As this sea control coverage thinned out with range, PLA forces would in theory gain more operational flexibility. This might be offset, however, through the intelligent use of the one or two U.S. Navy aircraft carriers available in theater during a war’s opening weeks. I’ve previously noted how these carriers ought to be used to provide situation-dependent sea control support to Surface Action Groups (SAG) operating further forward, and alluded to their utility in providing situation-dependent tactical support to defenders in embattled First Island Chain territories like the Ryukyus. The positioning required for those tasks could also allow their fighters and AEW aircraft to screen CLF groups, military sealift convoys, and prioritized commercial vessels transiting outside effective land-based air coverage. With two carriers working together, it might even be possible to occasionally use actual or simulated shipping as ‘bait’ for luring Chinese strike aircraft raids into aerial ambushes.
It additionally should be noted that the U.S. and allied ability to delay or prevent the Chinese Ocean Surveillance System (COSS) from locating and correctly classifying transiting ships would severely complicate the PLA’s ability to cue effective anti-ship attacks. Emissions control, operational and tactical deception, and physical as well as electronic attacks against COSS assets would be essential aspects of any U.S. and allied sea lanes protection campaign. Emissions control and tactical deception would also greatly complicate PLA strike aircraft and submarines’ job of locating, correctly classifying, and targeting protected shipping. The use of “decoy groups,” perhaps using a mix of unmanned systems and actual manned low campaign-value platforms that together simulated a convoy or naval battleforce, might induce PLA attackers to waste precious time and weapons inventories engaging false targets. Better yet, it might cause them to move out of positions from which they could detect and intercept actual shipping. Attacking decoys would be particularly harmful to PLAN submarines, as every weapon wasted (and in the case of AIP boats, fuel burned moving into attack position and then "breaking datum") would eat into the amount of time the boat could remain on patrol before needing to head home for replenishment, and the time spent "breaking datum" would be time the boat would not be able to hunt effectively. Effective deception and concealment would likely have detrimental psychological effects on PLAAF and PLAN crews; over time these effects might become debilitating—and highly exploitable by U.S. and allied forces in their own right.
Lastly, U.S. political leadership might opt to selectively strike PLAAF airbases, PLAN submarine bases, and related PLA infrastructure on the Chinese mainland with long-range guided munitions in order to suppress PLA operational tempo. This would be especially likely if the PLA had set the escalation precedent of striking allied territories first at the opening of the war. Such strikes would have to be highly bounded and selective in terms of their targets in order to mitigate escalation risks. U.S. Navy submarines and U.S. Air Force intercontinental-range strike aircraft would probably perform these strikes, with additional strikes launched from Aegis combatants operating as offensive SAGs. Reducing the PLA’s ability to cycle anti-ship attackers into the Western Pacific would be of immeasurable help to the sea lanes protection effort.
With all these combined arms contributions in mind, the principal screening challenge from a surface combatant standpoint would be defending convoys and CLF ships against “leaker” anti-ship missiles fired by PLA strike aircraft and "pop-up” missile or torpedo attacks by PLAN submarines. The density of the PLA threat in a given area arguably would determine an escort’s necessary capabilities. Aegis combatants’ area air defense capabilities would probably be highly desirable for escort missions in the vicinity of the Ryukyus, Taiwan, and Luzon given the proximity to the Chinese mainland. It’s important to remember, though, that the U.S. only has nine Aegis combatants permanently homeported in Japan (with two more coming by 2017), and these warships would probably be charged with escorting the Navy’s Japan-homeported carrier, protecting the Navy’s Japan-homeported amphibious warships, executing offensive SAG missions, and performing ballistic missile defense tasks. The Navy has thirty-eight other Aegis combatants homeported in the Pacific, eleven of which are homeported in Pearl Harbor. However, not all would be surgeable due to the inter-deployment maintenance and training cycle (and this says nothing of the surge-readiness impacts stemming from the 2011 Budget Control Act). We might theorize that of the five West Coast-based carrier battleforces, the first might already be forward deployed in or near the Western Pacific as a crisis peaked, the second and third might be surgeable for arrival forward within 30 days, the fourth might be surgeable within 90 days, and the fifth would have to complete its ships’ (abbreviated) overhauls and pre-deployment workups before surging. Some of these Aegis combatants would not be detachable from their carrier battleforces, and those that were detachable might be needed more for offensive SAG operations.
Not all of the Aegis combatants would necessarily deploy with carriers, though. If we assume that two-thirds of the Pearl Harbor contingent surged as a crisis peaked, we might have seven Aegis combatants available for tasking along the First Island Chain. These warships would be well-placed for protecting shipping to the Ryukyus, Luzon, or eastern Taiwan. Even so, their use for these missions would trade against their use in offensive SAG operations.
The story would be similar with respect to the Japan Maritime Self-Defense Force’s (JMSDF) Aegis contingent. Japan fields six Aegis DDGs and plans to build two more by 2020. Nevertheless, their principal mission of homeland ballistic missile defense would prevent some number of them from performing sea lanes defense operations. The South Korean Navy’s three Aegis DDGs are not counted in this analysis as it is unlikely they would be offered up for operations that did not involve direct defense of their country’s sea lanes.
It should be clear that Aegis combatants’ use for direct protection of shipping would trade against a large number of other high-priority missions. Moreover, Aegis combatants would generally be tethered to the western half of the waters between the two island chain lines. This would hardly preclude their use for sea lanes and CLF protection, for example as a forward screening layer by virtue of their positions, but they probably wouldn’t be able to closely escort shipping all the way from port to port.
Therein lies the logic of a small surface combatant possessing medium-range anti-air and anti-submarine capabilities. Such a combatant would be entirely sufficient for close escort within waters in which air defense is provided by friendly AEW and fighter aircraft supported by aerial refueling aircraft. Closer to the Ryukyus-Taiwan-Luzon line, this kind of combatant would backstop Aegis combatants’ defensive coverage of a convoy.
The proposed LCS-derived frigate will possess the towed active and passive sonar arrays as well as helicopter capabilities needed for effective anti-submarine warfare. CSBA’s Bryan Clark has also outlined how it could receive the requisite anti-air capabilities for shipping escort.[ii] These improvements would not allow the LCS-derived frigate to detect a submarine-launched sea-skimming anti-ship cruise missile raid beyond effective shipboard radar coverage, though. Land or sea-based AEW support via the Navy Integrated Fire Control-Counter Air capability would be crucial to that end.
Bryan has additionally proposed a longer-range shipboard anti-submarine missile than the legacy Vertical Launch Anti-Submarine Rocket; such a weapon could be very effective in disrupting a PLAN submarine’s attack preparations.[iii] It’s worth pointing out that if COSS could not provide a PLAN submarine with a targeting-quality tactical picture to support firing anti-ship cruise missiles from over-the-horizon, the PLAN submarine would have to close within the range of its onboard sensors. If we assume the primary use of sonar for this purpose, that range might be one to two convergence zones from a target (perhaps 30 nautical miles in the first case and 60 nautical miles in the second case). A shipboard “rocket-thrown torpedo” able to quickly reach out to the first convergence zone and ideally also the second would thus be highly useful.
It’s important to note that the JMSDF already fields two light destroyer/heavy frigate classes that would anchor shipping protection in the approaches to the Japanese home islands and Ryukyus.[iv] As I noted earlier, though, there might not be enough of them to fully carry the shipping escort load within the waters Japan was primarily responsible for protecting. This suggests the utility of the LCS-derived frigate gaining medium-range anti-air capabilities.
One final point is that there would be a demand for LCS-derived frigates to participate in offensive SAGs. It would accordingly be desirable to backfit as much of the LCS-derived frigates’ anti-surface and anti-submarine capabilities as possible into legacy LCS hulls in order to free up as many of the frigates as possible for shipping protection tasks. The logic for using backfit LCSs instead of the frigates in forward-operating SAGs is simple: since the frigates are not presently slotted to receive medium-range air defense capabilities, and since Aegis combatants would be principally responsible for SAG air defense anyway, then the inclusion of backfit-improved LCSs instead of air defense-capable frigates in the SAGs would not alter the existing concept of operations.
The bottom line is that protection of shipping, including the CLF, would likely be far more resource-intensive than is often assumed in the strategy debates. Sea lanes protection would be absolutely critical to the U.S. prevailing in the war, and as such merits extensive study and analysis. I will note that I have never participated in campaign analysis of these questions, nor have I ever been “read into” any such analyses that might have been conducted. Detailed quantitative analysis may very well prove that some of my key assumptions and conclusions are incorrect. Even so, my errors almost certainly center on the specifics of the threat and not on its general nature or the needed seriousness of the offsetting response.
The views expressed herein are solely those of the author
and are presented in his personal capacity. They do not reflect the official
positions of Systems Planning and Analysis, and to the author’s knowledge do
not reflect the policies or positions of the U.S. Department of Defense, any
U.S. armed service, or any other U.S. Government agency.
[i]
The discussion that follows is heavily influenced by CAPT William J. Toti, USN
(Retired). “The Hunt for Full-Spectrum ASW.” Naval Institute Proceedings 140, No. 6, June 2014. Toti’s article
is seminal on modern anti-submarine warfare and should be read in its entirety
in parallel to this post.
[ii]
See Bryan Clark. “Commanding the Seas: A Plan to Reinvigorate U.S. Navy Surface
Warfare.” (Washington, D.C., Center for Strategic and Budgetary Assessments,
2014), 27, 50-51.
[iii]
Ibid; 27.
[iv] A third similarly-capable JMSDF
destroyer class
exists but would generally be tied to providing air defense support to Kongo-class DDGs on ballistic missile defense
patrols.