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"Giant kites" (lemmy.world)
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[-] grue@lemmy.world 80 points 10 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 26 points 10 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 15 points 10 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 9 points 10 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 8 points 10 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 6 points 10 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 10 points 10 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.

[-] snf@lemmy.world 5 points 10 months ago

I have it on good authority that the Wellerman will handle this issue, along with any concerns with tea and sugar supply

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[-] Rice_Daddy@lemmy.world 4 points 10 months ago

Sailing cargo ship is a thing. There's a record breaker recently in fact.

[-] merc@sh.itjust.works 3 points 10 months ago

It would be really interesting to see a fully rigged ship with dozens of sails where the rigging was pulled by motors and controlled by computers rather than humans. It would also be interesting to see what they could do with modern materials. Nylon sails, carbon fibre masts, steel lines, etc.

Having said that, I would bet that a real modern cargo ship would probably use fancy solid wing-style sails.

[-] eskimofry@lemmy.world 8 points 10 months ago

You underestimate the power of wind, stranger.

[-] Lev_Astov@lemmy.world 4 points 10 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.

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[-] Liz@midwest.social 3 points 10 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.

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[-] SonicBlue03@sh.itjust.works 64 points 10 months ago

Hoist the mainsail and shiver me timbers.

[-] Tylerdurdon@lemmy.world 13 points 10 months ago

Arrrr me packages going to be delayed? I'll keel haul the lily lubber!

[-] Feirdro@lemmy.world 38 points 10 months ago

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

[-] Anyolduser@lemmynsfw.com 19 points 10 months ago

https://en.wikipedia.org/wiki/Spinnaker

When a vessel is running (meaning moving in the same direction as the wind) it can fly a spinnaker, which is just a kite on short lines.

[-] Bloodyhog@lemmy.world 2 points 10 months ago* (last edited 10 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 2 points 10 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.

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[-] nilaus@lemmy.world 13 points 10 months ago

The mast on the ship in the picture is litteraly 127 feet.

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[-] lakemalcom10@lemm.ee 34 points 10 months ago
[-] Supervivens@lemmy.world 61 points 10 months ago* (last edited 10 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.

[-] SubArcticTundra@lemmy.ml 9 points 10 months ago

The retrofitting part is great news

[-] grue@lemmy.world 3 points 10 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).

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[-] buzz86us@lemmy.world 21 points 10 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 9 points 10 months ago* (last edited 10 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 5 points 10 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.

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[-] kabynbojski@lemmy.world 18 points 10 months ago

But they'll steal the wind! How is that helping the environment?

[-] Thermal_shocked@lemmy.world 5 points 10 months ago

and who's making money off it. cause if there is no money, no one will do it unfortunately.

[-] snooggums@midwest.social 13 points 10 months ago

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

[-] Retrograde@lemmy.world 5 points 10 months ago

My immediate concern with these is lightning strikes on the kites

[-] snooggums@midwest.social 4 points 10 months ago

They will have planning for that, just like they do the container ship towers which also have to deal with lightening.

[-] Retrograde@lemmy.world 2 points 10 months ago

True, I bet it would be really cool to watch these mechanisms in action

[-] eran_morad@lemmy.world 13 points 10 months ago

Why the fook is the flag flying against the wind?!?

[-] BradleyUffner@lemmy.world 43 points 10 months ago* (last edited 10 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 5 points 10 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.

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[-] Kolanaki@yiffit.net 10 points 10 months ago

If they really were kites, ships could sail across the sky.

[-] casmael@lemm.ee 9 points 10 months ago

We have missed you Mr Picard Maneuver x

[-] The_Picard_Maneuver@lemmy.world 4 points 10 months ago
[-] herrvogel@lemmy.world 3 points 10 months ago

Hey I literally just finished watching The Battle episode a few minutes ago for the first time. K thx bye now

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[-] phorq@lemmy.ml 7 points 10 months ago
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[-] captain_aggravated@sh.itjust.works 4 points 10 months ago

The thing about those big kite sails is the wind has to be coming from pretty much astern for them to work; if the ship is sailing into even a quartering headwind they're of no use.

There's a technology...I forget what they're called, some kind of turbine, where you have a couple of tall spinning cylinders on the deck, which interact with the wind in such a way to provide thrust for the ship, this is mechanically simpler, fewer ways it can go wrong, you can just hinge them down and secure them in a storm or to pass under bridges, and they can drive the ship in quartering headwinds.

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this post was submitted on 18 Feb 2024
842 points (97.8% liked)

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