Wave propulsion

Discussion in 'Propulsion' started by Paulc, May 26, 2014.

  1. Paulc
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    Paulc Junior Member

    I invented a wave power device that drives a propeller and an alternator from the motion of ocean waves. The first prototype is complete. At this point I am looking for collaborators; manufacturers, boat builders, etc.

    Is anyone is interested?

    Paul
     
  2. groper
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    groper Senior Member

    Show us the prototype and perhaps people might become interested ... until then it's just hot air.

    I don't suppose you've considered the number of people who get on the Internet and claim to have the next greatest invention only for it to be complete folly?
     
  3. Paulc
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    Paulc Junior Member

    I tried posting a video of my prototype but this site freezes at 97% upload???
     
  4. Grey Ghost
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    Grey Ghost Senior Member

    Post it on youtube
     
  5. Paulc
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    Paulc Junior Member

  6. P Flados
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    P Flados Senior Member

    You used a stationary surface and a moving object to extract energy.

    When you are floating, you normally have no stationary surface unless you connect lines/chains/cables down to the bottom.

    Wave energy extraction systems have been developed with a single floating platform and a multiple floats such that the relative motion between a float and the platform can be used to extract energy. You want to be able to extract energy with both slow and fast motion from a float (relative to the platform). It gets complicated fast, and tends to be very high maintenance.
     
  7. Paulc
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    Paulc Junior Member

    True, but do you see any reason why all that couldn't be worked out?
    Max energy could be extracted by suspending a plate under the waves. This has been successfully done with generating electricity, but transportation fuel is $4 a gallon compared to about $.15 a Kwh. So there is more money in propulsion.

    I'm hoping to raise development money thu crowdfunding. This solar concept raised $2,000,000 https://www.indiegogo.com/projects/solar-roadways
     
  8. groper
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    groper Senior Member

    Have you calculated the potential energy available after conversion from this system? Ie. It's efficiency?

    The larger the buoyant force, the larger the thrust. Conversely, the larger buoyant force in comparison to the total boat displacement would reduce the available heave so there would be a practical limit in available energy for a given size system that fits into a typical boat. This may not be enough energy to be practically useful - I don't know.

    Another issue is the non linear power delivery. This would be uncomfortable and would need multiple units to smooth out the power strokes. This all adds up to alot of complexity.
     
  9. Paulc
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    Paulc Junior Member

    A cubic foot of water weighs 62lbs. At a 70:1 weight to thrust ratio an oscillating one cubic foot float could propel 4340lbs of ship. That is assuming 100% efficiency, and in the real world it will be nowhere near, but the numbers do work in the favor of the concept.
     
  10. groper
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    groper Senior Member

    Ok let's look at this.

    Sorry, but my brain only works in the metric system...

    So if we assume a 1 cubic meter float, oscillating a distance of 1m. Force due to gravity 9.8m/s2. This gives us 9800N.m on each power stroke. If we then assume a wave period of 6 seconds, we have one power stroke delivering 9800N.m every 6 seconds, or a total energy of 9800joules per 6 seconds. Averaged over time, we get 1633 J per second.

    Then convert joules to watts, 1633 joules per second = 1.6kW. Now you see why I like the metric system btw :)

    So we then connect this to a typical water propeller, with an efficiency of 70% typical, we have a propulsive force equal to just over 1kW assuming no losses in the mechanical drive train that turns it.

    Now the problem as I see it, the boats displacement must be significantly greater than the float used to drive the propeller, otherwise the float causes the entire boat to rise instead of raising the float relative to the rest of the ship. That is, if the entire ship displacement is 1 cu meter, then you cannot generate anything unless you anchor it to the sea floor as the entire ship rises and falls with the wave period. If you have a 1000cu meter displacement ship, then it's heave position in the seaway will be relatively stationary assuming 1m wave height. In this situation, the local wave height relative to the hull could be used to generate some power, however 1kw won't even compensate for the windage of such a large vessel.

    In short, I can't see enough energy density in this system that would make it useful for propulsion. It could be harnessed as a small generator to save fuel burned in electrical power generation aboard ships, but the maintenance and other costs hardly make it appealing or cost effective...
     
  11. Paulc
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    Paulc Junior Member

    You think that the ship would have to be 1,000 times the size of the float? I disagree

    Regardless, as I’ve stated if you hang a horizontal plate down under the wave there would be no vertical pull on the hull.
     
  12. groper
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    groper Senior Member

    1000 times was simply to illustrate a point. For boats, 1kw of propulsion is not enough for a 1 tonne displacement vessel.

    My 12m catamaran, has a displacement of 4 tonnes, it also has 40kw of Installed power for propulsion and is considered very efficient. After prop losses, I would end up with something a bit under 30 kw max. Standard cruising would use more like 20kw as not full throttle. So 4kw per tonne gets it done for most efficient displacement vessels.

    Boat propulsion needs to have a high energy density or its more of a burden than anything useful. This same reason is why you don't see solar electric boats everywhere already despite the incentives from the government.

    How would this flat plate work?
     
  13. gonzo
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    gonzo Senior Member

    Also, there are no calculations shown for the drag of the plate. Assuming the plate will always be normal to the direction of travel is not realistic. Further, the plate will move up and down which will cause turbulence and add to the drag.
     
  14. kjell
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    kjell Senior Member

    New wave propulsion using side rolling converted in to fish tail propulsion.
     

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  15. wavepropulsion
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    wavepropulsion Pirate Member

    Your idea is not bad Paulc.
    I believe the fin must be near the bow and the propeller astern in your system. And what Gonzo said as well.
    But you must try in the water, what I see as drawback is just improving the fin you will have less loses in power and be able to use it better in different sea conditions, without the propeller.
    Another good option of your system is to plug it to an engine when the conditions are not right, or to a lever to work in manual mode if is a small boat. But this can be done with almost all the wave propulsion systems.
    Try it in the water and you will have new ideas. After the wind blows, after you take different waves. But never be disappointed mate.
     
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