The passage of submarines through waters subject to coastal State sovereignty is the focus of this chapter. Coastal State sovereignty over its territorial waters is subject to the right of all ships, including submarines, to innocent passage. Submarine passage may not prejudice the peace, good order or security of the coastal State, it must be on the surface with flag flying, and adhere to requirements in place for navigational safety, potentially including any traffic separation schemes or routeing measures. For international straits subject to the regime of transit passage and in archipelagic sea lanes, submarines may stay submerged. The requirements associated with passage through international straits and archipelagic waters are examined in this chapter, including the parameters of coastal State rights to regulate these forms of passage and respond to potential violations of passage rights.

This chapter focuses on the different ways that strategic uses of submarines have influenced developments in international law. It highlights the security dimensions in discussions at the failed Second Law of the Sea Conference in 1960. Superpower dynamics during the Cold War also influenced decisions leading to the negotiations for the UN Convention on the Law of the Sea as well as the negotiations themselves. The growing importance of nuclear-powered submarines, as well as nuclear weapons on conventionally-powered submarines, spurred international agreements on nuclear non-proliferation and disarmament. This chapter brings to the fore the strategic importance of military submarines for major maritime powers in recent decades as it provides critical context for contemporary development and application of international law. We conclude Part I of the book in this chapter in bringing together key themes in the legal history of submarines that continue to influence the modern international law of submarines.

This chapter sets out the rationale for and provides an overview of the content of Submarines in International Law. It discusses a definition of submarines and describes a legal taxonomy of submarines; explaining how submarines may be categorized in a way that is legally relevant by considering the owner/operator, the purpose, their mode of power, and weaponry aboard. A critical consideration in addressing the international laws regulating submarine operations is the sovereign immunity that may apply and legal consequences of that immunity. Whether a submarine is nuclear powered or nuclear armed may also hold legal relevance. It is also important to acknowledge the growing private use of submarines for diverse reasons: criminal activity, research and for leisure. These uses are also regulated under international law and the chapter explains the different bodies of international law that are canvased in the book.

This chapter analyses submarines activities against requirements under the law on the use of force (jus ad bellum). Key actions at issue in this regard are the submerged passage of a foreign-flagged submarine in the territorial waters of a coastal State, as well as coastal State responses against a submerged submarine. We examine when submarine activities may constitute a prohibited threat of the use of force, as well as an unlawful use of force, in violation of Article 2(4) of the UN Charter. Military submarines may be deployed lawfully in response to an armed attack, provided the requirements of the right of self-defence are met. Submarines may also exercise a lawful right of unit self-defence where that response is necessary and proportionate. Responses of coastal States against submarine operations are also assessed within the law on the use of force.

In this chapter, we examine the allocation of rights and duties between States in relation to foreign-flagged submarine activities in the exclusive economic zone (EEZ) of a coastal State. Submarine activities include military activities and intelligence gathering, as well as extending to different forms of research. We assess the difference between military research and other forms of marine scientific research and the concomitant rights and duties of States in relation to these different types of research. Privately owned submarines may also engage in commercial activities in the EEZ associated with the exploration and exploitation of natural resources, the laying of submarine cables and pipelines, and for leisure or tourism purposes. The chapter identifies the applicable rights and responsibilities under international law to regulate those activities, as well as explaining limits on the rights of States through reference to due regard and non-abuse of rights.

In this chapter, early efforts at legal codification relevant to submarines are seen in the work of learned societies, such as the Institut de Droit International and the International Law Association, as well as in discussions leading to the conventions adopted at the two Hague Peace Conferences. However, submarines were not specifically addressed but fell within a category of belligerent warships; an early proposal to ban submarines as weapons being unsuccessful. Discussions at this time concerned passage in territorial waters and straits, and particularly the rights and duties of belligerents and neutrals. International law on navigational rights in territorial waters was unsettled as World War I began. The critical role of submarines during World War I prompted States to adopt laws that specifically addressed submarines, including requirements to surface in the territorial sea. The chapter reflects on these emergent laws regulating submarines in both times of war and peace.

In this chapter, we assess the international law regulation of the newest forms of submarines, underwater maritime autonomous vehicles (UMAVs) and ask what changes for States’ rights and duties when an autonomous vehicle operates uncrewed and underwater. A core issue has been whether UMAVs are ships or not and we address differences emerging for floats and gliders particularly. Whether uncrewed submarines are ships or not has implications for navigational rights and duties. We also consider questions emerging under the law of armed conflict and distinctions for autonomous maritime systems (such as mines and torpedos). While State-owned and operated UMAVs are a primary focus, we also consider the international laws applying to the use of UMAVs by terrorists or criminals seeking to smuggle goods. This chapter concludes Part II of the book and brings together the key questions that remain to be answered in regulating submarines in international law.

This chapter examines legal developments in submarine regulation taking into account the political context existing prior to World War II, including tensions in the Pacific with Japan’s aggression against China. Notably, States adopted the 1936 London Protocol on Submarine Warfare seeking to align requirements for submarines with obligations imposed on surface warships. Tensions in the 1930s also prompted Turkey to initiate a revision of the legal regime governing the Turkish Straits, leading to the Montreux Convention and the near complete prohibition of submarine passage in these waters. With the outbreak of World War II and unrestricted submarine warfare, questions emerged as to the viability of rules set out in the 1936 London Protocol. States also moved to revise laws of neutrality with more targeted consideration of submarines. The chapter thus reflects ongoing legal developments concerning navigational rights of submarines in territorial waters and the regulation of submarines during armed conflict.

In assessing international law governing submarine warfare, we consider how peacetime rules from the law of the sea apply in an armed conflict and focus on the law of neutrality and the law of armed conflict (international humanitarian law). The allocation of rights and duties within different maritime zones continues, albeit with some modifications, during an armed conflict. Most notably, the law of neutrality establishes how those rights and duties change depending on a State’s status as a belligerent or neutral. The use of submarines during armed conflict is also governed by the law of naval warfare and they are largely subject to the same rules that restrict surface warships in relation to targeting, as well as the means and methods of warfare. While submarines are predominantly governed as warships, we note how operational limitations of submarines may affect the interpretation of some rules.

This chapter draws out international laws applicable to ensure the navigational safety of submarines and to establish what laws apply when a submarine is ultimately lost at sea. The discussion is concerned with both military and private submarines during times of peace. To avoid collisions, submarines must account for surface traffic as well as submerged traffic and deploy appropriate signals and sounds. Submarines prompt distinct questions with regards to navigational safety. Where a submarine is in distress and ultimately sinks, consideration is further needed as to international law rules on search and rescue, as well as the law of wrecks and possible salvage. For submarines that have been lost at sea for a long time, safeguarding underwater cultural heritage may become a key consideration. When lost at sea, the relevant laws are comparable to other ships or warships but the difficulty rests in the interaction of those rules.

The use of submarines in World War II and the development of submarine technology into the Cold War had implications for different fields of international law. This chapter addresses the peace negotiations and agreements that were adopted after World War II, which concerned the decommissioning (to varying degrees) of submarines and efforts to revise the Montreux Treaty. International law developments were sometimes slow, as evident in responses to violations of the law of naval warfare. Equally, the chapter highlights the rise of nuclear technology in relation to submarines and the modest advances in international agreements on nuclear tests. Despite the growing strategic importance of submarines in the Cold War, their explicit regulation in the 1958 conference and treaties on the law of the sea was scant. Instead, international laws relating to the passage of warships and military activities on the high seas generally impacted international laws regulating submarine operations.

Following World War I, the regulation of submarines was manifested in several signature developments that are discussed in this chapter. Following disarmament requirements in the Treaty of Versailles, the major powers further sought to limit armaments, especially submarines, through the negotiation of the 1922 Submarine Treaty and the 1930 London Naval Treaty. These agreements purported to restrict the number of submarines and other naval vessels held by any one State, but were ultimately unsuccessful. Also in the inter-war period, agreement was sought on the regulation of the Turkish Straits, with restrictions imposed on Turkey’s control over these waters and stipulating what vessels were allowed passage and under what conditions. Finally, the 1930 Hague Codification Conference entailed detailed discussions over the rights of warships, submarines and other vessels in the territorial sea. While this conference did not lead to the adoption of a treaty, the work achieved influenced subsequent codification efforts.

After the second world war, the International Court of Justice decided two contentious cases: Corfu Channel (1949), which addressed straits used for international navigation; and Fisheries (1951), which considered baselines marking the start of the territorial sea. Both were initiated by the United Kingdom after two other states, Albania and Norway respectively, tried to prevent British vessels from operating without permission in their coastal waters - warships in one case, trawlers in the other. Taken together, the decisions set out the parameters of the modern approach to the law of the sea: preserving the naval powers’ traditional freedoms of navigation while recognising the coastal states’ claims to resources in the waters off their coasts.

Future naval and air forces will be comprised increasingly of unmanned and autonomous systems. Nearly 100 nations and nonstate actors currently operate unmanned and autonomous systems to support combat operations. These platforms have proven their ability to enhance situational awareness and improve mission performance. Unmanned systems will be used to augment manned platforms and will conduct missions that are considered dull, dirty and dangerous, thereby reducing risk to human life at a reduced cost. Introduction of these systems and vehicles will require states to modify how they characterize these platforms under international law as ships, warships, commercial aircraft and state aircraft to ensure that they are able to legally perform the missions that they have been designed to perform. This will require filling gaps in domestic and international law and regulations to better regulate and control the employment of these systems in the marine environment to ensure safety of navigation and overflight and protection of the marine environment.

Advances in long-range precision strike missiles, such as cruise missiles, ballistic missiles and hypersonic weapons, threaten the survivability of surface warships. In response, states are deploying submarines in the water column and expanding military activities on the seabed. Concepts such as “upward falling payloads” and networked “hydra” seabed installations envision prepositioned sensors and weapons emplaced on the continental shelf along an adversary’s coast. This chapter explores the legality of military operations on the continental shelf of a coastal state. The coastal state has sovereign rights and jurisdiction over the living and nonliving resources of the seabed and subsoil in accordance with the UN Convention on the Law of the Sea. Foreign military activities are generally permissible on the continental shelf of a coastal state so long as they observe due regard for the resource rights of the coastal state. Coastal states enjoy the exclusive right to construct artificial islands on their continental shelf but they lack competence to regulate military seabed installations and structures on the continental shelf.

Section E seeks to show how the law on the conduct of hostilities that would apply in relation to the use of conventional weapons also applies in respect of nuclear weapon operations. The Rules and Commentaries deal with persons participating in the hostilities, who are distinguished from protected civilians, and with specific issues of naval and air warfare. The Rules and Commentaries on nuclear targeting address the notion of ‘attack’, the principle of distinction, prohibited nuclear attacks, the definition of military objectives, proportionality and active and passive precautions. As to methods of nuclear warfare, the Section addresses perfidy and ruses, the improper use of protective indicators and emblems, as well as the concept of zones. The Section further includes Rules and Commentaries on persons and objects entitled to specific protection and on the protection of the natural environment in times of armed conflict.

Taking its lead from a famous scene in 2 Henry IV and drawing upon the latest historical scholarship, this chapter surveys the modernization of England’s military capacity during the reign of Elizabeth I. By contrast with the success of England’s naval revival, the parallel effort to overhaul the antiquated county militia system and to create armies for service abroad achieved only partial success. While bows and bills were gradually replaced by guns and pikes and a proportion of each county’s militia was formed into “trained bands,” the sheer scale of the effort meant that the modernization of England’s military capacity on land always remained a frustratingly incomplete endeavor. Even so, Elizabeth’s privy council and the lord lieutenants of the counties made greater progress in this effort than has typically been recognized and managed to sustain war on multiple fronts over a period of more than twenty years.