What if instead of 9/11, a shipborne IED attack on a major harbour?

[Joku_]

What if al Qaida had commenced a shipborne IED attack on a major harbour, such as Hamburg, Rotterdam or Los Angeles? Assuming a ship loaded with 20 000 tons of ANFO would have made it to the harbour, it would have been approximately equal to the Little Boy bomb.

Just how destructive this would have been to world logistics and economy? I'd imagine that the number of deaths would have likely been smaller than in OTL, but the economic damage would have been larger.

 

[Monk78]

The economic damage was far greater when we had to get involved in 2 wars for almost 20 yrs

I think the terrorists were just aiming for symbolism and body count

 

[Sekhmet_D]

Such an attack would not have achieved the same emotional impact as 9/11.

 

[Gunnarnz]

Such an attack would not have achieved the same emotional impact as 9/11.

Yeah, I think this is the important bit. Destruction to logistics and economy, even if greater in dollar terms, doesn't have the same impact. It's also worth noting that if you want the US to react massively (as they did IOTL), you really need to attack an American target. Hitting Rotterdam or Singapore or something won't cause the same emotional response.

 

[Gillan1220]

Yeah, I think this is the important bit. Destruction to logistics and economy, even if greater in dollar terms, doesn't have the same impact. It's also worth noting that if you want the US to react massively (as they did IOTL), you really need to attack an American target. Hitting Rotterdam or Singapore or something won't cause the same emotional response.

So in that list is always New York or Washington, D.C.

But let's say the AQ attacked New York Harbor instead?

 

[Monk78]

Only thing that tops that is to attack the Statue of Liberty

 

[lionhead]

What if al Qaida had commenced a shipborne IED attack on a major harbour, such as Hamburg, Rotterdam or Los Angeles? Assuming a ship loaded with 20 000 tons of ANFO would have made it to the harbour, it would have been approximately equal to the Little Boy bomb.

Just how destructive this would have been to world logistics and economy? I'd imagine that the number of deaths would have likely been smaller than in OTL, but the economic damage would have been larger.

the problem with this of course is the fact those harbours are huge. Most of them have several sealanes too. So the damage they can do with even such a big explpsion is going to be limited relatively. If they want as much structural damage they can go for a feul depot, moor their ship there and blow it up causing a ton of damage and cleanup. But the casualties will be limited.
They can also go for maximum casualties by for example targetting a cruiseship, but that would cause more international deaths whilst they probably would want to hit the country they target the most. Bu most harbour are not close to any residential areas so the casualties will still be limited.
They can also go for an attempt to block the seaway and cause the harbour to be inaccessible, for a while at least. But like i said most of those harbours have multiple enry and exit points, except for probably Rotterdam. But the question is how much damage you can really do to a seaway with a blast on a ship, even in th 20kt range.

Rotterdam harbour for example has a large reclaimed land area called the massvlakte extended into sea which is used to dock large, deep sea ships and unload containers. blowing up the seaway into Rotterdam is not going to affect the maasvlakte so shiping will continue there and probably be expanded upon as long as the seaway is closed from debris. If they target the maasvlakte then the seaway nito rotterdam won't be affected, so hardly any loss in infrastructure.

New York harbor on the other hand is different matter as residential areas are closeby. On the other hand, terrorists will more likely moor the ship at manhattan island and then blow it up, causing way more damage and casualties than otl september 11. probably even damage the statue and severely damage the WTC, depending on location.

 

[RedSword12]

The problem is that it would be mighty difficult to get a big enough ship, register it, and sail it in chock full of explosives past the naval authorities without arousing suspicion. Security for the operation would have to be airtight, even more than IOTL, and I don't think the feasibility is particularly high. Not impossible; history is replete with examples of the implausible, but it is not likely.

 

[Monk78]

The problem is that it would be mighty difficult to get a big enough ship, register it, and sail it in chock full of explosives past the naval authorities without arousing suspicion. Security for the operation would have to be airtight, even more than IOTL, and I don't think the feasibility is particularly high. Not impossible; history is replete with examples of the implausible, but it is not likely.

It might be more realistic in Lagos , Karachi , Bangkok or Alexandria where you can bribe local officials to look the other way

 

[Joku_]

the problem with this of course is the fact those harbours are huge. Most of them have several sealanes too. So the damage they can do with even such a big explpsion is going to be limited relatively. If they want as much structural damage they can go for a feul depot, moor their ship there and blow it up causing a ton of damage and cleanup. But the casualties will be limited.
They can also go for maximum casualties by for example targetting a cruiseship, but that would cause more international deaths whilst they probably would want to hit the country they target the most. Bu most harbour are not close to any residential areas so the casualties will still be limited.
They can also go for an attempt to block the seaway and cause the harbour to be inaccessible, for a while at least. But like i said most of those harbours have multiple enry and exit points, except for probably Rotterdam. But the question is how much damage you can really do to a seaway with a blast on a ship, even in th 20kt range.

Rotterdam harbour for example has a large reclaimed land area called the massvlakte extended into sea which is used to dock large, deep sea ships and unload containers. blowing up the seaway into Rotterdam is not going to affect the maasvlakte so shiping will continue there and probably be expanded upon as long as the seaway is closed from debris. If they target the maasvlakte then the seaway nito rotterdam won't be affected, so hardly any loss in infrastructure.

New York harbor on the other hand is different matter as residential areas are closeby. On the other hand, terrorists will more likely moor the ship at manhattan island and then blow it up, causing way more damage and casualties than otl september 11. probably even damage the statue and severely damage the WTC, depending on location.

Yes, looks like in Rotterdam you could either blow it up in the inner harbour and cause a nasty refinery while also blasting nearby residential areas and likely closing off the inner parts if other ships get caught in the blast, or you could make a mess of the Massvlakte area, in which case the casualties would likely be relatively minor.

New York harbour is surprisingly compact for a city of that size, but in that case you could instead blow up the Wall Street and half of Manhattan, as you said...

 

[lionhead]

Yes, looks like in Rotterdam you could either blow it up in the inner harbour and cause a nasty refinery while also blasting nearby residential areas and likely closing off the inner parts if other ships get caught in the blast, or you could make a mess of the Massvlakte area, in which case the casualties would likely be relatively minor.

New York harbour is surprisingly compact for a city of that size, but in that case you could instead blow up the Wall Street and half of Manhattan, as you said...

View attachment 815689View attachment 815690

yep, i think the final conclusion we can make is that terrorists with that kind of explosive power will not choose a harbor as a target. Plsu the fact that kind of explosive power is kinda implausible, considering the size of the cargo.

 

[Horton229]

This scenario is similar(ish) to Frederick Forsyth's novel The Afghan, where a ship carrying LPG is used as the weapon.
As @RedSword12 mentioned above, the biggest difficulty with the scenario is getting a ship of sufficient size in position. Even if you can modify a ship, getting it to the right place is going to be hard in todays climate. A questionably registered 20k ton ship sailing towards a major city will raise alarm bells, but I suppose its possible the signs are missed and it gets through.

 

[Aber]

Just how destructive this would have been to world logistics and economy? I'd imagine that the number of deaths would have likely been smaller than in OTL, but the economic damage would have been larger.

Here's the benchmark; 2.9kT
https://en.wikipedia.org/wiki/Halifax_Explosion

EDIT: Don't forget the tsunami it will generate.

 

[Joku_]

This scenario is similar(ish) to Frederick Forsyth's novel The Afghan, where a ship carrying LPG is used as the weapon.
As @RedSword12 mentioned above, the biggest difficulty with the scenario is getting a ship of sufficient size in position. Even if you can modify a ship, getting it to the right place is going to be hard in todays climate. A questionably registered 20k ton ship sailing towards a major city will raise alarm bells, but I suppose its possible the signs are missed and it gets through.

Is 20 kilotons even *that* big for a cargo ship? And why would you need to modify it instead of just loading it with the stuff?

Although now that I think about it, the waters might not be deep enough to sail it right to the beach of Manhattan... Although pre-9/11 climate was probably easier for pulling off shenanigans.

 

[CaptainCalvert]

Here's the benchmark; 2.9kT
https://en.wikipedia.org/wiki/Halifax_Explosion

EDIT: Don't forget the tsunami it will generate.

There's also Beirut, which was a port warehouse explosion rather than a shipborne one. It was estimated to be in the half to one kiloton range, so a bit smaller than Halifax but still a useful reference for what could be expected.

 

[Simon]

Here's the benchmark; 2.9kT

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

A quick Google search suggests that 20,000 tons of ANFO would be equal to 6.2 kilotons, so just over twice as powerful as that. For comparison Little Boy was 15 kilotons, but that was air burst as opposed to ground burst and I do have to wonder about the challenges of detonating that amount of ANFO and attaining its full explosive potential.

 

[Joku_]

A quick Google search suggests that 20,000 tons of ANFO would be equal to 6.2 kilotons, so just over twice as powerful as that. For comparison Little Boy was 15 kilotons, but that was air burst as opposed to ground burst and I do have to wonder about the challenges of detonating that amount of ANFO and attaining its full explosive potential.

No, 20 000 tons of ammonium nitrate would be equal to 6,2 kilotons. 20 000 tons of ANFO, which includes the added diesel fuel would almost be equivalent of 15 kilotons.

TNT equivalent - Wikipedia

en.m.wikipedia.org

 

[lionhead]

No, 20 000 tons of ammonium nitrate would be equal to 6,2 kilotons. 20 000 tons of ANFO, which includes the added diesel fuel would almost be equivalent of 15 kilotons.

TNT equivalent - Wikipedia

en.m.wikipedia.org

so why wouldn't the terrorist try to pack their ship with a more effective explosive like RDX or HMX? They'd need a lot less(half) so a smaller boat. Just a thought though.

 

[Joku_]

so why wouldn't the terrorist try to pack their ship with a more effective explosive like RDX or HMX? They'd need a lot less(half) so a smaller boat. Just a thought though.

More effective explosives are much more expensive, and they are also not a mass commodity used in agriculture, so they would be far more difficult to acquire. Even ANFO in this scale might require some state as a backer.

 

[Horton229]

Is 20 kilotons even *that* big for a cargo ship? And why would you need to modify it instead of just loading it with the stuff?

You might be right. Not sure how big a ship needs to be to carry 20k tons of 'cargo'.
TBH my thinking was clouded by the novel I mentioned above using it as a FAE equivalent, which needed modification. Loading it with explosives does negate the need to change it.