regenerating on a leash?

Discussion in 'Hybrid' started by lucdekeyser, Jan 5, 2013.

  1. lucdekeyser
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    lucdekeyser Senior Member

    In one vendor's advertisement regenerating takes about three times longer than spending the electricity. While docked there are solar cells and windmills to fill up the batteries again. I would guess that they are less efficient than regenerating from the prop while under sail. Is it feasible to have the boat "pace" along the anchor chain to regenerate instead? This would seem natural for a shunting proa on a ballestron rig or so and not too difficult to automate. Also GPS based positioning could eliminate the need for the chain and still keep the boat "on a virtual leash". This would mimic a big kite doing a figure eight in the sky.
    Wondering.
    Luc
     
  2. michael pierzga
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    michael pierzga Senior Member

    Shunting ? Pacing along the anchor ?

    You mean taking back and forth at anchor ?
     
  3. lucdekeyser
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    lucdekeyser Senior Member

    yep
    as a sailboat's version of a windmill?
     
  4. Milehog
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    Milehog Clever Quip

    And who would keep a lookout as the boat was doing this dance?
     
  5. lucdekeyser
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    lucdekeyser Senior Member

    The sail pacing park guard?
    It sure is an important point of concern. If the principle is valid and it can be automated then fail safe systems can be worked out.
     
  6. gonzo
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    gonzo Senior Member

    You'll probably spend more energy in controls than what you may generate. It will also take a lot of interior space and most likely you'll receive complains from bumping into other boats in the anchorage. Even without that system, boats hit each other if the scope is too long.
     
  7. philSweet
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    philSweet Senior Member

    Well, it's been tried. A Canadian friend and veteran of thirty years cruising did this. He had a tideflow hydrogenerator that came off an oil rig. Big SOB and solid metal. Warrantied for twenty years provided annual servicing was done. He had this attached to his outboard rudder and would pay out 400-500' of line and let her tack. Tradewind conditions in the Caribbean. His boat was a homebuilt 34' steel cruiser that weight 20K+ pounds. This was about 30 years ago. There is no good reason to even try this now that solar panels have become so cheap. It's not like you can leave the vessel unattended while you do this. And a suitable device would cost thousands.
     
  8. lucdekeyser
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    lucdekeyser Senior Member

    suitable device?
    the electric props are already installed for drive and being driven
    it would not take much to have an airvane switch from one tack to another when the boat reaches a preset maximum angle with the wind.
    left unattended?
    yes, that is the stickler in all but deserted waters. Of course, in harbors a dock hookup makes the most sense.
     
  9. whitepointer23

    whitepointer23 Previous Member

    This idea makes no sense at all when a wind generator works while the boat is stationary. Wind genny and solar are the only way to go.
     
  10. SamSam
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    SamSam Senior Member

    The difference between getting energy off a kite pacing and a boat pacing is the kite gets all the energy directly from the wind, whereas the the other way, wind power first has to be expended to move the boat and then collected from the boats motion through the water. Each conversion of force from one kind to another uses/loses energy.

    Also, the kite is always in a wind current, with periods of higher wind current between tacks, whereas the boat is not. The propeller generator would have no current at each tack and would slowly build up to speed and then wind down to a stop at the other tack.
     
  11. michael pierzga
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    michael pierzga Senior Member

    Yup...why complicate things by sailing around in circles , terrorizing everyone in the harbour , when you can just sit back, crack a cold beer, and let solar or wind charge your batteries ?
     
  12. lucdekeyser
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    lucdekeyser Senior Member

    It is a matter of generation efficiency and filling the periods of undersupply with the oversupply of energy and harvesting via different means: in this case, a small windmill vs a large sail driving a prop. And the latter is already installed infrastructure.
    Of course, I share your concerns, having a dozen of ghost ships pacing in a crowded harbor is not a comforting sight, but could do little harm (to other boats) in a secluded bay.
    Also, autonomous sailing algorithms are coming of age.
    It still may be safer than the captain under the influence of the extra beers consumed waiting for the batteries to fill up more slowly ;-)
     
  13. gonzo
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    gonzo Senior Member

    The wear and tear on rigging and sails will cost you more than running a generator too.
     
  14. WestVanHan
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    WestVanHan Not a Senior Member

    You can cheaply buy/build a 150-200 amp DC genset using a silenced single cylinder Kubota that'll run for 6-7 hours at full charge on a gallon of fuel.
    But you'll only run it at full charge for a bit,then idle back to top off.

    Take the heat off it for hot water,you may only run it every few days for a short time,and let the solar top off the bank....you may find your monthly diesel costs less than a day's worth of beer...
     

  15. lucdekeyser
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    lucdekeyser Senior Member

    Excellent points, gonzo & West. Thank you.
     
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