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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?"
Neither computers nor crews pilot vessels into harbours. Harbour pilots do.
UNIX/Linux Consulting
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.
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).
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.