Autonomous Naval Mines: An Upcoming Threat to the Freedom of Navigation in the High Seas?

By: Aman Bahl


The law of naval warfare as it existed in 1907[1] and as it is apprehended in 2018 displays a few similarities but many differences. The fundamental similarity is that the law of naval warfare can be seen, then as now, as comprising predominantly of customary international law. The many disparities in this law have been caused by the major variations in the war at sea and the law of the sea. In the early nineteenth century, an international armed conflict at sea majorly depended on the use of capital vessels, while naval mines were installed at the sea bed only to provide for an additional precautionary measure.[2] However, the introduction of autonomous sea mines in the twenty-first century has revolutionised this scenario, the use of a capital vessel is no longer required.[3]

Captain Robert Rubel,[4] defines a capital vessel as “a ship type that can defeat any other ship type. In the days of sail and dreadnoughts, it was the type of ship having the most and biggest guns. It is the ship type around which fleet doctrine and fleet architecture are established.”[5] It would be safe to predict that with the recent advancements in technology, such as the development of artificial intelligence, the introduction of drones and of late self-driven cars, the Navy’s next capital ship will not be a ship. It will be a network of humans and machines, that will embody a superior source of combat power.[6]

A pre-programmed network of sea mines, widely referred to as autonomous naval mines could converge on masses of adversary ships, bringing to bear extraordinary force, leading to an unseen threat in the open seas. An autonomous naval mine consists of interconnected, undersea mines in the form of underwater drones. They comprise predominantly of two types,[7] first, the sensor drones, largely hunting for incoming targets, and second, the attack drones to combat an antagonist’s vessel, or lay aside to allow a friendly vessel to pass. The sensor drones transmit information to the attack drones.[8] These drones communicate with one another to coordinate their actions.[9] The attack drones are further classified as undersea turrets or free-roaming munitions.[10] The undersea turrets, attack drones operate as launch pads for firing torpedoes or other underwater missiles. While a free-roaming munition, an attack drone operates identically to a traditional sea mine. The attack drone manoeuvres to the adversary’s vessel and detonates in its proximity.[11]

Autonomous mine management would empower sea mines to recognise and respond to changes in environmental conditions that could mitigate their effects. With traditional bottom mines on the seafloor, strong tides and currents can shift the mines. These mines could recognize this shift and adjust, making them more capable and effective than ever before.[12]

Even with these substantial advantages, the concept of autonomous mines brings about some major challenges. These mines which are in the form of drones need to communicate with one another, it must be noted that communication underwater and in the air are not equally effective.[13] Traditional communication methods are based on electromagnetic transmissions that are ineffective underwater. Underwater communications must rely on acoustic communication, which is slower, has small bandwidth, and has high error rates.[14] An erroneous explosion of mine can be extremely disadvantageous.[15] Powering these drones also amounts to be a major problem. The lack of sunlight on the sea bed eradicates the possibility for the use of solar panels to power these drones. This problem can be mitigated by recharging these drones in timely intervals in different batches.[16]

The question that arises with the introduction of autonomous mines is that whether their use is against the principles of customary international law, and if their use hampers the foreign states right to freedom of navigation or innocent passage in the high seas or territorial waters respectively?

The Hague Convention VIII[17] (hereinafter 1907 Convention) and the United Nations Convention on the Law of the Sea[18] (hereinafter LOSC) are the two principal conventions that govern the deployment of naval mines. While two conventions date back more than 30 years, when the concept of autonomous naval mines did not exist, they, however, provide us with the fundamental principles governing these mines.[19] The intention of the 1907 Convention is stated as being to “mitigate the severity of war” and not to eliminate mining altogether and thereby ensuring freedom of navigation at sea at the price of aggressor’s rights to conduct hostilities at sea.[20]

Under the LOSC, foreign-flagged ships have no right of passage through the states internal waters, a state may legitimately deploy naval mines in its internal waters as well as in the territorial sea.[21] However, a clear onus would be placed upon that State placing these mines to ensure complete precaution that the naval mines should not result in damage to the ships that legitimately use the waterbody.[22] Any passage taken by a vessel in the territorial waters of a State is under its discretion and the state enjoys complete sovereignty to conduct activities as it pleases with very few restrictions, therefore, if it desires it can deploy naval mines.[23]

The coastal State within its territorial sea has duties and rights under the LOSC that would affect the deployment of naval mines, and vessels of foreign States do have a right of innocent passage.[24]

Therefore, on the assumption that due care is taken while employing autonomous naval mines, these mines would be in conformity with the principles of customary international law. If the naval mines are deployed as per the rules of the conventions their use would not hamper the foreign states right to freedom of navigation or innocent passage in the high seas or territorial waters of a foreign State.[25]

In conclusion, a good argument can be made that if the autonomous naval mines represent the Navy’s future capital ship, it would be preferable to have a contemporary treaty governing the use of these types of naval mines. Modern legislation that is relevant to the twenty-first century, the customary international law as well as the other legal rules would help in better governance and maintaining international relations.


[1] The first convention governing the use of Naval Mines was The Hague Convention VIII, the Convention on the Laying of Automatic Submarine Contact Mines, signed at The Hague 18 October 1907.

[2] David Letts, ‘Beyond Hague VIII: Other Legal Limits on Naval Mine Warfare’ (2014) Int’l L Stud Ser US Naval War Col 447.

[3] Kenneth Watkin & Andrew Norris, ‘Non-International Armed Conflict in the Twenty-First Century’ (2012) US Naval War College International Law Studies 201.

[4] Captain Robert C “Barney” Rubel USN, Ret Professor Emeritus, US Naval War College.

[5] Zachary Kallenborn, ‘Swarming Sea Mines: Capital Capability?’ (Center for International Maritime Security, 29 August 2017) <http://cimsec.org/swarming-sea-mines-capital-capability/33836&gt; accessed 14 March 2018.

[6] ibid.

[7] In general, there are four drone types: Attacker, Sensor, Controller, and Decoy.

[8] Zachary (n 5).

[9] ibid.

[10] ibid.

[11] ibid.

[12] ibid.

[13] John Heidemann, Milica Stojanovic, and Michele Zorzi, ‘Underwater Sensor Networks: Applications, Advances, and Challenges’ (2012) Philosophical Transactions of the Royal Society 158.

[14] ibid.

[15] Jules S Jaffe et al, ‘A Swarm of Autonomous Miniature Underwater Robot Drifters for Exploring Submesoscale Ocean Dynamics’ (Nature Communications, 24 January 2017) <https://www.nature.com/articles/ncomms14189> accessed on March 14, 2018.

[16] ibid.

[17] Convention (VIII) Relative to the Laying of Automatic Submarine Contact Mines (adopted 18 Oct 1907) US Statutes at Large, v 36 p 2332 Treaty Series No 541.

[18] United Nations Convention on the Law of the Sea (adopted 9 December 1984) 1833 UNTS 3 (hereinafter ‘Convention on the Law of the Sea’).

[19] Watkin & Norris (n 3).

[20] ibid.

[21] Convention on the Law of the Sea, art 24.

[22] Convention on the Law of the Sea, art 25.

[23] Convention on the Law of the Sea, art 24.

[24] Convention on the Law of the Sea, art 17; H A Smith, The Law and Custom of the Sea (Stevens & Sons Limited 1959) 119-121.

[25] In addition to the above-mentioned Articles in the LOSC and 1907 Hague Convention, the ICJ decision in the Corfu Channel Case (United Kingdom v Albania, ICJ Reports 1949), brings clarity to the fact that the coastal State may deploy mines in its territorial waters during times of peace, however they must take all efforts to ensure that an unreported danger does not exist and in case any damage is caused by the mines, the State is liable for the damage caused.


(Aman is currently a student at Maharashtra National Law University, Nagpur.)

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