Container Ship Breaks In Two, Sinks

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."

Comments

Declared underweight?

[Spy Handler]

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...

Re:Declared underweight?

[ron_ivi]

. 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 )

Re:Declared underweight?

[Jaime2]

How do you overload a ship? It has a load line on the side of the hull. If there's too much stuff on it, everyone knows just by looking.

Re:Declared underweight?

[Solandri]

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.

Re:Declared underweight?

[Rockoon]

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.

Re:Declared underweight?

[InvalidError]

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.

Re:Declared underweight?

[dryeo]

Having 2 crew members would have increased the chances the appropriate number of hand brakes were set. Often it is good to have people double checking their work.
Seems that there aren't many regulations on the number of handbrakes that need to be set as well.

Containers are always overloaded

[LoRdTAW]

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.

Re:Great photos

[Solandri]

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.

Re:So do those containers sink or float?

[citylivin]

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

Bromma has a solution

[Animats]

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.

Several possibilities

[Midnight Thunder]

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?