Can the Iranian sink a US Carrier Group?

[Chirios]

The scenario that I've often seen in breathless, crazed fiction is hte "Iran blocks Straits of Hormuz by scuttling a few ships in the lane and mining it". But given that it's a multi-mile wide lane, this too seems a little ridiculous. You can certainly increase navigation hazards and mine the shit out of it, but blocking it entirely seems infeasible, unless I'm missing something.

No its too wide and much too deep with the narrower areas being deepest as is pretty typical for straits like this. The water is shallow by ocean standards, but still several hundred feet deep. Even given forty of the largest tankers or container ships you couldn't make a very worthwhile barrier.
http://upload.wikimedia.org/wikipedia/e ... z_full.jpg
Anything much over about ~75m and blockships aren't going to work, though the superstructures could create partial barrier

Seriously? I didn't know that. So the other month when Iran said it was going to block the straits if the UN passed that sanction it was talking out of it's arse?

If you really wanted to use blockships a perhaps better and less ship intensive idea would be to send them against the Arab oil terminals directly and attempt to block them before the Arabs and US can put enough planes in the air to sink the wrecks; since anti ship missiles fired by patrolling warships are unlikely to sink tankers, and the vulnerable bridges could be abandon in favor of controls from a protected position in the engine rooms. Even then it would take multiple successful blockships to block any of the major terminals, the facilities are just too big for the obvious reason that they are designed to handle entry and exit of multiple supertankers per day.

Could the Iranians do that?

EDIT: I just remembered, wasn't the original worry that they were going to mine the straits?

[Sea Skimmer]

Seriously? I didn't know that. So the other month when Iran said it was going to block the straits if the UN passed that sanction it was talking out of it's arse?

As you just figured out, it just meant it was going to block it with mines, artillery, small craft attacks and various other weapons, not physically block it. Its worth considering that the waterway is narrow enough that plain old shore batteries with artillery shells or unguided barrage rockets can fire clear across the straits, and even tank guns could go halfway across. Stuff like that would be endless trouble. The US can easily shoot down the Styx and C-802 anti ship missiles Iran has, we can't shoot down hundreds of barrage rockets fired at once, it'd take a massive air effort to constantly suppress the launchers before they fire. Iran has hundreds of multiple rocket launchers. The pressure would be pretty heavy to make some kind of Marine landing to secure the Iranian shore.. with all the problems that brings. Securing a strait is one mission for which marine forces are invaluable.

Frankly a physical blockship block would be a lot less troublesome then all of the above, because even if Iran was able to place a solid wall of ship hulks spread across it, that'd be easier to blow a gap in that then just to clear the estimated 2,000 naval mines Iran has. Most of those are WW1 floating contact types that can be swept conventionally, but many are among the most modern types of influence bottom mines which have to be located and destroyed one by one. Mines have caused almost all damage, and the only losses of US warships since WW2, excluding very small craft like Swift boats that aren't ships. Iran could and would also spread thousands of decoy mines to use up time, and is entirely capable of manufacturing new mines and attempting to plant those, while using its limited missile forces to attack US and allied minesweeping forces. Problem is, this all means economic suicide for Iran even if the west and Arabs didn't start bombing them like crazy until they had no economy left anyway. The Iranians are bluffing, everyone knows it, but since we can't trust the stability of the Iranian government, which is the whole reason why nobody wants them to have nukes, we have to act like the threats are real.

[ChaserGrey]

Now that we are back on this subject, can we have a source with more credentials than that self-declared 'armchair general' that Iran even has sunburn missiles?

In the no doubt vain hope of extracting something worthwhile from this mess, I checked my trusty Jane's. You can read this bit in the free section, which lays out exactly how many Sunburns Iran has- 8 launchers and 24 missiles, bought from Ukraine. Nasty customers, no doubt, but not enough to saturate a carrier group's defenses even if they get them all in the air simultaneously.

[Protip: If you have just launched a Mach 3 antiship missile at a carrier, sticking around to reload and get off another shot is Not Recommended. There's nothing that ruins your day quite like a swarm of angry Hornets.]

[Sea Skimmer]

Janes is a questionable resource for otherwise unsupported claims; all they really seem to do anymore is aggregate other peoples material. As far as I can tell Iran has never displayed this weapon, while it goes so far as to build wooden mockups of S-300 batteries that are blatantly fake and parade them around. Kind of weird no? They might have it, they might not, makes no big difference but I'd favor no.

Also keep in mind 'launcher' doesn't mean you only have one shot. The only known coastal defense launcher the Russians offer for Moskit has two missiles side by side for example, but other designs would be entirely possible with one missile or up to four missiles. More then four is highly unlikely in view of the massive weight of this weapon, two is already pretty huge. Now meanwhile the NATO code name Sunburn was actually applied to three different Soviet weapons, and Iran if it had 'Sunburn' missiles from Ukraine they could be the older P-80 Zubr or the much longer ranged P-270 Moskit. The third one is P-100 which was a submarine variant of P-80 that never did much owing to its limited range. Failure to include specific information on the missile type likewise, makes the Janes report questionable. A Ukrainian source would not be expected to use a western code name. They'd logically name it by the P number, or the industrial code number which is 3M80 for Zubr and 3M82 for Moskit.

Also keep in mind the P-270 missile only flies at mach 3 when it cruises at an altitude of 10,000m or more for extended range, at which point it is a sitting duck on radar and IR sensors. P-80 doesn't do this because it was rocket powered and had limited range to begin with. On the deck when its a much greater threat the designs do about mach 2.2 which is actually slower then US target drones have been capable of since the 1970s.

[Julhelm]

Don't they have those wake-homing torpedoes that they can launch from their Kilos? Certainly a much bigger worry than ASMs since IIRC the only known decoy is to put a frigate between the carrier and the torpedo.

[UnderAGreySky]

How close can they get to a carrier battle group without being caught? Especially through the net of destroyers and USN SSNs surrounding it? They seem to have just three Kilos anyway.

[Julhelm]

AFAIK the USN's ASW is optimized for finding nukes and they are less capable against SSK's. So a great skipper could probably stand a decent chance.

[Sarevok]

They have helicopters with active sonar they could use with impunity. IIRC great effort has gone into refining active sonar so it could find stationary manmade objects on the sea floor.

[UnderAGreySky]

Heck, who needs helicopters? A line of sonobuoys could do the same job too...

[Vehrec]

Is there any active anti-torpedo system in the entire world? Some sort of Anti-sub rocket or depth charge launched out towards an incoming torpedo? Probably, you could use another torpedo for this, but that gets expensive and impractical fairly fast I would imagine.

[Ryan Thunder]

Is there any active anti-torpedo system in the entire world? Some sort of Anti-sub rocket or depth charge launched out towards an incoming torpedo? Probably, you could use another torpedo for this, but that gets expensive and impractical fairly fast I would imagine.

Why not something like ASROC?

[Sea Skimmer]

Don't they have those wake-homing torpedoes that they can launch from their Kilos? Certainly a much bigger worry than ASMs since IIRC the only known decoy is to put a frigate between the carrier and the torpedo.

I'd worry more about one of those openly suicidal midget submarines they have then the competence of Iranian Kilo. They don't have wake homers, Kilo only has 533mm tubes, you need 650mm for wake homers to work well. 650mm fired from land or surface vessels cannot be ruled out though. Even then you have that pesky 50% chance that the wake homing torpedo turns the wrong way when it finds the wake, and many tactics can disrupt wake homing such as having the escorts and CVN cross wakes repeatedly in turns. The USN may also have an anti torpedo torpedo in service by this point. They've been testing a small 6.75in one since 2000 which should work a lot better then the Mk46 mod fielded in the early 1990s that never seems to have been satisfactory. Decoys also exist which can disrupt the way certain kinds of wake sensors work.

AFAIK the USN's ASW is optimized for finding nukes and they are less capable against SSK's. So a great skipper could probably stand a decent chance.

Depends on the platform, the medium frequency sonar on Perry class frigates isn’t so bad at shallow water ASW for example, and the USN has put a lot of effort into fielding sonar buoys for shallow water operations. Emphasis has switched from passive to active sonar, and this is very bad news for an SSK that cannot run like hell like a nuke boat can. The USN could also begin laying its own mines to restrict Iranian sub operations.

[cosmicalstorm]

Thank you for posting Skimmer. By the time I got to the third page I was seriously worried this was going to be 4 pages of AndroAsc pouring shit through his typing fingers onto the internet.
One question about their subs in relation to the US forces-- Can Iran really hide their submarines?
I suspect that at this point the entire strait area is one big US owned acoustic array?
I've also heard rumors about exotic tech for submarine detection, such as shining blue and green lasers and using massive computing that can detect a submarine's underwater wake. And when they are detected, killing them ought to be routine. I would bet that the entire Iranian submarine fleet is being actively tracked by the navy as I type this and that they will all be gone within hours if not minutes of the initiation of any hostilities. I wonder if they would have time to start an attack after hostilities commenced?

[Sea Skimmer]

Is there any active anti-torpedo system in the entire world? Some sort of Anti-sub rocket or depth charge launched out towards an incoming torpedo? Probably, you could use another torpedo for this, but that gets expensive and impractical fairly fast I would imagine.

The basic problem with a torpedo to torpedo defense system is the screw on the enemy torpedo is pretty damn quiet compared to all the other noise in the ocean, not the least of which is the noise of the ship under attack and the self noise of the anti torpedo (endless torpedo seeker problem). The scale of the challenge has been compared to trying to hear someone talking normally 25 feet away in the middle of a rock concert. The Russians do have a operational anti torpedo system intended specifically to counter wake homing torpedoes, which can attack them by releasing floating mines and firing barrages of time fused depth charges from RBU launchers, but against wake homers the fire control problem is simplified by the torpedo always approaching up your own wake! A regular active or passive or wire guided torpedo can come from any direction including swimming vertically up below the ship, so its vastly harder to cope with.

One question about their subs in relation to the US forces-- Can Iran really hide their submarines?
I suspect that at this point the entire strait area is one big US owned acoustic array?

I doubt it is wired for sound by the US, it might be by one of the local powers. The US does have deployable seabed arrays that might quickly go into place, but its still very hard to detect an SSK on battery power by passive means. Once they snorkel they are going to be dead; which is why really the midget submarines are a bigger deal then the Kilos as they are simply more numerous and would be less distinctive snorting. It'd also be much easier to physically conceal them in bases and within other shipping traffic. Iran's Kilo fleet isn't that active, likely because they are just to big and demanding for Iranian crews. Its hard to sustain a submarine program for anybody when you have just a few boats. I suspect the worst damage Irans Kilos would do is quickly and covertly laying mines. Once they fire torpedoes... well we just found the general location of the Iranian sub now didn't we! Then the sub gets hunted to death or battery exhaustion which is also death. The gulf is small enough that minelaying missions could be conducted more or less entirely on battery power.

I've also heard rumors about exotic tech for submarine detection, such as shining blue and green lasers and using massive computing that can detect a submarine's underwater wake. And when they are detected, killing them ought to be routine. I would bet that the entire Iranian submarine fleet is being actively tracked by the navy as I type this and that they will all be gone within hours if not minutes of the initiation of any hostilities. I wonder if they would have time to start an attack after hostilities commenced?

The laser method seems to be paper only, at least in terms of providing wide area coverage. You can detect submarines from satellites within limited circumstances via the wake when the submarine runs shallow, both from the surge in surface height it creates and the mixing of colder deep water with the warmer surface water being visible on IR photos and FLIR (this also works for ASW aircraft). Also bubbles are created even by a deep running submarine which can be detected by various means, Soviet nuclear submarines had a wake detector sensor for this for a long time, but it literally only works if you actually sail through the enemy wake (rather like placing a wake homing torpedo seeker on the sub). Wake sensors can work multiple ways some of which are laser based.

The massive amount of civilian traffic in the gulf is likely to make any such methods less then highly. Its literally a big mass of ships from the very smallest to the very largest, and any submarines within it are likely to move only very very slowly minimizing the signature on any kind of sensor. Also the gulf has so much trash and debris in it, while also being shallow that MAD won't work well, though the US largely abandon MAD anyway because the search area is so small and false alarm rate so massively high (iron ore on ocean floor = bad). All that debris ect.. also helps degrade sonar performance.