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Comment by dboreham | Hacker News Reader

This seems like a system architecture error. Boats do weird shit sometimes and so bridges need to be deigned to not fall down when a boat crashes into them. Requiring a huge boat to be steered to meter resolution when clearly that's not always going to happen is top shelf stupidity. Up there with backup generators in the basement below the water table.

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My civ engineer friend says that bridges are supposed to have barriers in front of their pylons for this particular reason - in the event of a collision, the barrier would be destroyed but not the pylon.

I can’t find any bridges which have a barrier that can protect against a fully loaded container ship. I have seen plenty of barriers which would protect against personal watercraft and smaller working ships like smaller tugs/coast guard ships/shrimping boats, etc.

But a loaded container ship at 8 knots is not going to be stopped by anything remotely feasible.

Container ships weigh between 50,000 and 220,000 tons. A US aircraft carrier weighs 100,000 tons.

https://en.wikipedia.org/wiki/Dolphin_%28structure%29?wprov=...

If they're designed to stop a bulk carrier then presumably they can stop a container ship.

That article gives an example of being hit by https://en.wikipedia.org/wiki/MV_Summit_Venture

deadweight tonnage of 33,912, gross tonnage of 19,735, and a net tonnage of 13,948.

The one that took down this bridge:

https://en.wikipedia.org/wiki/MV_Dali

Her registered gross and net tonnages are 91,128 and 52,150, respectively, and her deadweight tonnage is 116,851

Many times larger.

Closer than I expected though! It’s possible there are some out there made for this scenario.

The Key Bridge had dolphins but not fenders, some descriptions since the incident have indicated that it has fewer dolphins than some other bridges.

Some bridges have fenders, my understanding is that with existing brudges whether they can be retrofitted, even if resources exists, depends on the channel and the kind of traffic it needs to handle, because they take up soace that can be nontrivial in a tight channel.

They do. I would think that that bridge certainly did as well, it’s part of a busy port. It’s not exactly hard to imagine it happening.

My guess, and it is a total guess, is that the protection on the bridge was nowhere near sufficient for a ship of that tonnage.

I’m assuming it was built to whatever the correct standard was when constructed in the 70s. I’m also assuming the ship weighed far more, or perhaps traveled noticeably faster, than the cargo ships going into the port back then.

Basically I’m guessing it needed an upgrade in its protective barriers but it wasn’t recognized or hadn’t happed if it was.

Top shelf stupidity is thinking a container ship’s momentum can be stopped by normal barriers.

I’ve see pictures of the barriers before the accident and they were there, but they looked like they were tailored to 70s era ships not the container laden ships of today

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