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

    Well done Mr 1J1.
    That's an amazing photo.
    These rotors seem to be springing up like ..... mushrooms .

    "The solution is fully automated and senses whenever the wind is strong enough to deliver fuel savings, at which point the rotors start automatically – optimising crew time and resource"

    "In addition to the installation onboard the M/S Viking Grace, Viking Line will also install two Norsepower rotor sails onboard a new build cruise ferry vessel which is currently being built in China and due to be operational in 2020."
     
  2. 1J1
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    1J1 Senior Member

    Also found this interesting solution:


    eConowind BV – IWSA Member | International Windship Association http://wind-ship.org/en/econowind-bv-iwsa-member/

    Image of a prototype unit: #econowind - Twitter Search https://twitter.com/search?q=%23econowind
     

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  3. 1J1
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    1J1 Senior Member

  4. 1J1
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    1J1 Senior Member

    http://www.motorship.com/news101/en...ototype-eco-flettner-drive-for-german-coaster

    The rotor weights about 100 tonnes? And I wonder were they would install "adititonal rotors" if they mean this ship.
     
  5. rwatson
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    rwatson Senior Member

    That is surprising. I wouldn't be surprised to find that this was a mistyping. 10 tonnes would be more like it I am sure, given that is a composite rotor. I don't think you could get 100 tonnes of steel underneath unless it was almost solid .
     
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  6. rwatson
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    rwatson Senior Member

    Hi 1J1

    I have the answer. The head of the project was kind enough to provide these details. My opinion that 100 tonnes was too high is correct.

    " Thank you for your inquiry. I take the chance to put some light on this issue. The additional weight of the Flettner rotor installation depends on various factors. The rotor must withstand all loads having impact. Therefore the position of the rotor is relevant. On Fehn Pollux the rotor is positioned on the forecastle deck which has strong advantages in aero- and hydrodynamics. Thus the rotor needs to withstand sea impact according to the classification rules. A rotor installed on the top deck of a passenger ship (Viking Grace) may be lighter as not being exposed to sea impact. Another issue is the weight of the steel foundation on the ship. In the future shipyards could offer ships “prepared for Flettner rotor installation”. To find a suitable position for such foundation and strengthen the local steel structure around can be realized at very low cost. Then a retrofit of a rotor later on would be very easy, quick and cost efficient, additional weight minimized. In the case of Fehn Pollux the existing steel structure has to be strengthened, thus adding weight. To give you precise figures: the rotating cylinder weighs less than 8 metric tons. It can be lighter depending on the installation (loads) and the material (e.g. carbon fibre, but high cost material). The total weight of the rotor including the foundation is about 30 metric tons. Additional strengthening of the local steel structure depends on the ship and place of installation, e.g. about 5 metric tons in this case, summing up to about 35 metric tons. Future shipbuilding will be able to reduce the weight significantly, we are just starting with this technology.

    Hope that this was useful. Please share the information as we need correct data spreading out.

    Best regards,

    Michael Vahs"

    Prof. Capt. Michael Vahs

    Faculty of Maritime Sciences
    Hochschule Emden/Leer
    University of Applied Sciences
    Bergmannstrasse 36
    26789 Leer
    Germany
    Mob:+49 170 4477351
    Tel.: +49 491 92817-5022
    Fax: +49 491 92817-5011
    E-Mail: michael.vahs@hs-emden-leer.de
    Internet: www.hs-emden-leer.de
     
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  7. 1J1
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    1J1 Senior Member

    Now it makes more sense, thanks! I'm curious too see how they would arrange the foremast & mast above the wheelhouse in order to have toplights free of obstruction.
     
  8. 1J1
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    1J1 Senior Member

  9. thiseasm
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    thiseasm Junior Member

    Good afternoon Mr. Rwatson,
    since the day you told me about Ayrs I am trying to contact them to buy the booklet and they do not reply. Do you know if I could find a copy somewhere else?
    Thanks in advance.
     
  10. rwatson
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    rwatson Senior Member

    I was just thinking about getting a copy myself.

    I wrote off to Captain Vas for a formulae for spin load, but have not heard back yet.

    I will have a go myself, and see if I have some better luck.
     
  11. thiseasm
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    thiseasm Junior Member

    Who is Captain Vas?
     
  12. rwatson
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    rwatson Senior Member

    Post 486 - letter from Rotor Designer
     
    Last edited: Jun 15, 2018
  13. rwatson
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    rwatson Senior Member

    Limited success.

    I also haven't got a reply from the Amateur Society, but another contact supplied me the info via another source.

    I have attached a copy of the Yacht Associations magazine, which on page 29, has Joseph Norwoods review of Alexander Thoms calculations for calculating skin drag under rotation, which is an important part of the problem. As I recall, this is identical to the commentary in his "21st Century Multihull" paper.

    The conclusions from the calculations are not definitive, but they do provide a valuable discussion of the process.

    I think I will re-post this link over in the "brains trust" section of the Boat Forum, and see if we can have some experts comment on the formulae.

    I will be searching out other sources too. Stay tuned.
     

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  14. thiseasm
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    thiseasm Junior Member

    Thanks for the reply. Also provide a link for this ''brains trust" section of the Boat Forum.
     

  15. rwatson
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    rwatson Senior Member

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