Football Field-Sized Kite Powers Latest Freighter

coondoggie writes to tell us that a new freighter set to launch in December will be receiving a hefty dose of power from a kite the size of a football field. The 460-foot ship, owned by the Beluga shipping company, hopes to see as much as a 50% drop in fuel consumption during optimal conditions. "The SkySails system consists of a towing kite with rope, a launch and recovery system and a control system for the whole operation. The control system acts like the autopitot systems on an aircraft, the company says. Autopilot software sends and receives data about the sail etc to make sure the sail is set at its optimal position. The company also says it provides an optional weather routing system so that ships can sail into optimal wind conditions.The kites typically fly at about 1,000 feet above sea level, thereby tapping winds that can be almost 50% stronger than at the surface. "

This could be tragic.

[lstellar]

I feel sorry for all those wayward seagulls.

Reinventing the wheel, and getting $$$ for it

[pwnies]

????B.C. - Random Dude "You know this wind would be pretty cool if it were used to run a ship"
*Investors throw money at random dude*

1769 - James Watt "You know this steam engine thing would be pretty cool if it were used to run a ship"
*Investors throw money at Watt*

1896 - Karl Benz "You know this gas powered combustion engine thing would be pretty cool if it were used to run a ship"
*Investors throw monoey at Benz*

2007 - SkySails "You know this wind thing would be pretty cool if it were used to run a ship"
*Beluga corp. throws money at SkySails*

Seems to me that SkySails is a few millenia back on their innovation.

Re:Reinventing the wheel, and getting $$$ for it

[CIANCHAMBLISS]

The difference between conventional sails and the kite (from the article) - the wind 1000 feet up is going to be stronger than the wind at the surface. Also, with this technology, it looks like it is easier to retrofit the existing fleet of ships with a sail than to add a conventional sail.

Re:Reinventing the wheel, and getting $$$ for it

[Anonymous Coward]

Also, the lever arm is shorter. A conventional mast needs to be very tall to get the most sail area, which is a lever from the water line to the top of the mast. This means that the wind is producing more torque on the ship, causing it to tilt ("heel") from the wind. Since the kite attaches directly to the deck, its lever arm is only from the water line to the deck. Heeling makes a sail less efficient, but has no effect on the kite.

Furthermore, the kite has upward lift, which helps pull the bow out of the water. This makes it feel less of the effects of waves, smoothing out the ride a bit.

The biggest difference, though, is that it can be used in high winds, everything from 10-40mph. A traditional sailboat cannot sail in such high winds.

dom

Re:Reinventing the wheel, and getting $$$ for it

[wanerious]

d00d, that's just when it starts to get fun.

This is essentially a giant spinnaker. The main disadvantage is that it is really only good for downwind propulsion, whereas a conventional sail can make some progress upwind at an angle.

Re:

[WinterSolstice]

I was thinking the exact same thing - this is just a super-sized spinnaker. Unless I totally misunderstand, tacking would be impossible with this "kite".

Re:

[Michael Woodhams]

Kite surfers can tack into the wind, can't they? I don't see why this couldn't. The kite is steerable, so it doesn't have to be directly downwind of the ship.

Re:Reinventing the wheel, and getting $$$ for it

[E++99]

The main disadvantage is that it is really only good for downwind propulsion, whereas a conventional sail can make some progress upwind at an angle.

Not true. This type of kite is more effective at steering into the wind than a conventional sail. A conventional sail always has a significant vector of force in the direction of the wind, and relies on the ship's keel to redirect that force. A kite can steer 90 degrees towards the wind, generating lift directly perpendicular to the wind direction. If a kite was attached to the center of a ship with a keel, I'd guess you could get close to 10 degrees of direct upwind. As it is, this is about products for cargo ships and yachts, and the kite pulls from the bow. The SkySails site says you can go within 50 degrees of direct upwind, 70 degrees with full power, which sounds realistic to me.

It's a kite, not a spinnaker!

[Terje Mathisen]

I do kite sailing in the winter here in Norway, and the kite shown in the article is almost identical, except for size of course, with the kite I use. (I have also windsurfed since around 1990.)

My kite is a Peter Lynn Venom II http://www.peterlynnkiteboarding.com/ [peterlynnk...arding.com], this is a twinskin kite which keeps its airfoil shape due to internal air pressure: A set of small mesh openings in the leading edge allows air into the opening between the front and back side.

This form of kite is an airfoil, not a spinnaker, the difference is huge:

A spinnaker is effectively a large bag to catch the wind, while a kite works best by having air moving faster on one side than the other. Among other things, this means that a kite allows you to sail much faster at an angle to the wind instead of straight downwind.

Another nice trick you can do with a kite, unlike a windsurfing rig, it to let the kite loop around in little figure-of-eights: This makes the airfoil move even faster through the air, increasing the lift particularly during a lull in the wind.

Terje

Re:

[Seraphim_72]

I do kite sailing in the winter here in Norway

...oh sure like we are supposed to trust the opinion of an insane person ;)

Re:Reinventing the wheel, and getting $$$ for it

[linoleo]

This is essentially a giant spinnaker.

d00d, a modern traction kite is to a spinnaker like a modern wind turbine to a 16th-century windmill. These are airfoils, and yes you can go upwind with them - ask any competent kitesurfer. Rest assured though that you are not alone [kiteship.com] in your confusion.

A traction kite develops more power per area than a sail for 3 reasons:
1. no spillage (reduction in effective area due to heeling);
2. stronger winds at higher altitudes (where SkySails is flying, winds are roughly double those near ground, generating 4 times as much force);
3. higher airspeed (up to another factor of 2) than ship speed when working (looping or figure-8ing) the kite.

Taken together, these mean that traction kites can have *way* (as in, up to a factor of 20 or so) higher power density than *efficient* sails. A spinnaker is not an efficient sail.

SkySail's projections are in fact rather conservative - these are German engineers after all. They've convinced me - in fact they've got my money riding on them.

Re:

[StarfishOne]

It is actually possible for certain kites to make the ship sail against the wind. By using the kite to generate electricity. :D

Ship propulsion by Kites combining energy production by Laddermill principle and direct kite propulsion [tudelft.nl] (PDF!)

Re:Reinventing the wheel, and getting $$$ for it

[DerekLyons]

Furthermore, the kite has upward lift, which helps pull the bow out of the water. This makes it feel less of the effects of waves, smoothing out the ride a bit.

Unless they put a lot of [heavy] steel stiffening in, the ship will flex at the attachment point rather than lift the bow. Ships aren't rigid.
 
On top of which, even if the kite were attached at the eyes - you don't want upward force. Upward force doesn't contribute as much to propulsion as lateral force.

Getting $$$ for vaporware

[goombah99]

If you look at the pictures on the site it sure does not look like a football field sized parasail. And the recovery system is proportionally small too.

I don't know how atmospheric winds work but I assume they mostly blow in one direction. How high against downwind can a kite be made to fly. I assume these wing kites can sail a bit off directly down wind but unless they can fly more than 90 degrees off downwind like a sailboat then it's hard to see how this helps for the return journey.

Thus this 50% effi

The wind direction varies according to lat./long

[WindBourne]

The winds DO have prevelant directions, but those vary depending on where you are in the world. Some of the winds will go from east to west and others will go from west to east. As to how close you can get to the wind depends on a number of factors. Our c-scow could go about 5 degrees off the wind without a luft but only with 1 of our sails, the 2 other sails would allow about 10 degrees.But trying to make it go INTO the wind? No. The important thing was to have a DEEP center/side board, so that beats and r

Re:Getting $$$ for vaporware

[necro81]

Thus this 50% efficiency figure seems to me to only apply to one direction of travel. Overall, if one uses the same amount of energy in both direction then that's only a 25% savings. Not bad perhaps.

I don't know about you, but a 25% gain in efficiency seems pretty good to me. I wouldn't mind being able to get by on 25% less electricity or natural gas at home.

The real question isn't necessarily the efficiency gain in percentage terms, but whether the fuel savings can offset the cost the kite system. No. 6 fuel (which most ships use) is relatively cheap, because it is one refining step above tar. Seriously, it is really nasty stuff, and doesn't burn cleanly at all. A big cargo ship will go through thousands of gallons of it a day, maybe in just hours. If you can use 25% less fuel in a year, that starts to look like hundreds of thousands of gallons of fuel saved per year, which in turn could mean hundreds of thousands of dollars a year in savings.

Re:

[TheRaven64]

From what I've heard, shipping is a fairly low-margin business which makes large profits due to large volumes. A 25% savings on fuel costs might only be a 5% or even a 2% saving in overall costs, but could double the profits for a trip.

Re:

[wordsofwisedumb]

Given that kites could be several hundred feet beyond the bounds of the boat this makes passing another ship with the same system a major event. It might even require more coordination than air traffic.

Optimum conditions

[EmbeddedJanitor]

happen maybe 1% of the time? What is more interesting is how the system performs over a whole year.

Still, good to see that people are trying different ideas.

30-50% is more like it

[Quadraginta]

All they need is to have a moderately strong, steady wind that is abaft the beam. Plus good enough weather that they don't risk the kite and its hardware. If you sail the traditional sail-era trade routes the wind is abaft the beam quite a bit more than 50% of the time, the wind is steady at 1000' in the open ocean pretty much always as long as the weather is good, and you can supply your own finagle factor for how often the weather is good.

Frankly, I think the major limitation on any kind of sail power has been crew cost. Big freighters run with tiny crews these days, and often not very well trained and not especially reliable, except for the top few officers. Getting a crew that can handle a big sail competently, without endangering the cost of the apparatus, sounds expensive. But maybe they've got a robotic, computerized control system that can eliminate that problem.

Re:

[orclevegam]

They mention directing the ship into areas that provide better conditions. I wonder if this isn't a tradoff between energy efficiency and shipping time. If the ship re-routes from the optimal path in terms of distance to the one that's longer but provides better weather to reduce fuel, that seems to imply that time is a less important factor than cost. Of course in many cases in which you're shipping things by boat it's the case that time really is less important than cost, as if time was more important you

not so much time as schedule, I think

[Quadraginta]

I don't think it's so important how long it takes for a cargo to get somewhere so much as it's important that it get there when it's scheduled to do so, not earlier and not later. Modern manufacturing, to say nothing of port operations, rail schedules, et cetera, are pretty reliant on things being delivered at a certain hour on a certain day. If a boat happens to come in a day late or something, everything is flung out of synchrony -- you have to pay workers who are doing nothing, because the boat isn't t

Re:

[TubeSteak]

I wonder if this isn't a tradoff between energy efficiency and shipping time.

Just so everyone has an idea of the time spans involved:

Pacific Rim* to West Coast USA - 11 to 15 days
Pacific Rim to East Coast USA - 25 to 50 days
Europe to East Coast USA - 7 to 14+ days

The other important routes are Europe to Pacific Rim & Pacific Rim to the Mediterranean.

Saving 10~50% in fuel costs is no joke when these boats are burning >$20,000 tons of fuel per day. The only businesses that would care about slightly slower shipping are those running Just-In-Time inventory systems and they can e

Re:30-50% is more like it

[sk8dork]

yeah, according to the skysails website, and shown in a live action promo video, the launch and retrieval of the sail is completely automated, as is the steering. a person should be able to operate the whole thing by pressing the launch button in the control room to start it, and press the retrieval button when done. i recommend watching the video, it was interesting and good to see in action.

Link to video...

[rHBa]

Thought this might interest those who didn't RTFA (or didn't have time to trawl through the website looking for it):

http://www.skysails.info/index.php?id=71&L=1 [skysails.info]

Re:

[florescent_beige]

I just watched their promo video at SkySails [skysails.info]. (The video is here [streamingfarm.tv]). They can point as close as 50 degrees off the wind, so tacking is possible. In other words, if oil went up to $1000 a barrel they could theoretically sail either way across the Atlantic, albeit taking 2 or 3 times as long.

They show 30% fuel savings, but oil prices have gone up a lot recently, so it might well be closer to 50% now. It launches and recovers automatically and has an automatic control system.

Re:

[Archangel Michael]

"hey show 30% fuel savings, but oil prices have gone up a lot recently, so it might well be closer to 50% now."

I'm not sure where you get the 50% from, because 30% fuel savings, say from 1000 gals to 700 gals will always be the same result. Now the 30% fuel savings can be leveraged by fuel cost savings, but that is also going to be only 30%, but the actual difference in absolute $ will increase, but that is not a percentage of anything.

So, 30% is 30% unless they can make bigger kites that can operate on hig

Re:

[Danny Rathjens]

Nice video. It shows how "football field-sized" in the article title was completely wrong. :) (They mentioned - and you can see - a 160 square meter sail which is about 1/20th of a football field)
They also mentioned it paying for itself in 3 to 5 years. They must be charging an insane amount of money for it to cost 10% to 30% of 3 to 5 years worth of fuel costs for a freighter. :) Then again, those percentages were only fuel savings while it is operating. So overall fuel savings would be a smaller perc

Never thought it would see the light of day

[dj245]

I first heard about this when I was an undergrad studying naval architecture. Because of the poorly trained, tiny crews, many of whom don't even speak all the same language, my classmates and I never thought it would happen on a commercial ship. Clearly it has. Maybe it will even become common someday. Then again, it could be as unwieldy and difficult to manage as nuclear powered freigthers and oil tankers- examples of which you can pretty much count on one hand.

The main problem I see is the addition

Re:

[swb]

How often do ocean going ships come close to having accidents on the open oceans?

I'm sure its probably more often than I would otherwise think given the ideal routes from high-traffic origins to high-traffic destinations, but you'd think they would have some kind of rules about operating it only XX miles from ports and have some kind of radar tie-in that would cause the kite to not deploy or undeploy should shipping traffic come within some danger zone.

Re:

[Quadraginta]

...then marine insurance rates would almost certainly go down.

Most of the power?

[JonathanR]

So a kite that provides most of the ship's power can only afford a 50% reduction in fuel consumption? Hmmm...

Re:Most of the power?

[littlerubberfeet]

Motive power is only the largest fraction of consumption on a ship. On all ships, auxiliary equipment must be powered. This ranges from the small consumers, such as navigation equipment and lighting, to the large consumers, such as reefer containers and engineering subsystems. A 10,000 TEU Maersk liner might have 250 reefer slots, and that sucks a lot of power, as does the bunker fuel heater (though usually steam, but still energy from the engine).

Then consider that engine efficiency doesn't scale linearly with fuel consumption, and that propellers on large ships are fixed, not constant speed. This means that a ship moving at 17 knots HAS to make, say, 83 RPMs (for a big Sulzer). So, the kite might provide 50% of motive power, but the ship will only be able to cut the fuel pumps 20%-25%, and can't cut RPMs at all, else the prop starts dragging and cavitating.

Re:

[kalirion]

Plus you have to consider the power going to manage the kite....

Re:

[cadeon]

I hear that back in the day, devices like these created a 100% reduction in fuel use.

Re:

[ToastyKen]

So a kite that provides most of the ship's power can only afford a 50% reduction in fuel consumption?

I'm more confused by how there's a 50% reduction in fuel consumption, but only 10-20% reduction in greenhouse gases. This articles sounds like it needs to cite some verifiable sources. :P

Re:

[iamacat]

That's because the other 50% of the time the wind is blowing in the wrong direction

Re:

[Cassius Corodes]

Well they have to give 10% of the fuel in taxes as well...

Re:

[Total_Wimp]

"So a kite that provides most of the ship's power can only afford a 50% reduction in fuel consumption? Hmmm...

I'm no physics guy and I've never worked on a ship, but I'll bet modern ships go faster than wind power alone would allow, and I'll bet a lot of the extra fuel consumption is to maintain that forward speed.

I picture it like a lot of solar electricity generation. You may generate a significant fraction of your energy needs with the solar panels on your roof, but you still need power from the grid to

They might be able to get this off the ground...

[The Ultimate Fartkno]

...but in the end I don't think it'll fly. Too bad, as the failure of such an interesting idea will really knock the wind out of their sails. I hope they don't blow it.

Re:They might be able to get this off the ground..

[pwnies]

"That will do Austin."

Re:

[An dochasac]

A promising idea if they've done their deep engineering homework. The biggest problems I forsee are the possibility of large gradients across the kite, slack and tortion from monster waves, lightning and how to dump excess power.

Re:

[magarity]

tortion from monster waves
 
What to do with your kite is the least of Mr. Sailor's worries when monster wave comes along.
 
I would expect a big red quick-release button on the bridge would cut the thing free in a crisis. Preferably by means of explosive charges. Explosions during a crisis are always just the thing to get the crew extra motivated.

Yay old tech

[Jackdaw Rookery]

This strikes me as a good example of the reusing old tech.

I think some of the article misses the point:

'What if fuel prices go down?' What if they don't? Prices will not go down in the long term and the companies using these will benefit the most.

'These can't be used in a head wind.' Well no sh*t Sherlock, thanks for that. It's to cut fuel use, not eliminate it. Any cut will be good for the company and the environment.

Re:

[JonathanR]

But No.6/Bunker-C is all the residual shit that can't be used for anything else. It'll get burnt somewhere, somehow. Refiners will find a way to sell it.

Re:

[Dahamma]

Refiners will find a way to sell it.

Or dump it in the San Francisco Bay if they can't...

Then again, I'm not sure getting a kite the size of a football field tangled in the Bay Bridge would have been much prettier.

Re:

[tkw954]

But No.6/Bunker-C is all the residual shit that can't be used for anything else. It'll get burnt somewhere, somehow. Refiners will find a way to sell it.

Right on. It's like people who drink milk but refuse to eat meat. Or won't use glue made from animal parts.

Re:

[kindbud]

'These can't be used in a head wind.'

These sails can [symaltesefalcon.com].

Re:

[moosesocks]

You can go upwind [wikipedia.org] in just about *any* masted sail.*

The Maltese Falcon is more or less just a modern reinterpretation of a square sail [wikipedia.org] rig, with the added advantage of being able to completely rotate the rig, allowing it to sail closer to wind.

I've heard quite a bit of debate from experienced sailors as to the comparative merits and drawbacks of this design. I'm no expert, but the one thing that is certain, is that it's astonishingly expensive (just like everything else about the boat). Not practical for c

Re:

[Otter]

You'd have to have a ship with enough lateral resistance -- you can't just throw one of these on an ordinary freighter and go upwind like you could with a kiteboard.

But it kills birdies....

[TheNarrator]

Certainly some bird is going to get hit by that kite! It will look ugly flying offshore hundreds of miles from where we can see it! The kite is made from polymers derived from fossil fuels! It somehow violates the second law of thermodynamics! It will sap energy from global winds leading to something bad! Won't somebody please think of the children [ of oil company executives]!

Seriously though... I can't think of any alternatives to fossil fuels that haven't run into enormous amount of flack.

Re:

[Koyaanisqatsi]

Insightful? Are you mods on crack? Is not fossil fuels we're running out off, it's sense of humor ...

Certain to be considered a security risk...

[phorest]

Once the pirates learn that there's a tasty morsel attached to that giant kite on the horizon...

Re:Certain to be considered a security risk...

[porky_pig_jr]

not if you put a giant skull and bones on the kite.

Re:Certain to be considered a security risk...

[vrt3]

I know you're just being funny, but pirates have other and better means to locate possible targets, such as AIS (http://en.wikipedia.org/wiki/Automatic_Identification_System), which tells them not only exactly where the target is, but also where it's heading, how large it is, what kind of cargo it is transporting, how many crew members are on board, ... . AIS transponders are required on all ocean going vessels (except small yachts and stuff, though even that is probably about to change).

AIS-receivers plus a good VHF-antenna cost only a few hundred dollars so cost is not an issue to the pirates.

This is an "update" from a July, 2006 article

[puppetman]

The original article is here:

http://hardware.slashdot.org/article.pl?sid=06/07/08/1735227 [slashdot.org]

The original article claimed a 33% savings in fuel costs. This new article claims a 50% savings under optimal conditions. Interestingly, the greenhouse gas savings are only 10-20%. Where is the logic in that?

Re:

[mangu]

This new article claims a 50% savings under optimal conditions. Interestingly, the greenhouse gas savings are only 10-20%

Obviously, conditions aren't always optimal.

Just put some solar fans on the ship to go faster!

[wsanders]

There was an endless thread once in Make magazine's forums arguing the pros and cons of putting solar powered fans on a sail-powered car to make it go faster! Sheesh.

And obviously, as recent events prove (http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2007/11/09/BAD8T8PLU.DTL [sfgate.com] ) , you need a non-dumbass boat driver who knows where the bridges are.

I hope they put beacons on the sail and rope

[darkonc]

Otherwise, sooner or later, some unlucky pilot is going to suddenly find his left wing clipped off while flying at 900ft. (possibly damaging the kite control lines, in the process).

Re:

[Slashdot Junky]

I was wondering how a ship kite would impact air traffic. Perhaps only short haul island hopping planes would fly at this attitude away from land, and the ships would only use the kites far enough out to only have high altitude flights above their shipping routes.

-Slashdot Junky

Re:

[darkonc]

It's not likely to be that much of an impairment, as you're looking at the probability of a low-flying plane flying over what is essentially a moving mathematical point on the map. On the other hand, one such impact (especially by a small commuter plane on take-off/landing) could be very tragic.

Dupe!

[GodfatherofSoul]

I read about this a while back [wikipedia.org].

Re:

[hazem]

You really mean that we read this over a year ago right here on slashdot:
http://hardware.slashdot.org/article.pl?sid=06/07/08/1735227 [slashdot.org]

The linked article doesn't work any more, but it had the same stupid picture in it - with a photoshop sail drawn over a ship. It would be nice if they at least showed a picture of a working prototype and not the same dumb photoshop drawing.

Global Calming

[ch-chuck]

Bah, all these industrial sized sails and windmills are sure to lead to a depletion of the planetary wind system. All we need is the media to hype it up and people will be observing how it used to be windier years ago.

Spinnaker?

[LoudMusic]

So ... it's a really big spinnaker [wikipedia.org]?

Cool. I like it.

Re:

[arivanov]

Yep. My thought. And it is about as much use as a spinnaker. Very nice in steady wind in the right direction. And not something you want to even think of if the weather is shite.

It's a washout!

[iamacat]

What happens when the kite falls into water and the wind is not enough to lift it up wet? Or worse, what if it falls on top of the ship and hurts sailors, breaks things or rips? It seems we are too hasty to discard centuries of experience in designing sails, masts and lines. Even a spinnaker is at least tied to the top of the mast to keep it from falling and main sails are still useful in head and side winds.

Re:

[Vancorps]

Or the automated control mechanism already pleasant retracts the kite if wind is insufficient to keep it up. This would also prevent it from falling into the water.

This thing is 1000' up, you'll have plenty of time to react if wind isn't sufficient. As another poster said as well, if the wind is unpredictable then they wouldn't launch. If wind became unpredictable then the system pulls it all back in.

The real concern with this is durability of the kite. Hold long before it needs replacement, what's it t

Re:It's a washout!

[statemachine]

What happens when the kite falls into water

From my experience of flying kites above 500 feet (perfectly legal in the U.S. as long as the kite is 5 lbs. or less and not a hazard) the wind doesn't die. I had more problems with the line and structural integrity of the kite. The line may break, the kite may collapse, or the winds may start blowing the wrong way long before you have to worry about a perfectly good kite dipping into the water.

From The Investor Ripoff Department

[Anonymous Coward]

Give me a frickin break! This is purely an investor ripoff scheme. Sails? I mean kites? 50% energy savings? Did they fail to mention that the voyage will take 5 times longer to accomplish this savings and that if they throttled the regular engines back from 20+ knots to a point where the trip time was the same, the "savings" would evaporate?

Why do you suppose we shifted from sails to steam and then to internal combustion engines and then back to steam/nuclear in various Navies? It's because they are more ef

Size of a Football field?

[Tired and Emotional]

Law 1 of Football says that a football field is between 90 and 120 metres in length and 45 and 90 metres wide. That's just the playing surface. That's roughly 4000 square metres to 10000 sq metres. (International competition is between 6400 sq.m. and 8200 sq. m.)

The test sail, if you drill down, is 160 sq. m.

Hardly the size of a football field.

Re:

[RedWizzard]

The test sail, if you drill down, is 160 sq. m.

Hardly the size of a football field.

The homepage says that kites with areas up to 320 sq m will be available in 2007. Given that 2007 is almost over I'd say the homepage is a little out of date. According to this page [skysails.info] SkySails for cargo ships range between 160 and 5000 sq m. It's not unreasonable to describe 5000 sq m as football field-sized.

size of a football field ...

[eck011219]

But how many bowling balls does it weigh?

Really, we're all geeky adults here. Can't we use real units? And moreover, we're not all in the U.S. (I happen to be, but still).

When it docks in the U.S., it's 100 yards long by 160 feet wide. Apparently when the ship docks in a Canadian port the sail will expand to 100 meters long and 59.4 meters wide. When it docks anywhere in the rest of the world, it will expand to anywhere from 100 to 110 meters wide to 64 to 75 meters wide. I guess it'll fold out or something.

And when it docks in Australia, it will run about 165 meters long by 135 meters wide (and while it will be hard to figure out how it works or what it's doing, it will be brutally violent).

Can we find anything more ambiguous to compare it to? How many loaves of bread long is it?

Re:

[vux984]

I, for one, have a better ability to visualize how large "a football field" is than ~100 x ~70m, even if the former 'measurement' is ambiguous. All football fields are in the same ballpark (haha), and higher precision isn't needed.

I mean if they said it was about half a hectare, that would be about as precise and far less meaningful.

Re:

[marcushnk]

Quote :
And when it docks in Australia, it will run about 165 meters long by 135 meters wide (and while it will be hard to figure out how it works or what it's doing, it will be brutally violent).

Just what are you trying to say about Australian football?!?! :-P

No doubt, let's get some useful units here

[commodoresloat]

How many cubits is that? And how many libraries of congress can it hold?

American Football or Association Football?

[fantomas]

But which football code are we talking about? The different games have different sized pitches you know... ;-)

Total Cost of Ownership

[ACMENEWSLLC]

TCO is often overlooked.

Take a look at private boats -- sail VS diesel. Sure, sail power is free, right? No. The cost of the sail which wears out, the cost of the lines & riggings. Add it all up and get TCO. Depending on what you are doing, diesel may be cheaper. Especially in commercial applications.

The cost savings in fuel is offset by the cost in the kite, riggings, and management of the kite. The TCO will be interesting to see. I would be surprised if it was any better than a wash in savings.

Re:

[phorest]

We like the cut of your jib!
We have a job for you at careers@" [gartner.com]

What? You forgot the biggest factor

[tacokill]

Don't forget "number of nautical miles traveled" somewhere in your calcs.

It makes a substantial difference where the inflection point is.

What is required of the ship?

[Michael Woodhams]

Could you mount this system on any ship and expect it to work? Or do you (e.g.) need a purpose-designed hull (e.g. yacht-like keel) to resist sideways forces from the kite?

Also, I think you can tack into the wind with one of these. The kite is steerable, so it doesn't have to be directly downwind of the ship. It is just a scaled-up version of kite-surfing. (Tacking travels extra distance, of course, so it might not always be economic to use the kite.)

Waterworld

[Bent Mind]

Though I don't think it was the size of a football field, I remember this concept from Waterworld [imdb.com]. As I recall, the kite gave the Mariner's boat quite a boost.

That'll keep Walmart stocked.

[Ralph Spoilsport]

Now all they have to do is figure out how to get all the crap from the superSail container ship to the store when oil hits $200 a barrel...

RS

Related development

[XNormal]

Makani power [makanipower.com] are planning to generate electricity using high altitude kites - at a cost competitive with coal power.

There's very little information about them for now but they did get a $10M investment from Google. Here [pbs.org] is what Cringely dug up about them from old Usenet posts of one of the team members.

Or better yet why?

[LWATCDR]

Why put them on the sail. What are the odds that the sail will be pointing at the sun... Why put them on the sail/kite at all instead of the ship? Why risk them getting lost if the sail goes into the water or the cable fails? Why try to make the as flexable as the sail so it is easy to store in case of storm or headwinds? The electrical load of a freighter is actually pretty small compaired to the propulsion load. So are you going to carry a big honking electric motor to use make in to an hybrid? If so why care the extra weight and drag on the screw shaft for something you could only use for a few hours each day?

Why not? Because it wouldn't really help in any way and would cost a lot of money.

Re:

[phantomcircuit]

Most large ships are hybrids.

Conventional generator powering an electric motor reduces wear and tear.

Re:

[dbIII]

A couple of reasons. A very large surface area and the ship is probably deisel-electric anyway. Those big honking electric motors are already connected to the propellers.

Even better...

[mangu]

Why not add lightweight solar cells to the top of the kite?

You don't need solar cells at all. Just make both kite and cable conductive. There's an electric potential gradient [google.com] of about 200 Volts/meter in the atmosphere. A kite flying at 300 meters height has a voltage difference of 60 kV with relation to the ship. Of course, the current will be small, but with a surface as big as a football field substantial power could be used.

Re:

[dbIII]

There's an interesting series of SF short stories by Terry Dowling where the characters travel around in vehicles powered by large arrays of solar kites. The stories are collected in "Rynosseros", "Blue Tyson" and "Twilight Beach."

Re:Field?

[Yetihehe]

Football field is a potential field generated by a standard football ball resting in air with temperature 22C and pressure 1013.25 hPa

Re:

[calebt3]

And what is a football?

Re:

[MontyApollo]

An area 120 yards long and 53 1/3 yards wide where American football is played.

Which Field???

[Archangel Michael]

Or better yet, what kind of football field?

Soccer (aka Football everywhere but the US)
American Football
Canadian Football
Australian Rules Football

Re:

[0100010001010011]

No matter where you are in the world, you should have an idea of what a football field looks like. Whether American Football, Football (Soccer to us in the US), Rugby, Aussie Rules or Canadian Football these sports are played throughout the entire world and played on roughly the same sized field. It's an easy visual way of representing how big the kite is. Other things such as Libraries of Congress and VW Beetles may be more abstract and furthermore not every country has a library of congress or got the VW

Re:

[MontyApollo]

I think he was commenting on the use of the word "field" rather than "pitch". In North America we say football field, while I believe the rest of the world says football pitch.

Re:

[calebt3]

Actually, I was making a joke about not knowing what a football is.

Re:What is autopitot?

[TheStonepedo]

They use a pitot-static tube to measure a pressure. By finding the pressure gradient across the kite it can be reconfigured to harness the wind optimally or reeled in if the wind is too strong. The entire process from measurement to reading to adjustment is automated: autopitot.

Re:

[TheStonepedo]

I have no idea, man. I'm glad you understood it. That means a few dozen people got it and the one with the mod points fell for it.

Re:

[ChrisA90278]

"How do you let the kite take to the sky?"

My guess is that you've never been on a sailboat. You'd run the kite up a mast with a halyard. That would get it 60 or 80 feet up in the air and from there the wind would take it. I had a )aprox.) 1,000 square foot spinaker on my boat. You'd be serprized at the power in could generate even in a light breeze. I had some strong 5/8 inch diameter lines on it that would stretch with ever little gust of wind.

So if you could just get the first 1,000 square fiit 60 fe

Re:

[dbIII]

How - a smaller kite. Google Cody and Hardgraves for how they got thair large kites into the air.