By Chiwen Ku and Yucheng Chen

This article discusses the legal status of Unmanned Underwater Vehicles (UUVs)[1] and the legality of the seizure of the USS Bowditch (T-AGS 62) by the PLA Navy (Dalang III-Class) on December 15, 2016. The seizure of the UUV occurred around 50 nautical miles northwest of the Philippines’ Subic Bay. According to U.S. Pentagon officials the UUVs belongs to the U.S. Navy and was conducting routine operations such as measuring salinity and temperature in the international waters of the South China Sea. As such the UUVs enjoys sovereign immunity and its operations complied with international law.[2] However, China considers UUVs as unknown objects so they seized it and brought it on board to ascertain ownership, then returned it to the United States.[3] Even though there was no further issue between the the U.S. and China, this incident left room to discuss the legal status of UUVs as either a warship or a vessel and further discuss China UUVs development.

Before we go on to the discussion of legal status of UUVs we need to know what rights and duties UUVs can enjoy and assume. Based on United Nations Convention on the Law of the Sea (hereafter refer to as the Convention),[4] a vessel enjoys innocent passage in territorial seas (hereafter refer to as TS), and freedom of navigation in exclusive economic zones (hereafter refer to as EEZ) and in the high seas. Warships enjoy the same EEZ and High Seas’ rights; however, regarding innocent passage in TS, there remains ambiguity as the Convention does not require warships to obtain prior notification or permission to sail through TS, but there are opposing views on this as some countries insist to regulate warships passing through TS. This is why we need to establish the legal status of UUVs.

(a) Vessel or Warship?

According to the Convention, article 94 (4) states that each ship must have masters and officers possessing appropriate qualifications, especially in seamanship, navigation, communications and marine engineering. Likewise, the crew are required appropriate qualifications and numbers for the type, size, machinery and equipment of the ship. Additionally the crew are required to follow international regulations relating to safety at sea, the prevention of collisions and the reduction and control of marine pollution.[5] In addition, article 1 (b) of the International Convention On Salvage shows “Vessel means any ship or craft, or any structure capable of navigation.”[6] Furthermore, article 29 of the Convention states “warship means a ship…under the command of an officer duly commissioned by the government of the State…and manned by a crew which is under regular armed forces discipline.”[7] In other words, a ship is not only a structure to sail, but also requires human presence.[8]

The above discussion states that a vessel is defined by having a human presence. What separates a warship from a vessel is according to the Convention, article 29 defining warships as.

“a ship belonging to the armed forces of a State bearing the external marks distinguishing such ships of its nationality, under the command of an officer duly commissioned by the government of the State and whose name appears in the appropriate service list or its equivalent, and manned by a crew which is under regular armed forces discipline”.[9]

At this point, we need to establish a legal definition for UUVs as they relate to warships. James Kraska states UUVs are not warships due to the absence of human presence. Therefore UUVs are entitled to sovereign immunity as a property of a State[10] because articles 1.3.3 & 1.3.4 of the Code for Unplanned Encounters at Sea state that.

“...a naval ship is a descriptor that is assumed to include warships, naval auxiliaries, and submarines;…a naval auxiliary is a vessel, other than a warship, that is owned by or is under the exclusive control of the armed forces of a State and used for the time being on government non-commercial service. Because they are State owned or operated and used for the time being only on government, non-commercial service, auxiliary vessels enjoy sovereign immunity”.

After examination of the said treaties, there is no clear definition of UUVs’ legal status[12] but at least UUVs do enjoy sovereign immunity as UUVs are working for States.

However, the Convention does not mention what is the requirement of "human presence" and whether it is necessary for the crew of armed forces to be on board, or if remote control meets the requirement. Thus, we still have to know states’ practices representing customary international law.[13]

(b) How do States’ Practices define the legal status of UUVs?

The previous paragraph shows human presence is one of the conditions for having a legal status of UUVs based on treaties. So, this section will examine States’ practices on how they treat UUVs.

At first, the IMO (International Maritime Organization, hereafter refer to as IMO), being in charge of maritime issues, in the 98th meeting in July 2017 enacted some rules for Maritime Autonomous Surface Ships (hereafter refer to as MASSs) in order to facilitate safe navigation. The IMO defines MASSs “as a ship which, to a varying degree, can operate independently of human interaction[15] and “...Most predictions are that autonomous or semi-autonomous operations would be limited to short voyages, for example from one specific port to another, across a short distance”.[16] In brief, IMO basically defines MASSs as a ship for the purpose of managing and ensuring the navigation safety of autonomous vessels and other vessels at sea. However, IMO’s definition of MASSs’ navigation is assumed to be conducted over short distances.

In addition, Maritime UK published a guidebook, “Being a Responsible Industry-an Industry Code of Practice,” regulating the use and military application of UUVs. However, the text does not specifically indicate the legal status of UUVs and pertain only to the vehicles’ use within the territorial sea of the United Kingdom.[17] In other words, the Royal Navy has not define the legal status of UUVs but has formulated relevant regulations and requested all relevant units to follow the rules and to use the vehicles only in its territorial sea.

Additionally, the German Navy issued a handbook, “Commander’s Handbook: Legal Bases for the Operations of Naval Forces,” pointing out UUVs are considered as equipment of warships and is controlled by the warship and therefore its legal status should be the same as warships and enjoy the rights given by the Convention.[18] In short, if UUVs are dispatched by warships and perform the assigned tasks, the vehicle is equivalent to the legal status of warships.

According to the U.S. Navy’s publication, “Navy Unmanned Undersea Vehicle (UUV) Master Plan,” UUVs are defined as a

“Self-propelled submersible whose operation is either fully autonomous (pre-programmed or real-time adaptive mission control) or under minimal supervisory control and is untethered except, possibly, for data links such as a fiber optic cable”.[19]

The U.S. Navy’s Commander’s Handbook mentions “UUVs engaged exclusively in government, noncommercial service are sovereign immune craft”.[20] The United States believes that if UUVs are used to perform official duties then it would be regarded as a ship enjoying sovereign immunity. Therefore, UUVs enjoy rights and assume obligations of ships under the Convention. Even though they are never clearly defined as warships.

Thus, based on IMO and states’ practices, UUVs are regarded as ships and enjoy sovereign immunity but are only used in short-distance navigation in territorial waters and if UUVs are performing official duties. UUVs are not equivalent to the legal status of warships.

In summary, lack of clarification leaves the legal status of UUVs to be uncertain. States’ practices of UUVs’ use show that they can be regarded as ships. However, with the increased appearance of autonomous UUVs, they still do not meet the requirement of human presence. This leads to a situation where we have no standard definition or classification of UUVs upon which to create a legal status. Hence UUVs’ legal status is defined by States’ practices. This explain the different point of views on legal status of UUV belonging to the USS Bowditch. Thus, some experts call for the internationalization for a legal status of UUVs for them to be regulated for safety of navigation. UUVs are still in a legal grey area encouraging nation states on the misuse of UUVs. The following section will discuss the development of China’s application of UUVs.

The main advantage of UUVs is that it operates without a human, is less expensive than a human operated vehicle and replaces human risk in the conduct of dangerous operations. They operate in conditions and perform task that humans are not able to do efficiently, or at all.[21] In addition, Artificial Intelligence (AI) is seen as indispensable to the development of future warfighting capabilities or support for military operations.[22] The Chinese government sees AI technology as a “leapfrog development” opportunity to catch up with the U.S. military, implying AI technology for less advanced countries can skip a development stage. In other words, for countries behind the current generation of technologies it actually offers an advantage in adopting the next generation technology.[23]

Although there still are limitations of underwater communications, China is forging ahead and making some forms of AI mandatory. China shows its intentions for AI to transform their military into the worlds’ strongest. For example, the Chinese government released “New Generation Artificial Intelligence Development Plan” in 2017.[24] It reveals China’s ambition to “lead the world” in AI by 2030. According to a report, in the South China Morning Post in July 2018, Lin Yang, a scientist of Shenyang Institute of Automation of the Chinese Academy of Science, claimed China has plans to develop new-generation military underwater robots by 2021. He also runs a project with the goal to develop AI-driven unmanned submarines to handle surveillance, mine laying, and attack missions.[25]

When China seized a the U.S. UUV in December 2016 this further convinced Beijing to enhance its unmanned military systems to counter an enemy such as the U.S. and invest in developing its own capabilities.[26] Some unmanned military systems have been approved for utilization in a potential invasion scenario against Taiwan or U.S. and its allies.[27] As stated in China’s military strategy “White Paper,” the global trend of the military modernization is characterized by long-range, precise, smart, stealthy, and unmanned weapons.[28] An April 2020 Rand report, “People’s Liberation Army (PLA) Operational Concepts,” reveals China’s innovative military strategy and doctrine integrates big data and AI technologies with military concepts of joint force operations.[29] Thus, we see China’s effort to prioritize and integrate AI technology across the military spectrum including UUVs.

China released its Belt and Road Initiatives (BRI) in 2013, outlining Beijing’s long-term plans to become a major maritime power. The PLA is actively advancing its employment of military robotics and “unmanned” (無人, i.e., uninhabited) systems.[30] Chinese sources indicate that this includes using AI to build a concept of “intelligentized military.”[31] According to Lyle J. Goldstein’s article in The National Interest, the PLA Navy is promoting their capabilities in submarine warfare with a heavy emphasis on UUVs and integrated AI technology.[32]

There is a significant trend by the PLA Navy in expanding its development and increasing the deployment of unmanned systems such as autonomous vessels and UUVs. The PLA Navy signaled its intention by displaying its very first large-size UUV, the HSU001, during the PRC’s 70th Anniversary Parade on October 1 2019. The HSU001 could sit on the ocean floor for extended periods of time to gain artificial maritime intelligence, surveillance, reconnaissance and play an outsized role in PLA Navy amphibious warfare.[33] China also shows its ambition to elevate its presence in the Indian ocean with increasing deployment of UUVs. The Indian government discovered 12 China-deployed Haiyi class UUVs in the eastern Indian Ocean this April. An Asia Times report points out these UUVs could be utilized to facilitate submarine movements and in case of a conflict locate and disable underwater mines.[34]

As of yet no standard definition or classification of UUVs exists upon which to define a legal status. UUVs are still in a legal grey area allowing some nation states to exploit the unrestricted usage of UUVs. The Chinese government sees AI technology as a “leapfrog development” opportunity to catch up to a U.S. super power. China is also relying on AI technology to support its ambition for a world class military by 2050.

The PLA Navy is making continues gains in UUV technology extending the underwater operational duration for maritime intelligence, surveillance and reconnaissance. Clearly, UUVs will play a significant role in the PLA Navy’s amphibious warfare plan. The take-away here is that China has committed itself to the application of its considerable AI technology to strengthen their underwater warfare capacity as evidenced by their continued advances in UUV development.

Chihwen Ku is an assistant professor in the Department of Political Science, Fu Hsing Kang (FHK) College, National Defense University (NDU). Yuchen Chen is an assistant professor for the Graduate Institute of China Military Affairs Studies, FHK College, NDU. The authors appreciate the assistance of those who took the time to read and comment on drafts of this paper.