Human Powered Boat

Discussion in 'Boat Design' started by SolomonGrundy, Feb 12, 2005.

  1. SolomonGrundy
    Joined: Feb 2005
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    SolomonGrundy I'm not crazy...

    Hpc

    Skippy,
    Good point. Paddle wheeles were considered in the begining because if their utter simplicity. Makes alot of sense if reliability and simplicity are paramount. But reliability and efficiency are most important.
    BTW, the only motor I know of that rotates is in a Mazda. all others must convert linear motion to rotary at a loss. that's why RX-7's are so bitchenly (look, I made a new word...) torquey for their weight.
     
  2. D'ARTOIS
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    D'ARTOIS Senior Member

    Most probably you are an outdoors man. Me too. I did endurance, trials, etc. A couple of years ago, in my early 50's I walked twice France-Holland, the first time over a distance of 660 stat. miles, the 2nd time from Cannes (after the boatshow) to Holland, at 900 stat. miles.
    My average was between 30 miles on a bad day and close to the double on a good day. Biggest problem were sores and exhaustion. You will have an additional problem: the weather. Furthermore, this prop. system will be of little help when it starts to spook. You need definately a pair of oars to keep your boat in the desired direction in case of bad weather. I have the non plus uktra bike, nontheless, after 140 km I am off ( 84 st. miles). Biking is one of the most asking and severe sports (not for nothing all those drugs and painkillers).
    You need absolutely the oars to balance when it gets rough.
    My one penny...........
     
  3. Tim B
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    Tim B Senior Member

    hummm, a very interesting idea. here's a few thoughts...

    firstly, find yourself a good bicycle and somewhere with a few hills. plot out the gear ratios on a graph (teeth on big gear / teeth on little gear (or check on my website <under 'free stuff'>)) then cycle around for a few weeks, and work out whether you work best at high or low crank RPM. Make a mental note of the gears you use and rough speeds.

    For intance, I regularly use gear ratios of between 2.8 to 3.2 up-hill and 3.2 to 4 on the flat or down-hill, but I tend to be most efficient at high torque and low RPM (in terms of average speed for given tiredness). However, I know other people who prefer to work at lower gear ratios in a low torque high RPM state. You're preference may change, of course dependant on how tired you are.

    On the boaty side, check it out on a sheltered lake first!!! Then in a quiet bay, try it around San Fransisco bay (guessing you're in the states) and if that hasn't discouraged you, I wish you the best of luck.

    In terms of design I'd go for a yacht-type hull which would either be pumped-out or would self-drain. the addition of some form of bulb keel should give you all the stability you need and make it easier to right if you have an accident. I would keep the hull structure very, very light. remember also that power goes up as speed cubed (ie. twice as fast needs 8 times the power) so if you want to go at any speed at all, the design will have to reduce the wave-drag to a minimum.

    anyway, good luck

    Tim B.
     
  4. Skippy
    Joined: Nov 2004
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    Skippy Senior Member

    That's true SG, but engines below say 10-12 cyls rely at least partially on the rotational momemtum of the flywheel for the compression, exhaust, and intake strokes. I guess I'm thinking in terms of what the engine as a whole looks like to the rest of the vehicle. Thanks for responding.

    [Revision: Okay, you could make a 4-cyl back&forth design. It's not really the # of cyls, it's just the standard design uses rotation to drive the nonproductive strokes.]
     
  5. SolomonGrundy
    Joined: Feb 2005
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    SolomonGrundy I'm not crazy...

    Hpv

    For the record, SolomonGrundy made it through Hell week of BUD/S. (Class 146). Yes, the tenacity required is significant. That however, is not a consideration.
     
  6. icetreader
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    icetreader Senior Member

    paddle wheel

    Skippy,
    A few years ago I met with a manufacturer of water bikes who decided to switch from a propeller to paddle wheels in order to increase efficiency.
    There's already significant knowledge about paddle wheels in the context of HP.
    It looks like the fewer and broader the paddles the more efficient the system is. In some way it's reminding of the broader and slower propeller, one large and slow-moving tail instead of many small and fast-moving fins etc.
    Y.
     
  7. SolomonGrundy
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    SolomonGrundy I'm not crazy...

    Hpv

    Sounds intriguing, but why are there no paddle wheels crossing oceans?
     
  8. icetreader
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    icetreader Senior Member

    There are even less HP boats crossing oceans :)
    With such a limited source of energy and the inability to use most of it most of the time such tiny differences in efficiency become increasingly important.
    In my opinion the question is how to achieve optimal speed when you are in fact not pedaling hard - more in a "cruising" or "leisure" mode.
    If you apply the KISS principle rigorously you'll also want to get rid of any kind of transmission: belts, gears etc.
    Y.
     
  9. SolomonGrundy
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    SolomonGrundy I'm not crazy...

    Hpv

    Unless I plan to turn the shaft with a direct crank, which I hope to avoid... I will need some sort of transmission of power from my legs to the prop., that in itself necessitates gears, pulleys, cranks, sprockets, chains or whatever.
    Icetreader, I am interested in finding out which craft you speak of (less horsepower) that have made similar ocean passages, where can I find the information of which you mention?
    Thanks.
     
  10. icetreader
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    icetreader Senior Member

    HP cross ocean

    The manufacturer that switched from propeller to patented paddlewheel was Micromarine, in Massachusetts.
    The paddlewheel I was thinking about is a US patent I saw a few years ago (search: www.uspto.gov) - It has three blades that change their angle so as to enter the water and move through it with maximum efficiency.
    Here's a thread about this type of solution from Max Mosig (maybe it's the same one?): http://www.ihpva.org/pipermail/hpv-boats/2000q4/000507.html

    Otherwise, Remy Bricka crossed both the Atlantic and Pacific paddling standing in two long pontoons (version of Skijak?)
    Tori Mulden crossed the Atlantic in a rowing boat
    Mick Bird circumnavigated the globe in a rowing boat

    There's an article on a new type of propeller that you may find interesting:
    http://www.well.com/user/pk/SPAprofboat.html

    And some more links:
    http://members.aol.com/jfreeent/rsrch.htm
    http://www.ihpva.org/Water/
    http://www.microship.com/microship/index.html
    http://home.gci.net/~alconda/projects/projects.htm
    http://www.humanpoweredboats.com/Photos/ExpeditionHPBs/ExpeditionHPBs.htm
    http://www.prophish.com/nyrio.html
    http://home.earthlink.net/~ccbroome/boat.html

    Y.
     
  11. SolomonGrundy
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    SolomonGrundy I'm not crazy...

    Icetreader,
    I think you are slightly misinformed in some regards. Mick Bird made it to Java. Not a circumnavigation. His boat Reach has been presumably destroyed in the tsunami.
    My question to you stands. Who crossed any ocean with 1/4 hp. I shall give you the benefit of the doubt regarding any Pacific crossing on pontoons, however I shall attempt to verify your claim.
     
  12. SolomonGrundy
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    SolomonGrundy I'm not crazy...

    Remy apparently crossed the Atlantic from the Canaries to Trinadad, quite a feat. But he had the advantage of the Equatorial current (not in any way to diminish his awesome achievement) but the Atlanitc is an entirely different Ocean than the Pacific and I can find no mention of any attempt by him on that ocean.
     
  13. JEM
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    JEM Senior Member

    Cally to Catalina would be a good warm up.
     
  14. SolomonGrundy
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    SolomonGrundy I'm not crazy...

    Swam it.
    Okay...it was a relay.
     

  15. Eric Sponberg
    Joined: Dec 2001
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    Eric Sponberg Senior Member

    Solomon,

    A lot of traffic here before I could get a chance to answer your quesions. Yes, an aluminum prop is no problem. In fact, since the prop is in the water all the time, and weight down low is desireable, then an aluminum prop might be beneficial. Its machining would have to be accurate, and may have to look like something similar to that on the Gossamer Albatross, wherein the inner diameter parts of the blades have much longer chords and higher angle of attack than the outer diameters of the blades. These blades have a lot of twist in them because air speed (and in your case boat speed) is so slow. For that matter, laminated wood blades would also be possible. I just like carbon fiber.

    I am not really familiar, I have to admit, with all the possibilities of an up-and-down or back-and-forth pedal system. I stand corrected if you can get more power out of them than a crank. The purpose of my comment was that using a propeller, you necessarily have to have rotational motion, so if you start with rotational motion, I would think your mechanical system would be the simplest. It is hard to get simpler than a cycle crank, chain (or belt) and sprocket.

    I would also anticipate some kind of gearing or derailluer would be appropriate. The more RPM you can get, the more power you deliver, and you want to get as much RPM with the least amount of leg (or full-body) motion. How much gearing-up you need is a matter of testing--try some different settings and see what happens. I think you will find that, just like on a bike, flat water (like flat land) will let you go to high gear, and that as the water gets wavy (land gets hilly) you have to drop back into lower gears. RPM is one of the unknowns in the design of a powering system, and typically, you start with RPM and power available first, and then determine diameter and pitch of the propeller. Go through different iterations at different RPMs and powers, and you will finally settle on a suitable propeller diameter and pitch that will fit with your vessel design. And variable gearing should definitely be taken into account.

    Someone above brought up the idea of sliding seat and using the whole body for power--this might be worth investigating. I have a brochure on a neat rowing machine that I picked up years ago in which you pull on a handle and strap, and the strap is connected to a flywheel inside a circular water tank. It had a sliding seat, so you used your whole body for exercise. There was a slip clutch in the hub, I think, so that you pull in one direction (backward as in rowing) using arms, body, and legs on the sliding seat, and on the reverse stroke, the strap retracted without drag for the next pull. So in such a system, you get power from the whole body that goes directly into rotational motion to the linkage with the propeller.

    As for paddlewheels, I personally believe that a propeller is going to be simpler and more efficient than paddlewheels. That is why we have very few paddlewheel boats these days. The better paddlewheel systems have feathering systems to reduce paddle drag on half the stroke, and I would imagine that on such a boat as yours, the feathering system would be a little too intricate or cumbersome to work reliably for an ocean crossing.

    I assisted Tori Murden in the rebuilding of her boat for her last transatlantic attempt, so I got a really good idea of what is involved in rowing in lumpy water (I have also read a number of accounts of other rowing exploits). Rowing is totally inefficient because your oars and strokes are all over the place. Tori places a lot of emphasis on clean strokes for competition rowing, but in the ocean, you are lucky just to get the blades in the water long enough for a stroke because the boat is moving all over the place.

    In a propeller system, the prop is always in the water and is always turning when you are working it, therefore, simply on time, the propeller is always going to be producing power--it has to be more efficient just from that regard. I am unsure about whether you want a coasting feature, maybe that would be OK. You would also probably want a locking feature or a feathering feature so that the prop will not turn when you don't want it to. It depends on your hull design.

    Therefore, I vote for sticking with the propeller, some kind a crank, chain/belt and sprocket as the simplest, most reliable, and most efficient.

    Eric
     
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