6 ms·

It's called the Flettner rotor, it uses the Magnus Effect. Cool stuff but not exactly new tech. It gives a nice read, here's some links to wikipedia on the topi

by fmsf 8y ago

It's called the Flettner rotor, it uses the Magnus Effect. Cool stuff but not exactly new tech. It gives a nice read, here's some links to wikipedia on the topic: https://en.wikipedia.org/wiki/Magnus_effect https://en.wikipedia.org/wiki/Magnus_effect and https://en.wikipedia.org/wiki/Rotor_ship https://en.wikipedia.org/wiki/Rotor_ship I'm curious of what will be the results.

bobowzki 8y ago
First ship was built 1924 so it's almost 100 years old tech by now. Still cool though.
curiousDog 8y ago
Apparently this is a turbo sail and not the same as the Flettner rotor. The Wikipedia article you linked to mentions the same. Ones powered by electricity and one by air? Both seem to take advantage of the Magnus effect though
- spydum 8y ago
  https://www.google.com/amp/s/amp.theguardian.com/environment/2017/mar/14/spinning-sail-reboot-cut-fuel-make-ocean-tankers-greener https://www.google.com/amp/s/amp.theguardian.com/environment... It’s not a turbosail. Turbo sails don’t rotate..
  - curiousDog 8y ago
    Ah, looks like you're right! I got confused by its mention in the article.
robfitz 8y ago
They claim 7-10% reduction in fuel usage, with fuel making up 60% of their total costs. Given that they soon expect to be spending $5 billion/year on fuel for 800 ships, fuel spend is a bit north of $6 million/year for an "average" ship. But size seems to vary widely (they note that only the 80 of their largest ships are being considered for these sails). At an installation cost of $2 million, saving 10% of an "average" ship would return 600k per year, or a 3.5 year paypack, which seems well worth doing where possible. And they'll obviously get better than that on their 80 largest. Not a magic bullet by any means, but certainly seems worth using.
- gameswithgo 8y ago
  As long as they are reliable and have non-crazy maintenance costs it should be profitable now. I imagine some time and competition could cut that install cost in half too.
  - village-idiot 8y ago
    Economies of scale too.
- taneq 8y ago
  I think that's something we lose sight of in software sometimes, where we're used to some token effort improving performance by 10x or more. In the real world, if you can make something 10% more efficient, that's a game changing, industry conquering advantage.
  - IronWolve 8y ago
    Too true. Like the new dodge ram etorque, using its electric motor to replace the alternator, it can launch the truck and let the combustion motor take over at highway speeds. 1-2 mpg is a large improvement for a truck. 1500 dollar option that pays for itself, and a good step towards getting battery tech into trucks. I've seen it mentioned boats/ships using electric assist will also be another catalyst for battery tech integration, fuel costs on those large ships are always a topic. Bolt on solutions that are affordable with quick turn around on investment.
  - ballenf 8y ago
    Agree, but with a few caveats: - The cost needs to be fairly easy to measure - Some degree of competition in the industry exists (otherwise the capital could be used to increase revenue or acquire small potential rivals before they're too large to afford, among other higher return places to spend the capital) - The industry is mature and sources of larger savings already exhausted - Prospect for some future much bigger savings small (or at least not in conflict with the current effort) - Prospect for the industry as a whole very good (in a shrinking market, 10% savings becomes lower priority than selling off assets quickly enough at high enough cost without subsidizing a competitor or startup) - Industry consolidated enough (or capital costs of the improvement low enough) to finance the upfront cost
jessriedel 8y ago
> Rotor ships take advantage of this same effect by spinning a large vertical cylinder, typically using an electric motor, and using the resulting force for propulsion. I always thought sails were partially defined by being passive. I wonder why these aren't called "rotor fans" if they're electrically driven? Is there anywhere it's discussed when rotors are expected to outperform normal fans? They seem to be used only on large ships, but I can't see a first-principles explanation for that.
- kitd 8y ago
  "Fan" implies the propulsion is in response to air being forced backwards. These rotors create lift in a forwards direction from the wind blowing across them, a bit like having a fixed wing pointing up.
  - kenneth 8y ago
    Regular sails actually work similarly to a wing, in that pressure differentials on either side create a force we call lift on a plane, rather than simply being "pushed from the back" by directly catching the wind. That's why a sailboat can go in almost any direction regardless of which direction the wind is blowing.
    - jessriedel 8y ago
      Edit: sorry, nevermind, I was confused as to what you were claiming.
      - jessaustin 8y ago
        Reading the parent carefully, I find nothing that contradicts what you have written in response. Pressure is just force over area.
        jessriedel 8y ago
        Thanks, upon re-reading I agree. I misinterpreted the "pushed from the back" statement.
gameswithgo 8y ago
The fundamental tech may not be new but the details are, this is lighter and (hopefully) more effective than previous attempts.
dorfsmay 8y ago
> Cool stuff but not exactly new tech They explain that in the article, and the fact that it newer tech and lighter columns to get a net benefit. Having grown up in France, I knew about Cousteau's Alcyone (it was a big deal at the time) and had been wondering why it hadn't been used more since then.
- kevin_thibedeau 8y ago
  Rotor ships predate the turbosail.
aberoham 8y ago
Great video explanation: https://youtu.be/XAztqxq2z9k?t=5m50s https://youtu.be/XAztqxq2z9k?t=5m50s
toomim 8y ago
Here's a video demonstrating Flettner Rotos on a boat: https://www.youtube.com/watch?v=__8-QSXgupA https://www.youtube.com/watch?v=__8-QSXgupA
eigenvector 8y ago
Notably, wind turbine OEM Enercon already used it on one of its transport ships. https://en.wikipedia.org/wiki/E-Ship_1 https://en.wikipedia.org/wiki/E-Ship_1

by fmsf 8y ago

bobowzki 8y ago

First ship was built 1924 so it's almost 100 years old tech by now. Still cool though.

curiousDog 8y ago

Apparently this is a turbo sail and not the same as the Flettner rotor. The Wikipedia article you linked to mentions the same. Ones powered by electricity and one by air? Both seem to take advantage of the Magnus effect though

spydum 8y ago
https://www.google.com/amp/s/amp.theguardian.com/environment/2017/mar/14/spinning-sail-reboot-cut-fuel-make-ocean-tankers-greener https://www.google.com/amp/s/amp.theguardian.com/environment... It’s not a turbosail. Turbo sails don’t rotate..
- curiousDog 8y ago
  Ah, looks like you're right! I got confused by its mention in the article.

robfitz 8y ago

They claim 7-10% reduction in fuel usage, with fuel making up 60% of their total costs. Given that they soon expect to be spending $5 billion/year on fuel for 800 ships, fuel spend is a bit north of $6 million/year for an "average" ship. But size seems to vary widely (they note that only the 80 of their largest ships are being considered for these sails). At an installation cost of $2 million, saving 10% of an "average" ship would return 600k per year, or a 3.5 year paypack, which seems well worth doing where possible. And they'll obviously get better than that on their 80 largest. Not a magic bullet by any means, but certainly seems worth using.

gameswithgo 8y ago
As long as they are reliable and have non-crazy maintenance costs it should be profitable now. I imagine some time and competition could cut that install cost in half too.
- village-idiot 8y ago
  Economies of scale too.
taneq 8y ago
I think that's something we lose sight of in software sometimes, where we're used to some token effort improving performance by 10x or more. In the real world, if you can make something 10% more efficient, that's a game changing, industry conquering advantage.
- IronWolve 8y ago
  Too true. Like the new dodge ram etorque, using its electric motor to replace the alternator, it can launch the truck and let the combustion motor take over at highway speeds. 1-2 mpg is a large improvement for a truck. 1500 dollar option that pays for itself, and a good step towards getting battery tech into trucks. I've seen it mentioned boats/ships using electric assist will also be another catalyst for battery tech integration, fuel costs on those large ships are always a topic. Bolt on solutions that are affordable with quick turn around on investment.
- ballenf 8y ago
  Agree, but with a few caveats: - The cost needs to be fairly easy to measure - Some degree of competition in the industry exists (otherwise the capital could be used to increase revenue or acquire small potential rivals before they're too large to afford, among other higher return places to spend the capital) - The industry is mature and sources of larger savings already exhausted - Prospect for some future much bigger savings small (or at least not in conflict with the current effort) - Prospect for the industry as a whole very good (in a shrinking market, 10% savings becomes lower priority than selling off assets quickly enough at high enough cost without subsidizing a competitor or startup) - Industry consolidated enough (or capital costs of the improvement low enough) to finance the upfront cost

jessriedel 8y ago

> Rotor ships take advantage of this same effect by spinning a large vertical cylinder, typically using an electric motor, and using the resulting force for propulsion. I always thought sails were partially defined by being passive. I wonder why these aren't called "rotor fans" if they're electrically driven? Is there anywhere it's discussed when rotors are expected to outperform normal fans? They seem to be used only on large ships, but I can't see a first-principles explanation for that.

kitd 8y ago
"Fan" implies the propulsion is in response to air being forced backwards. These rotors create lift in a forwards direction from the wind blowing across them, a bit like having a fixed wing pointing up.
- kenneth 8y ago
  Regular sails actually work similarly to a wing, in that pressure differentials on either side create a force we call lift on a plane, rather than simply being "pushed from the back" by directly catching the wind. That's why a sailboat can go in almost any direction regardless of which direction the wind is blowing.
  - jessriedel 8y ago
    Edit: sorry, nevermind, I was confused as to what you were claiming.
    - jessaustin 8y ago
      Reading the parent carefully, I find nothing that contradicts what you have written in response. Pressure is just force over area.
      - jessriedel 8y ago
        Thanks, upon re-reading I agree. I misinterpreted the "pushed from the back" statement.

gameswithgo 8y ago

The fundamental tech may not be new but the details are, this is lighter and (hopefully) more effective than previous attempts.

dorfsmay 8y ago

> Cool stuff but not exactly new tech They explain that in the article, and the fact that it newer tech and lighter columns to get a net benefit. Having grown up in France, I knew about Cousteau's Alcyone (it was a big deal at the time) and had been wondering why it hadn't been used more since then.

kevin_thibedeau 8y ago
Rotor ships predate the turbosail.

aberoham 8y ago

Great video explanation: https://youtu.be/XAztqxq2z9k?t=5m50s https://youtu.be/XAztqxq2z9k?t=5m50s

toomim 8y ago

Here's a video demonstrating Flettner Rotos on a boat: https://www.youtube.com/watch?v=__8-QSXgupA https://www.youtube.com/watch?v=__8-QSXgupA

eigenvector 8y ago

Notably, wind turbine OEM Enercon already used it on one of its transport ships. https://en.wikipedia.org/wiki/E-Ship_1 https://en.wikipedia.org/wiki/E-Ship_1