CIWS effectiveness

[orca]

I'm hoping to hear what others think about the expected effectiveness of various CIWS, mainly in regard to missile defence. The typical naval CIWS such as Phalanx, AK-630, H/PJ-11, etc have PH? in the 70-80 range.

Some new larger caliber weapons such as RAPIDFire, Bofors 40 Mk 4, and 57mm Bofors Mk110 have a much lower PH in the DB than many of the smaller caliber CIWS systems. This despite reportedly various specialized anti-air rounds including guided projectiles, proximity fuses, etc. I understand the longer range is an advantage. But why such a lower PH in the DB for these?

For example this article on the Bofors 40 Mk 4 claims (how accurately I don't know) that it is superior to Phalanx.

https://www.navalnews.com/event-news/se ... ts-evolve/

[kahta]

Is there a difference in the rate of fire?

[thewood1]

No expert, but I would assume that larger calibers have longer range. At longer range accuracy would start to deteriorate. Maybe run a test where the WRA is set to even out range considerations.

[SunlitZelkova]

I have done a few tests with Japanese and American AShMs against a Chinese CBG. The CIWS on the Liaoning (30mm H/PJ-12) was very effective... to a point.

At the end of the day though, I think the deciding factor in an engagement is overall salvo mass. In one test, I was planning to utilize multi-mission Tomahawks and LRASMs launched from F/A-18s for a TOT strike. The mission didn't work (I am still learning the ropes of the newer mission planner functions) so the Tomahawks were never launched.

But even with just 40 LRASMs targeted against the CBG (on the carrier), not only did some of the escorting Type 054As fully expend their SAM loads trying to shoot them down, many escaped through the Liaoning's FL-3000 SAM fire and came within range of the carrier. The CIWS did down many, but three missiles still made it through.

The ship only suffered light damage to modules, but suffered 5% structural damage from taking one hit. If the 600 some Tomahawks aboard the American CSG had properly fired, the carrier would certainly have been sunk.

Point defense is very hard against enormous missile salvoes. In the scenario, the Liaoning also had a combat air patrol up, was also escorted by Type 052Ds, and had its AEW helo in the air. I also manually forced the CAP mission to launch more fighters that were ready onboard, but not in the air because of the 1/3 rule on the mission. And yet three missiles still made it through.

Rather than relying on SAMs or CIWS for defense, my opinion after having created that little test is that extending air cover as far as possible out to sea is the most important factor in protecting naval assets. The J-15s in the scenario were limited to a 100 nm diameter circle around the CBG, but if they had been flying at a greater distance, they might have intercepted the F/A-18s before they could launch their missiles.

[thewood1]

"Rather than relying on SAMs or CIWS for defense, my opinion after having created that little test is that extending air cover as far as possible out to sea is the most important factor in protecting naval assets. The J-15s in the scenario were limited to a 100 nm diameter circle around the CBG, but if they had been flying at a greater distance, they might have intercepted the F/A-18s before they could launch their missiles."

The USN figured that out decades ago. They planned on fighting Soviet long range AShMs by killing as many of the missile carriers as they could and forcing the rest to fire early. Hence the F-14 and the AIM-54. Today, its the E-2D, F-18, AIM-120, and AIM-260, plus a tanker fleet. Some of that is slowly being changed as SM-6s continue to extend their range of coverage. The deciding factor will be missile inventory and attrition.

[SunlitZelkova]

"Rather than relying on SAMs or CIWS for defense, my opinion after having created that little test is that extending air cover as far as possible out to sea is the most important factor in protecting naval assets. The J-15s in the scenario were limited to a 100 nm diameter circle around the CBG, but if they had been flying at a greater distance, they might have intercepted the F/A-18s before they could launch their missiles."

The USN figured that out decades ago. They planned on fighting Soviet long range AShMs by killing as many of the missile carriers as they could and forcing the rest to fire early. Hence the F-14 and the AIM-54. Today, its the E-2D, F-18, AIM-120, and AIM-260, plus a tanker fleet. Some of that is slowly being changed as SM-6s continue to extend their range of coverage. The deciding factor will be missile inventory and attrition.

Indeed. I suppose my surprise comes more in the context of hypothetical PLAN operations. A number of PLA watchers seem to think a few months-long blockade and air bombardment is a more likely strategy the PLA will adopt for Taiwan, rather than a quick, hotly contested amphibious operation.

Trying to pull this off without operating deep into international waters and airspace would significantly put PLAN assets at risk in the event of US intervention. On the other hand, operating that far would certainly involve operating close to other countries, namely the Philippines and Japan, creating a risk of needlessly expanding the conflict.

Perhaps this dilemma was part of the rationale for China's development of ASBMs. In theory they would provide the kind of reach a carrier battle group would, but without the escalatory character in the mere presence of such an asset. Not being seen would of course come with the trade off of providing less of a deterrence effect.

[Dimitris]

Larger-caliber guns in AAW mode have two significant advantages compared to "traditional" CIWS:

1) The (often much larger) engagement range offers multiple shot opportunities. This can be very significant for overall PK (even relatively low-PK individual shots pile up into a respectable total probability). A traditional CIWS may get at best 2 shots and often just one.

2) The larger caliber offers options for fragmentation warhead, proximity fuze (CMO models this) as well as guided ammunition.