Pedal Powered Boats

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

  1. beppe
    Joined: Jul 2008
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    Location: Udine, Italy

    beppe Junior Member

    free shaft: a great invention!

    Hi Rick
    this is a remarkable achievement! I considered the bended shaft option when I started my first waterbike design, some 15 years ago (after I saw it depicted in the fampus article by Abbott, Brooks and Wilson in the 'Bishop catamaran') but I discarded it believing that vibration and shaft instability could at least reduce the efficiency. We never thought about an unsupported shaft and a self stabilizing prop. Is that a novel idea of yours? This is brilliant!
    The only questions I would like to ask are the following:
    1. why the prop is not in front? It should increase the efficiency (I don't know how much, but in principle I think it should) because the props works in undisturbed water and also stabilize even better the shaft that is subjet to traction instead of compression. The problem of the vulnerability of the prop is not relevant for competitions or record boats and after a few years of watrbiking it seems not as relevant as is seemed before also cruising boats, too.
    2. In cruising boats I would like to have the possibility of inspecting the propeller; btw this is an important feature of the 'kick-up' connection I would like to propose for the Open Waterbike ( a short video of how it works at )
    This have proved necessary in severla cases, for example for freeing the prop from weeds, checking damage, beach launch etc.)
    Could this feature be implemented within the 'free shaft' solution?
    Best regards and congratulations for your brilliant invention and implementation.
    Giuseppe 'Beppe' Carignani
    founder, The Open Waterbike Project
  2. Guest625101138

    Guest625101138 Previous Member

    1. The prop needs to push to stabilise. If it pulls it tries to dive and go into pushing motion. Vic Garza was the first to point out the self-stabilising feature of a water prop to me - he was happy to have the information in the public domain. I believe the forces involved are well understood by the aircraft industry. It is not difficult to work out once you know that it actually works.

    2. The curved spring steel shaft just allows me to pull it up to inspect the prop. My previous system was a pull cord from the back of the seat attached to a lever that lifts the prop clear of the water. You will see the cord on the lever in the attached video bouncing around. I can easily throw weed off by lifting the prop clear of the water while spinning. My latest arrangement is simply to have the prop beside the seat so I can reach down and clear any fouling. I can just look over the side to check the prop unless the water is terribly murky.

    My spring steel shafts are very forgiving they will just bounce over logs and rock. Vic has a video of an electrically driven prop just bouncing from rock-to-rock but still pushing the boat up a shallow creek. He uses fibreglass shafts and more conventional 2-bladed aluminium prop.

    Rick W.

    Attached Files:

    1 person likes this.
  3. beppe
    Joined: Jul 2008
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    Location: Udine, Italy

    beppe Junior Member

    Open Waterbike Drive Unit geometric interface

    Hello Rick and colleagues
    as an engineer, I agree in principle with your 'issues' about twisted chain arrangements. It is actually an horrible way to use a chain... but after a decade of waterbiking with twisted chain drive legs I must admit that they are remarkably simple, light, efficient and reliable (this is the most surprising thing), while I have withessed double-bevel failures...
    Anyway, I would like to propose a completly different approach for solving the question - and not only this one, within The Open Waterbike Project.

    What I would like to do is to propse to the community a standard interface for connecting any drive unit to a waterbike, taking advantage of so many years of collective archiectural design. I believe that we can collectively agree to a good architecture, all of them have already been tested by someone, and the advanteges and shortcomings are well known, not by myself but possibly by some other member of the pedal powered boat community.
    I set a page of The Open Waterbike Project

    defining the startup geometrical interface, including the proposed measures and the proposed geometry in a dwg file.

    I also enclose the measures at the end of this reply, and the dwg file (attached).

    The concept is based on a 'forward' tube, allowing also for a kickup feature, as shown in a short video at

    The idea is to accomodate any drive unit, twisted chain, chainless, possibly also your fascinating free shaft.
    The Open Waterbike platform can thus work also as a real-world laboratory to assess in a very convincing way the real value of any solution - and of course opening up a market for it.

    I look forward to get your opinion and that of the colleagues on these specific issues:
    1. is the 'forward tube' a sound concept for an architectural standard for pedal powered boats?
    2. do you agree with the measures proposed or do you suggest any variation?

    I look forward to your opinion. Best Regards to all

    Giuseppe 'Beppe' Carignani
    founder, The Open Waterbike Project

    Appendix: OW Drive Unit geometric interface - proposal - see also the enclosed dwg file

    Fundamental measures

    Vertical measures

    VCP - crank axle axis to propeller axis: 800 mm [32']

    VCT - crank axle axis to forward tube axis: 225 mm [9']

    VWT - water level to forward tube axis: 200 mm [8']
    VWC – water level to crank axis: 425 mm [17']

    VWP - watel level to propeller axis: 375 mm [15']

    ETD - Forward tube diameter (external) european: 50 mm

    ATD - Forward tube diameter (external) american: 2'

    VCS – crank axle axis to seat (lower point): 0 to 100 mm [0 to 4']

    Horizontal measures

    HCS– pedal axis to seat: ADJ (adjustable from … to …)

    DPT – from crank axle axis to forward tube axis: 275 mm [11']

    Derived measures

    PFA - from pedal (axis) to forward tube axis: 100 mm [4']

    MPD - maximum propeller diameter: 600 mm [14']

    (with a 75 mm [3'] clearance form water level to prop tip)

    Attached Files:

  4. Guest625101138

    Guest625101138 Previous Member

    I have difficulty with such constraints. The most commercially successful pedal powered boat is the Hobie Mirage. I cannot see how your envelope fits this unit. You have already contemplating constraints that suit your drive leg.

    Here is a nice boat that Chris Ostlind designed using Hobie pedal thrusters:
    Why not standardise on the Hobie geometry as this is already the most popular? It is clear a nice hull will perform well with these drives. They are simple and robust.

    Here is the worlds fastest pedal canoe:
    How does this fit with your constraint. Why not just standardise on one of the Hydrocycle drives as it is better engineered than the twisted chain:

    Rick W
  5. Guest625101138

    Guest625101138 Previous Member

  6. beppe
    Joined: Jul 2008
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    Location: Udine, Italy

    beppe Junior Member

    The Open Waterbike Project goals

    Hi Rick
    the Open Waterbike Project is about innovation, and the idea is that modularization could enable collective distributed innovation managed by a community of peers.
    I know the crafts you mention, and I agree that they are fine well engineered products; the eclipse drive unit is also very innovative.
    But I beleve they make a bad platform for innovation, also because they are monohulls canoes and multihulls seem in principle more suitable (even if we didn't yet decide).
    Just to give a couple of examples, some members of the Open Waterbike Project want to work on waterbike innovations as:
    - hybrid human-wind powered waterbikes, equipped with a automatic wingsail;
    - human powered boats for disabled people.
    They don' want to start from scratch, they need a platform.
    I believe that the canoe architecture is not a good platform for such developments.
    The idea of using a well engineered drive unit is very good, but we still need a standard interface, that is exactly what we (the Open Waterbike community) are trying to do.
    I propose the idea of the forward tube because is came out after a lot of architectural testing, and it seems to me the most suited for starting a technical discussion about architectures, but it is just a proposal, and I will be happy to exchange it for a better one or to improve it with the contribution of all the people interested.
    Thank you again for your immediate answers to any message; I know you are lukewarm about The Open Waterbike project but i keep you in high esteem as a pedal boat inventor and builder, so I seek yur advice, please be patient... by the way, I believe the pedal boat community needs new debatable issues and I believe the Open Waterbike attempt is a good one!
    best regards to you and all the colleagues
  7. Guest625101138

    Guest625101138 Previous Member

    My first sticking point is the word waterbike. I suggest you think about it. It is predominantly European terminology that just does not make sense. What you have is in no way a bike that goes on water - a bike by definition has two wheels. It is first and foremost a boat.

    If you call it a human powered boat then it brings in all other forms of propulsion. Essentially the architecture you are aiming to derive is based on leg muscle propulsion. So pedal powered boat seems the most apt description.

    A mono hull is far superior to a catamaran from a drag perspective. The catamaran requires 39% more power for the same speed. This is a significant penalty for the catamaran. My view is that a stabilised monohull has other advantages as well. Performance advantage being significant. But it is easier to transport and, in fact, two boats can be placed on a single car.

    I use my catamaran for tinkering and experimental work but it does not provide the same level of satisfaction I get from powering along in my two preferred stabilised monos. The latter is no pain to transport and launch. No set up required; in the water and away I go.

    Rick W.
  8. Guest625101138

    Guest625101138 Previous Member

  9. Tiny Turnip
    Joined: Mar 2008
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    Location: Huddersfield, UK

    Tiny Turnip Senior Member

    I wholeheartedly support Rick here - whereas I am hugely enthusiastic about human power, boats, and learning, I struggle with constraining invention! It may very well be that it is worth developing parameters for deep, linear strands of research, especially for honing 'best performance' data, however, learning environments (such as this forum) which encourage discussion, transfer of technologies across disciplines, and exploration are most likely to lead to real innovation, and development needs *both* types of learning. I would question that pursuing the fastest possible pedal boat is a particularly useful goal in itself, (if you just want to go fast on the water, there are other much better ways to do it without damaging the environment) though it may well lead to innovations or technology transfer in, say, propellor design, high efficiency transmission, or other areas particular to the field, which are of great importance. My point is that there are other potential developments of great importance that setting speed as the *only* parameter rules out.

    I am perhaps an hour (or three, including varnish!) short of completing my pedal powered project, which has benefitted hugely from Rick's generous contributions of time and expertise through the relatively unstructured learning environment of this forum.

    This will not be the fastest pedal powered boat, but should be reasonably quick. By combining a number of existing components, I hope to have assembled a boat based on Dart18 hulls, crossmembers and rudders, with recon seacycle sealed pedal units and props, trice recumbent seats, and a bit of ply and timber butchery. It should carry 4 adults, allow swimming, fishing, lobster potting, and the ******** of a two person pup tent on the deck for camping, in a total assembly time of 12 hours so far, for about £1500 uk pounds stirling, including road trailer (and still useable alternative Dart rig!). I am quite excited about what I hope will be a pretty practical and useable boat, for not too much money, and a few low skill (mine) hours of woodwork and assembly. But it won't fullfil any of the open waterbike criteria.
  10. Guest625101138

    Guest625101138 Previous Member

    I am looking forward to the report and photos from the first shakedown cruise.

    Every pedal boat I have made I have improved substantially after the first trial. I am hoping my next one is close to the money first time out as it is just a lighter version of the last one with a bit more innovation. With some effort and warm weather for painting this week I might have it in the water on Sunday.

    Rick W.
  11. Guest625101138

    Guest625101138 Previous Member

    I just refreshed my memory on your project.

    One of the things I suggested was engine calibration. Have you had a go at this?

    The more you get into pedal boating the more interested you get in the engine performance. I have found the first 10 minutes does not mean much. You need to be at it for about 1 hour before you find out if it is set up right and what the cruising speed will be.

    Rick W.
  12. Fanie
    Joined: Oct 2007
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    Location: Colonial "Sick Africa"

    Fanie Fanie

    He he... Rick, I have found that to be very true. Finally at my advance age :rolleyes: I'm not much interested in paddling, just about any non-physical propulsion tickles my fancy :D

    You have too much energy. I save mine for important things... like fishing.

    Sorry, just couldn't resist. I find the drive unit quite interesting. Would like to see what you have found to be the most efficient.

    On a shaft with a wind vein it may well be wind driven.
  13. tinhorn
    Joined: Jan 2008
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    Location: Massachusetts South Shore.

    tinhorn Senior Member

    I'm looking forward to seeing both of these new boats! I'm fascinated with pedal power, too, but haven't been able to even begin work on my own projects. Thanks for sharing yours.
  14. beppe
    Joined: Jul 2008
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    Location: Udine, Italy

    beppe Junior Member

    Open Waterbike misunderstandings

    Hello TT
    i agree with most of your post, especially about the usefulness of this fourm as a 'learning environment', but it seems you are not so well informed about The Open Waterbike project. Please let me set a few records straight:

    You wrote: 'But it won't fullfil any of the open waterbike criteria.[/QUOTE]'

    Oh I bet it fulfills most of the Open Waterbike requirements (
    You aren't trying to build an unsafe, dangerous, unfriendly an inefficient boat, are you?

    You wrote: 'I struggle with constraining invention!'
    Me, too.
    We (the Open Waterbike community) are NOT trying to constrain invention. We are NOT trying to provide people with constraints, we are trying to provide them with useful reusable components with which to build and innovate pedal powered boats in an easier way, sparing the time spent in adapting unfit components. This requires interfaces, not constraints. The availability of a platform of reusable modular componenst could be the gateway to innovation, as it was in so many cases.

    The Open Waterbike has nothing to do with constraints. If you have a look at the dwg file I posted earlier you will see what I mean.

    The Open Waterbike project is a bold attempt, maybe an impossible one, but it is aimed at supporting and improving human powered boating, as we all want. Strong informed criticism is always welcome and helps improving the project (this is why I appreciate so much Rick's contributions) while an misinformed dismissive attitude could contribute to undermine the project in these early phases. Please do not do that.

    I wish you success to your project and look forward to learning more from this forum.

    Best regards and good luck!

  15. beppe
    Joined: Jul 2008
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    Location: Udine, Italy

    beppe Junior Member

    Open Waterbike architectural dilemma

    Dear Rick
    thank you for raising the monohull-multihull dilemma, this is the
    first architectural question the Open Waterbike community should
    address (I already proposed it,
    There are so many facets in your mail that I'll try to address only
    the most important of them in this - I suspect I'm writing too long
    posts, annoying the colleagues...
    I don't like the catamaran architecture, BTW it has a bad image being connected in common views with low-performance beach watercrafts, so I like very much the idea of a monohull Open Waterbike, but I see a number of issues I believe are difficult to solve.

    I agree, a monohull has lesser drag and is potentially much efficient.
    This is a toll we should pay if we embrace the multihull architecture.
    Could you please give the source of the figure (39%) you mentioned? It seems
    high and doesn't add up well with other less direct measures I have (i'll give the details in a next post) but I know your data are usually accurate.

    Also, in principle it is easier to transport a monohull, but I believe
    this can be solved, for example with a clever and fast assembly
    system; moving two lighter hulls could even be better for some people
    than loading on a car one heavier hull and you can possibly transport
    four narrower hulls on a car. You didn't mention it, but multihulls
    are also usually more complicated and therefore more expensive one more important point in favour of your view.

    So, I agree that until now a monohull has a distinctive advantage.

    Now coming to a few problems to solve and issues to address if we want to adopt a monohull architecture,

    The major problems to solve:

    1. Addressing the Open Waterbike requirements
    in particular safety and user friendliness even for unexperienced
    I believe the enclosed image can explain the concept. You can see a well dressed lady pedalling at five knots (BTW the speed limit in Venice, Italy) through the narrow channels, no training, no fear, no wet shoes.
    The Open Waterbike is intended to address the needs of common people, not only watersports enthusiasts.
    Question: could these requirements be addressed with a canoe architecture?
    What if a pedal powered canoe capisizes, it could happen even in calm water to an unexperienced rider?

    Two more subtler points are:
    2. suitability as a platform for developing modular innovation
    3. one-to-one module-function modularization

    I'll address them in future posts, if someone is interested.
    I'll also try to answer later to two interesting points of you post ('waterbike' name and hybrid propulsion), I believe I have reached the maximum acceptable length of a post...

    Thank you again for your critical but useful contribution to the Open Waterbike project, Rick

    Best regards

    Attached Files:

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