Regenerative Propulsion Help

Discussion in 'Propulsion' started by Vinosail, Sep 26, 2010.

  1. Vinosail
    Joined: Sep 2010
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    Vinosail New Member

    Hi, I'm new to this forum and at the moment I’m doing a feasibility study on regenerative propulsion for boats my thesis, could anyone please provide me links to any related articles or give me any suggestions?

    Academically, there isn’t much on this topic I’ve found so far. So far I’ve come across this: http://www.solomontechnologies.com/ and the Cata Lagoon 450 catamaran which uses this kind of system

    The basics of my study is to simply have a sailboat with a propeller, when the sail is erected and the boat is propelled by the wind, the propeller will free-wheel in the water and act as a turbine to charge up the batteries.

    Thanks a bunch
     
  2. Landlubber
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    Landlubber Senior Member

    ..there have been plenty of shaft generators tried and still available, do a Google search will find a few. Many people have used small aircraft generators geared to suit as they are very reliable and powerful. Try those too.
     
  3. apex1

    apex1 Guest

    These systems just don´t work, thats why you do not find much about them. No one is willing to sacrifice a lot of speed to charge a battery he would not need if he wouldn´t have such nonsense system.

    A forum search on "hybrid" topic will give you a lot to read.
    Or have a look here:
    http://www.boatdesign.net/forums/hybrid/so-why-doesnt-work-34765.html

    Regards
    Richard
     
  4. baeckmo
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    baeckmo Hydrodynamics

    Spot on! It´s like sailing all time with a dragging anchor! If you want "free charging" capacity, go solar panels.
     
  5. Landlubber
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    Landlubber Senior Member

    ...welll not really true Apex, they do work, maybe not as effeciently as some claim, but they do work....

    "The basics of my study is to simply have a sailboat with a propeller, when the sail is erected and the boat is propelled by the wind, the propeller will free-wheel in the water and act as a turbine to charge up the batteries."

    given the paramaters of the basics...

    if the vessel has a fixed blade prop that turns anyhow when sailing, the shaft driven gensets do provide power.....
     
  6. apex1

    apex1 Guest

    Well if efficiency is not required, yes of course. But, as I said:
     
  7. WestVanHan
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    WestVanHan Not a Senior Member

    I was on sailboat from Australia to Vancouver,if we (as an experiment) generated power via the prop we'd drop 2 knots, plus the cutlass bearing would wear out much faster.
    So the 4 hp kubota was run for a couple hours every second day (to recharge the fridge and charge what little we'd used) and burned 1l of diesel...for $60 cost in fuel the whole trip.

    I guess you could do it, I'm suer the sailboat forums have much info on it.

    And it's a good way to ruin the transmission,unless you are making an electric boat and don't get me started!!
     
  8. Landlubber
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    Landlubber Senior Member

    ...yep, true, so if he is doing a feasability study, then matye we should show just what you have done and then suggest that (as Apex says) it is not worth it......

    I have used the little suckers too, but certainly did not loose 2 knots, that is a lot.....the prop should be locked anyhow, it causes less drag than a rotating one...
     
  9. CDK
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    CDK retired engineer

    The basics of your study is not true, which makes it a waste of time.

    A free-wheeling prop doesn't cause much drag but cannot be used to generate energy because then it isn't free-wheeling anymore. At that point it delivers torque, so absorbs power and slows down the boat.
     
  10. Landlubber
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    Landlubber Senior Member

    CDK, why is it that the slower turning prop (delivering torque to the shaft with a shaft generator) slows down a boat more than a faster, naturally turning prop, surely they both must cause water "friction"...can it be explained simply?
     
  11. CDK
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    CDK retired engineer

    Quite simple to answer.
    Power is torque times rpm. As long as the torque is 0 there is no power consumed (except friction of course).
     
  12. Landlubber
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    Landlubber Senior Member

    ...yep, OK, so it increases the friction thru the water by absorbing the energy to the genset...understand.

    The prop still turns, the friction thru the water is less or more cos the prop is now turning slower? ...and why
     
  13. Vinosail
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    Vinosail New Member


    I think I may have stated my study incorrectly, basically the propeller rotates due to the incoming flow as the boat moves forward, thereby the propeller is to be used as a generator.

    As for such a system working, I was under the expectation that it would work because of a few commercial units I saw around, particularly this:

    http://www.cata-lagoon.com/site_agents/pdf/L420_Hybrid_motorisation_GB_01-2007.pdf

    http://www.sailing-cruise.net/catamaran-lagoon-420-hybrid/
     
  14. apex1

    apex1 Guest

    Well, they DO work, no doubt.

    But Beneteau would give you 25 million Euro if you could make the world forget that they ever produced that ****!
     

  15. mark775

    mark775 Guest

    But don't discourage the research! I spend some hours every day anchored in one to three knot current. If it were simple and not too much money, I'd love to generate a little power at these times (to run the Espar, computers, radars, top off the batteries, and such).
     
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