Everything Old is new again - Flettner Rotor Ship is launched

Discussion in 'Boat Design' started by rwatson, Sep 1, 2008.

  1. rwatson
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    rwatson Senior Member

    Heeey - it cant be such a bad idea after all.

    http://www.enercon.de/www/en/windblatt.nsf/562a62338e7e78dcc1256e8900540f58/4cfe8bb9e5c0aa10c125749b00356510/$FILE/ENERCON%20PR%20E-Ship%20010808%20en.pdf

    and wow - found a great site for detailed history of Flettners inventions.
    you know the 'trim tabs' on big rudders - his idea

    http://www.rexresearch.com/flettner/flettner.htm
     

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    Last edited: Sep 1, 2008
  2. Knut Sand
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    Knut Sand Senior Member

    Not a new idea, but it's nice to see that someone uses it on a large scale. Credit to them.

    On the other hand..... Seem that the living quarters/ bridge are in front of the ship, makes sense, with these rotors filling up the front view.

    Doesn't make sense then again, with the free fall lifeboat all the way aft...:confused:

    Ok, probably equipped with rafts also, then...
     
  3. Ilan Voyager
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    Ilan Voyager Senior Member

    I hope that will work...the rotors seem pretty small for giving enough power on a such freighter. So it's just a complement of power.

    With the living quarters just over the bow, a good winter gale in North Sea will make life miserable. Good stomachs required. How do you piss with 1/2 G vertical accelerations and decelerations?

    Only the best runners will reach the free fall lifeboat.
     
  4. dsuursoo
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    dsuursoo Senior Member

    huh. last time they did one of those, it was pretty slow. not worth it for any kind of time-sensitive cargo at all.

    unless they're not going to propel it with those... i seem to recall seeing vertical axis wind turbines on a couple of boats, even that tri they used in waterworld... wonder how that really pays off, power wise?

    and you just pee in time with the positive G forces. having spent a fair bit of time in the bering sea(similar to the north sea, but a bit quicker to get nasty, from what i hear), it's not so bad, generally a lot of fun.

    it'd be something to see this actually work faster than a crawl.
     
  5. Zilver
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    Zilver Junior Member

    According to the pdf document the vessel has got two 3500 kW main engines.
    The flettner rotors (no vertical axis wind turbines btw) will probably serve in a "fuel saving" way, just like the kite system from skysails.

    I'm visiting Kiel in a few weeks, so maybe I can take a look at the building site....

    Hans
     
  6. rwatson
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    rwatson Senior Member

    To give you an idea of the power produced by spinning those things at 200 rpm, multiply the area of each cylinders cross section ( silhouette ) by seven. This is the equivalent sail area they replace.

    An article on the effectiveness on a much smaller boat fitted with one rotor provides some actual figures

    http://www.rexresearch.com/flettner/flettner.htm

    Popular Science January 1984

    "Power Mode --- Ave. Wind (Knots) --- Ave. Boat Speed (knots) --- Ave Fuel Saving (%)

    Rotor-Assist --- 16.1 --- 7.0 --- 44
    Rotor-assist --- 12.9 --- 6.0 --- 27
    Rotor Sailing --- 17.7 --- 5.3 --- 100

    Under rotor power alone, the Tracker reached a maximum speed of 6.1 knots in an 18.4 knot wind and a true wind angle of 122 degrees.

    Bergeson is demonstrating the Tracker to fishing-boat owners, talking to large shipping companies, and presenting scientific papers at maritime conferences. And interest is growing. He now has a Navy contract to study the conversion of a military sea-lift ship to rotor-assisted propulsion. He is also conducting similar studies for a number of independent shipping companies, including major oil and cruise-ship companies.

    The economic potential certainly is there. Bergeson has calculated that the world’s shipping fleet consumes 730 million barrels of petroleum a year at a cost of $30 billion. If only 20 percent of the world’s fleet adopted sail assist, the savings would be on the order of 91 million barrels a year --- almost $3 billion.

    The payback to an owner can be astonishingly quick. The entire rig for the Mini Lace cost $250,000. But the owner’s records show that the sailassit saves $48,000 worth of fuel a year. In addition, average speed is increased by 5 percent, which means that the ship can make more trips. Extra income from this source was $9200. At that rate, the rig would pay for itself in a little over 4 years. But there’s more. On the New Orleans-Jamaica route, where winds are usually unfavorable, the fuel savings was an incredible 36 percent, and the speed was up 18 percent. If the ship were used on similarly favorable routes, the payback would fall to an astonishing 1.7 years. "
     
  7. dsuursoo
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    dsuursoo Senior Member

    shiny. but the engineering looks like it's a bit of a job... i wouldn't want to be the guys installing those things on a sealift ship.

    still, if it works, right?
     
  8. Ilan Voyager
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    Ilan Voyager Senior Member

    It's crossing with the other thread... The ciphers given are for a very slow boat, these speed (5 to 7 knots) have no use in modern freighters. What was the cargo capacity? We have just the nice ciphers not a global study.
     
  9. rwatson
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    rwatson Senior Member

    Last edited: Aug 27, 2010
  10. apex1

    apex1 Guest

    Although a proven system since Flettner launched the "Buckau" and still one of the environmental friendliest solutions, it does not scale down to yacht sizes.

    For us motoryacht people the Skysails kite will become the more interesting back up propulsion. (at least from some 60ft up)

    Regards
    Richard
     
  11. rwatson
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    rwatson Senior Member

    Cant see why not myself

    The late, great naval architect Lloyd Bergeson got a 42 foot motor yacht (the 17 ton Tracker ) converted around 1984. At 12 knot wind speed the craft recorded a 27% fuel saving. At 16 knot wind speed, there was a 44% fuel saving.
    (Popular Mechanics January 1984)
     
  12. apex1

    apex1 Guest

    Was not aware of that.
    And still have severe doubts regarding stability on a motor yacht.
    Is there any online publication?

    Regards
    Richard
     
  13. mydauphin
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    mydauphin Senior Member

  14. apex1

    apex1 Guest

    Reportedly she did perform well. No real wonder, the "turbo sail" is nothing else but a Flettner rotor. Cousteau developed a new name, nothing else.

    Regards
    Richard
     

  15. DougCim
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    DougCim Junior Member

    Without going into any simple reasoning, I am fairly certain that adding rigid wing-type sails would do more than these spin-tube things do.

    In particular, the notion of adding a "motorized" sail to save fuel seems rather odd.
    ~
     
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