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Spinning Metal Sails Could Slash Fuel Consumption, Emissions On Cargo Ships (sciencemag.org)
sciencehabit shares a report from Science Magazine: U.K. soccer star David Beckham was known for "bending" his free kicks over walls of defenders and around sprawling goal tenders, thanks to a physical force called the Magnus effect. Now, the physics behind such curving kicks is set to be used to propel ocean ships more efficiently. Early next year, a tanker vessel owned by Maersk, the Danish transportation conglomerate, and a passenger ship owned by Viking Line will be outfitted with spinning cylinders on their decks. Mounted vertically and up to 10 stories tall, these "rotor sails" could slash fuel consumption up to 10%, saving transportation companies hundreds of thousands of dollars and cutting soot-causing carbon emissions by thousands of tons per trip.
Rotor sails rely on a bit of aerodynamics known as the Magnus effect. In the 1850s, German physicist Heinrich Gustav Magnus noticed that when moving through air a spinning object such as a ball experiences a sideways force. The force comes about as follows. If the ball were not spinning, air would stream straight past it, creating a swirling wake that would stretch out directly behind the ball like the tail of a comet. The turning surface of a spinning ball, however, drags some air with it. The rotation deflects the wake so that it comes off the ball at an angle, closer to the side of the ball that's rotating into the oncoming air. Thanks to Isaac Newton's third law that every action must have an equal and opposite reaction, the deflected wake pushes the ball in the opposite direction, toward the side of the ball that's turning away from the oncoming air. Thus, the spinning ball gets a sideways shove.
Rotor sails rely on a bit of aerodynamics known as the Magnus effect. In the 1850s, German physicist Heinrich Gustav Magnus noticed that when moving through air a spinning object such as a ball experiences a sideways force. The force comes about as follows. If the ball were not spinning, air would stream straight past it, creating a swirling wake that would stretch out directly behind the ball like the tail of a comet. The turning surface of a spinning ball, however, drags some air with it. The rotation deflects the wake so that it comes off the ball at an angle, closer to the side of the ball that's rotating into the oncoming air. Thanks to Isaac Newton's third law that every action must have an equal and opposite reaction, the deflected wake pushes the ball in the opposite direction, toward the side of the ball that's turning away from the oncoming air. Thus, the spinning ball gets a sideways shove.
... it seems we have come full circle on ship propulsion technology.
There is no XUL, only WebExtensions...
They need to use electricity to spin.
But most importantly, the 'sails' are not strong enough to push the boat without other propulsion. Makes me wonder how effective they are.
A lot of weight and equipment to provide a week thrust. I'd like to see a comparison of thrust per watt on these things vs an electric airboat fan vs. a standard electric underwater propeller.
excitingthingstodo.blogspot.com
..."English," in tennis and pool.
It little behooves the best of us to comment on the rest of us.
Modern table tennis bats can impart a large amount of spin to the ball, causing it to drop quickly or float, depending on the direction of imparted spin.
If the wind is always perpendicular to the way you want to travel. Of course the most reliable wind is from the ship moving forward thanks to its actual engines, which certainly isn't perpendicular to where you want to go. So now you have to apply a force to counter it to go in the direction you want to go.
What you want is mostly in the article.
“Our largest rotor sails can provide forward thrust equivalent of up to 3 megawatts of main-engine power while drawing less than 90 kilowatts of electricity,” Riski says.
The Emma Maersk, a recently launched cargo ship, boasts 111 MW of propulsion. It's likely that these rotary sails are indeed more efficient than an underwater propeller but unable to deliver the same power as an underwater propeller without covering the deck in rotary sails. Having a few to lower fuel costs of the less efficient underwater propeller is simply economical. If it's actually economical, you'll see it on more and more ships just like those little winglets on airplanes.
saving transportation companies hundreds of thousands of dollars and cutting soot-causing carbon emissions by thousands of tons per trip.
Ha! The engines are already terribly inefficient and they could easily be optimized a little and do both of these things. So why not do it? Simple, it has to always work because time is money. Besides, we would all be better off if we connected all six continent with a single intercontinental railroad. Not only would things arrive faster, it would be better for the environment.
Anons need not reply. Questions end with a question mark.
I seem to recall reading about this as a kid back in the 60s in Popular Science. It was supposed to make shipping freight cheaper. But for some reason it never caught on. Is this round 2, fifty years later?
A few nukular wessels could transport millions of time of goods with the only carbon emissions being the crew members poops.
Maybe use hydrodynamic drive.
Rotor ships are right up there with Sterling engines, fuel cells, and a lot of other "great ideas" that turn out not to be so great in practice. When a fairly simple technology like this hasn't caught on for over a century, there's probably a good reason for it. My guess is in the case of rotor ships, it's higher purchase price, higher maintenance costs, higher weight, higher center of gravity, vulnerability to high winds, and insufficient savings under real weather conditions.
around sprawling goal tenders...
David Beckham never did that, because he played Football, not Ice Hockey.
They are goalkeepers, (or just 'keepers).
Another good read is How to Avoid Huge Ships by John W. Trimmer.
No sig today...
Gustav Magnus discovered what came to be known as the Magnus effect while studying why artillery projectiles would drift in the direction of spin.
For a good visual example, watch the Veritasium video on the Magnus effect. Not only does it explain the effect using a spinning basketball dropped off a dam, but it also has pictures of what these ships will look like with rotor sails.
This review for the book is hilarious:
As the father of two teenagers, I found this book invaluable. I'm sure other parents here can empathize when I say I shudder at the thought of the increasing presence of huge ships in the lives my children. I certainly remember the strain I caused so long ago for my own parents when I began experimenting with huge ships. The long inter-continental voyages that kept my mom and dad up all night with worry. Don't even get me started on the international protocols when transporting perishable cargo. To think, I was even younger than my kids are now! huge ships are everywhere and it doesn't help that the tv and movies make huge ships seem glamorous and cool. This book helped me really approach the subject of huge ships with my kids in an honest and non judgmental way. Because of the insights this book provided, I can sleep a little better and cope with the reality that I can't always be there to protect my kids from huge ships, especially as they become adults. I'm confident that my teens, when confronted by a huge ship, are much better prepared to make wiser decisions than I did. At the very least my children certainly know that they can always come to me if they have any concerns, questions or just need my support when it comes to the topic of huge ships.
Rotor ships exist, the power requirement is quite negligible compared to props or fans, and yes they put out a low power range but it's about HOW they put that power out, nullifying nose winds that waste power at the propeller and allowing them to "sail" closer to the wind with less resistance in any direction.
Of course you doubt it works, you haven't studied them and the barcalounger is very comfy for such work.
in 1925 .. http://www.popularmechanics.com/science/a2345/4235579/
This is like Dr. Evil who held the world hostage to his Evil scheme, that is, until he was paid . . . one . . . million . . . dollars! Number Two had to take him aside to explain that a person having been in frozen suspension since the 60's might not be aware that one million dollars is not really all that much money taking inflation into account.
So this device cuts "soot causing carbon emissions" by "thousands of tons", "slashing fuel consumption by 10%"?
Such suggests that the emissions are in the tens of thousands of tons and nines-of-thousands-of-tons of that awful "soot causing carbon" is, what is the correct word, still "spewed" into the atmosphere?
Slashdot is "News for Nerds" and presumably many of us have technical backgrounds where we understand that a 10% improvement can be significant were it combined with other such improvements, but can we be spared argument-by-a-large-number?
Personally, I enjoyed this review:
I wish I'd read this highly informative title in the late 90s. My husband and I both suffer from PTHSCD (post-traumatic huge ship collision disorder) which we acquired while piloting our own huge ship. I remember it like it was yesterday -- we were carrying over 3 million gallons of blue paint to Morocco when, wouldn't you know it, we collided with our competitors. They had about 4 million gallons of red-brown on board, and before we knew it, we were all marooned.
This one was also quite a helpful review:
When on my jet ski in the Chesapeake bay this summer I was confronted by a huge ship moving up the channel. You can imagine my horror when I realized I had only 1 hour and 45 minutes or so before the lumbering behemoth was sure to pass through my area. With no place to hide and only a water jet propelled small craft beneath me for transport, I quickly withdrew my Kindle Fire from the storage compartment beneath my seat and preceded to read the book How To Avoid Huge Ships. One hour later and with only 45 minutes to spare, I implemented the expert advice provided by the author and turned my jet ski in the opposite direction of the huge ship to avoid certain disaster.
Irony: Agile development has too much intertia to be abandoned now.
See the Wikipedia page on Rotor Ship. This is a 1920's invention, and a relatively large ship was built in 1926 and is documented in the German Wikipedia. Even if you don't translate the page, the photo is clear.
Bruce Perens.
I've heard that the United States Navy has just put in a special expedited order for 50,000 copies of this book.
OK, humor aside...We've all seen/experienced these effects in everything from pool to baseball, etc. but it is ALWAYS good to learn the "why" behind the "what".
"Why wait for shipping? Start listening today!"
Of topic but... "Spinning Metal Sails": I was looking for a name for my Styx cover band.
I think you underestimate just how much I just dont care.
the sails are bunny hopping
Kites sure seem to have more potential with significantly lower capital expense and proportional benefits. (5-10% reduction in fuel consumption)
https://en.wikipedia.org/wiki/... Ironically, check out the "see also" section...
What am I missing ?
Create usable Fusion energy.
I suspect maintenance costs are going to kill this idea. Ask anyone who owns a boat (power or sail) used in the ocean. You spend almost as much time maintaining it as you do using it, and replacing corroded parts is one of your biggest expenses. Even if they made the rotors out of a corrosion-resistant material like fiberglass, the fact that you need to rotate them means a lot of precision metal parts which are going to corrode and wear unless on a strict maintenance schedule. (Yes propellers spin, but they're fully submerged so you can use sacrificial anodes to protect them from corrosion. Something up in the air with droplets of saltwater mist on it is going to corrode almost overnight.)
It's the same problem the NS Savannah encountered. Making it nuclear power dropped its fuel costs to near zero. But the increased labor required to operate and maintain the nuclear reactor ended up making it more expensive than a cargo ship powered with fuel oil.
to total. Must be looking for alternatives
Seems like a rotor sail could drive a generator collinear with the axis of rotation no matter what direction the wind comes from, then apply it directly to propulsion using electric drive.
Worst case, the wind comes from the front, but instead of just being a counter-force, it contributes to forward motion to some degree.
And of course, if there are lossy angles, you pull them down.
Just speculating.
I've fallen off your lawn, and I can't get up.
I remember first reading about this 40 years ago.
Those were good. This one hits the Trifecta:
"Last month when I was on a fishing trip I noticed that there was a huge ship on the horizon coming my way. Needless to say I was terrified. luckily I was adequately equipped with How to Avoid Huge Ships by John W. Trimmer, and the AutoExec Wheelmate Steering Wheel Attachable Work Surface Tray. Acting quickly I threw my Hutzler 571 Banana Slicer off of my AutoExec Wheelmate Steering Wheel Attachable Work Surface Tray, sending perfectly sliced discs of banana everywhere. Using the stable surface of my AutoExec Wheelmate Steering Wheel Attachable Work Surface Tray I was able to read the needed to knowledge to avoid that huge daunting ship. How to Avoid Huge Ships by John W. Trimmer is a true life saver."
His ignorance covered the whole earth like a blanket, and there was hardly a hole in it anywhere. - Mark Twain
Creimer forgot to login today.
That isn't "slashing' anything. What was wrong with normal sails? Oh wait - they are FAR more efficient than this ridiculously stupid invention... and we can't have that...
https://www.google.co.uk/search?client=firefox-b&dcr=0&tbm=isch&q=sail+ships&chips=q:sail+ships,g_3:victorian&sa=X&ved=0ahUKEwjS0tbroZXWAhWEIsAKHVzsD_EQ4lYILigC&biw=1920&bih=958&dpr=1
Gee... look, all those huge ships were completely powered by the WIND in their sails, we can't have that, too old fashioned! Let's waste millions of pounds on fuel instead.
Very interesting. Probably it is a completely ignorant observation, but I am quite surprised by the simple shape of the rotor sail. Why is it a cylinder rather than a drop / cone / pineapple shape? And why is the rotor sail smooth? Wouldn't it be possible to increase the Magnus effect with golf ball style dimples or alternatively with fins to scoop the air more efficiently? Why is it not integrated with a static fin to optimally direct the airflow? I would have thought that some level of autorotation would make sense with this kind of approach as well. Is it because for some reason the technology is still in an early phase of development or is a smooth cylinder simply the most practical & efficient way to leverage on the Magnus effect?
This is what happens when millennial academics, having no knowledge of history because they have wiped their own history books of anything unpalatable, "rediscover" tried and failed inventions of a century ago.
This is what happens when millennial academics and automatons care more about "disrupting" the status quo than realizing that it's the status quo for a reason.
This is why the US had its industrial and technological peak in the 60's, when solutions were devised by actual engineers, in a time when engineering was considered a valued and even somewhat glamorous profession. Engineers were respected because they knew their shit, and they knew how to solve problems.
Now, engineers are cattle, expected by their "educated" masters to come up with seven perpendicular red lines, some of which are in blue ink, and some of which are in green ink. No problem, right?
This is why I quit engineering and became a teacher. I realized that if someone doesn't get to the kids and teach them some actual science and actual facts, we're doomed for good as a nation. I thought this would be easier than it is - the political headwinds to teaching actual facts are great.
Case in point. I was teaching about the solar system and was talking about the different factors that affect Earth's climate. As a demonstration, I used a lightbulb and a dimmer to demonstrate solar forcing as one of the factors that influences a planet's climate - brighter bulb or closer distance = hotter; dimmer bulb or farther distance = cooler. It did not take long for the reprimand to come. I was told never to teach about solar forcing again and stick only to CO2, Methane, and other greenhouse gases (except water vapor) as influencing factors on climate.
School #2 is much better. Anyway, sorry that turned into sort of a treatise, but it needed to be said.
Well of course they are. If they provide 3 MW but only need 90 kW input, most of the energy is clearly coming from somewhere else i.e. the wind.
The problem with these sails is that they can only produce thrust at right angles to the direction of the wind and, of course, there has to be wind. This is the main reason why you need engines too.
All I want is a secure system where it's easy to do anything I want. Is that too much to ask ~~ Randall Munroe
I wonder if it could be used for lift in aircraft design in place of traditional wings. It seems it would also apply to rotating cylinders instead of wings. I would guess that lift would be variable depending on the rate of rotation.
E Proelio Veritas.
The idea isn't new, the incredible claims aren't new and actually testing it isn't new either. What have changed since last time this was attempted and failed?
The wake behind a ball is NOT like the tail of a comet - the tail of a comet points (approximately*) away from the sun, not opposite to the direction of motion.
Comet tails are not caused by some kind of drag - the comet moves in a vacuum in (almost**) geodesic motion around the host star.
* Yes, there are actually two tails, dust and gas, directly not exactly away from the sun. The point is really that comet tails do not follow comets around the sun.
** M_comet/M_sun is normally pretty small, etc.
There is nothing new about this: https://en.wikipedia.org/wiki/Rotor_ship
A German engineer called Anton Flettner built one of these in the 1920s.
IIRC; There were some major mechanical engineering problems to be solved before the concept could be scaled up to the size needed for commercial shipping.
1) Freakin' huge tubes, essentially only mounted at one end meant doing some serious engineering on the drive motors, bearings and so on, so as to not snap off in bad weather. On a conventional sailing vessel, you douse sails so as to not snap masts, you can't do that with a Magnus rotor.
2) as others have pointed out, the sheer height of a rotor large enough to make a practical difference imposes some pretty serious limitations on routes, since clearance under bridges becomes a deal breaker. Also, that height means that the gantry cranes typically used in port for handling shipping containers might conflict with the rotors.
3) Most existing ships can't be modified to incorporate these structures because a) limited deck space and b) The structure of the hull wouldn't be strong enough to take the loads without a lot of (expensive) modifications.
On a more financial/social level; international shipping is very demanding. Relatively low margins, yet with literally tens of millions at risk with each ship load encourages a great deal of cautious, conservative behaviour. Using the latest and most efficient engines and scaling ship size up is an obvious next step to take when planning and building new vessels. The demands, risks and savings and opportunities are very well understood. Building a Magnus ship means very different hull designs, increased risk of loss at sea, changes to infrastructure, new required skills for ships crew and so on. That is a much harder sell, particularly since a failure to meet expectations for efficiency means the ship becomes a money sink. A Magnus ship converted back to completely conventional propulsion wouldn't be as efficient as conventional designs.
The bottom line is that, while a Magnus ship could work, it would be hard to make cost effective enough to justify the risks
I need a wheelchair van for my son. Help me get the word out. https://www.gofundme.com/wheelchair-van-for-jj
Wish I had mod points for you today.
Hey, Windows users, there is no such thing as "forward" slash, there is only slash and backslash.
How tough would they be? Rotors could last many years.
And kites can crash in spite of best efforts. They would need some kind of recovery yardarm. This assumes crashing doesn't rip it off the ship or destroy it.
(-1: Post disagrees with my already-settled worldview) is not a valid mod option.
Rowing --> Sails --> Coal/Steam --> Diesel --> Sails
I should think full-circle would go all the way back to rowing.
Or are you trying to spin it?
You're sure that isn't the sort of thing that would cause more problems than it solves? We're not exactly ten for ten on those kind of violent interventions. Probably the cost of a bullet is pretty close to the cost of a meal in those parts, without considering the money spent to put a warship and trained soldiers there to fire said bullets. It's also possible that some of these people might shoot back. I'm not saying that your plan is bad, but I think you should maybe revisit the idea that shooting people is a good way to solve problems. Many people do not like to be shot, and at the very least it tends to be extremely expensive.
Those who advocate genocide deserve every protection afforded by law, and none afforded by common human decency.
Last I heard the ship carrying the books hit an iceberg, is taking on water, with a fire on board, and was surrounded by sharks. No word yet if the sharks had fricken lasers on their heads.
The US Coast Guard, US Army and US Air Force were sending aircraft to the area to assist in fighting the fire and treat the injured. They had to turn back because they hit A Flock of Seagulls. Not birds, the 1980s rock band. The band's record label and agent were not available for comment. The B-52's also had to turn back. Not the aircraft, also a 1980s rock band. When asked why they were involved in the incident they simply replied they felt a need to "Roam".
Man, they just can't get a break.
I am armed because I am free. I am free because I am armed.
Their tin roof was probably still rusted.
In the 1850s, German physicist Heinrich Gustav Magnus noticed that when moving through air a spinning object such as a ball experiences a sideways force. The force comes about as follows....
This has to be the most Slashdot way ever to explain something that everyone who has ever played a sport ever needs no explanation for.
Try not to maim yourself walking from your desk to bathroom today.
Somewhere I found a video of a 1923 Magnus equipped cargo ship.
Great idea,NEVER gets off the ground.
First read about this in the 80's but that idea and implementation has been around since the 1920's ie. almost a century.
Rotor ship
"Consensus" in science is _always_ a political construct.
Didn't _Popular Science_ publishing something about this a few decades ago? Perhaps around the time they were hyping the Rolamite and ROVAC?
https://duckduckgo.com/?q=popular.science+rolamite
https://duckduckgo.com/?q=popular.science+rovac
There's no time like the present. Well, the past used to be.