Studying the Impact of Lost Shipping Containers 236
swellconvivialguy writes "Looking at a picture of the world's largest container ship, it's easy to visualize how 10,000 containers fall overboard from these vessels every year. Scientists from the Monterey Bay Aquarium Research Institute are now undertaking the Lost Container Cruise, an attempt to gauge the effects of shipping containers lost at sea by studying a tire-filled container, which marine biologists discovered in the Monterey Bay National Marine Sanctuary. (The research [PDF] is being funded by a multi-million dollar settlement with the operators of the Med Taipei, the ship that lost the cargo.) The work is not unlike studying a deep water shipwreck: Use robotic submarine to take pictures and collect sediment samples; repeat."
Re:Can't they tie them down? (Score:5, Informative)
Re:Can't they tie them down? (Score:5, Informative)
Except for steel railings, the shippers do everything you have mentioned. The reason for no railing is that the containers themselves are the structure and they are stacked far above the hull of the ship.
Here is the tie down that goes between the containers http://www.tandemloc.com/0_securing/S_AD54000A.asp [tandemloc.com]
Here is a picture of the lashing used http://www.flickr.com/photos/blueship/137784714/ [flickr.com]
Re:Can't they tie them down? (Score:5, Informative)
Loading order (Score:4, Informative)
The article should really look a bit into why container ships are loaded the way they are. The article contends, with no fact to support this contention, that one of the issue is that heavy containers that are loaded high on the sip are a major cause of the issue. Their solution is to load heavy containers first. Lets look into what would be required to do this feat.
1a. Every time a container come it it would be sorted by size so that the large one would be easily accessed first.
Issues:
containers come in one at a time over quite a long period of time. what happens if many light ones come after all the heavy ones? The heavy ones get burried.
1b. Alternately, sort the containers before they are loaded.
This would require more space and handling each container at least one additional time.
Lets assume that all the heavy containers are in the bottom of the ship. The article neglects the fact that container ships usually make more than one offloading stop. They are currently loaded so that the containers can be unloaded at each stop while still maintaining the balance of the ship. If the heavy containers are at the bottom, it would require unloading containers above the heavy containers, unloading the heavy containers and re-loading the light containers. This takes time and space.
Every minute a container ship is tied up at a dock costs money. The sorting and excess loading/unloading take time. Most ports are also very crowded and do not have the space required to do the sorting of containers to make sure heavy containers are loaded lower. There is also a limited number of berths for container ships. The longer a ship is in port means fewer ships can be loaded and unloaded by that port.
One final point, everything breaks. Even light containers go overboard. A perfect example is the container full of tires. Compared to shipments such as metals, tires are relatively light but a container full of them still went overboard. Given rough enough water even an empty container can break loose.
Here are some of the parameters that container loading software uses to place containers on a ship.
the weight of each container being handled
which port each container will be unloaded at
if the container is refrigerated, and needs to be plugged in during the voyage
if the container’s contents are hazardous, as these could be potentially explosive if placed next to a refrigerated container
advising Customs of the ship’s arrival and reporting the cargo on board
the order in which the containers will be loaded and unloaded.
A lot of science goes into the efficient loading and unloading of containers; sorting by weight is taken into account but not the overriding consideration.
Re:Can't they tie them down? (Score:5, Informative)
I worked at a container terminal while putting myself through university, many years ago. This is why those containers in the photo are still stuck together...
A device called an intermodal box connector (AKA "IBC", a hefty steel pin with a twistlock mechanism) is used to connect containers to each other. They fit into holes (four on the top, two on the bottom) on the corners of the container.
This is the usual method for loading and locking them together: A container is dropped onto a ship and locked down (via IBCs welded to the deck). Then, four IBCs are placed in the top holes of the container and another container is lowered. The IBCs slide into the four holes on the bottom of the new container and their twistlocks are turned. No chains are required. For extra safety, some companies erect a steel scaffold/frame around the outside of a block of containers to keep them from swaying in rough seas. Otherwise, the IBCs are the only things holding the containers together.