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View Full Version : How many torpedoes to take out an Aircraft Carrier?


rabbit
09-04-2002, 11:12 AM
Assuming you plunked a Nimitz class carrier in the middle of the ocean totally unprotected and disregarding how you'd get the torpedoes to it, how many of them would it take to sink the carrier? Direct hits on the hull below the water line.

KarlGauss
09-04-2002, 11:36 AM
This related thread (http://boards.straightdope.com/sdmb/showthread.php?s=&threadid=96282&highlight=carrier), on whether cruise missles could destroy a carrier, may be of some interest.

Milton De La Warre
09-04-2002, 11:47 AM
Answer: Most likely only one, if no one did anything about the hit.

But that's not how it would work in real life. Common sense and training would dictate that they'd seal off the damaged areas so that the water wouldn't fill the rest of the ship. This is what they have DCs (Damage Control) people for.

In real life, the answer would depend on a lot of factors. What kind of torpedoes, where exactly they hit, time between hits, etc.

rabbit
09-04-2002, 12:26 PM
Good thread that one, but its not exactly what I want to know (although it touches upon it, I'm looking for a little more detail), and I SHOULD'VE added that the ships crew were onboard. The question is for a short story I'm trying to write, and I'm interested in how many hits would guarantee the ship sinking. Has to sink in the story. So given that there would be crews trying to seal decks, put out fires, etc, how many hits would guarantee the thing sunk. (By the way, I specified a Nimitz as its the biggest class of warship afloat. Figured it would take the largest number of hits to sink).
As for what kind of torpedoes, say something like the MK-48's or similar. (Excess of 200kg warheads is what I read on the Navy web site). And all the hits are hitting below the waterline.

Ringo
09-04-2002, 01:04 PM
While not Nimitz class, the following carriers were big ships with concerned Damage Control folks afoot. It took two to do in the IJN Unryu (http://64.124.221.191/Unryu.htm), but only one for the Taiho (http://64.124.221.191/Taiho.htm).

Whack-a-Mole
09-04-2002, 02:13 PM
Torpedoes are much more devastating today than they were back in WWII. Also, although a Nimitz class carrier is the biggest warship afloat it isn't necessarily the best armored. Although I think the entire battleship fleet has been mothballed but I suspect that an Iowa class BB might be harder to sink via torpedo than any aircraft carrier. The German battleship Bismarck took somthing on the order of 300 shell hits and at least two (and I think more) torpedo strikes to sink her (some say she was scuttled by her crew to make her sink).

WWII torpedoes would strike the sides of the ship where they generally possessed the greatest amount of armor. Today's torpedoes swim under the ship and explode under the keel. The armor is far less there and the explosion has a very good chance of breaking the 'back' of the ship. If that happens it's all over for the vessle and I don't think any amount of damage control could save it.

The question is, could a modern torpedo break the back of an aircraft carrier? I don't know if one could do it but I'd be willing to bet two would (just a guess though).

ftg
09-04-2002, 02:49 PM
Magnetic, under-the-keel, torpedoes were used from the very early days of WWII.

In any case, 1 torpedo would do it. "Below the waterline"? Below the ship! Once the keel is broken, all the damage control of the crew and watertight compartments ain't going to save it.

For an example, I Googled on the Indianapolis sinking. The Japanese captain set the 2 torpedoes for too shallow a depth and consequently they actually struck the side (he thinks). The ship was breaking up and sinking fast within 2 minutes. The 2nd torpedo turned out to be unnecessary. Given the speed of the sinking, some conjecture that the captain was wrong and they really did explode under the keel. The armour of the Indianapolis was no doubt far greater than a current carrier.

"But we delivered the bomb."

Whack-a-Mole
09-05-2002, 09:43 AM
Originally posted by ftg
For an example, I Googled on the Indianapolis sinking. The Japanese captain set the 2 torpedoes for too shallow a depth and consequently they actually struck the side (he thinks). The ship was breaking up and sinking fast within 2 minutes. The 2nd torpedo turned out to be unnecessary. Given the speed of the sinking, some conjecture that the captain was wrong and they really did explode under the keel. The armour of the Indianapolis was no doubt far greater than a current carrier.

I don't know that the armor on the Indianapolis was necessarily greater than that on a carrier (especially a modern carrier).

The USS Indianapolis was a heavy cruiser which makes it a LONG way off of a full-blown battleship (roughly 10,000 vs. 50,000 tons [Iowa class]). Basically heavy cruisers mounted near battleship sized cannons (albeit fewer) on a relatively light hull. In short, they could dish it out but they couldn't take much in return (all relatively speaking of course).

As a result I'm not sure using the Indianapolis as a benchmark is useful.

GrizzRich
09-05-2002, 10:16 AM
Theoretically, only one... but I propose a different set of circumstances.

In my scenario, the torpedo would not even have to hit the ship. Instead, releasing a tremendous amount of compressed air (bubbles) below the ship, making the weight of the water providing buouyancy to the ship lower. With the release of enough bubbles, the ship would sit lower and lower in the water, ultimatelyly taking on enough water over the top of the hull to sink itself.

Milton De La Warre
09-05-2002, 10:42 AM
Grizz, that's something similar to what happens when a torpedo or mine goes off under the keel. The water is displaced (sort of like a big bubble), and the ship is alternatively lifted up and then unsupported by the water that would normally surround the hull below the waterline. The ship is bent in the middle upwards and then falls into a sort of temporary hole. This is what breaks the keel.

Your explosion would be a lot bigger, essentially temporarily removing the water from under the ship, then letting it come over the top. Of course, any explosion of that magnitude would damage the ship's structure so badly that the water wouldn't have to come over the top of the hull ---it's be coming in from every other direction.

I am not not and have never been a DC. but I tend to beleive that a Nimitz could survive an under-keel explosion with good DC work. This is because the ship's hull is so big that I would think there is some degree of redundancy in its structural integrity, so that a hole (or big ass dent with underlying structural disruption) dead under the keel would not necessarily be so big that it would disrupt the whole lengthwise rigidity of the hull. You can tell I am no marine architecht, either.....

Consider the mine damge to the Tripoli in the Gulf War.

BF
09-05-2002, 11:04 AM
I had posted a response, I think in the other thread, so I'll go ahead and repost. As an ex-fire control man on a 688 class sub, we had scenarios which included torpedoing and sinking a Nimitz class ship. It was posited that it would take four to six Mk. 48 ADCAPs to sink a ship of this size. All of them set for influence detonation under the keel.

culture
09-05-2002, 11:22 AM
Qualifications: A forensic engineer working in the marine engineering field for many years. Spend a year working on the Valdez grounding and ensuing damage to the vessel.

Warships are not armoured against torpedo attacks, at least not in the sense most people use the term, meaning thick layers of steel. The armour belt on a battleship, for example, typically ends slightly below the waterline. The hull steel below this point is typically not much thicker than used on any commercial ship. The "armour" against torpedos is in the form of multiple hulls and water-tight compartments, or in simple terms, space. Some WWII battleships were fitted with torpedo blisters, which in essence simply added an additional layer of hull down the sides of the ship below the waterline. I am not certain if this feature is present on modern carriers.

Therefore, to sink a ship you need to hole enought compartments to make it sink or become unstable. Without damage control, instability would be the most likely cause of sinking, assuming all watertight doors were closed at the time of impact. If you ever go into an aircraft carrier, or modern ( say since 1930 or so) warship, you will find that they are a maze of small, water tight compartments. If you flood to many on one side of the ship, the ship will become unstable and turn turtle. Obviously, without damage control, any size hole will eventually result in sinking.

Of course, this all ignores fires and secondary explosions, which are a subject into themselves.

However, to answer you question, I would estimate three to six (depending on many variables). I am a font of wisdom on this stuff. Ask as many questions as you like.

RickJay
09-05-2002, 11:25 AM
rabbit, I think your story could work with any number from one to six.

The effect of a torpedo hit on a ship is by its very nature chaotic; there is structural damage, fires, leaks, holes in the hull. It's impossible to say exactly how many torpedo hits would sink an aircraft carrier. One hit could sink it if your luck was bad enough, but if your luck was good, it might survive ten.

KarlGauss
09-05-2002, 11:42 AM
Notwithstanding the various factors that RickJay mentions, can the effects of torpedo (and other) hits on a vessel be modeled*? Could this give a sense of the probabilities for the potential outcomes and/or the rate at which they're likely to happen.

*not that this is likely to be in the public domain

Whack-a-Mole
09-05-2002, 02:32 PM
I'm surprised no one has mentioned nuclear-tipped torpedoes.

Ok, maybe unfair for your story but they DO exist and I think had you ever seen a reall shooting war with the Russkies break out during the cold war they might even had been used. A carrier battle group is one tough nut to crack so the use of one torpedo that would take everything out would be very attractive. I imagine most navies would happily trade any one submarine for an entire battlegroup.

culture
09-05-2002, 02:43 PM
I don't know. It seem to me that if you lauch a nuclear torpedo at a carrier battle group you have much more to loose than a submarine, like say, one of your only two naval ports, or perhaps a city if you really pissed someone off.

Whack-a-Mole
09-05-2002, 03:19 PM
Originally posted by culture
I don't know. It seem to me that if you lauch a nuclear torpedo at a carrier battle group you have much more to loose than a submarine, like say, one of your only two naval ports, or perhaps a city if you really pissed someone off.

Seems to me merely torpedoing a carrier with a plain old torpedo (or even missing and just attempting to do so) would be a good way to lose some of your ports or more. With 5,000 plus sailors on board taking out a carrier would be a bigger deal than the toppling of the WTC. The US would frown mightily on anyone that attempted such a thing.

Whack-a-Mole
09-05-2002, 03:26 PM
Originally posted by culture
I don't know. It seem to me that if you lauch a nuclear torpedo at a carrier battle group you have much more to loose than a submarine, like say, one of your only two naval ports, or perhaps a city if you really pissed someone off.

Seems to me merely torpedoing a carrier with a plain old torpedo (or even missing and just attempting to do so) would be a good way to lose some of your ports or more. With 5,000 plus sailors on board taking out a carrier would be a bigger deal than the toppling of the WTC. The US would frown mightily on anyone that attempted such a thing.

rabbit
09-06-2002, 04:09 PM
good stuff then. 4 -6 torpedos. Ill use 2 volleys of six hits then. (What... Im a firm beleiver of overkill).
The nuclear tipped torpedo definitely raises some interesting possibilities....

Thanks all.

Tranquilis
09-06-2002, 05:18 PM
The Mk 45, or "Nuclear Torpedo" was pulled from active inventory long, long ago.

"Taking Out" has a lot of different meanings. Sink it outright? Render it uneconomically reparable? Render it combat ineffective for the duration? Render it combat ineffective for a specific period of time?

To sink a Nimitz outright would require four Mk 48s, minimum, and lucky placement. 6 to be sure. 4 torpedos and random placement would quite possibly render it unreparable, or maybe only ineffective for the duration. Two or three would certainly take a carrier out of action for one battle, and maybe the duration, depending on a number of factors (how long the war, how long to get to repair facilities, where the hits were, how good immediate damage control was, etc). One torpedo might not even stop a carrier, or it might render it combat incapable for a long, long time. Hint: Aim for the screws.

robby
09-06-2002, 08:03 PM
Originally posted by Whack-a-Mole
I'm surprised no one has mentioned nuclear-tipped torpedoes...A carrier battle group is one tough nut to crack so the use of one torpedo that would take everything out would be very attractive. I imagine most navies would happily trade any one submarine for an entire battlegroup.

I'm pretty certain that a single nuclear torpedo would not take out an entire battlegroup. Carrier battlegroups are quite spread out.

This hypothetical submarine with the nuclear torpedo also has to get within shooting range of the carrier, which again, is difficult to do. Why? Among other factors, because of the U.S. submarine(s) screening the battlegroup.

Incidentally, there are few navies that have effective submarines that could successfully prosecute an attack on a carrier or its battlegroup.

Sam Stone
09-06-2002, 11:02 PM
I read somewhere that torpedoes break the spines of ships through cavitation. Basically, they explode under the keel and create a big air bubble the ship collapses into. Any truth to that?

robby
09-07-2002, 12:29 AM
Originally posted by Sam Stone
I read somewhere that torpedoes break the spines of ships through cavitation. Basically, they explode under the keel and create a big air bubble the ship collapses into. Any truth to that?

Essentially correct, but not cavitation, and not an air bubble. Others have mentioned the effect previously in this thread.

Cavitation is the vaporization of water due to the lowering of pressure behind the blades of ship's screws (propellers). The resulting water vapor bubbles subsequently collapse, producing noise and pitting of the surface of the blades. Cavitation may also occur on rudder surfaces, and in pump impellors.

A torpedo exploding beneath a ship vaporizes a large amount of water, producing a huge steam bubble. (Actually, combustion gases make up a good portion of the bubble as well.) If the bubble is beneath the center of the ship, there is no mid-section support for the ship, and the keel breaks. Rapid sinking ensues.

Joe_Cool
09-07-2002, 02:32 AM
Originally posted by robby


Essentially correct, but not cavitation, and not an air bubble. Others have mentioned the effect previously in this thread.

Cavitation is the vaporization of water due to the lowering of pressure behind the blades of ship's screws (propellers). The resulting water vapor bubbles subsequently collapse, producing noise and pitting of the surface of the blades. Cavitation may also occur on rudder surfaces, and in pump impellors.

A torpedo exploding beneath a ship vaporizes a large amount of water, producing a huge steam bubble. (Actually, combustion gases make up a good portion of the bubble as well.) If the bubble is beneath the center of the ship, there is no mid-section support for the ship, and the keel breaks. Rapid sinking ensues.

Sorry, but I have a really hard time buying this. The fact that it exploded with enough force to create the bubble at all means it had enough pressure to displace all that water in the first place. That means it is at much higher pressure than the water was. As the bubble expands and loses pressure, water fills the area from the sides and below.

The way torpedoes work is this:
The warhead explodes. Gases and the shockwave from the explosion need to go somewhere. Water is heavy, so the area of the explosion is under a good deal of pressure. Depending on thickness, punching a hole in a piece of steel is likely easier than lifting a 30 or 40 foot column of water. So the hull of the ship is displaced by the explosion, blasting a hole in it. This efficiency increases with depth.

Basically the pressure of the water "contains" the explosion more effectively than air, so more of the blast is directed toward the hull than would be above water.

Tuckerfan
09-07-2002, 03:21 AM
What's the yield on a nuke torp? In the film Trinity and Beyond: The Atomic Bomb Movie they talk about how an underwater nuke test yielded a far bigger blast than anyone expected at the time. Given that they weren't into the megaton range at that point, and the film footage shows a mind-boggingly huge blast (you can see ships being carried high into the air by the blast), I can well imagine that a 1 megaton blast could wipe out a carrier group.

Joe_Cool
09-07-2002, 10:46 AM
I know exactly which one you're talking about: Operation Crossroads, shot Baker (July 25, 1946). It sank 9 ships at a single whack, including the carrier USS Saratoga (CV 3).

Picture of the shot, and other info (http://www.mikey.net/bikini/Bikini/operation_crossroads%20web.htm)
Picture of the Saratoga going under (http://marshall.csu.edu.au/html/WWII_Pix/s259372.jpg)

robby
09-08-2002, 06:57 PM
Joe_Cool, here is a cite:

http://www.fas.org/man/dod-101/navy/docs/es310/uw_wpns/uw_wpns.htm

When a warhead is detonated at close range beneath a ship, the steam void initially lifts the ship upwards from the middle. This tends to weaken the ship's keel. After the steam void has reached its maximum volume the surrounding water pressure will collapse it. The ship then falls into the void, still supported on its ends. The keel will then break under the ship's own weight. The compression of the steam void will raise the temperature and the bubble will oscillate a few times. The ship may be destroyed during the subsequent oscillations if it manages to survive the first.

Tuckerfan, from the same source:

The energy in the underwater shock wave attenuates very quickly with range. Therefore, the shock wave from an underwater explosion does not cause the same level of damage as one would expect from studying explosions in air.

Also, note that eight of the nine ships sunk in Operation Crossroads were within one-half mile of the explosion. The ninth ship was not much farther away. Basically, the entire "battlegroup" was within a area not more than one square mile. Modern carrier groups are spread out over an area of hundreds of square miles. Operational battle groups do not look like the "bulls-eyes" seen in photo shoots.

Also, I don't believe any nuclear torpedo ever produced was anywhere near the megaton range. Shooting such a weapon would be suicidal. With respect to a battlegroup, the two closest ships to the detonation would be the target ship and the sub firing the torpedo.

Pushkin
07-27-2003, 06:57 AM
Originally posted by Joe_Cool
I know exactly which one you're talking about: Operation Crossroads, shot Baker (July 25, 1946). It sank 9 ships at a single whack, including the carrier USS Saratoga (CV 3).


The underwater explosion looks like the poster we have in our living room (student house) quite awesome. Especially as it replaced a Bob Marley banner :D

Icerigger
07-27-2003, 07:09 AM
In 1944 the U.S.S. Archerfish sunk the Japanese 60,000 ton carrier Shinano with four torpedoes. The Shinano is the largest warship ever sunk by a submarine.

xash
07-27-2003, 05:17 PM
There is an ongoing discussion on this topic here:

How do you take an aircraft carrier out? (http://boards.straightdope.com/sdmb/showthread.php?s=&threadid=200499)

Please continue the discussion in that thread. I'll close this.

-xash
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