The recently announced Indo-Pacific Outlookby the Association of Southeast Asian Nations (ASEAN) at the 34thSummit indicates the Southeast Asian perspective on the evolving geostrategic environment. Unsurprisingly, ASEAN highlights cooperation, stability, peace, freedom of navigation and other values in the statement. The Outlook, however, leaves a question: how will ASEAN protect these values when diplomatic measures fail?
Under the ASEAN way, it would not be realistic to expect strong words such as those implying the use of force in any official statement, but member countries bordering critical straits could indirectly convey the message by demonstrating relevant defense capabilities. Among a variety of defense capabilities, tracking foreign submarines through enhanced undersea surveillance could be a relevant option.
The major strategic significance of Southeast Asia in the Indo-Pacific region is mostly found in several critical sea lanes where various powers’ military assets travel through channels connecting the two oceans. Under the United Nations Convention on the Law of the Sea (UNCLOS), military vessels and aircraft enjoy the right of innocent passage through these sea routes, whether classified as international straits or archipelagic waters, and coastal countries track these movements. Modern technology makes it feasible for coastal states to readily track foreign military aircraft and surface vessels, a task that is more about safety than security. But tracking submerged submarines is another matter with a much higher barrier to entry.
In the face of complicated hydrographic conditions along with the improving stealth of submarines, there are high requirements for detection in terms of sonars, training, joint operations, and other elements of undersea surveillance. Therefore, successfully tracking submarines requires a high degree of military professionalism and capability. But once successfully tracked and trailed, a submarine receives a clear but private message of deterrence.
This kind of covert deterrence would fit the geopolitical context in Southeast Asia. Firstly, it is generally legitimate for a littoral state to detect underwater entities because submarines should sail on the surface during innocent passage in territorial waters, while a submerged transit is acceptable under UNCLOS in passing sea routes and international straits. But only when a littoral state can identify the locations of foreign submarines transiting underwater can it determine whether UNCLOS is violated or obeyed. In other words, Southeast Asian countries have a sovereign right and legal obligation toward undersea surveillance.
Tracking submerged submarines also presents a credible level of readiness for uncertainty. Overt exercises can be tailored for specific scenarios to prove certain levels of joint operations and other tactical skills, while bilateral and multilateral exercises highlight partnership, alliance, and other interstate security ties. Exercises are often much broader than the single capability of tracking submarines. Exercises, however, are either fully or semi-planned, and tracking foreign submarines is a truly dynamic encounter between two sides without an advance arrangement. Furthermore, Southeast Asian countries already have routinely conducted various bilateral and multilateral exercises with regional and extra-regional counterparts.
Tracking submerged submarines is usually beyond the microscope of conventional and social media, and can avoid the open hostility or other forms of public outcry that often transpire after close encounters between surface vessels. As the detecting side can deny any information on the tracking, publicity of the event would be more controllable compared with open statements or actions. For the country of the tracked submarine, such encounters are usually negative for national pride and military professionalism, so decision-makers would not have much incentive for revealing the encounter.
Improving Hardware and Challenges Ahead
Since the end of the Cold War, Southeast Asian navies, particularly those of Indonesia, Malaysia, and Singapore, have built up their anti-submarine warfare (ASW) capabilities, including through several types of undersea sensors. These three countries have acquired survey vessels to establish their individual hydrographic databases. They have also procured state-of-the-art anti-submarine warfare helicopters such as the Super Lynx, S-70B, and AS-565MBe and deployed them on their respective frigates and corvettes which have towed or hull-mounted sonars. Furthermore, all three navies possess submarines to play the role of targets during training.
Some characteristics impose challenges on the ability of Southeast Asian countries to track submarines. Large areas of territorial waters are natural obstacles for Malaysia and Indonesia. The numbers of maritime survey vessels they have in service are rather small for accumulating and updating their hydrographic data. By the same token, these two countries’ sensors and platforms, including ASW helicopters or ships, are likely not numerous enough to cover their broad territories or responsively deploy to where contacts are found.
Thanks to its tiny size, Singapore’s assets cannot be geographically diluted, but it shares other constraints with its neighbors, including a lack of fixed-wing ASW aircraft. The Indonesian CN-235 and the Singaporean Fokker-50 maritime patrol aircraft (MPA) only have limited ASW capabilities, and Malaysia’s smaller Beech-200 MPAs have no payload space for ASW weapons. Finally, operational experience is another common challenge for these three countries, as they began to introduce their sophisticated ASW assets mainly in the post-Cold War era where opportunity for practice was slim.
Currently, the three navies are on a trajectory of improving their ASW capabilities, such as through the towed sonar arrays found in Malaysia’s upcoming frigates and Indonesia’s plan of building underwater surveillance systems. These efforts would gradually make tracking foreign submarines underwater more feasible in the foreseeable future.
Unlike in the Cold War-era, some Southeast Asian countries, especially these three bordering critical straits, do not have empty arsenals. Although their defense capability is still inferior to most extra-regional powers, some wise and tailored applications of their military assets would support ASEAN agenda’s beyond diplomatic and economic means. Successful tracking foreign submarines would make the ASEAN Outlook more valid in the Indo-Pacific geostrategic landscape.
Shang-su Wu is a research fellow at the S. Rajaratnam School of International Studies (RSIS), Nanyang Technological University in Singapore.
Featured Image: A Chinese submarine transits in the Yellow Sea (Wikimedia Commons)
The containers arrived at Norfolk early in the morning, with the snow a powdered sugar-like dusting on the trucks as they moved through the port. The darkness failed to hide their arrival from the Russians watching them through the hijacked security cameras. Another shipment in the cold weather of nondescript containers, their true propose not yet revealed. The containers had traveled for 36 hours to arrive on time and be loaded onto the requisitioned container ship MV Lt. Lyle J. Bouck. The watching Russians marked the containers as convoy supplies without a second thought, oblivious to what they had just missed.
Days before the containers were moved an AI had considered each ship’s cargo carefully. It speed, tonnage, fuel, acoustic signature, and survivability from a number of threats were all variables in the calculation. Ultimately, the AI decided that this convoy was not worth protecting. The cargo was all non-personnel, and the ships were old and only the commander’s ship was manned. The Navy had been stretched thin even with the Royal Canadian Navy and the Coast Guard ships that had been pressed into convoy duty. No ships would be assigned to protect them. They would be listed as unprotected, having to use the winter storms to shield themselves from satellites, as they attempted to dash across the Atlantic, praying for the best.
Vasily Sokolov read the report gleaned from a backdoor purchased off the Dark Web, checked the box for ‘no escort’ and moved on. He scrolled through the supply manifest slowly and then pulled up the satellite imagery for the ships, a satellite composite only four hours old. The only visible armaments on the ships was the M109 Paladin, undoubtedly with its hypervelocity projectiles for air and missile defense. It sat atop a stack of red and blue containers, moored to them by large metallic brackets. A bulky cable snaked its way back to the superstructure of the ship, terminating in its dark underbelly. Vasily checked the ‘3D’ box and turned the ship, revealing a short ugly dome perched atop the superstructure, the predictive software pulling from known ship plans and previous satellite imagery. Quickly checking the projected dimensions on the dome against shipment records, Vasily confirmed that it contained the fire control radar that had been bolted on by techs the day before. With three of the ships in the convoy carrying a Paladin, it was hoped there would be some protection from hypersonic missiles. Vasily chuckled, as if missiles would be wasted on these low-value ships. A quick look at the aft decks of the ships confirmed that each was carrying two ‘Grasshoppers,’ the ASW drone that the Americans used. As he moused his way through the other ships, he could see Paladins emplaced onboard the other convoy ships, and prefabricated hangers being assembled on the back decks for the Grasshoppers. The tiny dots of technicians on his computer screen would be working through the night to get them finished in time to depart on their dangerous voyage.
The convoy sailed at 0800, picking up a low-pressure front that the predictive weather AI’s expected to turn to rain in the next 16 hours. The winter storms of the Atlantic were notorious, but the front seemed destined only for continual, dismal rain. The Grasshoppers went to work immediately, making sure that they weren’t picking up a tail when they exited the anti-drone net across the mouth of the harbor. The cycle of one hour on, two hours charging would continue as long as the weather permitted.
At 2100, in the darkness of the cloudy night, the containers were opened. Large cylinders were wheeled out and quickly put underneath the superstructure and covered in canvas. In the morning, they would be unseen by any satellite that managed to catch the convoy, and the Russians would be none the wiser. The convoy’s secret weapon, two Mk. 2 Autonomous Underwater Combat Vehicles (AUCVs) were prepared for battle. As their last restraint was being tightened the rain began, cloaking the convoy in its misty hold; the convoy would hide under this front for the rest of its journey.
Vasily Sokolov looked at the computer screen and leaned back. He stifled a yawn, and longed to go back to bed, but, no, there was a war going on, and his job needed to be done. His eyes ran down to the last box simply titled ‘Recommendations.’ Once again he paused, the convoy was equipped to deal with hypersonics, but not torpedo carriers, so that’s what he would recommend. One should be enough for an unarmed convoy, no, two for safety. Better safe than sorry his father had always said. Give them torpedo interceptors? No, the convoy wouldn’t be able to fight back, they only had 12 Grasshoppers. Better to load as many torpedoes as possible. His mind made up, Vasily Sokolov cracked his fingers and began to type.
The rain had begun to lessen in the middle of the Atlantic as the Captain arrived on the bridge from her all too short sleep. The USNR had called her up, and assigned her to what she considered to be little more than a oversized bathtub with propellers. The Captain’s voice echoed out across the bridge as she put on her VR display. “What does the report say?” The Tech looked out at the whitecaped waves as the threat report started to print out.
“Report for 41°37’41.5″N 31°33’22.5″W. Two Type 34 Autonomous Torpedo Carriers detected, no other threats at this time.”
“Two Mother Hens” the Tech called out, “both are probably carrying a full load of eggs, no interceptors, the Autonomous Acoustic Monitoring AI predicts them to be here, but no one’s sure.” The Captain grumbled, she had never been comfortable with the idea of the football-sized drones floating through the water replicating SOSUS, but it was undoubtedly effective. “They went silent 4 or 5 hours ago, switched over to electric,” the Tech continued. “Any idea on what type of eggs?” the Captain asked with her light southern drawl. “Nope, the report has nothing on the torps,” the Tech replied wearily once again staring back out at the waves. The captain sighed as she stripped off the VR display, and went off to make up for her lack of coffee. For a brief moment her eyes gazed across the overcast rain and the Grasshoppers doing their job. There was nothing else she could do.
Ten miles out the Mother Hens were studying the acoustic signatures of the convoy. The onboard AI’s knew everything that Russian Naval Intelligence had gleaned about the convoy and were locked in deliberations. After a few minutes, they decided on a simultaneous pincer movement from the front and back as their plan of attack, and both slowly set off to get into attack position.
Grasshopper 4 was completing a set of passive dips on the north side of the convoy as droplets of rain pinged off its aluminum body. It had just popped up and moved 300 feet further north, covering the left flank of the convoy, and lowered its sonar when something unexpected happened. Imperceptible to the human ear, but detectable to the computer was a slight rumble. The computer reached a decision in seconds, deciding to stay put in the cold, grey rain, and requested Grasshopper 7 to immediately move into the area. Onboard the Bouck, a track popped up on the freshly-caffeinated Captain’s VR display, simply reading ‘possible threat.’ Beneath the waves of the Atlantic, the Mother Hen continued on its way oblivious to the threat above. Grasshopper 4 asked for permission to go to active sonar but the Captain denied it as Grasshopper 7 sped its way towards Grasshopper 4, and the Bouck’s own Grasshopper 9 lifted off. The active could wait. As Grasshopper 4 waited it compared the rumble to previously recorded signatures in the Grasshoppers’ database, the VR display showing a rapidly increasing chance that the contact was a Mother Hen. Calmly, the Captain watched the hostile track as the probability reached 60 percent, and then gave the order to fire.
Across the waves, Grasshopper 4 dropped the lower part of its body. The dull-grey, square casing discarded from the torpedo as it fell into the black water below, and the torpedo immediately went active. The Mother Hen detected the crash of debris ahead, and within milliseconds of hearing the first ‘ping,’ let off its own countermeasures. On the Bouck’s bridge the Captain looked on at the command map. Three of the four-noisemaker patterns were known, having been stolen from Russian firms under cyber espionage, and the torpedo immediately ignored them. The fourth noisemaker was unknown, and the Captain watched as the torpedo waivered for a heart-stopping second, then turned to chase the first Mother Hen.
The first Mother Hen had made it far too close to the convoy, nearly guaranteeing a hit with its torpedoes. The onboard AI considered trying to run but discarded the idea instantly. With an air of sadness, the first Mother Hen turned in towards the convoy and the oncoming torpedo, and unceremoniously fired all of its ‘eggs.’ A wave of torpedoes lanced out in a spread: the Hen’s final gamble. As the torpedoes left, the two canisters on the Mother Hen’s back were blown upwards in a silver stream of bubbles towards the surface. One immediately broadcast the position of the convoy and the fate of the doomed Mother Hen. The second one popped out, and with an eruption of fire flew after Grasshopper 4. With little formality the missile closed, as Grasshopper 4 tried to hug the dark ocean for safety, before being turned into a bright ball of flame. The sorrow that was felt upon the loss of Grasshopper 4 was immediately overshadowed by the churning sea that signaled the death of the Mother Hen. Grasshopper 7 dipped into the cold waters and went active, ensuring that the Mother Hen was not playing dead. No return on the sonar. A confirmed kill.
Onboard the Bouck, the VR display changed to ‘threat destroyed.’ On the bridge, the Captain had already ordered a hard turn to starboard, turning parallel to the torpedoes and minimizing the convoy’s cross section. With the threat of incoming torpedoes and the possibility of a second Hen, the Captain unveiled her trump card. With an unceremonious crash into the Atlantic, the two carefully hidden Mk. 2 AUCV’s dropped into the waves, their long grey forms diving into the depths. All available Grasshoppers simultaneously rose from their charging ports in a frenzy of activity, as they moved across the convoy seeking out their enemies.
One of the Mk. 2’s now sat underneath the hull of the Bouck, trying to hide the fact that two were now in the water. The other Mk.2 assessed the incoming torpedo spread. The Mk.2’s AI pulled information from Grasshopper 7 and its own sensors, overlaying the convoy’s turn, and projecting forward. Three threats, the Mk.2 AI decided, and it dived and launched. Six ‘Silverfish’ torpedo interceptors raced out from the Mk. 2, closing in on the inbound torpedoes. The Captain looked on from the bridge. By the way the Mother Hen’s torpedoes were dodging, it was obvious they were outdated; clearly the Russians had underestimated the convoy’s defenses.
The Silverfish jabbered the whole way there, determining the Mother Hen’s torpedoes’ type and patterns. The first torpedo went left when it should have gone right, meeting its end in a mess of debris. The second torpedo dodged the first Silverfish, slipping through by diving at just the proper time, only to be met by the second Silverfish. The third torpedo dodged left, then right, the first Silverfish missing by mere inches, shortly followed by the second Silverfish mistaking a feint for a move and shooting underneath the torpedo.
The Mk. 2 looked on impassively, quickly calculating the chance of hitting the third torpedo, and launched a further three Silverfish. The torpedo was within 1000 feet and closing as the Silverfish streaked towards it, separated by mere seconds. The torpedo danced left, right, up, and down in an attempt to throw off the Silverfish gaining on it. But in the end it was not successful, the second Silverfish tearing its engines to pieces leaving it dead in the water. The Captain looked up coolly from the command map, only to hear klaxons blare.
The second Mother Hen had made it much closer to the convoy, slipping in through the convoy’s baffles while they were distracted, and finding itself a wolf among a flock of sheep. Sitting under the hull of one of its prey, it reached its decision and cut its engines, drifting slowly back, unseen in the darkness of the Atlantic.
The Captain sat up in shock as the VR display squealed an alarm, ‘FISH IN THE WATER! FISH IN THE WATER!’ and twisted around to see the tracks of four torpedoes from the second Mother Hen heading towards the Bouck and her sister ship the Sgt. William L. Slape. Behind her the Mk. 2 that had dealt with the initial torpedo barrage spit out the last of its 12 Silverfish at the new incoming wave, hoping that the interceptors would overtake the torpedoes before they hit. A Grasshopper also dropped down behind the convoy and went active, trying to acquire the threat. Within a second, another barrage of torpedoes from the second Mother Hen headed towards two other ships in the convoy, traveling underneath the water, preparing to pop up and hit the ship’s hulls perpendicularly.
The Captain waved her hand and the VR display stopped its alarms and calmly showed the tracks towards her convoy. Below her the fresh Mk. 2 was considering its options. It could try to destroy the torpedoes targeting the Bouck and the Slape, or it could go after the torpedoes targeting the ships farther forward. Grasshopper 5 noticed a lack of sound as one of the torpedoes targeting the Bouck stopped accelerating; it was now unguided and slowing as its propeller stopped, the watertight seals failing and the engine being swamped. The tracks of the Silverfish from the first Mk. 2 glowed green on the VR display, but it was more than clear that they would not stop the torpedoes in time.
The fresh Mk. 2 made its decision, and started to flip 180 degrees. Halfway through its turn it launched all 12 of its onboard Silverfish towardsthe torpedoes planning to pop-up, and brought its motors onto full. The Captain watched as her Mk. 2 launched its Silverfish, and her VR display show a 94 percent kill chance on the torpedoes targeting the ships farther down the line. The fresh Mk. 2 dropped both its torpedoes on the now acquired Mother Hen and pushed its engines to full, accelerating towards the torpedo.
The VR display shuddered as the rear end of the Bouck was lifted six inches from the water and its rear decks were covered in a spray as the Mk.2 met the oncoming torpedo. The torpedo tried to fight until the end, but the Mk. 2 imposed its bulk between the torpedo and the Bouck. An explosion was seen in the distance, the death of the second Mother Hen that had attacked. There was a second of calm then the Slape lifted several feet in the air as she too was hit. Two great spouts of water shot up from the side of the Slape as the torpedoes impacted just below the waterline. The VR display made an all-clear noise as the Silverfish intercepted and destroyed the remaining torpedoes, overtaking them and shattering them into a thousand pieces. Damage reports flooded in from the dying Slape. Like stricken rats, the Slape’s Grasshoppers, recharging from their last shift, fled the ship as it filled with water quickly shuttling to open charging ports on other convoy ships. The VR display marked the Slape as a loss, with a bright red outline, as the Grasshoppers buzzed, diligently searching for more enemies.
Behind the convoy a beacon popped up transmitting the location and death of the second Mother Hen. The Captain watched its progress as the noise of the fight slowly faded from her ears. Slowly the Mother Hen’s beacon was swallowed into the Atlantic, along with the shattered wreck of the Slape. The rain slowly picked back up in intensity as it covered the convoy with its grey cloak.
Vasily looked once more at his computer screen as it displayed the fate of the Mother Hens. “Spasibo”, he said to himself as a wry smile grew on his face, “Thank you for showing me your countermeasures.” He perched a cigarette between his smiling lips, reached out, and began to type, “To all AI Anti-Shipping Deployments….”
Evan D’Alessandro is a student at Luther College studying astrobiology, data science, and international relations. He enjoys military history and policy debate, and aspires to become a naval intelligence officer in the future. He can be contacted at email@example.com.
Featured Image: Torpedo Exexutor, concept art by Markus Biegholdt, 3D art by Miroslaw Cichon.
This article originally featured in The Naval War College Review in 2008 and is republished with permission. Read it in its original form here. Read Part One of the republication here.
By Gabriel Collins, Andrew Erickson, Lyle Goldstein, and William Murray
Sensors, Systems, Research, Development, and Training
American efforts at exploiting advancements in commercial off-the-shelf technology have received attention. One article observes that “the updated (COTS) CCS MK II [fire control] system is not only used on the Los Angeles and Ohio classes, but is also used on the new Seawolf and Virginia class submarines”;44 another points out that “92% of the hardware and 90% of the software used in non-publicly available projects in fact come from popular commercially available technologies.”45 China’s intense interest in the U.S. Navy’s use of COTS may stem in part from Beijing’s effort to develop a world-class commercial information technology industry and to incorporate its products into the PLA.
Chinese analysts also monitor American submarine sensor development. One article notes, “At present, the U.S. is the world leader in developing periscope technology and using it on its submarines.”46 U.S. efforts to bolster the submarine force’s mine warfare capabilities receive particular attention.47 Moves to develop and acquire the Long Term Mine Reconnaissance System (LMRS) have been noted, with one researcher stating that “the U.S. is now buying 8 long-range mine scouting systems to be put on the Los Angeles and Virginia class nuclear attack submarines.”48
Chinese observers pay fairly close attention to American submarine-related research and development efforts. For example, websites on Chinese naval matters frequently report on the awarding of Defense Advanced Research Projects Agency (DARPA) and Office of Naval Research (ONR) contracts.49 Chinese journals take advantage of these announcements and also scour the U.S. open press for sources that can be exploited. For example, a rather lengthy article in the June 2002 issue of 现代舰船 (Modern Ships) reprinted the “Submarine of the Future” briefing slides (complete with a logo in the upper left-hand corner of each) generated by the DARPA-sponsored, Lockheed Martin–led industrial consortium “TEAM 2020.” These slides depict futuristic hull forms, sonar configurations, propulsors, weapons storage ideas, interfaces for unmanned underwater vehicles, and other elements of advanced submarine designs and concepts.50 It seems that little, if any, publicly released information regarding U.S. submarine-related research and development escapes the attention of Chinese analysts.
In keeping with the technological dynamism of U.S. platforms and their constant improvement, Chinese analysts also credit the American submarine force with an extremely rigorous selection and training process for commanding officers. In a coauthored article in Modern Navy, Rear Admiral Yang Yi, a PLA expert on the United States and former naval attaché in Washington, emphasizes that “the U.S. Navy’s selection process for the commanding officers of nuclear submarines is very strict.” Yang details the numerous education and training programs that successful candidates must attend, as well as the periodic qualifying tests they must undergo. A major emphasis of his article is the extent to which submarine commanders must periodically update their “specialized [technical] knowledge.”51
Although China is emerging as a submarine power, its submarine force, and indeed its navy overall, generally lacks blue-water experience, to say nothing of a combat history. Of course, this paucity of experience stands in stark contrast to the U.S. submarine force, and PLA Navy analysts are acutely aware of that disparity. In fact, Chinese naval analysts have expressed particular admiration for the record of American submarines in World War II, pointing out that “the U.S. submarine force had the fewest losses” of any major submarine force “but had high combat effectiveness. According to statistics, the U.S. submarine force destroyed 1,314 enemy ships during the war.”52 Moreover, Chinese sources indicate an appreciation for the accumulated knowledge that the U.S. Navy has achieved through decades of intense submarine operations. Another Chinese source observes: “The U.S. is a country with 100 years of experience in building submarines, and with so many years of experience the USN constantly emphasizes the ability of a submarine to take punishment [and survive].”53
While there are numerous Chinese writings on the U.S. Navy’s submarine force’s campaign against Japan, this article focuses on the Chinese perceptions of American submarine operations during the Cold War. Some of the observations made in this context may explain aspects of contemporary PLA Navy submarine doctrine. For example, an article in Modern Ships relates an anecdote of a “Soviet Type 627 [known in the West as “November”] nuclear attack submarine [that] once went all out in a race with a U.S. Navy aircraft carrier, revealing the Soviet attack submarine’s capabilities. [This revelation] apparently has had a major impact on the development of a new class of American submarines.”54 This appraisal of the peacetime interaction between the two navies may suggest that overly aggressive tactics employed by the Soviet Navy yielded too much information to the U.S. Navy. In general, it is quite clear that Chinese sources understand that a “main mission of [U.S.] nuclear attack submarines [during the Cold War] was to deal with the Soviet Navy’s SSBNs.”55
With respect to the Cold War at sea, one Chinese book published in 2006 is worthy of particular note.56 The translation of a Russian book, Secrets of Cold War Undersea Espionage, states that “U.S. nuclear and conventional submarines would often lurk along the routes of Soviet warships, and even within Soviet territorial waters, conducting intelligence activities.”57 It is noted that “the SOSUS [Sound Surveillance] system substantially helped the U.S. to cope with the capabilities of the Soviet submarine force.”58 The subject of acoustic signatures is also raised: “In the ocean, there are simply too many sources of noise. . . . In order to cope with this problem, the U.S. decided to build an acoustic signature catalogue (resembling a fingerprint) for Soviet submarines.”59
Chinese ASW and the U.S. Navy Submarine Force
When considering Chinese views of the American submarine force, it is certainly relevant to consider how China appraises its own antisubmarine warfare forces. Generally, China considers its ASW forces to be weak. One Chinese naval analyst observes: “[Chinese] people are focused on China’s submarine force (both conventional and nuclear) development, but often neglect the threat we face from [U.S. Navy] submarines.”60 It is, moreover, suggested that “there is still a relatively large gap between [China’s] ASW technology level and that of the world’s advanced level.”61 In appraising the ASW capabilities of its own surface forces, another naval analyst notes, “Across the world, most naval ships are now equipped with towed array sonars, which has increased their ASW capabilities, but most of our ships only have hull mounted sonars.”62 Finally, there is a concern that these antisubmarine assets are themselves highly vulnerable: “Submarines can carry out ferocious missile attacks from tens or even 100–200km ranges, causing the submarine hunting vessels to become the hunted targets.”63
Chinese aerial ASW is also highlighted as a particular weakness. One Chinese analyst judges that the Z-9 helicopter lacks adequate range and internal space for the ASW mission.64 A second argues that while the Z-8 has better range and capacity, it is too big for most surface combatants to carry and chronic engine troubles have limited production.65 The Russian-import Ka-28 ASW helicopter is reported to be capable but few in numbers.66 As for Chinese maritime patrol aircraft, some designs have apparently been developed, including a variant of the Y-7 Fearless Albatross, but the outlook is said to remain bleak.67 Thus, one evaluation of Chinese aerial ASW concludes, “Our country at the present stage does not have an ASW maritime patrol aircraft . . . but the number of submarines in our peripheral seas is increasing, and their technological sophistication is also increasing. This contradiction is becoming more obvious every day, creating a grim situation.”68
In Chinese discussions of Russian ASW systems, there is a pointed recognition that the Soviets leaned heavily toward the use of tactical nuclear weapons (e.g., nuclear depth charges and torpedoes) in ASW operations.69 Tactical nuclear weapons are also mentioned in the context of mine warfare. An article in the July 2006 issue of Modern Navy, in discussing possible PLA Navy use of sea mines, suggests the potential combat value of nuclear-armed versions.70 It will be important to watch closely for any sign of Chinese efforts in this direction.
While the overall impression is that of Chinese ASW weakness, there is one notable exception. Significant prioritization appears to be given to the use of sea mines for the antisubmarine mission, as if to produce a “poor man’s ASW capability.”71 One discussion explains, “Because of a tremendous change in the maritime strategic environment, since the early 1990s the PLA has made mobile ASW sea mines a focal point of weapons development.” The analysis continues, “[China] is energetically undertaking the research mission [of] using [mobile ASW sea mines] against U.S. nuclear submarines.”72 The same discussion also hints at a review possible PLA Navy ASW role: “The major mission of self-guided sea mines is to isolate American nuclear submarines outside the First Island Chain.”73
It is noteworthy for the future development of Chinese antisubmarine warfare that hydroacoustics has been called a “key point” technology for state investment.74 The conventional wisdom has long been that the Chinese submarine force is focused entirely on the anti-surface ship mission. This assumption may have become outdated, perhaps especially after the PLA Navy received the last of eight new Kilo-class diesel submarines (and accompanying weaponry) from Russia in 2006. According to Professor Li Daguang of China National Defense University, these new Kilos have four missions: to blockade Taiwan, threaten carrier battle groups, employ land-attack cruise missiles as a “strategic weapon,” and “form an underwater threat to the U.S. nuclear submarine force.”75 There is also preliminary evidence that China is moving toward deploying antisubmarine rocket weapons on its newest surface combatants.76 This system is no “silver bullet,” as the Chinese would still have severe, perhaps insurmountable, targeting and cueing problems, but successful acquisition and deployment of ASROCs would extend the engagement range of Chinese ASW weapons significantly. It is also worth noting that Chinese sources discuss “many openly published dissertations concerning underwater targeting for a homing depth charge.”77
To reverse the equation: How do Chinese naval analysts appraise American ASW, and in particular the submarine force’s part in it? Clearly, the PLA Navy understands the overall centrality of SSNs in U.S. antisubmarine warfare. Thus an article in Modern Navy states: “The nuclear attack submarine . . . is the most effective tool for ASW.”78 However, some PLA Navy observers appear rather unimpressed by American efforts in ASW. The same official Chinese Navy journal observes: “The U.S. Navy actually has not had sufficient exercises in the [ASW arena] and also lacks experience.”79 In the same article, it is likewise noted that “conducting ASW in the littorals represents a special difficulty for the USN” and that “the combat advantage of the U.S. Navy nuclear submarine force in the littoral areas is far from obvious.”80 On this note, Campaign Theory Study Guide, a 2002 textbook written by China National Defense University scholars that draws on a variety of high-quality doctrinal publications, emphasizes that “nuclear powered attack submarines have difficulty operating in close proximity to shore due to natural conditions.”81 Another Chinese naval analysis suggests that “up to 2005, the USN has altogether 350 ASW platforms, just 11% of the number of [ASW] platforms it fielded in 1945. Moreover, many of these current naval and air platforms are not specialized for ASW, but more often are multi-mission platforms.”82 This quantitative comparison across historical periods is crude in some ways, but there is no denying that inherent physical principles combined with the vast geographical area of the Pacific Ocean will likely keep ASW an asset-intensive mission, even in the age of “net-centric warfare.”
The U.S. Navy Submarine Force-Level Trajectory
Chinese discussions of the American submarine force focus heavily on the continuing decline in its size. As one article from a People’s Republic of China (PRC) naval interest publication states, “The decline of U.S. submarine strength is inevitable.”83 Indeed, that a wide variety of Chinese naval sources share this evaluation suggests that this “decline” now passes for conventional wisdom within the PLA Navy. The Chinese naval community is likely paying close attention to internal U.S. debates, knowing that investments made (or forgone) today in submarine fleet modernization shape the future fleet.
Some Chinese assessments of the Seawolf program appear to point out indirectly the internal political tensions that hold down American submarine build rates now and perhaps in the future. One volume notes: “Although the Sea Wolf– class SSN gathers the era’s most advanced technology in a single hull, and possesses beyond-first-class performance, the appraisals of ‘Sea Wolf’ by American public figures from all walks of life differ, with a roughly half-and-half split between praise and condemnation.”84
Taking the long view, Chinese naval strategists recognize that force levels have dropped drastically from Cold War levels. One source observes, “Since 1989, the U.S. Navy’s nuclear-powered attack submarine [force] has been reduced by half.”85 A more recent Chinese naval press article estimates that “[U.S.] nuclear attack submarines will decline in number by close to 40%, eventually reaching 30 boats.”86 This calculation is roughly consistent with a projection in Modern Navy that anticipated a sustained build rate of one boat per year.87 Rear Admiral Yang Yi, writing in 2006 on the future size of the American submarine force, quoted one American analysis as follows: “China already exceeds [U.S. submarine production] five times over. . . . 18 [USN] submarines against 75 or more Chinese navy submarines is obviously not encouraging [from the U.S. perspective].”88
A Reputation for Mastery?
This article demonstrates that Chinese strategists are keenly interested in the U.S. Navy’s submarine force. Thousands of articles have reviewed various aspects of American submarine capabilities, operations, and developmental trends. There is clear evidence that Chinese naval analysts have enormous respect for U.S. submarines, submariners, and their weapons. Certainly, China aspires to be a submarine power and hopes to emulate certain aspects of American experience. However, it is equally clear in these writings that the U.S. submarine force is seen as a key challenge in any military confrontation between Beijing and Washington. It is significant in that regard especially that Chinese analysts are increasingly drawing attention to, and seeking to remedy, their antisubmarine warfare deficiencies. The study also reveals an apparent assumption within Chinese naval analytic circles that American submarine force levels are on a downward trajectory.
The authors are research faculty in the Center for Naval Warfare Studies at the Naval War College in Newport, Rhode Island. They are members (Dr. Goldstein is the founding director) of the College’s China Maritime Studies Institute. The opinions expressed in this report are those of the authors alone and not the assessments of the U.S. Navy or any other entity of the U.S. government.
“美国雷声公司拟用商用流行技术更新潜 艇作战系统” [U.S. Raytheon Corporation Draws Up a Plan to Use COTS to Upgrade Subs’ Systems], 情报指挥控制系统与仿真 技术 [Intelligence, Command, Control, and Simulation Technology], no. 10 (2003), p. 19.
戴维 [Dai Wei], “ESM 对潜艇支持的新 作用” [ESM’s New Role in Submarine Support], 情报指挥控制系统与仿真技 术 [Intelligence, Command, Control, and Simulation Technology], no. 7 (1999), p. 19. 46. 李平, 陆炳哲 [Li Ping, Lu Bingzhe], “美 国虚拟潜望镜研究及进展” [Research and Progress of the American Virtual Periscope], 船舶电子工程 [Ship Electronic Engineering] 26, no. 5 (2006), p. 199.
This article does not analyze Chinese examinations of U.S. sonar, navigation, combat control, ESM, or radio systems.
巡抚 [Xun Fu], “中国海军反潜武器的发展” [PLA Navy Antisubmarine Weapons Development], 舰载武器 [Shipborne Weapons] (August 2005), p. 29.
Tai Feng, “Does China Need Antisubmarine Patrol Aircraft?” p. 73.
Xun Fu, “PLA Navy Antisubmarine Weapons Development,” p. 30.
Tai Feng, “Does China Need Antisubmarine Patrol Aircraft?” p. 73.
Ibid., p. 75.
Ibid., p. 73.
See, for example, ibid., p. 72; and Xun Fu, “PLA Navy Antisubmarine Weapons Development,” p. 30.
刘衍中, 李祥 [Liu Yanzhong and Li Xiang], “实施智能攻击的现代水雷” [Carrying Out Intelligent Attacks with Modern Mines], 当 代海军 [Modern Navy] (July 2006), p. 29.
For a much more detailed discussion of this issue, see Andrew Erickson, Lyle Goldstein, and William Murray, “China’s Undersea Sentries: Sea Mines Constitute Lead Element of PLA Navy’s ASW,” Undersea Warfare (Winter 2007), pp. 10–15.
Lin Changcheng, “The Hidden Dragon in the Deep,” p. 30.
Ibid., p. 31. The “first island chain” comprises Japan, its northern and southern archipelagoes, South Korea, Taiwan, the Philippines, and the Greater Sunda Islands. See Xu Qi, “Maritime Geostrategy and the Development of the Chinese Navy in the Early Twenty-first Century,” trans. Andrew S. Erickson and Lyle J. Goldstein, Naval War College Review 59, no. 4 (Autumn 2006), pp. 47–67, esp. note 11.
Xun Fu, “PLA Navy Antisubmarine Weapons Development,” p. 28.
陈位吴 [Chen Weiwu], “解放军新基洛” [The PLA’s New Kilos], 国际展望 [World Outlook] (July 2006), p. 25.
Xun Fu, “PLA Navy Antisubmarine Weapons Development,” p. 29.
Ibid., p. 32.
许世勇 [Xu Shiyong], “美海军实施网络反潜 新战略” [The U.S. Navy’s New Network ASW Strategy], 当代海军 [Modern Navy] (September 2006), p. 44.
Ibid. For an equally unimpressed American view, see John R. Benedict, “The Unraveling and Revitalization of U.S. Navy Antisubmarine Warfare,” Naval War College Review 58, no. 2 (Spring 2005), pp. 93–120.
Xu Shiyong, “The U.S. Navy’s New Network ASW Strategy,” p. 44.
薛兴林 [Bi Xinglin, ed.], 战役理论学习指南 [Campaign Theory Study Guide] (国防大 学出版社 [National Defense University Press], 2002), vol. 3, p. 261.
石江月[Shi Jiangyue], “‘中国潜艇威胁’与美 军反潜战的复兴” [“The Chinese Submarine Threat” and the Revival of the U.S. Military’s ASW], 现代舰船 [Modern Ships] (May 2007), p. 17.
胡锦洋 [Hu Jinyang], “外媒: 中国海上‘狼 群’挑战美军潜艇霸权” [Foreign Media: China’s “Wolf Pack” at Sea Challenges American Submarine Hegemony], 海事大 观 [Maritime Spectacle] (July 2006), p. 45.
Wang Yu and Yao Yao, eds., World Naval Submarines, p. 127.
孟昭珍, 张宁 [Meng Zhaozhen and Zhan Ning], “潜艇承担的新任务” [Submarines Assuming New Missions], 情报指挥控制系统 与仿真技术 [Intelligence, Command, Control, and Simulation Technology] (April 2003), p. 12.
石江月[Shi Jiangyue], “美国海军需要什么样 的舰队?” [What Kind of Fleet Does the U.S. Navy Require?], Navy Require?], 现代舰船 [Modern Ships], (December 2006), p. 12. 87. 张晓东, 王磊 [Zhang Xiaodong and Wang Lei], “美国海军未来 20 年发展规划” [The 20-Year Development Program of the U.S. Navy], 当代海军 [Modern Navy] (August 2006), p. 51. 88. Yang Yi, “Who Can Estimate the Future Number of Submarines?” p. 28.
Featured Image: Virginia-class submarine Indiana (SSN-789) Departs for Sea Trials, May 2018. (via Navsource)
Over the last few years, the Russian Federation pursued an increasingly assertive foreign policy in Eastern Europe. Geopolitical infringements on Crimea and Eastern Ukraine are coupled with hybrid warfare and aggressive rhetoric. The buildup and modernization of the Russian armed forces underpins this repositioning and Russia has taken major steps in increasing its conventional and nuclear capabilities.
The significant rearmament of its Western exclave Kaliningrad requires special attention.1 The recent buildup of Russian A2/AD forces in Kaliningrad, coupled with increasingly assertive behavior in the Baltic Sea, poses a serious challenge for European naval policy. Should Russia make active use of its sea denial forces, it could potentially shut down access to the Baltic Sea and cut maritime supply lines to the Baltic states. The full range of Russia’s A2/AD capabilities in Kaliningrad comprises a wide array of different weapon systems, ranging from SA-21 Growler surface-to-air missiles2 to a squadron of Su-27 Flanker fighters and another squadron of Su-24 Fencer attack aircrafts3 that can be scrambled at a moment’s notice to contest Baltic Sea access.4 German naval capabilities to counter the SS-C-5 Stooge anti-ship missile system,5 Russia’s mining of sea lanes, and its attack submarines are of particular interest in retaining Baltic sea control.
Russian A2/AD Systems
The K300 Bastion-P system includes in its optional equipment a Monolit-B self-propelled coastal radar targeting system.6 This radar system is capable of, according to its manufacturer, “searching, detection, tracking and classification of sea-surface targets by active radar; over-the-horizon detection, classification, and determination of the coordinates of radiating radars, using the means of passive radar detection and ranging.”7The manufacturer further states that sea-surface detection with active radar ranges up to 250 kilometers under perfect conditions, while the range of sea surface detection with passive detection reaches 450 kilometers.8
With regard to its undersea warfare capabilities, the Russian Baltic Fleet currently only operates two Kilo-class submarines. Of these diesel-powered submarines, only one is currently operational with the other unavailable due to repairs for the foreseeable future.9 However, the entire Russian Navy’s submarine fleet is currently undergoing rapid modernization and the Baltic Fleet will receive reinforcements consisting of additional improved Kilo-class submarines.10 Despite the fact that the Baltic fleet remains relatively small in size, these upgrades amount to “a level of Russian capability that we haven’t seen before” in recent years.11
With its formidable ability to float through waters largely undetected and versatile missile equipment options capable of attacking targets on water and land, the Kilo-class presents a serious threat to naval security in the region.12 In fact, its low noise level has earned it the nickname “The Black Hole.”13
The Baltic Sea is relatively small in size and has only a few navigable passageways that create chokepoints. Therefore, it resembles perfect terrain for the possible use of sea mines.14 While often underestimated, sea mines can have a devastating impact on naval vessels. Affordable in price and hard to detect, they can be an effective area-denial tool if spread out in high quantities.15 Russia still possesses the largest arsenal of naval mines, and according to one observer, Russia has “a good capability to put weapons in the water both overtly and covertly.”16 The versatility of possible launch platforms, ranging from full-sized frigates to fishing boats, makes an assessment of current capabilities in Kaliningrad a difficult endeavor.
A Possible Scenario for Russian A2/AD Operations in the Baltic Sea
Given Russia’s long-term strategic inferiority to western conventional capabilities, a realistic scenario will bear in mind that Russia is not interested in vertical conflict escalation. Instead, it is primarily interested in exploiting its temporary regional power superiority.17 Thus, its endgame will not be to destroy as many enemy vessels as possible, but rather to send a signal to opponents and deter them from navigating their ships east of German territorial waters as long as needed.18 Ultimately, A2/AD capabilities only have to inflict so much damage to make defending the Baltic States appear unattractive or too costly to decision makers, especially if those measures can create the perception of Russian escalation dominance.19
Russia is very inclined to use means that offer plausible deniability, to possibly include sea mines.20 The Baltic Sea is still riddled with sea mines from both World Wars21 and if Russia manages to lay sea mines undetected, it can make the argument that any incidents in the Baltic Sea involving sea mines were simply due to old, leftover mines instead of newly deployed Russian systems.
Should measures to deploy sea mines in the Baltic Sea fail, Russia may consider use of a more overt, multi-layered approach to sea denial. We can expect that a realistic scenario will feature a mixture of above-mentioned approaches that include submarine warfare as well as the use of anti-ship missiles. Russia could also make use of its naval aviation assets and other missile capabilities stationed in Kaliningrad.
Strategic Implications and NATO’s Interests
It is difficult to interpret the deployment of these weapon systems and missiles as anything different than an addition to Russia’s A2/AD capabilities. Russia is actively trying to improve it strategic position to deter possible troops movements on land as well as on the water.22 They mirror Russia’s claims to its sphere of influence in Eastern Europe and serve as an example of Russia’s attempts to exert authority over its periphery, effectively giving Russia the potential to deny access to the Baltic Sea east of Germany.
If Russia increases its A2/AD capabilities in the Baltic Sea, it complicates NATO’s access to the Baltic states during a potential crisis. This is especially startling due to the fact that NATO troops are currently stationed in the Baltics and cutting off maritime supply routes would leave those troops extremely vulnerable. If Russia can effectively cut off NATO’s access to the Baltic states, it increases the “attractiveness to Russia of a fait-accompli.”23 Ben Hodges, then-commanding general of the United States Army in Europe, shared these concerns: “They could make it very difficult for any of us to get up into the Baltic Sea if we needed to in a contingency.”24 In case regional states will be called to fulfill its alliance commitments in the Baltic Sea, Russian submarine blockades, along with mining and missile deployments, will be a major roadblock and possibly threaten safe passage for European vessels.
NATO has an immense national interest in maintaining freedom of navigation in the Baltic Sea and ensuring free access. On average, 2,500 ships are navigating the Baltic Sea at any time and its shipping routes are vital to European economic activity.25 In the 2016 German Defence White Paper, this is clearly identified: “Securing maritime supply routes and ensuring freedom of the high seas is of significant importance for an exporting nation like Germany which is highly dependent on unimpeded maritime trade. Disruptions to our supply routes caused by piracy, terrorism and regional conflicts can have negative repercussions on our country’s prosperity.”26 Thus, if Russia impedes freedom of navigation in this area with its A2/AD capabilities, it will significantly damage Germany’s and other European nations’ export potential. However, vulnerabilities are not limited to shipping routes but also include the Nord Stream gas pipeline and undersea cables upon which a large part of European economies depend.27
In sum, Russia’s A2/AD systems, along with updated submarine capabilities and the potentially disastrous effects of disrupted undersea pipelines and communication cables, enhance Russia’s strategic position and makes hybrid warfare a more realistic scenario. This kind of instability would have serious security and economic implications for NATO.
Should the Baltic Sea fall under de facto authority of the Russian Federation or witness conventional or hybrid conflict, then NATO would face dire economic consequences and live with a conflict zone at its doorstep. This is especially concerning given the poor state of Germany’s naval power in particular. The German Navy lacks most capabilities that would qualify it as a medium-sized navy, and its strategy is mostly agnostic of a threat with significant A2/AD capabilities just East of its own territorial waters.28 Since it is in Germany’s vital interest to maintain freedom of navigation in the Baltic Sea and plan for a potential use of Russian A2/AD capabilities, the German Navy should shift its operational focus to the Baltic Sea. Having outlined the means through which Russia can deny access to the Baltic Sea, specific recommended actions can follow.
Effectively countering the effects of anti-ship missiles stationed in Kaliningrad requires two measures. First, it requires the German Navy to equip its ships and submarines with standoff strike capabilities that enable them to engage Russian radars and anti-ship missiles from outside their A2/AD zone.29 In practice, this requires the procurement of conventional long-range land-strike capabilities for the German Navy. To this day, the entire German fleet lacks any form of long-range land-attack weapon for both surface vessels and submarines.30 Second, if the German Navy has to operate within Russia’s A2/AD environment, it should equip its surface ships with more advanced electronic warfare countermeasures that disrupt sensing and enable unit-level deception.
Russia’s submarines are traditionally hard to detect, but they can be countered by Germany’s own class of 212A submarines. Those feature better sonars and are even quieter, giving them an advantage over Russia’s submarines.31 However, in order to fully exploit this advantage, Germany has to do a better job of committing resources to the maintenance of its submarines as all six of its active submarines are currently not operational due to maintenance.32
A large part of the effectiveness of anti-mine operations hinges on preemptive detecting. If Germany and other NATO allies can catch Russia in the act of laying mines, it will actively decrease the possible damage those mines can do to vessels in the future and thus their effect on sea denial.33 It can do so by increasing its sea patrols in the region. These patrols can include minimally armed vessels such as the Ensdorf and Frankenthal classes in order to avoid incidental confrontations and to assume a non-threatening stance toward Russia. If preventive action fails, Germany should be ready to employ a NATO Mine Countermeasure Group in order to clear as many mines as possible and to ensure safe passage of ships.
The buildup of forces on Russia’s Western border is paired with a more aggressive stance by the Russian military. Over the last months, the Baltic Sea became “congested” with Russian military activity, leading to increasingly closer encounters.34 In April 2014, an unarmed Russian Su-24 jet made several low-passes near a U.S. missile destroyer, the USS Donald Cook in the Baltic Sea.35 Later in 2014, a small Russian submarine navigating in Swedish territorial waters spurred a Swedish military buildup along its coast due to “foreign underwater activity.”36 And during July 2017, Russia conducted joint naval exercises with China in the Baltic Sea. By conducting a joint naval drill with China in these waters, the Russian military demonstrated strength and flexed its military muscle in a message specifically directed at NATO.37 These actions by the Russian military all point toward conveying the message that Russia does not want the presence of foreign militaries in Baltic Sea waters and is capable of taking countermeasures to exert its sovereignty in the region.
Tobias Oder is a graduate student in International Affairs at the Bush School of Government and Public Service at Texas A&M University. He focuses on international security, grand strategy, and transatlantic relations
 “The Baltic Sea and Current German Naval Strategy,” Center for International Maritime Security, last modified July 20, 2016, accessed September 22, 2017, http://cimsec.org/baltic-sea-current-german-navy-strategy/26194.
 Also known as S-400 Triumf.
 “Chapter Five: Russia and Eurasia,” The Military Balance 117, no. 1 (2017), 183-236.
 “Entering the Bear’s Lair: Russia’s A2/AD Bubble in the Baltic Sea,” The National Interest, last modified September 20, 2016, accessed September 24, 2017, http://nationalinterest.org/blog/the-buzz/entering-the-bears-lair-russias-a2-ad-bubble-the-baltic-sea-17766?page=show.
 Also known as K-300P Bastion-P.
 “K-300P Bastion-P System Deliveries Begin,” Jane’s, last modified March 5, 2009, accessed November 20, 2017, https://my.ihs.com/Janes?th=janes&callingurl=http%3A%2F%2Fjanes.ihs.com%2FMissilesRockets%2FDisplay%2F1200191.
 “Monolit-B,” Rosoboronexport,, accessed November 20, 2017, http://roe.ru/eng/catalog/naval-systems/stationary-electronic-systems/monolit-b/.
 Kathleen H. Hicks et al., Undersea Warfare in Northern Europe (Washington, D.C.: Center for Strategic and International Studies, 2016).
 Karl Soper, “All Four Russian Fleets to Receive Improved Kilos,” Jane’s Navy International 119, no. 3 (2014).
 “Russia Readies Two of its most Advanced Submarines for Launch in 2017,” The Washington Post, last modified December 29, 2016, accessed September 23, 2017, https://www.washingtonpost.com/news/checkpoint/wp/2016/12/29/russia-readies-two-of-its-most-advanced-submarines-for-launch-in-2017/?utm_term=.2976db8c1710.
 “The Kilo-Class Submarine: Why Russia’s Enemies Fear “the Black Hole”, The National Interest, last modified October 23, 2016, accessed November 21, 2017, http://nationalinterest.org/blog/the-kilo-class-submarine-why-russias-enemies-fear-the-black-18140.
 “Silent Killer: Russian Varshavyanka Project 636.3 Submarine,” Strategic Culture Foundation, last modified July 14, 2016, accessed November 21, 2017, https://www.strategic-culture.org/news/2016/07/14/silent-killer-russian-varshavyanka-project-636-3-submarine.html.
 Stephan Frühling and Guillaume Lasconjarias, “NATO, A2/AD and the Kaliningrad Challenge,” Survival 58, no. 2 (April-May, 2016), 95-116.; Alexander Lanoszka and Michael A. Hunzeker, “Confronting the Anti-Access/Area Denial and Precision Strike Challenge in the Baltic Region,” The RUSI Journal 161, no. 5 (October/November, 2016), 12-18.; Hicks et al., Undersea Warfare in Northern Europe.
 “Sea Mines: The most Lethal Naval Weapon on the Planet,” The National Interest, last modified September 1, 2016, accessed November 21, 2017, http://nationalinterest.org/blog/the-buzz/sea-mines-the-most-lethal-naval-weapon-the-planet-17559. In fact, even a small number of sea mines have the capability to disrupt marine traffic due to the perceived risk of a possible lethal encounter (Caitlin Talmadge, “Closing Time: Assessing the Iranian Threat to the Strait of Hormuz,” International Security 33, no. 1 (Summer, 2008), 82-117.).
 “Minefields at Sea: From the Tsars to Putin,” Breaking Defense, last modified March 23, 2015, accessed November 21, 2017, https://breakingdefense.com/2015/03/shutting-down-the-sea-russia-china-iran-and-the-hidden-danger-of-sea-mines/.
 Frühling and Lasconjarias, NATO, A2/AD and the Kaliningrad Challenge, 95-116, 100.
 Lanoszka and Hunzeker, Confronting the Anti-Access/Area Denial and Precision Strike Challenge in the Baltic Region, 12-18 Specifically, commentators outline various scenarios that all share the basic notion that the ultimate goal is to deny NATO forces access to its eastern flank (“Anti-Access/Area Denial Isn’t just for Asia Anymore,” Defense One, last modified April 2, 2015, accessed November 20, 2017, http://www.defenseone.com/ideas/2015/04/anti-accessarea-denial-isnt-just-asia-anymore/109108/).
 Andrew F. Krepinevich, Why AirSea Battle? (Washington, D.C.: CSBA, 2010). For a more detailed discussion of potential Russian escalation dominance, see David A. Shlapak and Michael W. Johnson, Reinforcing Deterrence on NATO’s Eastern Flank (Santa Monica, CA: RAND Corporation, 2016); “Demystifying the A2/AD Buzz,” War on the Rocks, last modified January 4, 2017, accessed September 24, 2017, https://warontherocks.com/2017/01/demystifying-the-a2ad-buzz/.
 Rod Thornton and Manos Karagiannis, “The Russian Threat to the Baltic states: The Problems of Shaping Local Defense Mechanisms,” The Journal of Slavic Military Studies 29, no. 3 (2016), 331-351. The idea behind plausible deniability states that Russia will only make use of means to disrupt Western forces if they cannot explicitly trace their origins back to Russia and that they cannot hold Russia accountable for these actions. This, in turn, leads to insecurity among NATO allies and prevents the alliance from taking collective action.
 “German Waters Teeming with WWII Munitions,” Der Spiegel, last modified April 11, 2013, accessed November 25, 2017, http://www.spiegel.de/international/germany/dangers-of-unexploded-wwii-munitions-in-north-and-baltic-seas-a-893113.html.
 Martin Murphy, Frank G. Hoffman and Gary Jr Schaub, Hybrid Maritime Warfare and the Baltic Sea Region (Copenhagen: Centre for Military Studies (University of Copenhagen), 2016), 10.
 “The Russia – NATO A2AD Environment,” Center for Strategic & International Studies, last modified January 3, 2017, accessed September 23, 2017, https://missilethreat.csis.org/russia-nato-a2ad-environment/.
 “Russia could Block Access to Baltic Sea, US General Says,” Defense One, last modified December 9, 2015, accessed September 23, 2017, http://www.defenseone.com/threats/2015/12/russia-could-block-access-baltic-sea-us-general-says/124361/.
 Frank G. Hoffman, Assessing Baltic Sea Regional Maritime Security (Philadelphia: Foreign Policy Research Institute, 2017), 6.
 Federal Ministry of Defence, White Paper on German Security Policy and the Future of the Bundeswehr (Berlin: Federal Ministry of Defence, 2016), 50.
 Murphy, Hoffman and Schaub, Hybrid Maritime Warfare and the Baltic Sea Region.
 Bruns, The Baltic Sea and Current German Naval Strategy.
 Andreas Schmidt, “Countering Anti-Access/Area Denial: Future Capability Requirements in NATO,” JAPCC Journal 23 (Autumn/Winter, 2016), 69-77.
 Hicks et al., Undersea Warfare in Northern Europe.
 Hicks et al., Undersea Warfare in Northern Europe.
 “All of Germany’s Submarines are Currently Down,” DefenseNews, last modified October 20, 2017, accessed November 21, 2017, https://www.defensenews.com/naval/2017/10/20/all-of-germanys-submarines-are-currently-down/.
 Talmadge, Closing Time: Assessing the Iranian Threat to the Strait of Hormuz, 82-117, 98.
 “Russian Warships in Latvian Exclusive Economic Zone: Confrontational, Not Unlawful,” Center for International Maritime Security, last modified May 15, 2017, accessed September 23, 2017, http://cimsec.org/russian-warships-latvias-exclusive-economic-zone-confrontational-not-unlawful/32588.
 “Russian Jet’s Passes Near U.S. Ship in Black Sea ‘Provocative’ -Pentagon,” Reuters, last modified April 14, 2014, accessed September 23, 2017, https://www.reuters.com/article/usa-russia-blacksea/update-1-russian-jets-passes-near-u-s-ship-in-black-sea-provocative-pentagon-idUSL2N0N60V520140414.
 “Sweden Steps Up Hunt for “Foreign Underwater Activity”,” Reuters, last modified October 18, 2014, accessed September 23, 2017, https://www.reuters.com/article/us-sweden-deployment/sweden-steps-up-hunt-for-foreign-underwater-activity-idUSKCN0I70L420141018.
 “Russia Says its Baltic Sea War Games with Chinese Navy Not a Threat,” Reuters, last modified July 26, 2017, accessed September 23, 2017, https://www.reuters.com/article/us-russia-china-wargame/russia-says-its-baltic-sea-war-games-with-chinese-navy-not-a-threat-idUSKBN1AB1D6.
Featured Image: Russian troops load an Iskander missile. (Sputnik/ Sergey Orlov)