Damn the Torpedoes: The Return of Naval Mining
Part 1 of a Series on Naval Mining Operations
Naval Mining Operations Persist
Few US Navy sailors in the fleet today can earnestly swap sea stories about their encounters with naval mines. Naval mining can seem as though it belongs to another time: an era of boilers and bunker fuel, of minelayers and minesweepers. Recent advancements in the United States Navy’s (USN) mining and counter-mining capabilities have received little public interest. Yet mines are far from being a relic of the past. New Russian mines in the Black Sea have damaged commercial shipping vessels as recently as 2023, and mines will undoubtedly be a feature in any future conflict between the USN and the Chinese People’s Liberation Army Navy (PLAN) as the militaries of both nations invest in new naval mine technology. For example, the USN’s Orca XLUUV and the PLAN’s UUV300CD unmanned, subsurface mine vehicles will each allow operators to covertly seed and maintain naval minefields and carry out countermining operations.
Without the wisdom of sea stories as a guide, we must look elsewhere for insights into this resurgent capability. This article offers a whirlwind introduction to the basics of naval mining, outlines minefield measures of effectiveness (MOEs), and presents a baseline minefield simulation. Simulations like the one demonstrated here can help planners evaluate potential minefield configurations and make informed investment decisions concerning emerging mining technologies.
The Basics: Mines and Missions
The three types of mines — moored, bottom, and moving — offer critical naval capabilities for achieving sea denial. These mines can be laid or seeded by aircraft, surface vessels, or subsurface vessels. Moored mines, like the one seen chained below, are perhaps the most frequently represented in media and laid by surface vessels. Bottom mines excel in relatively shallow water, and can be more easily laid in high quantities by bomber aircraft to achieve a dense minefield (i.e. one with no transitable gaps between effective mine radii). The distinction between these types of mines is vital because the physical characteristics and employment methods determine the suitable delivery vehicle, appropriate minefield location, and cost of each mine system. In this article, the simulation I will present only represents a homogeneous minefield consisting of bottom mines to simplify underlying assumptions.
Naval mining operations are separated into three minefield operation types and four mission tasks. The Joint Force1 delineates minefield operations types based on the minefield’s location and intended effects, as shown in the table below. Planners must consider a minefield's covert and overt characteristics when selecting a mine delivery vehicle and scheduling the timing of operations.
Every minefield has a specified mission. The mission2 determines the minefield’s composition, shape, and desired minefield metrics. The table below lists the four minefield missions and their associated purposes.
Generally, blocking minefields require densely seeded mines and should be resilient to countermining efforts. Alternatively, disruption missions may require only a few well-placed mines to impede traffic or motivate vessels to alter routes. For example, consider Russian naval mining operations in the Black Sea. These minefields are in enemy territory and thus characterized as offensive, and given their density and effects, likely support a disruption mission. Correctly identifying the underlying mission of an adversary’s minefield is critical, since this mission analysis can give naval planners an idea of the minefield’s likely density, shape, vulnerabilities, and supporting land or sea positions.
Minefield MOEs
Minefield effectiveness is evaluated using domain-specific MOEs. This article considers three: initial threat on sea route, casualty density distribution, and expected casualties. Initial threat on sea route captures the minefield's ability to produce the first casualty. Casualty density distribution and expected casualties assess effectiveness over successive vessel transits and consider minefield degradation. Naval planners should use these MOEs to evaluate minefield performance and properly resource minefield missions. For example, an effective blocking minefield requires a dense configuration. It should present a high initial threat on sea route, have a sizable left skew in its casualty density distribution, and have high expected casualties. In the table below, each MOE is described for computational purposes.
Minefield Simulation
The simulation presented in this article uses an offensive minefield with a blocking mission as a base case. Each simulation generates 100 sequential vessels that transit along an identified sea lane. The plot below shows an example of the generated minefield and vessel tracks.
In the simulation, a vessel can only degrade the simulated minefield by a single mine. In other words, no other mines explode once the ship is hit, and simultaneous mine detonations cannot occur. As with wide shipping routes, the randomly generated vessel track can potentially avoid the minefield altogether.
List of Model Assumptions
Minefield is preemptively established by covert subsurface vessel(s).
Mine type uses a 1000lb bottom mine, similar to middle-sized Quickstrike and the retired Mk 52 Mod 63.
Bottom mines are laid at 100 feet.
Mines are spaced to cover the intended 600 x 400 yard minefield area.
Mines will actuate when the appropriate vessel passes within 120 feet.
Vessels transiting the minefield have ~4000-ton displacement, similar in size to the United States Freedom-class LCS or the Chinese Jiangkai II Frigate .
Vessels become casualties when passing within 80 feet of an actuated mine.
Minefield Experimentation
This offensive blocking scenario is used to set up a simple experiment. In this experiment, the minefield capacity and probability of actuation are assessed against each other. In other words, the experiment looks to answer the question “Which has the bigger impact on minefield performance: minefield capacity or probability of actuation?”. This simple example can provide insight into whether investments should be made in improving technology, like actuation probability, or in obtaining larger quantities of lower-performing mines. The table below outlines the varied minefield parameters.
The first two scenarios assume mines are spaced by 80-yard intervals and vary the probability of actuation from 40% to 80%. Increases in actuation probabilities serve as a proxy for performance increases, like those that could result from a new generation of mine technology. We could also choose to vary the effective casualty range, minefield size, and actuation distance as further proxies for performance and underlying technological changes. Here, Scenarios 3 and 4 continue to vary the probability of actuation, but also increase the minefield capacity to 71 mines. Note that this increase in capacity results in an increase in the density (not the area) of the minefield. The chart below shows the resulting minefield’s casualty density distribution given this variation in input parameters.
The casualty density distributions indicate similar minefield performance for the two sets of scenarios despite the increase in actuation probabilities from 40% to 80%. In simple terms, dense minefields produce more casualties than sparse minefields. While this concept is easily digestible, the underlying requirements for sourcing, seeding, and maintaining 71 instead of 41 mines can be substantial. Assuming an XLUUV configured like the Orca can carry and emplace 8 tons of cargo or 16, 1000-lb naval mines, five total XLUUVs would be needed to seed the denser minefield in a single operation. While two additional vehicles may sound small, at $450M per XLUUV, the added capacity means the fictitious 5-vehicle squadron would cost over $2B.
The table below shows each scenario's initial threat and expected casualty MOEs.
Reinforcing the casualty density distribution, Scenarios 3 and 4 produce higher expected casualties. The simulation also indicates a negligible difference in expected casualties as a result of increasing probability of actuation. This is most likely due to the dense configuration of all scenarios, which creates casualties on subsequent mines after initial failures to actuate. Further research would be necessary to discount the need for investment in such advances.
Lastly, the four scenarios produce very little variation in initial threat on sea route outcomes. The constant minefield area likely contributes to this consistent performance. To confirm this relationship, a minefield covering a larger area with 37-mines was simulated. The minefield, with an increased 1400-yard frontage, produced an 85% initial threat on the sea route. Planners should seek to maximize the initial threat of a blocking minefield while balancing expected casualty performance. Potential options include increasing the minefield area or choosing a sea lane that requires vessels to transit the minefield.
In this example, the increase in expected casualties from seeding more mines might be worth the investment, given this mission and its operational implications. Simulations like the one above can build context around mining and countermining operational-level problems and can provide insights into strategic-level investments.
Conclusion
Though often neglected, naval mines remain a powerful and versatile tool in maritime warfare. While acknowledging the cost, conventions restricting mining operations, and complexities of mine warfare, the necessity of its capability can not be understated. With advancements in technology and the prominence of great power competition, the operational significance of naval mining will only increase. Models like the one presented can help answer important questions when investing in this critical capability. In this initial look, we can intuit that the density of mines plays an outsized role in effectiveness when compared to the actuation rate. This type of insight is invaluable for guiding capability investment.
The views and opinions expressed on War Quants are those of the authors and do not necessarily reflect the official policy or position of the United States Government, the Department of Defense, or any other agency or organization.
U.S. Defense Dept., Barriers, Obstacles, and Mine Warfare for Joint Operations, JP 3-15 (Washington, DC: Joint Chiefs of Staff, 2016), available at www.jcs.mil.
Edwards, Joshua (2019) "Preparing Today for the Mines of Tomorrow," Naval War College Review: Vol. 72 : No. 3 , Article 5. Available at: https://digital-commons.usnwc.edu/nwc-review/vol72/iss3/5
Operational Characteristics of U.S. Naval Mines (U), ORD 696(B), 1959. Accessed at https://maritime.org/doc/mines-usn/pgc6.php
while it is always interesting to see a scientific solution applied to the various aspects of Naval mine warfare, the many incalculable variations that can be applied, means it remains an artform rather than a science and is still the most perfect form of Asymmetric warfare.