Get more dolphins
Engineers say yeah that’s what happens.
To bridge experts, the collapse of Baltimore’s Francis Scott Key Bridge after being hit by a heavy cargo ship was as inevitable as it was devastating.
When a vessel as heavy as the Singapore-flagged Dali collides with such force against one of the span’s supercolumns, or piers, the result is the type of catastrophic, and heartbreaking, chain reaction that took place early Tuesday.
So maybe take all possible measures to keep that from happening? If you have a setup where massive container ships regularly go toddling under bridges, you’re gonna wanna make sure they don’t go oops on the way through.
No bridge pier could withstand being hit by a ship the size of the Dali, said Benjamin W. Schafer, a professor of civil and systems engineering at Johns Hopkins University. “These container ships are so huge,” Schafer said. “That main span has two supports. You can’t take one away.”
Those ships have grown and grown and grown. Remember the one that got stuck across the Suez canal, blocking shipping for days and days and days? It’s one of the new massive type.
Ian Firth, a British structural engineer and bridge designer, reviewed video footage and said there appeared to be at least two protective objects in the water next to the Key Bridge. The objects, known as “dolphins,” are supposed to protect maritime structures from being hit by vessels. But Dali, the container ship that struck the bridge, appeared to have come in “at an angle,” Firth said, which means the devices were unable to prevent the ship from striking the bridge, sending part of it tumbling into the water.
…
If the Dali had been traveling straight on instead of at an angle, Firth said, it probably would have hit the protective objects. And if there had been three or four vessel-protection objects around the bridge, the outcome might have been different, Firth said, adding that he expects lessons will be learned from Tuesday’s tragedy.
Firth noted that the bridge, which was built in 1977, was erected at a time when ships were not as big as they are now and the flow of traffic was not as busy. These days, structures are designed with better protective measures in place, he said, though he noted that even a brand-new bridge would have “come down in the same way” if it were hit by such a large vessel traveling at speed.
So make sure they don’t do that.
I’m wondering about the role of tugboats. One of their purposes is to keep larger vessels from crashing into things.
Schafer, who said he used to teach about the bridge in his Johns Hopkins classes since it was “one of the signature bridges of Baltimore,” called the collision “a huge infrastructure failure,” but not because of the bridge collapse. He said the shipping industry needs systems to keep a ship on track when it loses power.
Why yes. Fork out for some tugboat assistance when you have bridges to go under.
That idea occurred to me also. However, the only way we can all, individually or collectively, lead totally risk-free lives (of whatever duration) is to completely refrain from getting up out of bed, and to lie there prone awaiting death by thirst or starvation. Learning to crawl as ever-curious babies has its risks, which resulted in the invention of devices like the play-pen. And the transition to being a toddler risks frequent falls; unavoidably.
Such accidents as the Dali are a problem created by technology, and so there are probably technological fixes; each one with a price tag.
This Dali is big enough to bring down bridges; which latter cannot be easily replaced. Its container load is stacked as high on its deck as possible. And the international trade which demands such ships is a ‘good’ in it own right. Anyway, there are now far too many people in the world for us to revert to hunter-gatherer or subsistence economies, even if we wanted to.
The only technological fix that I can think of is to cut slots in the continental sea coasts, each big enough to hold the biggest container ship, and require the bridge-wrecking super-sizers to park in those in order to load and unload. Each slot could be fitted with sea-doors, like the lock-gates on the Panama Canal, and once parked, the ship could be raised hydraulically away from the at times stormy sea.
Such a fix would, of course, entail problems of its own. But the main problem is that rivers, bridges, ships and vehicular traffic are one helluva combo.
Tragically lives were lost this time. Several (thankfully now scrapped) older ships I worked on had power failures when arriving or leaving port. In all instances, the crew were able to react: anchors readied, tugs called and alerts broadcast.
Bar banning ships going near pillared bridges, this sadly will happen again, or another disaster in a harbour.
Calling for tugs is the most obvious answer but there are problems with that.
Tugs have three main drawbacks: they can be very slow; not big enough to alter a massive ship’s course if the ship is moving quickly; be very to expensive to hire. Most docking or harbour pilots dismiss the tugs as quickly as possible to keep costs down. Many times a pair of tugs would move from ship to ship, as there were only a handful in that port. In the USA in particular the tugs were of WW2 vintage in too many ports and not that reliable. Some countries insist on tugs all the way down a bouyed channel. Others, only on final approach to the berth.
If the Dali lost power like this, I am wondering why. Modern ships have several generators, and in some cases these can be used to turn the propellor shaft motors. Was the Dali using what is called ‘shaft generator’ in harbour? This is were the main prop shafts are used as dynamos; efficienet but only done when the ship is at full speed and off shore.
By the way, the Dali is not that big: at 300m and 95,000 tonne displacement, would be considered a medium sized ship, used for smaller ports (Colombo or Savanah for example). There are much, much bigger boxboats out there.
I was watching the footage again recently and it struck me that the power losses onboard the ship are blamed for the collision, but it’s trajectory was already alarming, and ships like that don’t turn fast or easy, I thought. It seems to me that saying the power outage was responsible was rather like saying the issue with you hitting the shop was the brakes when you’re already driving on the sidewalk. I thought a ship like that would be aimed squarely at the centre of the bridge, and nowhere near either bridge support.
Yes I wondered about that too. There was a graphic of the planned route and what actually happened in one news story I saw and the planned route itself looked bizarrely too snuggly with the bridge.