11.2.1 Shipwrecks and Cultural Heritage

Shipwrecks can offer a vast amount of information to those with the capabilities, time, and resources to conduct archaeological studies. With the advancement of technology, scientific expeditions have searched shipwrecks for signs of potentially polluting substances, the presence of marine organisms, and to gain an understanding of past human behavior (NOAA 2024b). Given that shipwrecks are often accidental, they offer a view into the social, cultural, and economic aspects of past experiences at a specific moment in time (NOAA 2024b). This means that those conducting archaeological studies of warships can also gain knowledge of their past armament and military history (Hayden Reference Hayden2023). Marine archaeologists have described shipwrecks as time capsules through which careful study can allow access to previously inaccessible stories and artifacts. Depending on the wreck site, tangible items may provide a cultural link to a State other than the vessel’s flag State. This introduces an added layer, given that a separate State may have an interest in the recovery of items through a cultural link, an interest in the preservation of the items, or an interest in the management and decisions regarding the wreck site.

The discovery of shipwrecks is not always the result of planned activities. Often, shipwrecks are located accidentally during environmental monitoring studies or as a serendipitous occurrence. There are times when it is necessary to conduct studies to gain a better understanding of certain landscapes ahead of a project, such as mapping exercises for underwater cables and offshore wind projects, in order to assess the potential for damage (Pater Reference Pater, Bailey, Galanidou, Peeters, Jöns and Mennenga2020). There have been instances where shipwrecks off the coast of a country have been stumbled upon during unrelated activities. The role of the coastal State remains the same regardless of whether a shipwreck was discovered through a planned archaeological expedition with appropriate permits, or accidentally without the proper equipment or resources. This is important to note, since States may consider shipwrecks to hold valuable cultural heritage significance, which can then alter the original scope of a project, or the role of all States involved with the shipwreck. Environmental assessments is one type of activity through which shipwrecks can be discovered, although, should a shipwreck be discovered by government or military vessels, States are not obligated to share that information under Article 13 of CPUCH, which states:

The discovery of a shipwreck can not only lead to a plethora of information; it can also be culturally significant for numerous States; it can help gain knowledge about a particular time in history; and it can offer acknowledgment of a final resting site. The exemption of government ships from alerting a coastal State of an underwater cultural heritage discovery can be an area for further study, as it potentially limits coastal State access, future studies, and security.

Meanwhile, discoveries of shipwrecks in an area where there are planned activities involve a question as to whether consent from the flag State of the sunken vessel – if it is different from that of the coastal State – would be required to move forward with such activities. Expanding coastal projects can include “trawling, dredging, offshore oil and gas explorations and port construction,” which may place undiscovered shipwrecks at greater vulnerability from destruction (Ridwan Reference Ridwan2019, 1623). The discovery of shipwrecks within the territorial sea, contiguous zone, or EEZ that have separate flag and coastal States can lead to discussions over activities that may interact with the shipwreck and surrounding ecosystem. As highlighted, “once a site or its artifacts are damaged or haphazardly removed, there is no way to access its information and recreate the story it might have told” (NOAA n.d.). The importance of cultural heritage connects to the untold stories that each shipwreck inherently contains. One shipwreck may hold significance for numerous States, and it is important to consider how States interact through existing international legal agreements, such as UNCLOS and CPUCH, when it comes to newly discovered shipwrecks with links to more than one State. The following section will discuss the role of emerging technologies in greater depth, followed by an analysis bridging cultural heritage and the ownership of shipwrecks.

11.3.1 Side-Scan Sonar

One technology to consider is the use of side-scan sonar. The application of side-scan sonar for underwater archaeological purposes has been actively used in the field since the 1960s (Goncharov Reference Goncharov2016). As this technology has continued to develop, it has become an increasingly important tool for the field of underwater archaeology. Side-scan sonar works by emitting and receiving acoustic pulses to aid in mapping the seafloor (NOAA 2002). These acoustic pulses can be emitted at different frequencies, ranging from 50 to 500 kilohertz, depending on the necessary breath and clarity (NOAA 2002). The pulses captured through this method are then used to create an image of the seafloor with shipwrecks and sites appearing in a darker shade than the seabed. One of the benefits of side-scan sonar is its ability to create 3D images of shipwrecks (Goncharov Reference Goncharov2016). It is also considered to be a less costly alternative to robotic technologies.

Scholars have noted the possible growth of side-scan sonar to continue developing through the use of global positioning systems for higher navigation and geographic references (Goncharov Reference Goncharov2016). One consideration between the use of side-scan sonar and global positioning systems to aid in the discovery of shipwrecks is the potential for conflict over access to the precise coordinates of a shipwreck. There are cases where multiple States having access to shipwreck coordinates could be considered potentially problematic, such as that of the San José, where Colombia has decided to keep private the precise coordinates of the shipwreck for security purposes. Another case involves the location of a French warship within US territorial waters (Gates Reference Gates2019) that was kept hidden. Similarly, the location of the Geldermalsen shipwreck has yet to be released publicly for fear of potential looting (Looram et al. Reference Looram and Lindley2024). These cases highlight how certain technologies used to locate and study shipwrecks can introduce potential security risks over sharing geographic details.

There have also been studies that take side-scan sonar a step further through its interaction with AI to detect shipwrecks from side-scan sonar imagery. A study conducted by the University of Michigan, AI4Shipwrecks, considers how machine learning can be utilized to uncover shipwrecks from side-scan sonar data (Sheppard et al. Reference Sheppard, Sethuraman, Bagoren, Pinnow, Anderson, Havens and Skinner2024). The use of AI may impact the amount of time necessary to identify shipwrecks, which can heighten interactions between underwater archaeology, UNCLOS, and CPUCH, as will be discussed in the following sections.

11.3.2 ROVs, AUVs, and USVs

Another technique to consider is the use of USVs, ROVs, and AUVs (NOAA 2024a). While side-scan sonar is a widely used technology within underwater archaeology, it is often deployed through the use of an USV. It is beneficial to cover how these technologies can aid in the discovery and study of shipwrecks.

USVs are used within multiple fields for numerous purposes, and they can be used to reach depths of up to 6,000 m (Merkusheva Reference Merkusheva2020). While the depth an unmanned vehicle can reach is impressive, it is also rare for an archaeological study to be completed within a single expedition, as it is common for teams to return to the same shipwreck multiple times to conduct studies and gain a better understanding of the area. Archaeological studies often include multiple AUVs and ROVs during a single mission, which can be costly but effective (Merkusheva Reference Merkusheva2020).

A specific case of the effective use of AUVs in locating wrecks is the discovery of the ARA San Juan submarine in 2018. The private company Ocean Infinity successfully located the wreck using five AUVs and two ROVs connected to a research vessel (Song Reference Song2023). The search for the submarine included collaboration between nineteen countries, and the official identification of the submarine was made through the use of an ROV (Villán Reference Villán2019). While the submarine discovered in this case would not fall under CPUCH’s 100-year time period in order to be designated a protected site, it is acknowledged as a memorial by Argentine officials. The submarine wreck site was found approximately 600 km east of Comodoro Rivadavia, off the coast of Argentina (Ocean Robotics 2018). This highlights Argentina’s role as the flag State of the submarine, with the absence of a separate coastal State given that the wreck was found within the high seas. This case provides an example of international collaboration in locating a potential wreck in times of stress and emergency, which differs from planned archaeological studies, although both include the use of highly advanced technologies.

USVs, ROVs, and AUVs introduce another issue to consider with legal implications distinct from the use of side-scan sonar and imaging technologies. This is centered on the fact that USVs, ROVs, and AUVs can increase human activity within previously challenging environments. It is worth noting the potential damage to archaeologically significant sites and wrecks caused by these vehicles, which can be explored in greater depth through additional research. USVs have been used in tandem with manned vehicles for the discovery of different shipwrecks through “launching, recovery, positioning, battery charging, and data transfer” (Zwolak et al. Reference Zwolak, Wigley, Bohan, Zarayskaya, Bazhenova, Dorshow, Sumiyoshi, Sattiabaruth, Roperez, Proctor, Wallace, Sade, Ketter, Simpson, Tinmouth, Falconer, Ryzhov and Abou-Mahmoud2020, 6). A goal of combining these technologies is to increase the level of coverage to be studied and maximize the study area (Roman and Mather Reference Roman and Mather2010). It is beneficial to maximize the study area, as it can present additional information, although it may be questionable from a legal perspective should the proposed study expand into multiple maritime zones.

There is also the issue of the amount of time it takes to conduct an effective study when using USVs and ROVs (Roman and Mather Reference Roman and Mather2010). Advantages of using robotic vehicles include their ability to “carry cameras, video cameras and acoustic sensors to take optical and acoustic images of the site” (Conte et al. Reference Conte, Gambella, Scaradozzi and Zanoli2009, 177). This reduces the instances of physical divers needed to survey a site, and while costly, it can provide highly accurate data over a larger area (Conte et al. Reference Conte, Gambella, Scaradozzi and Zanoli2009, 177). USVs and autonomous vehicles also fall under a distinct legal area compared to research vessels under UNCLOS. A limitation to the use of these technologies is within shallow waters, where they may not be as beneficial as in deep waters (Goncharov Reference Goncharov2016). An increasing number of expedition teams continue to employ multiple ROVs and AUVs for their efficiency, accuracy, timeliness, and ability to view and recover items from depths inaccessible to humans. Subsea vehicles allow for the potential of human interaction, although this presents changes that were not in practice at the time of the creation of Articles 149 and 303 of UNCLOS. These types of technologies have become standard practice for locating shipwrecks within deeper waters, and it will be important to ensure that existing practices over the legality of accessing shipwrecks in foreign waters continue to emphasize the importance of underwater cultural heritage and the preservation of wrecks.

11.3.3 3D Imaging and Photogrammetry

Three-dimensional images of the seafloor, in addition to containing outlines of shipwrecks, can be beneficial for coastal States in gaining access to a better understanding of the topography of their coastal waters. In addition to side-scan sonar, there have been innovations in the use of other 3D laser and scanning technologies (McCarthy et al. Reference McCarthy, Benjamin, Winton, van Duivenvoorde, McCarthy, Benjamin, Winton and van Duivenvoorde2019). Three-dimensional scanning systems have played a role in the documentation of cultural heritage, which may work in tandem with CPUCH (Bräuer-Burchardt et al. Reference Bräuer-Burchardt, Munkelt, Bleier, Heinze, Gebhart, Kühmstedt and Notni2023). The combined use of side-scan sonar and 3D scanning technology has made it possible to create more accurate documentation of objects on the seabed (Bräuer-Burchardt et al. Reference Bräuer-Burchardt, Munkelt, Bleier, Heinze, Gebhart, Kühmstedt and Notni2023). The use of traditional sonar technology helps create an image of the seabed. However, scholars have noted that “these shipwrecks on the seafloor usually appear as low elevation – high texture seabed features, such as many other small seabed features, with the wooden frame most often disintegrated and the cargo, mainly amphorae, dispersed around the wreck” (Ferentinos et al. Reference Ferentinos, Fakiris, Christodoulou, Geraga, Dimas, Georgiou, Kordella, Papatheodorou, Prevenios and Sotiropoulos2020, 7). The material with which the vessels were built also impacts their visibility when documented through 3D imaging technology.

Additional advancements in this area have centered on ways to capture images with greater clarity to aid in the identification of vessels and artifacts. Three-dimensional images as a result of side-scan sonar are helpful in capturing more detailed information for shipwrecks on the seabed, as compared to other versions of sonar technologies. Advanced photogrammetry has aided researchers in studying deepwater sites after returning to shore in order to identify and differentiate between objects to determine the flag State of origin, as was seen through the discovery of the US submarine S-28 (Hydro-International 2020).

ROVs, AUVs, USVs, sonar, and 3D imaging technologies can shift parts of the archaeological study of shipwrecks by decreasing the amount of time required at sea and increasing access to more accurate data. However, discussing how this interacts with UNCLOS and CPUCH is important, since these regimes include distinct rights and access with regard to archaeological objects.

11.4.1 United Nations Convention on the Law of the Sea

UNCLOS references underwater archaeology within Articles 149 and 303. Each article centers on the role of States pertaining to objects of an archaeological or historical nature found within different maritime zones. Articles 33 and 303 focus on activities within the territorial sea and the contiguous zone, while Article 149 focuses on the Area. There is a noticeable gap regarding archaeological objects found within the EEZ.

Article 303 (“Archaeological and historical objects found at sea”) states in part:

1. 1. States have the duty to protect objects of an archaeological and historical nature found at sea and shall cooperate for this purpose.

2. 2. In order to control traffic in such objects, the coastal State may, in applying article 33, presume that their removal from the seabed in the zone referred to in that article without its approval would result in an infringement within its territory or territorial sea of the laws and regulations referred to in that article.

While Article 303 does not directly reference shipwrecks, it can be expected that shipwrecks would fall under the phrase “objects of an archaeological and historical nature,” although there is no clear definition of what is considered to be an object of an archaeological nature. A focus is placed on the removal of objects from the seabed, and the article does not suggest other areas of importance, such as the examination of underwater objects. There is no direct mention of the role of the flag State concerning archaeological objects, as only the coastal State is referenced regarding its sovereignty over the waters in which the objects are located.

The focus on the control of traffic for the removal of objects hints at the likelihood of there being interest in the found objects from multiple States. The reference to Article 33, which focuses on the contiguous zone, notes that objects taken from this area without the consent of the coastal State would equal infringement upon their sovereign rights. This encompasses shipwrecks found within the territorial sea and contiguous zone, although there is a noticeable gap concerning the EEZ. The lack of a clear designation of rights for flag States and coastal States over shipwrecks found within the EEZ is an area to consider with the increasing number of shipwreck discoveries within this area.

Contrary to CPUCH, UNCLOS does not set a specific time period for the designation of shipwrecks as being archaeologically or historically significant. CPUCH states that an object must be underwater for a minimum of 100 years in order to be considered underwater cultural heritage and available for protective measures. Scholars have discussed whether UNCLOS can be interpreted to include a time period of 50, 100, or 200 years for objects to be considered archaeologically significant, based on time periods included within domestic instruments (Cottrell Reference Cottrell1994).

Article 149 (“Archaeological and historical objects”) states:

Thus, Article 149 includes three potential States that could have preferential rights over archaeological objects: the State of origin, the State of cultural origin, and the State of historical and archaeological origin. It is worth considering when and how these States may be distinct, as scholars have noted that there is no clear hierarchy within this Article to designate which States would gain ownership in the event that multiple States are involved (Henn Reference Henn2012). Scholars have argued that the use of the phrase “for the benefit of mankind as a whole” leads to an interpretation that underwater wrecks have “a commonness of ownership and benefit of shipwrecks with archaeological significance” (Cottrell Reference Cottrell1994). It echoes the goal of Article 303 in the preservation of objects, although there are no in-depth details concerning how objects should be preserved or disposed of. Scholars have also mentioned that “preferential rights suggest that one nation has a priority, but that there are simultaneous rights in other nations” (Cottrell Reference Cottrell1994). This connects to the idea that multiple States can have a role in, and active claims to, shipwrecks located outside of their national waters. However, Article 149 centers only on objects found within the Area, which encompasses the seabed beyond the continental shelf. When considering a map of the maritime zones referenced in UNCLOS, the Area would include not objects located within the EEZ but rather those below the water column of the high seas. The number of shipwrecks to be discovered may continue to increase in future years due to technological advancements in exploring the deep ocean. It is, therefore, helpful to consider the potential interaction between the State of origin, the State of cultural origin, and the State of historical or archaeological origin for vessels located and identified within multiple maritime zones.

Articles 33, 303, and 149 offer guidance for States to consider when making decisions on activities related to underwater sites or shipwrecks of historical or cultural interest. The overarching aim centers on collaboration to conserve, protect, or dispose of archaeologically significant objects and artifacts. An example of effective international collaboration can be seen through the discovery of the Titanic shipwreck. The UK was the original flag State of the Titanic, which was discovered by a team of divers within the high seas, off the coast of Canada in the North Atlantic. This is a well-known and much-studied case, leading to changes in international legislation, such as through the Safety of Life at Sea Convention.Footnote ³ The discovery of the Titanic shipwreck was possible through the use of Argo, an unmanned vehicle capable of reaching depths of up to 6,000 m and capturing images in challenging environments, as well as other deep-sea exploration technologies (WHOI 2024). However, it is significant that it was discovered within the high seas, as most newly discovered shipwrecks tend to be located within coastal waters.

Overlapping interests in ownership and preferential rights may be heightened when shipwrecks are thought to have precious gems, jewels, and stones on board. While all shipwrecks can be considered to hold significant cultural heritage for a variety of reasons, the presence of cargo and artifacts may affect how they are viewed by States. There are conflicting flag State and coastal State claims to the San José shipwreck by Colombia, Spain, Peru, a private company from the US, and Indigenous groups from Bolivia. Each of these States cites distinct reasonings for its claims to ownership over the artifacts surrounding the shipwreck. Colombia centers its claim on the fact that the shipwreck is located within Colombian waters and is part of its cultural heritage (Tumin and Glatsky Reference Tumin and Glatsky2024). Meanwhile, Spain claims that it should have access to the shipwreck since it is the original flag State, it has sovereign immunity, and it is the resting site of more than 600 Spanish sailors. Peru and several Indigenous groups claim ownership over the artifacts surrounding the shipwreck, given that colonial powers took the gold, silver, and emeralds from Peruvian, Bolivian, and Colombian mines worked by Indigenous people (Pinedo Reference Pinedo2024). A private salvage company based in the US claims ownership over content found on board given its claim to have discovered the shipwreck in 1980, years ahead of the discovery by the Colombian Navy. Sections of these differing claims have been taken to the Permanent Court of Arbitration, particularly cases between Colombia, Spain, and the US (Chen and Rios Reference Chen and Rios2024). This case highlights how the State of origin, the State of cultural origin, and the State of historical and archaeological origin have placed claims over the wreck. Article 149 mentions preferential rights, although there is insufficient expansion on these rights to gain a clear understanding of how they would impact a State’s claims.

This issue is further complicated by the fact that Colombia has not ratified CPUCH, while Spain has urged that the San José be considered as a protected site given its role as a resting place. This leads into the question of how technologies, and the inherent increased access, impact the designation and enforcement of shipwrecks as gravesites. While shipwrecks can be thought of as gravesites, they are also considered homes to marine ecosystems, materials to be exploited, and locations for potential bilateral cooperation or conflict. UNCLOS addresses a starting point for objects found within the territorial sea, the contiguous zone, and the Area, yet it leaves vague aspects of the management and ownership of shipwrecks. CPUCH was designed to resolve some of the uncertainty, but it has not been universally accepted.

11.4.2 Convention on the Protection of the Underwater Cultural Heritage

CPUCH, which entered into force in 2009, currently has eighty-one State parties. While fewer States have ratified CPUCH as compared to UNCLOS, the Convention continues to be relevant when it comes to the protection of the underwater cultural heritage. CPUCH has aided in the protection and preservation of shipwrecks and archaeologically significant sites across various areas of the ocean. One of its main focuses is the preservation of underwater cultural heritage, which is defined in Article 1(1)(a):

This Convention differs from UNCLOS in that it provides greater details on archaeologically significant objects, including a specified time period for which an object must be underwater in order to be considered underwater cultural heritage. The 100-year time period can aid in the designation of warships as underwater cultural heritage when more than one State is involved. There are existing domestic regulations governing the protection of shipwrecks, whether due to their understanding as gravesites or to the goal of limiting disturbance, and CPUCH serves to fill a gap in the management of shipwrecks that may involve multiple States. These issues become more complex as conflicts over the ownership of shipwrecks and their designation as gravesites arise, and when the States involved have not formally adopted the Convention.

In addition, underwater cultural heritage can be separated into tangible and intangible heritage. Shipwrecks and artifacts are considered tangible pieces of underwater cultural heritage, while intangible heritage would include oral stories and traditions passed down through generations (Micronesia 2024). Scholars have referenced how finding the location of certain shipwrecks originated through local knowledge and stories from fishermen and local inhabitants (Finney Reference Finneyn.d.). Local knowledge, combined with the technological capabilities of ROVs and AUVs, has led to the discovery of several wrecks. The argument in favor of the role of intangible cultural heritage as related to shipwrecks touches on the importance of oral stories in the discovery stage. This differs from UNCLOS, which does not reference tangible or intangible underwater cultural heritage when considering archaeological objects.

Article 7(3) of CPUCH states:

The role of the coastal State, as referenced in Article 7, is to inform the flag State of the discovery of an identifiable vessel within its territorial sea. There are no additional details provided on the continued role of the coastal State, such as to alert the flag State of future proposed activities that may impact the vessel. This can be challenging if the coastal State would need authorization from the flag State prior to conducting activities that may interfere with the sunken vessel. Balancing these varied interests over shipwrecks across maritime zones is important to ensure that wrecks are not unintentionally disturbed.

In addition to the enforcement of guidelines for known wrecks, it is also imperative to have oversight by the coastal State over expeditions to uncover potential wrecks. There have been cases where private divers have found shipwrecks within coastal waters and did not alert the national government as necessary under international customary law and domestic policy in certain States. In France, a group of commercial divers located the wreck of the Prince de Conty off the coast of the island Belle-Île-en-Mer in 1974, yet did not alert the French authorities of the wreck, preferring to keep it hidden (Mashberg Reference Mashberg2022). Years later, gold ingots recovered from the wreck were located in the US marketplace and were returned to France (Mashberg Reference Mashberg2022). The decision to return the ingots to France came as a result of the ship being flagged to France and being located within French territorial waters. However, China placed a claim to the ingots, citing that they were part of Chinese cultural heritage as they had originated from China (Mashberg Reference Mashberg2022). This shows the contrast in access to objects from shipwrecks from a maritime zone sovereignty claim compared to a cultural heritage claim. UNCLOS and CPUCH include sections that focus on the duty to alert the flag State should an object originally belonging to that State be discovered and identified. This assumes that the coastal State is involved in activities taking place over a shipwreck; however, with the role of ROVs and AUVs in accessing deepwater environments, there is the potential for the flag State to be the primary authority of the research expedition over sunken warships, with participation from other States. This leads to a question concerning the interaction and the duty of the flag State to alert the coastal State over data and objects discovered on warships.

11.5.1 Sovereign Immunity of Sunken Warships

The final element to discuss concerning the interaction of UNCLOS, CPUCH, and advancements in underwater archaeology focuses on the role of the sovereign immunity of sunken warships. As previously discussed, warships constitute a large number of recently discovered shipwrecks. Compared to other vessels used for commercial purposes, warships can have distinct legal protections (Dromgoole Reference Dromgoole2013). One of these distinctions is the sovereign immunity of the flag State over warships, which would be applicable irrespective of the maritime zone in which a warship was discovered.

Archaeologists are able to identify the original flag State of a sunken vessel based on access to historical logs, photographic evidence, and scientific testing to discover the State of origin. Through the use of photogrammetry, side-scan sonar, and other techniques, practitioners are able to gain clearer data to aid in the identification of sunken vessels. However, certain vessels may be difficult to identify based on environmental factors and the condition of the vessel. Scholars have mentioned the possibility of private salvage claims in instances where a ship is no longer able to be identified, and no flag State can be appropriately notified.

There is the potential for flag State jurisdiction over shipwrecks that have been successfully identified as warships under the principle of sovereign immunity. Scholarly discussions have considered whether sunken warships apply under the role of sovereign immunity, since they are no longer operating under the command of a captain or a crew and are incapable of navigation (Oyama Reference Oyaman.d.). This position stems from Article 29 of UNCLOS, which centers on the definition of warships:

The argument that sovereign immunity does not apply to sunken warships highlights the fact that sunken warships are not under the command of an officer or crew. However, State practice has shown that States often consider their sunken warships to be under their jurisdiction through sovereign immunity and their designation as war graves (Ronzitti Reference Ronzitti2011). There are scholars who support the view of sunken warships as being under the sovereign immunity of the flag State until the flag State has explicitly renounced its jurisdiction over the vessel (Ronzitti Reference Ronzitti2011). The application of sovereign immunity could place a right of access to the flag State, although it is likely that the coastal State would need to provide its consent if the shipwreck were located within its territorial sea, contiguous zone, or EEZ (Dromgoole Reference Dromgoole2013).

The coastal State is mentioned in Articles 149 and 303 of UNCLOS as having sovereign rights over objects of an archaeological and historical nature found within its waters. The CPUCH similarly gives rights of access to the coastal State. It then becomes important to consider the interaction between the coastal State and the flag State in cases that involve sunken warships if both have certain competing rights of access.

States have been able to manage shipwrecks effectively through bilateral agreements – as seen in the case of the HMAS Perth, an Australian warship located off the coast of Indonesia, by creating a conservation zone over the warship (Pearson Reference Pearson2023). Bilateral agreements between flag States and coastal States to create joint management plans over historic wrecks have been an effective measure and may be beneficial moving forward, as States continue to collaborate to conduct scientific studies of shipwrecks. The creation of a preservation zone surrounding US warships found off the coast of France has also been effective in preventing further damage (Mirasola Reference Mirasola2016).

11.5.2 Shipwrecks as Gravesites

Aside from the application of sovereign immunity, sunken warships and vessels may also simultaneously be gravesites. Increased access to shipwrecks means that there can be additional instances of disturbances that can interact with ethical concerns over shipwrecks as gravesites. It may be clear to acknowledge shipwrecks as gravesites considering those who perished with the ship; however, in practice, it can be difficult to enforce the idea of a sunken vessel as a gravesite without tangible evidence (Forrest Reference Forrest2003). Wrecks that have been submerged for years experience changes due to the environment, which may make it more difficult to identify exact objects or human remains. The use of robotic technologies and advanced imaging mechanisms can aid in capturing and verifying objects of an archaeological nature on the seabed without the need for retrieval. Without coastal State monitoring and patrol programs, it becomes difficult to enforce the management of underwater shipwrecks as gravesites to avoid disruption from commercial divers, tourism, and other actors.

Effective cases of the protection of shipwrecks as gravesites from unauthorized excavation use several types of mechanisms to surveil the area surrounding the shipwreck. This can be more imperative when it concerns wrecks that could cause damage to the surrounding environment if they are disturbed. The UNCLOS does not make direct reference to shipwrecks as potential gravesites, although Article 2(9) of CPUCH provides that States “shall ensure that proper respect is given to all human remains located in maritime waters.” Scholars have noted the discussion over the respectful treatment of shipwrecks as gravesites as a complex and challenging area (Delgado and Varmer Reference Delgado, Varmer, Guérin, da Silva and Simonds2014). The designation of a shipwreck as a protected gravesite can potentially impact further studies of the surrounding area and likely requires consent and collaboration between the various States involved. The definition of respectful treatment of shipwrecks is important, as technological advancements balance between assisting in uncovering data and not causing disruption to the site. An example is the expanding use of environmental DNA testing, which has been employed on skeletal remains discovered within the Antikythera shipwreck (Lewis Reference Lewis2016). The results of the environmental DNA testing can reveal aspects of the lives of sailors at the time of the sinking, as well as additional details about the State of origin (Briggs Reference Briggs2020). The Antikythera shipwreck involved a Greek vessel that was located within Greek waters off the coast of Crete (Theodoulou Reference Theodoulou and Sarris2015). This lessened the number of States involved in the management and ownership of the vessel, since it was discovered within the territorial sea of the original flag State.

Meanwhile, the management of sunken shipwrecks within the EEZ of a separate State can affect a number of decisions stemming from the ownership of the sunken vessel. For example, a State may decide to take action against a shipwreck that is considered a potentially polluting wreck, as well as making decisions concerning the removal of artifacts or other materials on board. Without clear ownership over a shipwreck, it can be hard to determine the correct authority to enforce actions that impact the wreck site, the surrounding marine environment, and the cultural connection to local inhabitants. It can be a timely process, involving national policies, to consider the wreck of a warship as protected within a foreign State’s EEZ, although this has been successfully negotiated through the wrecks of the HMCS Guysborough and the HMCS Athabaskan – Canadian warships located within the French EEZ (House of Commons, Canada 2018).

While UNCLOS and CPUCH are significant in deciding the role of flag States and coastal States regarding archaeological objects, there is a noticeable gap in the enforcement of protected shipwrecks as gravesites. Domestic legislation assists in filling these gaps with regard to shipwrecks flagged to the original State in whose waters they were located. This leaves a question concerning the ownership and enforcement of certain policies over wrecks outside of the national waters of their flag State. Several national policies surround State action over shipwrecks; these vary across States with distinct maritime histories, resources, and objectives. Examples of domestic policies concerning shipwrecks in foreign or international waters include the Abandoned Shipwreck Act of 1987 and the Sunken Military Craft Act of 2004 in the US, and the Protection of Military Remains Act 1986 in the UK (National Park Service 2023).

While regulations vary by country, most States that are heavily involved in archaeological research also have strict application processes and permits necessary for projects to move forward. Some States encourage the participation of a government official on board the archaeological research vessel to ensure that it is conducted according to plan. Other States, such as those that did not have active vessels at the time of the First and Second World Wars, may not have such an interest in accessing and studying foreign vessels. There have been cases where third parties, such as those outside of the flag State and the coastal State, have been involved in the disruption of wreck sites without the prior consent of the flag State or the coastal State. In these instances, it is important to consider how neither State was made aware of those activities until after the artifacts were taken and in transit, as is the case of the HMAS Perth (Hosty Reference Hosty2022).

Shipwrecks can also be potentially exposed to access by divers within the territorial sea. There have been cases of commercial divers excavating wreckage sites following the successful discovery of shipwrecks within different areas of the ocean, as seen in the case of the HMS Repulse and the HMS Prince of Wales (Grammaticas Reference Grammaticas2023). Shipwrecks are often exploited for their metal and other parts without regard to their applicability as marine conservation zones or gravesites. This can cause tension between the flag State of the vessel that has been excavated and the coastal State in whose waters the operations took place. Meanwhile, in instances where flag States and coastal States are working collaboratively toward the protection of a shipwreck, this can be derailed by actions taken by private companies contrary to the goal of protecting underwater cultural heritage. It is then difficult to consider the applicability of UNCLOS or CPUCH in safeguarding sites of archaeological importance from unauthorized excavation.

A case of competing interests over a shipwreck and its artifacts can be seen in the shipwrecks found by Enigma Recoveries off the coast of Cyprus and Lebanon. Enigma Recoveries used ROVs to excavate more than 588 artifacts from the wreck sites (Milmo Reference Milmo2016). These were then confiscated by officials from Cyprus, claiming that the wrecks were located within its waters. However, the private company claimed that the location of the wrecks is within the high seas between Cyprus and Lebanon (Maritime Executive 2020). The excavation was only possible due to the use of ROVs, and this sheds light on the importance of maritime boundaries when deciding ownership and access to shipwrecks. Along with technological advancements to study and preserve shipwrecks, there have been advancements that have led to a potential increase in tourism and commercial diving over shipwrecks. This is an area to consider for future research concerning legal access to shipwrecks in foreign waters by commercial divers and tourists (Ferentinos et al. Reference Ferentinos, Fakiris, Christodoulou, Geraga, Dimas, Georgiou, Kordella, Papatheodorou, Prevenios and Sotiropoulos2020).