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A cargo ship's 'WindWing' sails saved it up to 12 tons of fuel per day
- aoki 3y agoSurprisingly, these appear to be rigid foils (hence WindWing) instead of Flettner rotors.
- M95D 3y agoWhat I don't understand is why they didn't use normal sails instead. The sails could have a much larger area and a thinner mast would create less problems for docking, or it could even be a telescopic cilinder, able to be retracted below deck.
- hollerith 3y agoMy guess is that the WindWing requires much less labor. Even by the standards of the 1700s and earlier, working on a sailing ship had a reputation for being dangerous work that chews through sailors, and kidnapping people and not letting them leave the ship was a common way to "recruit" sailors. These days, when kidnapping is no longer in the Overton window, and even unskilled workers have more options than the workers of the 1700s had, it would be cost prohibitive to staff these sailing ships you propose, I am guessing.
- M95D 3y agoNo need to pull the ropes manually. We have motors now. https://www.yachtingmonthly.com/sailing-skills/mainsail-furling-systems-an-expert-guide-75261 https://www.yachtingmonthly.com/sailing-skills/mainsail-furl... https://solar.lowtechmagazine.com/2009/04/sailing-at-the-touch-of-a-button/ https://solar.lowtechmagazine.com/2009/04/sailing-at-the-tou...
- jasonwatkinspdx 3y agoTwo reasons: First, solid wings are dramatically better in lift drag ratio. They start out around 3x better per square meter than conventional sails on a bermuda rig, and can get up to 7x better with careful design. This is why the America's Cup boats with wings are dramatically faster than conventional rigs (the other reason being foils). Second, the simplicity of the rig. These designs are self trimming, which means there's a control flap you set, and that causes the wing to have a consistent angle of attack vs the wind. As the wind vector shifts around the sail just tracks it without needing any active control or electronics. You only have to change the control flap when the bow or stern crosses the wind during a turn. If you get into severe weather you just put the control flap in neutral and the wing just acts like a weather vane. Surprisingly enough a feathered wing like this has less drag than a bare cylindrical mast with no sail lifted. Aerodynamics can be counterintuitive. That's what's so cool about this technology. It really is just a bolt on.
- wolverine876 3y ago> solid wings are dramatically better in lift drag ratio Why has anyone used fabric sails? If they could build a wooden boat, they could have made wooden sails. Too heavy, and thus modern strength/weight materials were needed?
- mrcartmeneses 3y agoWeight and the fact that wings are a modern invention that requires an understanding of aerodynamics
- jasonwatkinspdx 3y agoYes, people 200 years ago did not possess the material science knowledge to build a solid wing that would not be insanely heavy, vs... canvas.
- pbronez 3y agoMy thought exactly. Some university should build a wing sail ship using exclusively materials and tools available during the Golden age of sail.
- machine_coffee 3y agoI wonder how well they hold up in strong storms, or if they can be folded away for safety.
- russellbeattie 3y agoThis was exactly my thought. We've all seen videos of giant ships caught in storms with green water splashing over the bow and are amazed they're able to stay afloat. Just from a glance at these sails, it looks like it would capsize the ship under in minutes in a decent storm. I would think either they fold down or they have to plan their routes very carefully to avoid bad weather.
- mattmaroon 3y agoAnd who says you can’t reinvent the wheel?
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- mayd 3y agoFrom the article: "Pyxis Ocean reportedly saved an average of 3.3 tons of fuel each day."
- kkoste 3y agoBut does the overall cost of these 'WindWings' recoup over the lifetime of cargo ship. Including the fact that they can now carry less cargo per trip. And the trip might take longer due to 'route optimizations'. Insurance is probably also going to be higher now that you have giant sails on top of the ships that makes it both more expensive but also i suspect less safe in rough seas(even when folded). I feel that is the only true measure otherwise cargo ship builders are not inclined to build more of these.
- mgiampapa 3y ago3.3 tons of fuel per day adds up to a lot of extra cargo that isn't fuel.
- Merad 3y agoA lot of these ships carry upwards of 150000 tons of cargo. Not sure if an extra 60-70 tons (assuming a 20 day trip) of cargo would be very meaningful. A quick google suggests that would only be 2 or 3 additional shipping containers.
- rascul 3y agoThat's approximately two Honda Civics.
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- bilsbie 3y agoWhy don’t sailboats use these?
- andrewflnr 3y agoSome really high end racing sailboats do use rigid "sails". But there's a lot to be said for a wind surface that can stow away. I assume regular sails are lighter. Also, of course, momentum and habit.
- rightbyte 3y agoThere are those who do. https://en.wikipedia.org/wiki/Wingsail https://en.wikipedia.org/wiki/Wingsail Apart from being complex and expensive, you can't reduce their size for hard winds. Rigid sails seems very inconvenient to fold too.
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- dghlsakjg 3y agoexpense, weight, and lack of flexibility. A fabric sail can easily be reduced in size by lowering it partially when the conditions call for it. Weight aloft must be counterbalanced in the keel in a monohull. A solid sail requires heavier supports than a fabric sail. Expense. A fabric sail can actually make a pretty good airfoil, rigidity adds an insane amount of expense to get you a level of performance that doesn't really matter to most.
- ajb 3y agoSo, they are saving 14% and expect to multiply that by 1.5 by having an additional wing. Is there any prospect of getting near 100%? Naively 15 wings would get there. From the image maybe 7 would fit on this ship without a redesign. Once it's proven, will it gradually evolve to taking more and more of the energy requirements? Obviously I realize there has to be some fuel in case the vessel would be becalmed, but apart from that, what are the limits?
- ilkke 3y agoWhy stop there? Add more than 15 sails and you could be generating fuel!
- wolrah 3y ago> Why stop there? Add more than 15 sails and you could be generating fuel! AFAIK there are a few companies that have been adding electric drive systems to sailboats that actually do work this way, not only can it be used to maneuver around when the wind is uncooperative but it can generate power when the wind is good, basically acting as a "hybrid" of sorts where hypothetically given enough battery storage and maybe some solar it could be possible to never have to plug in or run a combustion generator.
- wolverine876 3y agoWhy not put a windmill on the ship and generate electricity, turn the screw, and drive the ship? Not as efficient?
- willcipriano 3y agoIf it works what prevented ancient people from building windmill ships?
- dotps1 3y agolikely lots of moving parts with a less-than-ideal place to be conducting regular repairs