• grue@lemmy.world
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    4 months ago

    FYI, the main innovations of these kite sails compared to traditional sailing ships are that it doesn’t need masts that get in the way of cargo handling and that it requires fewer crew. In other words, it’s not faster or anything; it’s just cheaper.

    • barsoap@lemm.ee
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      4 months ago

      You also need vastly less sail area and the things are more reliable because wind gets quite a bit stronger and reliable at 100-300 metres up. The system actually isn’t new. AFAIU main reason for it not getting wide-spread adoption is that shipping lines, not ship owners, pay for fuel.

    • Liz@midwest.social
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      4 months ago

      Modern cargo ships are so huge traditional sails wouldn’t provide enough force to push them around. Neither will these kites, mind you. But, supplemental energy will still be a bonus, and a kite can reach higher and sit in faster, more stable winds.

      • grue@lemmy.world
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        4 months ago

        Modern cargo ships are so huge traditional sails wouldn’t provide enough force to push them around.

        Believe it or not, “proportionality” is a thing. You make the ship bigger, you make the sails bigger to match. Simple! Granted, previously, making sails bigger was limited by the weight of the things when hoisted by men operating manual winches, but now we’ve got motors now to solve that, and higher strength-to-weight ratio materials, too.

        Point is: I maintain that, in principle, you could make a post-Panamax sailing ship – even a traditional fully-rigged one – if you really wanted to, and it would be capable of sailing at hull speed on wind power alone. It’s just that they don’t want to for reasons unrelated to technical feasibility.

        • SomeoneSomewhere@lemmy.nz
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          4 months ago

          You’re assuming everything scales linearly, which is not necessarily accurate. The square-cube law rains on many people’s parades.

          • grue@lemmy.world
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            4 months ago

            I can see how you’d think that, but I’m really just asserting that these specific things scale well enough to still work at post-Panamax size.

            • nickwitha_k (he/him)@lemmy.sdf.org
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              4 months ago

              A bigger challenge would be sourcing enough shantymen to be feasible. I’m not sure that the world has sufficient production capacity to provide the necessary rum for more than a handful of ships.

          • SanndyTheManndy@lemmy.world
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            4 months ago

            Not really. Drag grows with area and so does force from a sail. The larger ships will be faster per unit volume if anything.

        • Lev_Astov@lemmy.world
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          4 months ago

          You underestimate the force of wetted surface area resistance. The sail area needed to move a modern cargo ship at the snail’s pace of old sailing ships would be unmanageably large. You simply couldn’t hold enough sail area to get them near their current speeds. These hybrid sail concepts are nice, but all they do is save some fuel.

        • Liz@midwest.social
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          4 months ago

          So, I got that information from a different Lemmy comment, and on the spur of your contradiction I went looking myself. My search results are flooded with mostly useless news articles (they went to tell stories, not relay technical information). Regardless, the most ambitious claim I’ve seen is to reduce emissions by up to 90% for a ship design that can’t handle shipping containers and is about 1/4 the size of the largest ships being produced today.

          Don’t get me wrong, I want this to happen. In fact, I would ban carbon-fuel shipping today, if I could make it happen. That being said, I don’t think we’ll ever get back to 100% wind power.

          • Lev_Astov@lemmy.world
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            4 months ago

            The sail kite project has had claims of up to 10% fuel savings for about 20 years, now.

            It’s all moot when we should just be focusing on figuring out practical nuclear shipping. It’s the only way to meet or exceed our current standard and be carbon-free. The NS Savannah proved it could be profitable ages ago, and that without any economy of scale to reduce costs.

          • eskimofry@lemmy.world
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            4 months ago

            Hmm i feel like there it was a case of working against the ocean whereas here I think it is working with the wind so it shouldn’t be THAT bad… but who knows…

  • Feirdro@lemmy.world
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    4 months ago

    They are literally kites—not sails. I’ve never seen a sail flying 100 ft above a ship before.

      • Bloodyhog@lemmy.world
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        4 months ago

        And the load on its sheets is enormous. Oh boy can it cause a problem if anyone makes a mistake handling it! Now imagine the load from the kites proposed. I wonder if that is even feasible with today’s materials.

        Edit: did some reading around. So it seems at current level the system can be used as a supplementary propulsion saving some fuel. Ahoy, mates, we are back and our sails are higher than ever!

        • Anyolduser@lemmynsfw.com
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          4 months ago

          When it comes to material stresses the sails can always be scaled down, but off the top of my head kevlar and zylon would be good candidates for getting the biggest, toughest sail in an economic fashion.

          If you want to go down a related rabbit hole take a look at the sails used in regattas. The technology and money that goes into them is ridiculous.

          • Bloodyhog@lemmy.world
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            4 months ago

            Oh I know something about regattas, did some myself, and the base of one of America 's cup boats is nearby. Truly impressive.

          • Mac@mander.xyz
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            4 months ago

            Congrats? I’m bringing up that the numbers in the comment were meaningless because they were way off what was proposed.

    • Supervivens@lemmy.world
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      4 months ago

      “What differentiates it from other wind solutions,” says Bernatets, “is that the wing is not just pulled by the wind and countered by the ship.” Instead, it flies in figure-of-eight loops, which multiply the pulling effect of the airflow to give what he calls “crazy power.”

      “Plus, we fetch the wind 300 meters above the sea surface, where it’s 50% more powerful,” adds Bernatets. The combination “explains why the power is tremendous for a system that is very compact, simple on the bow of the ship, and can be retrofitted on any ship, not just new ships,” he says.

      • grue@lemmy.world
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        4 months ago

        “What differentiates it from other wind solutions,” says Bernatets, “is that the wing is not just pulled by the wind and countered by the ship.” Instead, it flies in figure-of-eight loops, which multiply the pulling effect of the airflow to give what he calls “crazy power.”

        That’s an innovation over square-rigged ships, sure, but not so much over fore-and-aft-rigged ones (where the sails act like aerofoils).

      • EtherWhack@lemmy.world
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        4 months ago

        A 300m line holding turbulent sail kite would never have the chance getting tangled or snapping and killing someone when it whips back

        • SpaceCowboy@lemmy.ca
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          4 months ago

          Yeah there’s similar problems for the ropes that anchors are attached to as well, so they shouldn’t be using those either.

          • EtherWhack@lemmy.world
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            4 months ago

            The chain for the anchor can be much heavier as it doesn’t have to be suspended by something flying in the wind when being drawn out. The water also acts as a shock absorber (as do the individual links) if the chain were to break.

            • SpaceCowboy@lemmy.ca
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              4 months ago

              What about mooring lines? They snap too.

              The point is that people working on ships already know how to take precautions around lines that can break with enough force to kill a person. They establish zones on the ship that people can’t be in when the lines are being used. This is a very old problem that was solved a long time ago.

  • buzz86us@lemmy.world
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    4 months ago

    And what is wrong with taking stress off the engines? I hate how they report this like it is a joke, because it is still a solid step.

    • stom@lemmy.world
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      4 months ago

      They’re not a joke, they’re a product called Seawing, made by a French company. They’re being being actively tested and can be retro fitted to existing vessels rather than requiring a new design.

      • Guest_User@lemmy.world
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        4 months ago

        Correct, I think they were saying it was being reported on as if it was a joke. Not being taken seriously as a good step towards reducing carbon emissions.

        • Buddahriffic@lemmy.world
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          4 months ago

          I’m not sure who they wrote that headline for. “Giant kites” is one thing, but what really stood out to me was that they added on the “reduces carbon emissions” as if that part would be unexpected. Like the whole point of these giant kites is to pull the ships and reducing carbon emissions is icing on the cake, rather than sails coming back because they are a carbon-neutral method of propulsion.

  • snooggums@midwest.social
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    4 months ago

    I know this isn’t really anything new, but it dies look like they are making progress while is great.

    • BradleyUffner@lemmy.world
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      4 months ago

      Sails don’t billow into the wind. They are set at an angle to it. Just enough to inflate them, creating an airfoil. The remaining wind blows across the airfoil, creating “lift” (like vertical airplane wings) that pulls the boat along more efficiently. That’s why sail boats can actually go faster than the wind.

      From this photo, the wind is blowing almost parallel with the sails.

      • Churbleyimyam@lemm.ee
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        4 months ago

        The type of sail you’re referring to is ‘bermuda-rigged’, like the smaller ones at the front of the boat in the picture. The big ones in the middle of the picture are ‘square-rigged’ which are really only good for sailing downwind.