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Computer-Controlled Cargo Sailing Vessels Go Slow, Frugal
An anonymous reader writes "Big container ships are taking it very slow these days, cruising at 10 knots instead of their usual 26 knots, to save fuel. This is actually slower than sailing freighters traveled a hundred years ago. The 1902 German Preussen, the largest sailing ship ever built, traveled between Hamburg (Germany) and Iquique (Chile): the best average speed over a one way trip was 13.7 knots. Sailing boats need a large and costly crew, but they can also be controlled by computers. Automated sail handling was introduced already one century ago. In 2006 it was taken to the extreme by the Maltese Falcon, which can be operated by one man at the touch of a button. We have computer-controlled windmills, why not computer-controlled sailing cargo vessels?"
The other story of the 20th Century was "Just-In-Time", which meant reserves and stockpiles have been kept as low as feasible. That would be another factor limiting acceptance of sail - we'd need larger stockpiles to ride out any delays. Honestly though, with satellite imaging, and computer control - there's no real reason sail travel should be any less controllable and predictable than using fossil fuels. And at the speeds involved, there wouldn't even need to be any major code to do image processing and interpretation on the ship itself (though with the computer needed to handle the rigging, and the need to monitor against potential collisions, should be enough to actually do the planning on ship... but coordination would be better from a central site and general directions relayed via satellite.)
Neither computers nor crews pilot vessels into harbours. Harbour pilots do.
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Yeah... Let's send robot ships out there to travel to a port and then wonder WTF happened when it doesn't arrive... Did the scurvy pirates get it or did it drift off course or did it sink?
If only they could invent some type of Global Positioning System. I can see it now... you would need a couple dozen or so satellites to ensure coverage over the planet. They would broadcast some type of signal. Then all you would need is some type of devices to read the signal from two or three of these satellites to get a 2D or 3D positioning.
*runs off to patent office*
See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
I'm sorry Dave, I can't let you do that.
SkySail: using the a computer controlled parasail to improve fuel efficiency. Article http://www.popularmechanics.com/outdoors/boating/4235055.html
The unreliability of sail is an issue, though. I think we'll see "hybrid" shipping becoming more common -- kite sailing when the wind is favorable (or perhaps kite-assisted), fossil fuels when it is not. This will reduce costs & environmental impact, a nice combo.
Here's a discussion we had previously on kite-assisted shipping.
"Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
Its not just about fixed scheduling, its about weight and economies of scale. Sails are no longer viable with the size of the ships transporting cargo. The smallest ship I've dealth with holds 300 20ft containers with an avg weight of ~30,000 lbs. Some can be loaded with over 200 million pounds of cargo. I don't even think we have the materials developed to make sails for those physically possible.
The only practical application of sails for cargo ships is augmenting the engine, which we've seen before here on slashdot (too lazy to find the link).
"Dear mister pirate. This ship is equipped with 'ROMG'. This stands for remote operatable machine guns.
Way too messy. If the computer had the ability to control the ventilation system and hatch locks, the computer could lock them inside. That is when the nerve agent would be released. Post the video of those bastard's slow, agonizing death on YouTube. That would make them think twice about jacking ships.
I don't expect sail power would scale to the size of modern container ships.
Sure, a sail array may not be the best solution for getting a container ship underway from a standstill, but once the ship reaches open ocean, and a course is set, sails can be used to replace some of the engines' thrust, saving fuel.
Considering that container ships consume 100-400 metric tons of fuel per day, even a 5-10% savings would be pretty damn significant.
(Of course, 100-400 is a very broad range - the 4,250-TEU Arafura consumes ~65 MT / day, while the 11,000-TEU Emma Maersk chows down on 350 MT per day, so yeah, YMMV).
Marine Diesel is about $ 420-450 per metric ton right now.
As an intellectual exercise, let's take a 6,000-TEU ship consuming 100 MT/day, making the Shanghai-Long Beach run at express speed (15 days), and let's take the cost of MDO at $ 435.00 per metric ton.
At 5% savings, the sail array will save $ 2,175 / day. Multiply by 15 days = $ 32,625 saved per trip.
To put this into even more of a perspective, the average lifetime of a container ship is 27 years. Assume it's running 75% of the year. (27*365)-25% = 7,391 days. Take $ 2,125 saved per day * 7,391 days = $ 15,705,875 saved.
Is $ 15.7 million enough to pay for the sail array + computers? Seems like it to me.
Dependable schedules are one reason, the other big reason is that sails interfere with loading and unloading the boat.
Modern shipping extensively uses cargo containers that are rapidly loaded and unloaded using cranes. This advance has drastically lowered the per-unit costs of shipping freight in the last half-century (check out the book "The Box" for more details).
If adding sails makes it difficult to use a crane to unload containers from the deck of a boat (likely, imo), then it would make the per-unit cost of shipping skyrocket.
Cargo ship speeds go up and down with the costs of ship charter and fuel, and with the demands of customers. Read "The Box", a history of shipping containers and the ships that move them.
Right now, the Baltic Dry Index is down to where it was around 2000, after a huge 5x spike last year. So there's a huge glut of available container ship capacity, charters are cheap, and freight rates are way down. So operators have to optimize for low cost at the expense of speed and throughput.
There's also no big demand for speed from the customers. Much of what's being shipped is going into storage anyway. Unsold cars are piling up near ports, filling up storage and spilling over into rented parking lots. That's presumably happening with containerized commodities too, in cases where the buyer can't just cancel the order.
It's one of those things that happens in a depression.
You can not move forward by capturing energy being used to push you backwards. To move forward would require more than 100% of the energy that you're capturing. It doesn't work.
Those numbers only work when your personal interest rate is 0, which is rarely the case.
Realistically, you need to adjust for the time value of money. ($100 now is worth more than $100 27 years from now, as I could make interest off of it)
So, if we assume that the savings are every month, with a 3% interest rate compounded monthly, we'd have (12x27) payments of about $49,617 each with 0.25% interest per period:
PV(A) = (49_617 / 0.0025) * ( 1 - (1 / 1.0025**(12*27) ) )
Which works out to just over $11 million. The install cost would have to be less than this, to deal with the reoccurring costs of maintenance of the new system.
Oh ... and if the interest rate were 6%? That $11mil estimate would be cut to under $8mil, or about 1/2 of your estimate. In a good market where we might be able to make 18% return, over 27 years, it's worth less than $3.3M.
Now, I don't know how much container ships cost, but if I can add another ship and move more containers, that may give me a better benefit for the same cost.
(and, I know you later said that the actual savings were higher -- but the point is, you should _never_ just multiply reoccurring costs or savings by the number of periods to get the equivalent present value, especially for periods of years.)
Build it, and they will come^Hplain.
Some moron did the article. A moron who has never been to sea, obviously.
I challenge any weekend warrior to find me any cargo ships that make 26 knots, anywhere, today, last year, or last decade. In an emergency, a FEW of them might make that kind of speed, but they can't sustain it day after day, like naval ships can. A blown boiler is sure to ruin anyone's day.
Warships didn't even make a habit of running that fast, 30 years ago, when fuel was cheap. The first time I crossed the Atlantic, I asked "How long?" like any kid in the back seat of a car, on a long trip.
The answer: "We can be in Portugal in 5 days, if we burn x gallons per minute, or we can be there in 11 days, if we burn y gallons per minute. So, we'll be there in 11 days."
The destroyer I served on was capable of doing about 35 knots (officialy 30+) and we could catch ANY commercial freighter, tanker, container ship, or whatever.
IF, and I say IF, cargo ships were capable of 26 knots as the article says, THEN, they would be transiting the hi danger piracy zones at that speed, and the pirates wouldn't be catching them.
Many 19th century sailing ships could routinely take most commercial traffic in a race, even BEFORE companies started slowing down to conserve fuel. Revisit the sailing times for ships such as the Cutty Sark, then look at the sailing times for today's tankers and container ships. Real sailing times, not "best case scenario with favorable winds" sailing times. ;)
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