Cargo Sailing Ship: a near future reality?

Discussion in 'Boat Design' started by Laurent, May 28, 2014.

  1. Rastapop
    Joined: Mar 2014
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    Location: Australia

    Rastapop Naval Architect

    "propulsive force up to 2000 KW" is also nonsensical.

    Yes, it can. There are plenty of sails 10 or more times larger than those rotors.
    No-one is going to use sails the size of the rotors, so comparing the force generated by sails that size is ridiculous.

    No-one is going to use conventional sails the size of rotors (nor rotors the size of conventional sails), so that comparison is irrelevant.

    Kite sizes are closer, and I'm glad to see you now won't be implying ten times the performance when comparing them.

    And in some conditions the kite outperformed the rotors.
    You implied the rotors always outperformed the kite. Quoting half clauses is poor form.

    Which will outperform the other more consistently depends on the respective sizes compared.

    And still a conventional sail has a wider range of points of sail than rotors.

    And a rotor gets almost no benefit close to 180, while a conventional sail does.

    Correct. We don't disagree here.
    Pointing isn't something I brought up. You did when you incorrectly implied a rotor would benefit at more points of sail than a conventional sail would - it doesn't.

    A kite can be used in winds as low as 7 knots, and of course wind speed is significantly greater at the heights the kites sail at.

    And for the umpteenth time: no-one cares. No-one is going to use a sail the size of a rotor or a rotor the size of a sail.

    Yes, but the number of ANY type of flettner ships is minuscule, while the number of sailing ships is huge. Perhaps you could hazard a guess why? ;)

    You mean the one that happened almost 10 years before your 40 years started?

    And all that means precisely nothing today.

    Still heavier and more complicated than a kite.

    No problem: http://www.marinetraffic.com/ais/details/ships/305093000/vessel:BBC_SKYSAILS

    The choice isn't the crew's. The use of wind assistance is only going to depend on the bottom line.

    What rubbish. The kites sit just a few hundred metres ahead, and a few hundred metres up.

    Glad you agree they're cheaper.

    Don't backpedal. You know perfectly well rotors will be more expensive than a kite (you've even said so yourself).
    If the price of flettner rotors drops significantly then the status quo may change, but not until then.

    I don't discount rotors as a possibility. We're only discussing them because you say their failure to become popular means sails will also fail, which is utterly absurd.
    A kite sail is smaller, lighter, cheaper, and simpler to install.
    Judging kite sails (or even conventional sails) by the success/failure of flettner rotors is just ridiculous.
     
  2. Yobarnacle
    Joined: Nov 2011
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    Yobarnacle Senior Member holding true course

    I have two Albin 25s. One has conventional jib and main.
    I'm considering a different rig for the 2nd hull.
    This might be a chance to try the Flettner against an identical boat.
    But I'd need lotsa advice and design help.
     
  3. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    you keep saying this with no explanation.


    tell me how 2000 Kw is nonsensical in this polar diagram from your reference
     

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  4. Skyak
    Joined: Jul 2012
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    Skyak Senior Member

    Power can not equal force. The reason that the ship articles talk about power is that it equates to fuel savings -force would be meaningless. For meaningful comparison the ship SPEED is fixed. A ship that delivers goods at a different speed can not be compared economically.

    So force*speed=power

    Since speed is a constant they talk about power interchangeably.

    Can we stop the argument?

    On to the important point!

    -Wind power is the obvious renewable energy source for shipping.
    -Arguing about crude oil price is oblivious to the global reality of rising carbon dioxide levels and the cost of managing it.
    -ALL DEVELOPED ECONOMIES ARE SPENDING BILLIONS OF DOLLARS cutting CO2 emissions!
    -Shipping is a major source of CO2 emissions that currently
    1 pays no taxes on fuel
    2 is essentially subsidized by burning the byproduct of surface transport fuel refining

    The next step will be raising taxes on fossil fuels followed by a global carbon tax system. These are difficult politically -directly taxing voters. But do you know what isn't difficult politically? What makes an easy, popular political promise? STOP SUBSIDIZING IMPORT POLLUTERS!! With the stroke of a pen bunker fuel goes from $0.3/gallon to $1.30/gallon -so ships pay the same taxes as the voting public motorists. What politician can resist? Save the world and raise revenue without taxing constituents!
     
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  5. micah719
    Joined: Jul 2012
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    Location: Somewhere in Germany

    micah719 Plotting Dreamer

    Ok, so much for the big boys of international trade. What about the little ships, coasters, niche markets? A liveaboard cargo boat running as a mini tramp ship (in the maritime freight sense of the word "tramp", before this thread goes the way sailors think). Flat bottom, own derrick, own RIB lighter, own trailer/atv.
     
  6. Yobarnacle
    Joined: Nov 2011
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    Location: Mexico, Florida

    Yobarnacle Senior Member holding true course

    In the not so far future, people are going to be embarrassed by this temporary insanity that co2 is a pollutant!
    It's a political agenda to take away the few rights you have left! Wake UP!
    Let's please try to keep politics out of the discussions. :)
     
  7. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    yep
    world couldnt operate without Co2

    Next step for box ships is LPG/CNG and there are some under construction right now.
    All the big engine manufacturers have gas versions, high speed is spark ignition the larger are via the conventional diesel inject ( pilot injection)
    Has been around forever but only now pollution requirements are making it look like the best solution for slow speed engines that would otherwise be burning HFO
     
  8. FAST FRED
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    Many of the new builds have 3 fuel systems aboard , for the deep ocean , for coastal zones and for in shore while docking.

    Nut jobs like LA mandate to the world.
     
  9. johnhazel
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    Location: Michigan

    johnhazel Senior Member

  10. SamSam
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    Location: Coastal Georgia

    SamSam Senior Member

    You go first.
     
  11. Yobarnacle
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    Yobarnacle Senior Member holding true course

    Look who went first samsam.
     
  12. Kiteship
    Joined: May 2004
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    Kiteship Senior Member

    I am curious why you say this, Fred? Do you refer specifically to petroleum cost, or to energy costs in general? Do you refer to cost or to price (sometimes not the same thing)?

    Dave
     
  13. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    You don't see any irony here? This is like "Hey, you ignoranuses, lets have no name calling here!"
     
  14. Yobarnacle
    Joined: Nov 2011
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    Location: Mexico, Florida

    Yobarnacle Senior Member holding true course

    When a watermelon can't resist preaching CO2, I gong him!
     

  15. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    Now you're doing politics and name calling. What's a "watermelon'?
     
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