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View Full Version : Could terrorists sink an Aircraft Carrier? Is it within the realm of possibility?


astro
03-31-2004, 11:59 AM
Could scuba divers approach an aircraft carrier from underneath without being noticed and plant an explosive on the hull at a vulnerable point? Could you crash an airliner into one 9-11 style or would jets intercept you?

Larry Mudd
03-31-2004, 12:28 PM
There's no way SCUBA divers would be able to carry enough explosives to scuttle a carrier.

Could you crash an airliner into one 9-11 style or would jets intercept you?There might be a brief window of opportunity when the entire crew is watching Oprah. Other than then, it seems pretty doubtful.

UncleBill
03-31-2004, 12:33 PM
A sufficiently large sub-surface nuclear device detonated under the keel may create a large enough void that the "back" would be broken. I would say the ship would have to cruise over the device already placed in a choke-point area, it would be harder to approach the carrier while it is underway in the CBG's defensive spead.

astro
03-31-2004, 12:36 PM
A sufficiently large sub-surface nuclear device detonated under the keel may create a large enough void that the "back" would be broken. I would say the ship would have to cruise over the device already placed in a choke-point area, it would be harder to approach the carrier while it is underway in the CBG's defensive spead.


What about scuba delivered plastic explosives attached to the hull at various points?

Doomtrain
03-31-2004, 12:42 PM
Let's break it down some. You have two basic shots: When the carrier's at sea and when it's in port.

When the carrier's at sea, it's going to be carrying aircraft, probably running Combat Air Patrols, probably escorted by a battle group. A low flying civilian airliner would definitely stir questions and, if it was swooping towards the carrier, I don't think they'd hesitate to intercept and shoot it down. Even if it DID hit, I don't think the damage would be sink-worthy. Carriers are huge ships and designed to take a pounding to begin with. Maybe if terrorists had an old Soviet sub, they could sneak in close and fire some torpedos, but the escorts and ASW patrols would hunt them down and destory them afterwards. It'd probably take a nuclear torpedo to sink a carrier. Not outside being possible, of course, but a bunch of terrorists aren't likely to be able to take "Driving a Foxtrot Class Sub" for a couple months and then be able to sneak past a carrier battle group.

In port, you could maybe sneak in some bombs like the USS Cole attack (but even the Cole was damaged, not sunk, and it was a lot smaller than a carrier), but divers carrying explosives? They'd need hordes of em.

So is it within the realm of possibility? Certainly, but really unlikely.

Gatopescado
03-31-2004, 12:42 PM
I don't know too much about it, but I'm pretty sure any threatening/unknown aircraft that got too close would be "neutralized" before it got close enough to do any harm. An aircraft carrier would be a fairly "opptomistic" target and for even the most over-achieving terrorist.

Sounds like the plot to the next Steven Segal movie.

_________________
Plans? We don't need no stinkin' PLANS!

kunilou
03-31-2004, 12:52 PM
Rather than trying to sneak a horde of scuba divers carrying 10 lb. packs of explosives, I think your modern terrorist would try to get his hands on one or two Exocet missiles and find a suitable way to launch them. The Exocet proved surprisingly effective during the Falklands war.

Even then, a modern carrier is not just a big box floating in the water. With watertight compartments and whatnot, it would take several direct hits to cause enough damage to sink one.

LordVor
03-31-2004, 12:55 PM
I doubt a team of people could carry enough conventional explosives to do much of anything to it. As others have mentioned, a scuba diver couldn't even catch it unless it was in port. As for 9-11 style, aircraft carriers are heavily invested in anti-aircraft measures.

I would wonder if it would be more possible to, say, disable it by going after the screws...

-lv

BF
03-31-2004, 01:02 PM
Back in my squidly days, it was posited that it would take up to six Mk. 48 ADCAP (http://www.chinfo.navy.mil/navpalib/factfile/weapons/wep-torp.html) torpedoes to sink a Nimitz class carrier. That's a 650 lb(292.5kg) warhead time six for a total of 3900 lbs (1755kg). That's a lot of scuba divers.

back_online
03-31-2004, 01:03 PM
Could scuba divers approach an aircraft carrier from underneath without being noticed and plant an explosive on the hull at a vulnerable point? Could you crash an airliner into one 9-11 style or would jets intercept you?
I was in the Navy so might have a slight inside perspective (more than the average Joe (and 'cause read Tom Clancy ;) ) , and here is my unofficial opinion.

No, divers are not a threat to a carrier.
1st, every ship in our Navy is compartmentalized. This means each is room is water tight, and can be closed off to prevent excessive flooding and secure off areas which are damaged etc.
2nd the hull of our carriers is quite thick and would require an enormous amount of explosives to cause enough damage to put it a ship of that size in a serious hurt.
3rd Every Carrier is escorted by submarines, whose job it is to identify all motor craft in the vicinity of it's fleet. (I realize you said "divers" but divers are like ants to elephants in relative size to a Carrier. They could not move this amount of explosives within range of a carrier to cause it significant harm) I am not sure of the exact thickness of the hull, but I think it would amaze most of us. I am trying to remember, if it’s neat a foot thick in critical areas (near the propulsion plants).
-- Perhaps while dockside (where the sub escorts could not venture) a few dozen divers with underwater propulsion devices (called sleds) could manage something of the sort, but most of that is "Hollywood" kinda stuff and doesn't really happen.
The " passenger-airliner into a carrier" would not cause nearly the damage as it did to our brittle World Trade Centers. Keep in mind: Steel ship built to withstand high-speed travel, etc vs. Glass Building with a hollow honeycomb steel structure. The WTC was an issue of burning jet fuel into a very open environment which weakened its superstructure.
USS Enterprise (http://http://nuke.co.kr/aboutNuke/application/nu_weaphone_ed/aircraft_carrier/images/Enterprise.gif)
If it the ship were in "hostile" area, yes there would be an escort of fighters in the air.
My two cents…
James

Cerowyn
03-31-2004, 04:15 PM
Imagine a 747-400ER (http://www.boeing.com/commercial/747family/technical.html), a couple of hundred kilometres into a flight, with a take-off weight of 400,000 kg (allowing for a slightly less than full aircraft, and shy of a full load of fuel), cruising at 900 km/h. Assuming you could drop that much mass at just 900 km/h on the carrier, you're looking at kinetic energy of something like 1.62E17 joules, or the equivalent of about 54.4 megatonnes of TNT. Think that might do it?

Consider that not having to worry about the condition of the aircraft, other than the bulk of the mass hitting a tiny spot on the ocean, means that your velocity is really the maximum you can achieve with your engines and the aid of gravity. Your CIWS is pretty much useless at stopping the aircraft from hitting the boat, and even multiple anti-aircraft missiles are going to have to hit before the plane is on its terminal vector to avoid a potentially fatal impact.

Mr. Slant
03-31-2004, 06:04 PM
Imagine a 747-400ER (http://www.boeing.com/commercial/747family/technical.html), a couple of hundred kilometres into a flight, with a take-off weight of 400,000 kg (allowing for a slightly less than full aircraft, and shy of a full load of fuel), cruising at 900 km/h. Assuming you could drop that much mass at just 900 km/h on the carrier, you're looking at kinetic energy of something like 1.62E17 joules, or the equivalent of about 54.4 megatonnes of TNT. Think that might do it?

Consider that not having to worry about the condition of the aircraft, other than the bulk of the mass hitting a tiny spot on the ocean, means that your velocity is really the maximum you can achieve with your engines and the aid of gravity. Your CIWS is pretty much useless at stopping the aircraft from hitting the boat, and even multiple anti-aircraft missiles are going to have to hit before the plane is on its terminal vector to avoid a potentially fatal impact.

I guess my question here is precisely how far away the aircraft is going to be from her target when the Navy destroys the aircraft. If they noted you pointed on a direct intercept for the aircraft carrier, there's a certain range where you'd pick up a fighter escort or inbound SAM.
If you're a mile away and you get hit with a missile, I'm imagining your aerodynamic profile is going to change dramatically, and quickly. It doesn't have to change that much for you to change your approach such that you won't hit.

astro
03-31-2004, 06:07 PM
Imagine a 747-400ER (http://www.boeing.com/commercial/747family/technical.html), a couple of hundred kilometres into a flight, with a take-off weight of 400,000 kg (allowing for a slightly less than full aircraft, and shy of a full load of fuel), cruising at 900 km/h. Assuming you could drop that much mass at just 900 km/h on the carrier, you're looking at kinetic energy of something like 1.62E17 joules, or the equivalent of about 54.4 megatonnes of TNT. Think that might do it?

Consider that not having to worry about the condition of the aircraft, other than the bulk of the mass hitting a tiny spot on the ocean, means that your velocity is really the maximum you can achieve with your engines and the aid of gravity. Your CIWS is pretty much useless at stopping the aircraft from hitting the boat, and even multiple anti-aircraft missiles are going to have to hit before the plane is on its terminal vector to avoid a potentially fatal impact.

You're saying a fully fueled 747 has the explosive power on impact of a 54 megaton atomic bomb? Are you sure about that?

3.885AM
03-31-2004, 06:16 PM
Does this trip anyone else’s BS detector? ”equivalent of about 54.4 megatonnes of TN”. from just an airplane?

Ilsa_Lund
03-31-2004, 06:41 PM
Does this trip anyone else’s BS detector? ”equivalent of about 54.4 megatonnes of TN”. from just an airplane?

54.4 megatonnes of Tennessee? I believe that that would be the maximum instantaneous force possible on a single point. p=mv is a pretty general equation. It gives me 3.6x10^11 joules, though. I dunno.

Cerowyn
03-31-2004, 06:43 PM
Does this trip anyone else’s BS detector? ”equivalent of about 54.4 megatonnes of TN”. from just an airplane?Hmmm... guess my critical thinking filter was off when I figured that out. Should have written it out. :o

K=mv2/2

m=400,000 kg
v=900 km/h=900,000 m/h=250 m/s (is that right?? In any event, I forgot mentally to convert to m/s)

K=400,000 * 2502 / 2
=12.5E9 Joules

In other words, 4.2 megatonnes of TNT.

Doomtrain
03-31-2004, 06:45 PM
It trips my BS detector. Most of the hazard would be burning fuel (which is what brought down the WTC, IIRC), which carrier crews are trained to deal with.

I recall someone in another thread saying that the USSR thought they'd have to go nuclear to even consider taking out one of our carriers. I don't see an airliner doing a lot of damage.

Ilsa_Lund
03-31-2004, 06:45 PM
54.4 megatonnes of Tennessee? I believe that that would be the maximum instantaneous force possible on a single point. p=mv is a pretty general equation. It gives me 3.6x10^11 joules, though. I dunno.


Ah, those aren't joules. Those are kg*km/h. :o

Thaumaturge
03-31-2004, 07:17 PM
A diver in port making a large circle with prima-cord could possibly sink one, but carrying enough cord to the site and laying it properly without being detected would be incredibly difficult IMO. ( Also I'm unsure if prima-cord would detonate under water, but above water it cuts through steel columns in building demolitions with ease)

About the hull thickness- I remember reading about the new liner Queen Elizabeth ( or was that Mary? whichever one is newest) II that it has 2 inch thick steel plate on parts of the hull, and that was as thick as an aircraft carrier. 2 inches is a very thick skin considering it is made of steel. You could probably get away with not needing any other structural supports if it was an immobile object.

ltfire
03-31-2004, 07:19 PM
I doubt a team of people could carry enough conventional explosives to do much of anything to it. As others have mentioned, a scuba diver couldn't even catch it unless it was in port. As for 9-11 style, aircraft carriers are heavily invested in anti-aircraft measures.

I would wonder if it would be more possible to, say, disable it by going after the screws...

-lv

Disable it to what end? Swarm up and over like pirates, to take on a 5000 member crew with long swords? You're funny.
:D

UncleBill
03-31-2004, 07:47 PM
Perhaps I should have been more clear in my previous post regarding the "void" and "back" breaking. Ships are designed to be supported by the water, evenly from stem to stern. Imagine a very heavy model ship just laying in the dirt in your backyard, buried up to the "waterline".

An explosion underwater creates a 3-D overpressure sphere which expands roughly in a sherical way. During this overpressure phase, the "water pressure" inside the sphere is VERY low (vacuum-ish), so much that the overpressure shere collapses onto itself (as the whole shebang is rising to the surface) and creates a "ball" of very HIGH pressure water, which then rebounds outwardly to create the vacuum again. As this pressure phenomenon is rising, the surround "normal" water pressure decreases, so this compression/vacuum system maintains its strength pretty well. If this system rises up under the middle of the carrier's keel during the vacuum phase, the effect is the same as digging a big hole under that model of the boat in your yard, leaving only the bow and stern supported. The "spine" of the boat is NOT designed for that loading situation, and may very well snap. It may not sink completely, but it ain't going anywhere soon.

A sufficiently large (nuclear) device, pre-positioned underwater in the known path of a carrier (straights, canals, ports) and remotely detonated is the best way, from what I was taught.

Spiny Norman
03-31-2004, 08:13 PM
Disable it to what end? Swarm up and over like pirates, to take on a 5000 member crew with long swords? You're funny. :D Disabling the propulsion would make the carrier unable to to move where it needs to be and to perform flight ops when it got there. I don't think the Navy would consider that a laughing matter at all.

KeithT
03-31-2004, 08:37 PM
Hmmm... guess my critical thinking filter was off when I figured that out. Should have written it out. :o

K=mv2/2

m=400,000 kg
v=900 km/h=900,000 m/h=250 m/s (is that right?? In any event, I forgot mentally to convert to m/s)

K=400,000 * 2502 / 2
=12.5E9 Joules

In other words, 4.2 megatonnes of TNT.

12.5e9 J is right, but a megaton is 4.3e15 J, so your 747 has as much energy as a 3 ton conventional bomb.

Padeye
03-31-2004, 09:02 PM
Bear in mind that the flight deck of a carrier is considerably stronger than the upper floors of the WTC towers. It's made to have 60,000lb planes virtually crashing into its surface. Not to say there would not be heavy damage but the energy of a 747 crashing would be dissipated over a large area of the flight deck rather than being concentrated at one point as a bomb would do.

The hard part is getting the 747 there. Even in an unpowered long dive it's likely to quickly overspeed and probably tear itself apart just from aerodynamic loads. Aiming at the hull below the flight deck is good as it's a more vulnerable spot but the 747 would have to be more boat than airplane as the flight deck is around 65 feet from the water.

AHunter3
03-31-2004, 10:02 PM
I take it as an inevitable given that given enough time, unless the world situation morphs into one in which no organized collectivity has much of an axe to grind, some group sooner or later is going to detonate a nuclear device. It may be a simple Hiroshima-type uranium bomb rather than something akin to the modern hydrogen-fusion thingies, but some C- level college student did a term paper detailing exactly how you'd go about building one of those suckers a few years back, and if he could figure it out, I reckon other folks can too.

Also, in addition to attacking it in port or attacking it while at sea, there's one other possibility: infiltration / suicide mission.

Mr. Excellent
03-31-2004, 10:22 PM
I'm answering this without preview because I'm curious to see how my "cold" response jives with other people - so if I'm redundant, please forgive me the indulgence.

That said - It's very unlikely a man-portable chemical explosive could sink a carrier, so your scuba plan seems unlikely to work. I suppose a man-portable explosive might be able to possibly damage the propellor - but I do n't think the smart money is on your frogmen being able to operate effectively in the propwash. At best, maybe a man-portable explosive could be used to damage or destroy part of the sonar array - hardly worth the effort.

No way would a jet liner collision work - the carrier's onboard defenses, escort ships, and planes are intended to be able to defend it from large numbers of modern military aircraft and missiles - an airliner would be detected and destroyed long before it could pose a threat.

RickJay
03-31-2004, 10:45 PM
Rather than trying to sneak a horde of scuba divers carrying 10 lb. packs of explosives, I think your modern terrorist would try to get his hands on one or two Exocet missiles and find a suitable way to launch them. The Exocet proved surprisingly effective during the Falklands war.
It did indeed, but bear in mind the British ships destroyed by Exocets were much, much smaller than an American CVN. An Exocet would certainly damage a big carrier, but almost certainly could not sink it. In fact, they didn't sink any British ships, either; the ships lost were abandoned because of secondary fires.

Furthermore, the Exocets were as successful as they were in large part due to the Royal Navy ships not having sufficient anti-missle defenses. That was corrected in every modern navy in the world REAL quick after the Falklands Islands War. Nobody wants to re-learn that lesson. Fact is, if the Argentines had possessed thirty or forty missiles instead of just six, they'd have won the war.

It seems to me terrorists would have to get aboard the carrier and find a way to detonate one of the nuclear devices on board. Kaboom.

jweb
03-31-2004, 11:42 PM
I'll have to agree with other posters that it would be nearly impossible for terrorists to sink an aircraft carrier sans nuclear weapons.

However, sinking one may be a bit of overkill (no pun intended) depending on your objective. If your goal is to simply disable it, you'd have a much easier time. It would take much less divers/explosives to damage the shafts/screws of the carrier enough to render the entire carrier unusable. IIRC, a carrier has to maintain a fairly high speed (around 25 knots or so) to conduct flight operations. Damaging a shaft or two would prevent it from being able to reach those speeds.

Of course, I could be way wrong, as most of my knowledge on this subject comes from the Internet and Tom Clancy novels.

Ranchoth
04-01-2004, 12:01 AM
Would you believe that We've discussed this before? (http://boards.straightdope.com/sdmb/showthread.php?t=200499&highlight=carrier)

Danalan
04-01-2004, 12:17 AM
There are numerous subtle ways to sabotage or damage such a complex system as an aircraft carrier.

The problem is access. If you have someone inside, then a number of scenarios become available -- from adulterating the lubricating oil for various systems, to electrical/electronic interferrence, or even biological attacks. A storekeeper, cook, or even a corpsman could take out a lot of personnel fairly quickly with some simple pathogens. That could leave the ship vulnerable.

Attacks from the outside are more problematic. Most of the obvious large-scale force projection options are already thought of and protected against. Exocets won't do it -- they will be shot down by the Phalanx system. Airplanes just don't stand a chance. If they aren't supposed to be within 100 miles, they won't be a threat. Even if you were to crash a jet onboard, that's happened numerous times to carriers -- it's survivable.

Something like a million Wal-mart bags released where they can clog the cooling ducts -- now that could be bad. Swarms of bees, or birds -- that could be bad. A dirty bomb might cripple an aircraft carrier, but it wouldn't destroy it.

If you have a nuke, you don't use it on an aircraft carrier. It's easier to park it in San Francisco Bay or somewhere on the Hudson. That would get much more attention. Deploying a nuclear device as a mine would make for a large package -- for the bouyancy needed -- so the subs would see it.

It's within the realm of possibility, particularly if you have someone inside, but not likely.

Gunslinger
04-01-2004, 12:37 AM
The problem is access. If you have someone inside, then a number of scenarios become available -- from adulterating the lubricating oil for various systems, to electrical/electronic interferrence, or even biological attacks.
"Adulterating the lubricating oil"?! C'mon, man, think big! A carrier is packed full of kerosene and explosives!


Upon reflection, I will not elaborate any further on that point.