife videos. I doubt that I can beat a racing kayak with a wider hull. Maybe a tug of war will be in order, except that the kayaks he builds are so light we'd probably tear it apart. Maybe if I just tie to him instead of the kayak?

  28. #28
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    Default Re: pedal power

    Gib, I'll be on SSI late July for a week, staying in Ganges. Would it be possible to have a look at this new boat and visit w/ you?

    Steve C.

  29. #29
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    Default Re: pedal power

    Simplified Boatbuilidng - The Flat-Bottomed Boat by Harry Sucher (1973) has some designs for home-made fold-away prop systems. For engines, not for pedal power.
    I will beg you for advice, your reply will be concise, and I will listen very nicely and then go out and do exactly what I want! (Apologies to Lerner and Lowe.)

  30. #30
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    Default Re: pedal power

    Quote Originally Posted by Paul Pless View Post
    Where does pedal power via transmission to propeller rank in terms of power and efficiency with other forms of human powered boat propulsion, especially compared to rowing with and without a sliding seat?
    You could build a transmission and prop.







    The wooden gears have a nice sound when underway.
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    When we remember we are all mad, the mysteries disappear and life stands explained.

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  31. #31
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    Default Re: pedal power

    Gib, Got it, will get in touch either before I/we get to SSI or upon our arrival. Looking forward to your new boat and more boat talk.
    Steve C.

  32. #32
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    Default Re: pedal power

    That is the most beautiful prop I've ever seen in my life.

    It is a shame, however, that it is terribly inefficient for a human due mostly to the huge power limitations of HP.

    I hate to be a wet blanket and haven't followed this thread at all...

    So long as it all works for you, that's all that really counts.

    Cheers!

    Edit: For human power (HP), a propeller is amongst the most efficient versus paddling, oars (sliding seat or not). The most efficient props are 15" - 20" diameter, square (pitch wise) model airplane props. Plastic, graphite, fiberglass, carbon fiber, stainless (not that hard to make either).
    Last edited by Tom Christie; 05-20-2015 at 12:10 PM.

  33. #33
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    Default Re: pedal power

    Quote Originally Posted by Tom Christie View Post
    .......For human power (HP), a propeller is amongst the most efficient versus paddling, oars (sliding seat or not). The most efficient props are 15" - 20" diameter, square (pitch wise) model airplane props. Plastic, graphite, fiberglass, carbon fiber, stainless (not that hard to make either).
    That's why I think the Mirage drive is so efficient.

    It's like a great big prop except each blade only makes half a revolution then reverses pitch. You have the efficiency of slow turning 26" prop in half the space.

    Yeah, too bad I can only output 180 watts for 30 minutes. Visit your local gym and set the exercise bike to read in watts. Design your hull based on that.



    Cheers, Mack
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    When we remember we are all mad, the mysteries disappear and life stands explained.

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  34. #34
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    Default Re: pedal power

    The exercise machines at the gym are extremely inacurate.
    Do not rely on them for any wattage figures.

  35. #35
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    Default Re: pedal power

    Quote Originally Posted by Tom Christie View Post
    The exercise machines at the gym are extremely inacurate.
    Do not rely on them for any wattage figures.
    I'm sorry to hear that. I also did a static bollard pull test using a Mirage drive and fish weighing scales.
    I gave the inaccurate watts measurement and the probably equally inaccurate pull test results to the designers.

    Wait, what was this thread about?
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    When we remember we are all mad, the mysteries disappear and life stands explained.

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