Slashdot Mirror

← Back to Stories (view on slashdot.org)

Container Ship Breaks In Two, Sinks

Posted by Soulskill on from the how-not-to-ocean dept.

Cliff Stoll writes "Along with 7000 containers, ship MOL Comfort broke in half in high seas in the Indian Ocean. The aft section floated for a week, then sank on June 27th. The forward section was towed most of the way to port, but burned and sank on July 10th. This post-panamax ship was 316 meters long and only 5 years old. With a typical value of $40,000 per container (PDF), this amounts to a quarter billion dollar loss. The cause is unknown, but may be structural or perhaps due to overfilled containers that are declared as underweight. Of course, the software used to calculate ship stability relies upon these incorrect physical parameters."

29 of 361 comments (clear)

  1. Declared underweight? by Spy+Handler · · Score: 5, Interesting

    so they operate on an honor system?

    One would think they'd weigh the container themselves and charge accordingly. But then I'm not in the shipping business so I dunno...

    1. Re:Declared underweight? by Qzukk · · Score: 4, Insightful

      because the shipping company doesn't worry at all about overloaded containers or ships at all.

      Why should they? They're insured.

      --
      If I have been able to see further than others, it is because I bought a pair of binoculars.
    2. Re:Declared underweight? by Anonymous Coward · · Score: 4, Informative

      It was my understanding that the cranes weigh each container as they are loaded on the ship. This is done because they can't afford mistakes in calculating the center of gravity of the ship. There is no honor system.

    3. Re:Declared underweight? by mrchaotica · · Score: 5, Insightful

      I think a quarter-billion dollar claim might cause the insurance company to raise their premiums just a tad...

      --

      "[Regarding the 'cloud,'] ownership was what made America different than Russia." -- Woz

    4. Re:Declared underweight? by Trepidity · · Score: 4, Insightful

      Hell, +/- 1000 pounds would probably be good enough, and even that might be more sensitive than actually needed. A typical shipping container weighs on the order of ~30,000-50,000 pounds (~15,000-25,000 kg). A ship isn't going to sink because a declared-as-40,000 lb container was actually 40,050 lbs. Even if a company loading 1,000 containers systemically mis-declared by 50 lbs and they all got loaded in some asymmetrical way, that'd still only be a 50,000 lbs error, equal to about one shipping container. A modern cargo ship is not going to sink because of an asymmetric load, or an over-load, equal to one shipping container.

      If underdeclaring weight became a stability problem sufficient to sink the ship, my guess is that a substantial number of the containers were reporting numbers way off the real values.

      --
      10 PRINT CHR$(205.5+RND(1)); : GOTO 10
    5. Re:Declared underweight? by Q-Hack! · · Score: 4, Insightful

      You don't think the insurance company might have a problem with this? If the shipping company was insured, the insurance company will eventually step in and demand the shipping company fix the issue or start denying claims. If the shipping company wasn't insured, well... they end up going out of business. Either way, the problem is self correcting over the long term.

      --
      Some days I get the sinking feeling Orwell was an optimist.
    6. Re:Declared underweight? by Jaime2 · · Score: 4, Informative

      Perhaps they could paint a line on the side of a large vessel floating in water and see if the containers displace enough water to submerge the line. Oh wait, that's what they do with all container ships. It's impossible for the whole ship to be over weight. It is possible to have a poorly distributed load, but that's not likely to cause the type of accident that happened here (it would more likely lead to capsizing).

      Overweight containers are more of a financial issue than a safety issue. Leaving 500 containers on the dock or leaving under-loaded are both bad for business.

    7. Re:Declared underweight? by ron_ivi · · Score: 4, Interesting

      . If the shipping company wasn't insured, well... they end up going out of business.

      Wonder the corporate structure of those companies.

      Could they run each ship as an independant-but-almost-wholy-owned company and send just that not-quite-subsidary through bankrupcy, pushing the losses to other people? (kinda like the games it seems Cerberus did with GMAC & Chrysler Financial )

    8. Re:Declared underweight? by Anonymous Coward · · Score: 5, Funny

      Perhaps they could paint a line on the side of a large vessel floating in water and see if the containers displace enough water to submerge the line.

      Eureka!

    9. Re:Declared underweight? by Beardo+the+Bearded · · Score: 5, Informative

      Moments, how do they work?

      If you load the shit out of the topmost containers, it gets tippy as fuck. As an example of "huh", there's a thing that's going on the mast of a ship that I've worked on. The thing doesn't weigh that much -- although it's being loaded by crane, I could lift it by myself.

      To compensate, way more ballast than I can lift is going in the hull.

      --

      ---
      ECHELON is a government program to find words like bomb, jihad, plutonium, assassinate, and anarchy.
    10. Re:Declared underweight? by sjames · · Score: 4, Informative

      Many cranes DO have a scale built in. 250,000 Kg capacity accurate to 50Kg. That should do the job.

    11. Re:Declared underweight? by Solandri · · Score: 4, Interesting

      The containers don't magically appear next to the crane for loading onto the ship. They have to be lifted off of trains or trucks which bring them to the docks. Then they sit and wait for the ship to arrive and be unloaded. Then they're loaded onto the ship. It'd be trivial to weigh them when they're first taken off the train or truck.

      A more prone failure point is corruption among the dockyard workers - they get bribed to ignore that a container is overweight. This used to be common at airports before 9/11 and before they started charging for every checked bag. If you had an overweight bag which the airline would charge $75 for, you simply went to curbside checking. Slip the airline employee there a $20 and he'd tag it as if it were a regular bag. I was shocked the first time I saw my uncle do it (for a Delta flight at LAX), but the employee was blase about it as if it were normal. And now that I knew what to look for, I saw it happen several times in the few minutes I was there.

    12. Re:Declared underweight? by Rockoon · · Score: 5, Interesting

      The *rational* thing to do is make sure your ships are safe so that you don't waste a quarter billion dollars.

      It is almost certainly the case that the insurance companies already factor in the risk of overloading, because they've been insuring these ships and their cargo for a long time. I don't see anyone suggesting that overloading (or incorrectly loading) ships is something new. The insurance companies are armed with actual numbers that go back literally centuries to the East India Company and so forth.

      The ship sank. Its not an indicator of a failure of free market, nor is it an indicator that the insurance company isnt assessing the risks correctly. Its just an indicator that that particular ship at that particular time experienced a structural failure leading to its sinking.

      In all likelihood, the amount of oversight, construction rules, and so forth on the shipping industry is already very near optimal from a cost/benefit viewpoint.

      --
      "His name was James Damore."
    13. Re:Declared underweight? by ebno-10db · · Score: 4, Insightful

      The theory about self-regulation works just fine. It just doesn't stand up so well, when governments step in and bail out the industries and or insurance companies.

      Then I guess it worked real well in the 19th century, when governments didn't step in and bail out the industries and or insurance companies. Except it didn't.

      Oh, I know, I know! It works in the Platonic ideal of a libertarian paradise! To the extent that it doesn't work in our reality, it cannot not mean that there is anything wrong with the theory. Rather it must mean that we've deviated from that ideal world in some way, and must pay for our sins.

      Libertarianism: being based on axioms, how can it be wrong?!

    14. Re:Declared underweight? by ebno-10db · · Score: 4, Insightful

      Thank you for listing the ways in which self-regulation doesn't work. If it worked, then all those penalties should have been more than enough for them not to be so careless with the ship. The idea of regulation is to prevent problems, not to factor into some after the fact "they'll pay their dues" calculus.

    15. Re:Declared underweight? by evenmoreconfused · · Score: 5, Informative

      The usual tariff is based on a concept called "weight-measure", which works like this:

      - For cargo less dense than water, a given tariff is per cubic meter.
      - For cargo denser than water, the tariff is per metric ton (one cubic meter of water weighs one metric ton).

      If you think about it, this makes perfect sense, because anything heavier than denser than water has to be accompanied by enough air (i.e. empty space inside or outside the container) to make the average density of the shipment equal one, and anything lighter than water takes up just as much space in the ship as heavier cargo would. The result is that if you have e.g. a 2000 TEU ship, and each TEU is 35 cubic meters, a full ship will always generate 70,000 tariff units, whether it be laden with cotton candy or iron pellets.

      Of course, shipping companies play both ends against the middle and can, with optimization, get better than 100% billing (e.g. by using fluffy stuff like household goods to provide the airspace needed to compensate for containers full of car engines).

      In a previous incarnation I was a Systems Designer at a major container shipping company.

      --
      No. Well...maybe. Actually, yes. It really just depends.
    16. Re:Declared underweight? by InvalidError · · Score: 4, Interesting

      But the insurance company needs to prove that first.

      Until they cross-reference the claims with shipping weight and account for everything that was supposed to be on-ship, the overweight thing is only allegations.

      And frankly, if a ship can be sunk by a few dozens or even a few hundred overweight containers, you have a serious structural or stability problem considering the huge margins that need to be built into ships to accommodate the relentless bending stresses from rolling waves. I would not be surprised if metal fatigue turned out to be the root cause and in that case, overweight containers would merely cause the inevitable to occur sooner.

      As far as weight goes, cranes should be monitoring their motor torque (force) and container acceleration when pulling up. This would let them estimate weight somewhat accurately which should prevent major abuse. Since most shipping incidents involving overweight trains/containers have overloads exceeding 100%, +/- 20% accuracy at the crane would already go a long way towards preventing overload-related incidents.

    17. Re:Declared underweight? by serviscope_minor · · Score: 4, Funny

      Can you now explain to me how, in this case, the 'load line' did its job?

      Well, if the load line is horizontal, things are generally OK. If it's vertical like in the pictures, then your ship is probably sinking.

      Therefore if the load line reaches vertical you might want to consider taking some action, and certainly not just sailing off.

      --
      SJW n. One who posts facts.
  2. the front fell off by johnsnails · · Score: 5, Funny

    https://www.youtube.com/watch?v=WcU4t6zRAKg

  3. Why two? by sgt+scrub · · Score: 4, Funny

    Why can't ships break in three or break in four even? I mean really. What ever happened to creative engineering?

    --
    Having to work for a living is the root of all evil.
  4. Re:So do those containers sink or float? by dk20 · · Score: 5, Informative

    oddly enough there are special rules around this: http://en.wikipedia.org/wiki/Maritime_salvage

  5. Should've just paid the ransom by AEton · · Score: 5, Funny

    I guess the Da Vinci virus wasn't playing around. Bummer.

    --
    We recently had heard in the office over one of the Yellow Machine that's made by Anthology Solutions.
  6. Re:Tough ship by 0123456 · · Score: 4, Funny

    The forward section stays afloat for over three weeks before it bursts into flames before sinking.

    Was it carrying a 787 as cargo?

  7. Containers are always overloaded by LoRdTAW · · Score: 4, Interesting

    Family friend is a retired truck driver who frequently picked up and delivered containers out of the new jersey ports. One story he told me was he had to pick up a 40 footer and was sent in a single axle tractor. They have scales and you weigh out when you leave the port. He scaled out at almost 90,000 pounds (40,823kg)! For a tractor trailer in the USA, that is 10,000 pounds (4,536kg) overweight. The kicker? The container was supposed to weigh only 40,000 pounds, nearly half of what it weighed. He said they were frequently overweight and it wasn't uncommon for containers to be thousands of pounds over what the paperwork listed.

  8. Re:Great photos by Solandri · · Score: 4, Interesting

    For anyone unfamiliar with the terminology, hog is when a wave crest is at the center of the ship and both ends are in troughs. The ship's entire weight is supported by the midsection, with the two ends hanging as cantilever (unsupported) beams. It's one of the extremes marine engineers design ships to withstand (maximum moment), unsuccessfully in this case.

    The opposite is sag, where wave crests support the ends and a trough in the middle leaves the center unsupported.

  9. Re:So do those containers sink or float? by citylivin · · Score: 4, Interesting

    Some float, some sink. 10000 are lost during normal shipping every year. The ones that float tend to float a few feet under the top of the ocean. Making them extremely hazardous for other marine traffic.

    For years they have been trying to get all shipping and container companies to equip the containers with a kind of water permeable valve, but I think last time i read about it there was some resistance. Can't find any good articles about it though. Comes up every few years.

    http://webecoist.momtastic.com/2011/04/19/deep-cargo-an-ocean-of-lost-shipping-containers/

    http://en.wikipedia.org/wiki/Containerization#Loss_at_sea

    http://science.slashdot.org/story/11/04/06/0158207/10000-shipping-containers-lost-at-sea-each-year

    --
    As a potential lottery winner, I totally support tax cuts for the wealthy
  10. Bromma has a solution by Animats · · Score: 4, Interesting

    Bromma, which makes the "spreaders" which grab containers at 97 of the top 100 ports, now offers a solution. Their newer spreaders weigh the container as it's being lifted on to or off of the ship. Accuracy is within 1%. The container crane knows where the container is being placed on the ship, so weight and balance information for the whole ship is collected.

    It's being installed in Los Angeles now, London next, and can be retrofitted to existing Bromma spreaders. So there's a technical fix to this almost in place.

  11. Hogging by M0HCN · · Score: 5, Insightful

    It looks to me more likely the problem was excessive weight at the bow and stern rather then midships, the effect is called hogging and is a known way to snap a container ship (or oil tanker) in half, both have occured in the past.
    Basically the keel (The BIG beam running all the way from bow to stern down the bottom of the hull) can only take so much sheer stress and if the weight distribution does not match the localised boyancy implied by the current displacement you can very easily bend the ship.

    If and how it came to be loaded that way will be one of the things on the investigators list.

    There is of course software used to look at this stuff but it cannot realistically be run on the dock during a very tight turnaround, so the declared weights are used as the only data available in advance of starting loading. Not only does that mess of linear algebra have to give a fully loaded ship with the centre of mass and moment of inertia in the right regions (Important for stability and handling), it must also ensure that the total cargo mass per linear meter is roughly the same as the boyancy of that meter of wetted hull at all times during the loading.

    Further shippers will sometimes pay a premium for say not having a can of high value goods put in a corner on top of a stack where it is somewhat more likely to be lost, and some of those cans may be 'reefers' (Refridgerated containers) requiring both power and ventilation to remove waste heat, the problem swiftly becomes complex, doubly so as the ports stacking order also feeds into this if you want loading to go smoothly.

    A nasty accident, but nobody died, and the hull and cargo will have been insured, so a better outcome then is sometimes the case.

    Hope that explains why it is not just about total weight.

  12. Several possibilities by Midnight+Thunder · · Score: 4, Interesting

    I can imagine a few other issues:
        - load not being consistent from aft to stern
        - a rogue wave (though I didn't see any mention of it)
        - buoyancy change due to an area of reduced salt density
        - a structural defect

    There are all sorts of factors and until a complete investigation has been done, we are only dealing with imagined possibilities. In the case of inconclusive evidence, I would imagine proposals for avoiding this in the future would be based on most likely cause?

    --
    Jumpstart the tartan drive.