What is the risk though?
Engineers often build buildings for that 100 year storm. Should they build for the 50 year storm to save a buck?
This bridge will likely cost $500 million or more to replace. Over 50 years that is $10 million per year (this bridge was 45 years old). Can we run tugboats for less than that? And that doesn’t account for the economic cost of the port being closed for months while they clear the channel and the costs of clearing the channel.
Penny wise, pound foolish.
There’s a value judgment here that cannot be resolved by debate.
But you are falling into the trap of taking an isolated example of a fortuity as being predictive. It’s a very human thing to do, because this incident is on your mind right now, but it is all sorts of wrong as a way to think about risk.
If your five year old child is killed by lightning does that mean the average lifespan of a person is five years? No that is obvious nonsense, yet it is the same reasoning as you have just used.
Is 50 years the average time this bridge will last before being knocked over by a ship, if ships are permitted to operate as they have been? Yesterday’s incident is no evidence of a long term trend. And when you consider how many bridges there are in the world, and how many ships pass under them day after day, unescorted by tugs, it would seem it is not even close to the average.
Further you are simply ignoring the fact that escort tugs probably wouldn’t have made any difference.
Paper today said 35 major bridge collapses from ship/barge collisions since 1960.
Which is a remarkably low number.
$10M per year is $27,397 per day. I wonder what the extra maintenance, inspection, fuel, and staffing costs are for a couple of tugs to escort ships in/out of the harbor. Also…
Maybe you’d need a lot more than just two tugs if you want a real chance of staving off a disaster, in which case the costs go up even further. And you’d need to do this everywhere in the world where there’s a vulnerable bridge, including places where there hasn’t been a bridge/ship collision for much longer periods of time than this one. The Golden Gate bridge, for example, is now almost 90 years and hasn’t yet been taken down by a ship collision.
That leads me to a horrible thought.
What if whoever was at the con reasoned “we’re gonna hit the bridge, I don’t want to sideswipe it so the ship doesn’t sink in the channel.” And aimed for a head-on impact to save the ship, not considering what it would do to the bridge?
That couldn’t possibly be how this happened, could it?
(I can see the press is reporting the testimony that it didn’t go down that way, and the starboard turn was uncommanded and spontaneous apparently, so please disregard this paranoid fantasy.)
That kind of speculation is fantastic to say the least.
No way. The ship was being piloted by one of the harbor pilots, not the captain. There is zero chance the pilot tried to save the ship by going head on into the bridge.
This video suggests a possible explanation for the turn to starboard.
Based on Moran’s rates (one of the two tug lines in Baltimore) that would cover about two movements per day. They charge $3100 per hour for escorting, two hour minimum, and you’d need two tugs (one on each side) to possibly handle sudden steering emergencies like this.
I couldn’t find good stats on the number of large ships passing under the Key Bridge per day but I suspect it’s more than two. I saw two heading out in less than three hours on Sunday (one cargo ship carrying new powerboats and sailboats, one cruise ship).
There are probably better things we could do for safety with that much money.
Agreed. I’ve already backpedaled it.
Just a regrettable runaway “worst case” speculation on my part. I’m certain the crew and pilots did everything right that they could, but the mechanical failures made it impossible for their intervention to save the situation.
That damnable surprise starboard turn is so puzzling. I guess it was just bad luck to end up pointing the ship at the pier.
(@Dialo_Malison’s video has an interesting insight that the starboard turn could have been the result of interaction with changes in the bottom’s profile, such as the presence of another channel entering into the main shipping channel from the right – changing how the bottom resists the underwater bow pressure wave, for instance).
I doubt it would make any difference in this case.
The ship is so big and the bridge piers so undefended (so to speak) I can’t imagine a sideswipe would be “better” in this case. If that ship touches the bridge the bridge is coming down I’d think.
Also, I read the channel is shallow so I am not sure how much sinking the ship could even do.
In addition to departure, you’d also want to use tugs for arrival. You suspected more than two ships per day, so let’s assume:
that twelve 2-hour escort charges, grand total $74,400 per day. Over 50 years (assuming no inflation adjustment), that’s $1.36 billion.
This Fox story has police audio that wasn’t in the link posted earlier. The dispatcher sounded so bored at first. Yes, they stopped traffic and were trying to clear the workers from the bridge, but it is clear that they thought this was a routine precaution and everything would be back to normal in a couple of minutes.
I am really curious on what failed in the ship. I know aircraft must undergo a failure mode and effects analysis (FMEA) in an effort to identify the most likely failures and determine the results of those failures. (The results of the analysis will drive design changes to ensure redundancy and fail-safe outcomes.) I imagine the standards are must less stringent for ships.
Here is an article specifically discussing the susceptibility of the Golden Gate Bridge (and other CA bridges) to a similar incident:
To summarize: not only are the two towers far more massive than the Key Bridge (and engineered for seismic loads), the north tower is partly on land so a ship would ground well before it reached the tower while the south tower is surrounded by a massive fender (buffer) of concrete and filled with sand, making it unlikely that a ship would even reach the tower.
I will add the fact that the main span of the Golden Gate Bridge is 3.5x the span of the Key Bridge, so there is a lot more room underneath.
A tower of the San Francisco/Oakland Bay Bridge (which unavoidably has towers far from land) was sideswiped by a container ship in 2007, damaging the fender wall but leaving the tower untouched.
The Verrazzano-Narrows Bridge has similar protection around the bases of the towers (and an even wider span). Per the MTA:
The Verrazzano-Narrows Bridge, where the largest ship traffic passes, is a special case in that has a robust rip rap system (rock island around the tower bases) which would cause a ship to run aground before it could do significant damage to the bridge.
I apologize for not reading all 200 posts in case this question has already been asked.
Regarding the MAYDAY that closed the bridge, what is the change of notification? I presume the Maryland state police do not routinely listen to ship radio traffic.
Thanks.
No link or multiple links is the answer: The condensed story was in an email which linked each segment to a different Bloomberg online article.
I’ve seen round structures near bridges in the Arkansas river that would stop a tugboat or a barge, but probably wouldn’t be noticed by a vessel that size running (sailing?) over it.
The ship was reportedly suffering from a “severe electrical problem” while in dock for the two days before the crash. Refrigerated boxes were reportedly tripping breakers, and mechanics were running generators during repairs.
You might have to scroll down a bit for this update: