The North Korean submarine force may be one of the world’s least capable, operating some of the most obsolete submarines in existence—they grounded this Sang-o class boat on South Korea’s east coast on 21 September—but if just one of them is able to get under way, it becomes a threat a joint task force commander cannot ignore.
If the United States were to become involved in a major regional conflict with North Korea, the Democratic People’s Republic of Korea (DPRK) submarine force could pose a significant threat at the operational level. Lessons from the Falklands Conflict and studies of littoral warfare can help us analyze the capability and potential courses of action of the North Korean submarine force, thus allowing us to develop possible solutions.
The DPRK Submarine Force
Most of the submarines employed by North Korea are 1940s- or 1950s-vintage Soviet designs, including more than 20 boats of the Chinese version of the Soviet Romeo class.[1] After the transfer of four Romeo-class submarines from China in 1973 and 1974, North Korea began to produce its own Romeos. As of 1994, it still was producing one every two years.[2] Although similar to the late 1950s Soviet version, those submarines produced more recently are likely to have numerous changes in equipment—possibly with significantly improved performance.[3] It also is significant that almost all of these boats are less than 20 years old, which means most should be able at least to get under way and conduct basic submerged operations.
Lessons of the Falklands Conflict
The impact of Argentinean submarines on Admiral Sandy Woodward, British battle group commander in the 1982 Falklands Conflict, can provide insights into how the North Koreans could employ their submarines in a regional conflict.
At the beginning of the conflict, Argentina had four submarines. A World War II-vintage Guppy class, the Santa Fe, and an eight-year-old German Type 209, the San Luis, were operational; a second 209 was not deployed because of a noise problem, and another Guppy-class boat, though inoperable, was towed from port to port to give the illusion that it still was seaworthy.[4] All (or at least three) of these submarines affected Admiral Woodward’s operational decisions.
The Santa Fe, “a more likely candidate for a place in a naval museum than in combat,” made a round trip to Port Stanley and then traveled more than 1,000 nautical miles to South Georgia Island, where she was attacked by a British helicopter and forced to ground herself.[5] The San Luis, manned by an inexperienced, newly assembled crew, operated for six to seven weeks more than 800 nautical miles from her home base. Her crew claim they conducted three torpedo attacks against British surface ships, but they did no damage because of fire-control equipment problems and human error.[6]
Although these submarine operations were tactically ineffective, a significant portion of the operating time of two antisubmarine warfare carriers, more than a dozen frigates and destroyers, four nuclear-powered submarines, and one diesel submarine was diverted from other missions to provide protection from the submarine threat.7 In addition, antisubmarine Sea King squadrons maintained the equivalent of four aircraft continuously airborne for a month on antisubmarine and surface search sorties.8 British forces expended more than 200 rounds of ASW ordnance in their efforts to counter a threat that actually consisted of only one or two submarines.9
Why did a few poorly operated diesel submarines have such an impact? The answer lies in one of the submarine’s greatest assets—its stealth. The British did not know how many Argentinean submarines were at sea. Throughout much of the war, Admiral Woodward thought the Argentineans had both Type 209 submarines deployed, and the possibility caused the British grave concern:
When the British established that the Argentine conventional subs were out of port, the ubiquitous nature of a submarine went into effect. British ASW forces assumed they might be anywhere or everywhere in the theater of naval operations.10
The submarine threat affected the South Georgia assault, the Falklands landing, and aircraft carrier employment. During the South Georgia operation, Admiral Woodward noted in his diary, “South Georgia op seems bogged down for fear of [Argentine] submarine (conventional, Santa Fe).'"' For the Falkland Island invasion, landing plans minimized “the danger of submarine attack by steering well clear of the Port Stanley area.”12 Similarly, Admiral Woodward’s decision to keep the carriers away from the Islands during the invasion was in part because “the [Argentineans’ likely] submarine area is exactly where we would need to be to do the job.”13
Littoral Warfare Lessons
In the shallows, a submarine will be able to take advantage of geography, topography, oceanography, environmental factors, and heavy shipping volume, which combine to pose a significant technical and tactical ASW problem. In a Korean regional contingency, the North Korean submarine force would have an advantage because of its familiarity with the regional environment. In addition, a Romeo-class diesel is quiet and provides little Doppler effect when operating slowly on the battery.14 Active sonar would be limited by the shallow environment, as well as by the low target strength of a small, diesel submarine. By combining these factors with the lessons of the Falklands Conflict and the information provided by open-source literature on U.S. ASW methods, the North Koreans could develop a submarine employment plan to maximize the potential threat to opposing forces and minimize their risk of detection and destruction.
Just by getting under way and submerging, the North Korean submarines could create a threat that the joint task force (JTF) commander could not ignore. Even a nonoperational submarine can be a threat if it just “disappears”—for example, by scuttling—thus becoming unaccounted for.
Once at sea, the submarines could improve their likelihood of remaining undetected by avoiding operations that have a higher risk of detection. A submarine must snorkel, for example, but by staying submerged or bottomed during the day and snorkeling at night, it greatly reduces its chance of being discovered. Risk also would be reduced by deploying to areas least likely to be covered by ASW units, such as the North Korean coast, where the submarine would be under the protection of antiair and antiship defensive systems. The submarines might even be moved into Chinese territorial waters, where they would be virtually immune to prosecution, because the United States likely would not do anything that might draw China into a conflict.
The North Korean submarine force may not be operationally proficient, but their commanders and crews possess some degree of basic skill. If a few could venture into coalition shipping lanes or operating areas, the perceived threat would appear even greater. If the boats could match the Santa Fe's 1,000-mile transit, they could operate anywhere in the waters surrounding Korea or Japan—an area that includes many key maritime routes and vital choke points that would be used by naval forces, logistics shipping, and merchant shipping.15
In the Falklands Conflict, the diesel submarines were unable to employ their torpedoes effectively. The inexperienced Argentinean crew tried to use a complex antiship torpedo, which requires a large number of settings and a complex fire-control system.16 The North Koreans, on the other hand, would be using the same relatively simple weapon system they have trained with for 30 years. Even if unable to launch a torpedo successfully, they could lay mines at choke points (an easier task), thus threatening shipping.
Another consideration is the possibility that the crew would not be entirely North Korean. The Iranian Kilo submarines appear to be supported and partially manned by Russian personnel, as were the Libyan Foxtrots; a few Chinese advisors with a North Korean submarine crew might be just enough to bring about success.1[7]
Issues
In a conflict with a significant maritime aspect that is confined to a relatively small area, any opposing submarines at sea will affect the JTF commander's operational decisions. The JTF commander will be concerned with the ability to move and maneuver maritime forces, the diversion of maritime forces for operational protection, and the impact on logistics. The use of South Korean ports as bases of operation, with associated lines of operation and communication, also must be considered in light of the submarine threat.
Operational movement and maneuver. In a Korean contingency, the JTF commander would have numerous maritime forces at his disposal, including carrier battle groups, submarines, and amphibious forces. The commander's ability to use these assets fully, however, may be affected by the fear of losing a ship to a submarine. If even a single North Korean submarine is at sea, the JTF commander may not be willing to bet a high-value unit on the chance that the submarine crew will not be good enough to launch a successful torpedo attack.
The JTF commander would have to decide if the risk is too great to operate carriers in the seas around Korea and Japan. In the worst case, the carriers may be restricted to areas so distant that the usefulness of their aircraft would be limited. Similarly, the commander would have to weigh the benefit of an amphibious operation against the risk that a submarine might attack one or more of the amphibious ships. In the extreme case, amphibious landings might be considered too risky, eliminating or delaying the employment of operational maneuver from the sea.
In addition to their torpedo threat, the North Korean submarines could conduct covert reconnaissance, giving the North Koreans the capability to monitor the movement and employment of maritime forces, as well as South Korean or Japanese coastal activity. Even if this capability is limited, the JTF commander would have to assume that it exists and is being used. This is especially important when planning operations that depend on the element of surprise or that are to be used for operational deception.
Any impact on the operational maneuverability of the carrier or amphibious forces also would affect operational reach. This may not be significant if land forces in Korea and land-based air forces are capable of handling the conflict alone, but it could be crucial if the JTF commander must rely heavily on maritime forces. If Marines cannot be landed or if carrier operations are held up waiting for the completion of ASW operations, then operational tempo, momentum, and sequencing all may be driven by the submarine threat.
Operational protection. If the JTF commander decides to use carrier battle groups or amphibious forces in the waters around Korea, operational protection would be a major concern. Historically, ASW has required a high ratio of ASW assets per submarine.
Admiral Gorshkov observed that in World War II there were twenty-five Allied ships and 100 aircraft involved in ASW operations for each German submarine at sea. The same disparate use of ASW forces to handle the threat of only two small conventional enemy submarines seems to have taken place off the Falklands Islands.1[8]
The JTF commander may not have the dedicated assets to conduct this kind of ASW effort and may have to divert assets from other operations. This could affect other operations and extend the time before local sea control is regained.
Operational logistics. The submarine threat also could limit—or possibly prevent—access to South Korean ports, forcing coalition forces to operate from more-distant bases and complicating the logistics problem. For a submarine force with minimal capabilities, merchant shipping would be the easiest target to attack. The JTF commander would be risking the loss of vital ships and supplies by requiring them to transit possible North Korean submarine operating areas. The sinking of the Atlantic Conveyor—with all of the British heavy-lift helicopters on board—by an air-launched missile during the Falklands Conflict illustrates the great impact the loss of one key merchant ship can have. The loss of a maritime prepositioning ship in Korean waters would not have any less consequence. This may necessitate taking other options, such as splitting vital equipment and supplies among ships, and could have a major impact on the number and types of ships required for transport.
Courses of Action
One view of how to handle the submarine problem in littoral warfare was expressed by then-Vice Admiral William Owens:
It may be enough to know where the other submarines are. As long as they are not interfering with our primary mission, all we need to know is where they are and how to avoid them. Then they pose no threat to us and we can get on to more important things.19
This may be true, but the problem is knowing where the opposing submarines are at all times—especially if the commander must account for more than one or two. The obvious solution, then, is to neutralize the boats before they get to sea. Unfortunately, the North Koreans are likely to attack with little warning and probably would have their operational submarines at sea before offensive action could be taken against them. Still, the JTF commander must be ready immediately to attack those remaining or at least to mine the exit routes, to prevent them from deploying.
Trying to operate several submarines in a relatively confined area would imply that the North Koreans would have to keep fairly rigid control over the submarines. Destruction of the command-and-control structure would reduce their effectiveness over the long term, by denying North Korea the ability to change the submarines' operating areas or taskings.
A second long-term solution is to destroy the submarines' logistics and repair infrastructure. If they cannot obtain repairs or get parts and supplies, they eventually will become inoperable. Again, this takes time, and it will be difficult for the JTF commander to know when a submarine is no longer a threat.
The JTF commander also can take advantage of the littoral environment when determining where to employ his assets. Because a diesel submarine is more vulnerable to attack in deep water, the JTF commander can reduce the risk by operating in the deep-water basins when feasible and avoiding the shallow areas that favor the diesel submarine.[9] Areas where geography favors ASW efforts over undetected submarine operations can be used for tasks that do not require a ship to move from one point to another—such as carrier operations.
ASW efforts would be needed to provide protection for convoys between Japan and Korea. Fortunately, these routes are relatively short. Depending on the available assets, it may even be feasible to use ASW assets to keep maritime transit lanes swept clear of submarines rather than to escort convoys. Because the effective range of a torpedo is limited, these safe transit lanes would not have to be very wide. Although it would require more merchant ships and time, the use of smaller vessels between Japan and Korea might be beneficial, if the needed volume of cargo still could be carried. Smaller merchants provide a smaller target with a shallower draft and thus are more difficult targets. It also would limit the impact if one is sunk.
The North Korean submarine force may be one of the least capable, operating some of the most obsolete submarines in the world, but it cannot be ignored.
The only good solution is a multifaceted, integrated ASW plan, the first objective of which would be to neutralize the North Korean submarine force before it ever leaves port.
1 U.S. Office of Naval Intelligence, Worldwide Submarine Proliferation in the Coming Decade (Washington: 1995), p. 14; and Bernard Prezelin and A. D. Baker 111, eds.. The Naval Institute Guide to Combat Fleets of the World 1995 (Annapolis: Naval Institute Press, 1995), p. 386.
2 Andres de Lionis, “Anti-Submarine Warfare in the Third World,” Jane's Intelligence Review, April 1994, p. 191.
3 Prezelin and Baker, p. 386; and John R. Benedict, Jr., “Third World Submarine Developments,” The Submarine Review, October 1990, p. 49.
4 David Brown, The Royal Navy and the Falklands War (Annapolis: Naval Institute Press, 1987), p. 157; and Antony Preston, Sea Combat Off the Falklands (London: Willow Books, 1982), p. 101.
5 Ruben O. Moro, The History of the South Atlantic Conflict (New York: Praeger, 1989), p. 326; Brown, p. 57; Bruce W. Watson and Peter M. Dunn, eds., Military-Lessons of the Falkland Islands War: Views from the United States (Boulder, CO: Westview Press, 1984), p. 8; and Moro, pp. 84-85.
6 Benedict, pp. 53-54; and Steven R. Harper, “Submarine Operations During the Falklands War,” unpublished research paper, U.S. Naval War College, Newport, RI: 1994, pp. 10-11.
7 Benedict, pp. 53-54.
8 Brown, p. 264.
9 Benedict, pp. 53-54.
10 D. E. K. “Conventional Submarines in the Falklands War,” The Submarine Review, October 1983, p. 59.
11 Adm. Sandy Woodward, RN (Ret.), One Hundred Days (Annapolis: Naval Institute Press, 1992), pp. 96-97.
12 Ibid., p. 225.
13 Ibid., p. 231.
14 John F. Morton, “The Shallow Water Diesel: A New Priority,” U.S. Naval Institute Proceedings, March 1993, p. 127.
15 David Miller, “The Silent Menace—Diesel-electric Submarines in 1993,” International Defense Review, August 1993, p. 615.
16 Watson and Dunn, p. 11.
17 de Lionis, p. 191.
18 Watson and Dunn, p. 10.
19 VAdm. William A. Owens, USN, “Antisubmarine Warfare—Still a Priority,” U.S. Naval Institute Proceedings, March 1993, p. 124.
20 Timothy McElhannon, “Operational Maneuver and Anti-Submarine Warfare,” unpublished research paper, U.S. Naval War College, Newport, RI: 1995, p. 11.
Commander Lodmell is prospective commanding officer of the USS Rhode Island (SSBN-740) (Gold).