For anyone who is as interested in this as I am, the NY Times has done a really good set of illustrative examples of both the size of the Dali (a Neopanamax) and also of various bridge “bumpers” and other deflective measures, for those of us who cannot easily visualize them.
I have to add that honestly, given the size of the Dali, all the efforts to stop it that were attempted, including the dropped anchor that did not even slow it, IMO the only barrier sample shown in the first article that might have kept the ship from hitting the bridge support would be the rock islands and numerous concrete bollards surrounding the Sunshine Skyway Bridge in Tampa – and that bridge only got them after it got hit. The one shown in the picture is the rebuild of the one that got hit and collapsed, killing 35 in 1980. Hence the massive protective features.
How far the bow of the Dali was vertically above the waterline when it hit, and how far the bow was horizontally from the hull at the waterline when it hit, are questions I have not yet seen answered. So it is entirely possible that the the angle on the bow of the Dali between the deck and the waterline would have presented a protrusion that might have simply sailed over any water-based protections, and that plus the sheer size of the ship would have resulted in the same outcome even with such measures in place.
I honestly don’t know, and don’t pretend to. And certainly the protection that is never installed is going to fail 100% of the time, which is where govt (city, state, and fed) screwed up no matter which way you slice the rest. But I do not think it’s nearly as simple a question as it’s made out to be, nor that just any old bridge fender or bumper currently in use would have been able to keep the bow of the Dali, or any equally supersized ship with a protruding bow, from completely destroying the Francis Scott Key bridge support as it did.
This one deals with the sheer amount of force involved in the Dali pylon strike, estimates ranging between 12 million and 100 million newtons. It’s absolutely fascinating for geeks like myself, not that there’s anyone else like that in this community, no, of course not:
Our lowest estimate of how much force it would take to slow the Dali, if it were fully loaded, is around 12 million newtons, about a third of the force it took to launch the Saturn V rocket for the Apollo moon missions.
And our higher-end estimates, reviewed by several civil engineering experts, suggest it is realistic to put the force of the impact with the pier at upward of 100 million newtons.
The article then goes through a number of equations, tables and illustrations, then concludes:
Our own calculations are also an oversimplification. We don’t try to account for the ship’s rotation, the angle of the collision, and exactly how and where it collided with the pier (a smaller force applied in the wrong place can be more damaging than a large force applied elsewhere). The container ship would have also dragged a sizable amount of water with it, which would add its own momentum.
But the point is: Even the widest reasonable range is on the order of tens to hundreds of millions of newtons — a mind-bogglingly large force, by any estimate.
For anyone who is as interested in this as I am, the NY Times has done a really good set of illustrative examples of both the size of the Dali (a Neopanamax) and also of various bridge “bumpers” and other deflective measures, for those of us who cannot easily visualize them.
How Fenders Might Have Protected Against Bridge Collapse - NYTimes
archive link
The Dali Is a Big Ship. But Not the Biggest - NYTimes
archive link
I have to add that honestly, given the size of the Dali, all the efforts to stop it that were attempted, including the dropped anchor that did not even slow it, IMO the only barrier sample shown in the first article that might have kept the ship from hitting the bridge support would be the rock islands and numerous concrete bollards surrounding the Sunshine Skyway Bridge in Tampa – and that bridge only got them after it got hit. The one shown in the picture is the rebuild of the one that got hit and collapsed, killing 35 in 1980. Hence the massive protective features.
How far the bow of the Dali was vertically above the waterline when it hit, and how far the bow was horizontally from the hull at the waterline when it hit, are questions I have not yet seen answered. So it is entirely possible that the the angle on the bow of the Dali between the deck and the waterline would have presented a protrusion that might have simply sailed over any water-based protections, and that plus the sheer size of the ship would have resulted in the same outcome even with such measures in place.
I honestly don’t know, and don’t pretend to. And certainly the protection that is never installed is going to fail 100% of the time, which is where govt (city, state, and fed) screwed up no matter which way you slice the rest. But I do not think it’s nearly as simple a question as it’s made out to be, nor that just any old bridge fender or bumper currently in use would have been able to keep the bow of the Dali, or any equally supersized ship with a protruding bow, from completely destroying the Francis Scott Key bridge support as it did.
Just saw another great article in the same series, here’s a gift link (article unlocked):
Force of Ship Impact Was on the Scale of a Rocket Launch - NYTimes
This one deals with the sheer amount of force involved in the Dali pylon strike, estimates ranging between 12 million and 100 million newtons. It’s absolutely fascinating for geeks like myself, not that there’s anyone else like that in this community, no, of course not:
The article then goes through a number of equations, tables and illustrations, then concludes:
Well worth the read, for anyone interested.