Inspecting Ships Autonomously under Port State Jurisdiction: Towards Sustainability and Biodiversity in the EU

In: The International Journal of Marine and Coastal Law
Ríán Derrig Postdoctoral Fellow, WMU-Sasakawa Global Ocean Institute, World Maritime University Malmö Sweden

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This article examines the possibility of autonomous inspection robots being used to undertake inspection tasks conducted on the basis of port State jurisdiction in European Union (EU) Member States’ ports. A brief overview of technical research concerning such robots is offered. The article then outlines the EU legal framework concerning port State jurisdiction, and contextualises this legal landscape by recalling the history of attempts at the EU and international level to regulate in response to maritime disasters since the 1980s. Based on a close reading of the Port State Control Directive, alongside analysis of the aims pursued and policy options proposed in the context of the European Commission’s significant ongoing work on a review of this instrument, it is clear that the adoption of autonomous inspection technologies could offer significant benefits, permitting more efficient completion of existing inspection tasks and potentially changing what is and is not considered feasible in inspection scenarios.


This article examines the possibility of autonomous inspection robots being used to undertake inspection tasks conducted on the basis of port State jurisdiction in European Union (EU) Member States’ ports. A brief overview of technical research concerning such robots is offered. The article then outlines the EU legal framework concerning port State jurisdiction, and contextualises this legal landscape by recalling the history of attempts at the EU and international level to regulate in response to maritime disasters since the 1980s. Based on a close reading of the Port State Control Directive, alongside analysis of the aims pursued and policy options proposed in the context of the European Commission’s significant ongoing work on a review of this instrument, it is clear that the adoption of autonomous inspection technologies could offer significant benefits, permitting more efficient completion of existing inspection tasks and potentially changing what is and is not considered feasible in inspection scenarios.


Robotic systems capable of visually inspecting, measuring for corrosion and thickness, and cleaning the hulls and structures of large ships are currently the object of growing technological development and investment. These systems can be composed of multiple individual robots of different kinds – for example micro aerial vehicles (drones), underwater vehicles and crawlers that magnetically attach to a metal surface – potentially operating to varying extents autonomously and making decisions based on artificial intelligence capabilities. While these technologies are still under development, it seems likely that they will become more widely used in situations where the structures, and especially the outer hulls, of large ships are inspected and/or cleaned. By potentially facilitating more frequent and detailed inspections of the outer hulls and structures of ships by States asserting port State jurisdiction these technologies could contribute to the reduction of substandard shipping and to the protection of the marine environment. By inspecting for and subsequently removing accumulated organic matter (biofouling) on ship hulls, these robotic systems could support significant fuel savings through the greater fuel efficiency created by smooth hulls, leading to lower greenhouse gas (GHG) emissions. More rigorous monitoring and removal of biofouling could also protect marine biodiversity from threats posed by alien invasive species introduced to a new ecosystem having been carried there on a ship’s hull. This article addresses the question of how we can build these technologies into legal regimes that contribute to the enforcement of standards relating to the safety and maintenance standards of ships, the protection of the marine environment, and climate change mitigation. This perspective views these new technologies, not as posing new problems for European Union (EU) or International Maritime Organization (IMO) regulators, but as offering new possibilities.

This article outlines the legal framework applicable to the use of such autonomous robotic inspection systems by EU Member States asserting port State jurisdiction over ships entering their ports. Thus, by examining the EU’s harmonisation of the way its Member States fulfil their responsibilities as port States, the article focuses on a point of intersection between EU law and the law of the sea.2 The extent to which the aims pursued by EU legislation on port State jurisdiction – the improvement of ‘maritime safety, security, [and] pollution prevention’ – could be supported by the employment of autonomous inspection robots that are currently under development is analysed. This focus on EU port State jurisdiction as it relates to autonomous inspection technologies is useful for three main reasons. First, the European Commission is currently engaged in a process of revising the primary piece of EU legislation governing port State jurisdiction, Directive 2009/16 of the European Parliament and of the Council of 23 April 2009 on port State control (the PSC Directive).3 Through close analysis of the current version of the Directive alongside the Commission’s assessment of its operation to date, this article examines how wider adoption of autonomous ship inspection robots could support the aims pursued by this significant legislative initiative.

Second, the EU has been particularly active in policy areas related to these technologies, especially on reducing substandard shipping, and on combatting climate change. On the topic of reducing substandard shipping, an interest can be perceived, especially among Members of the European Parliament (MEP s), to use EU legislation to prompt Member States to exercise their jurisdiction as flag, coastal or port States with more force and frequency with the aim of making shipping safer, cleaner and less polluting. It could be argued that this interest connects with a wider current impetus to expand regulatory powers of the State over maritime spaces in ways not limited to the flag and zonal architecture of the United Nations Convention on the Law of the Sea (LOSC). This impetus was well-captured by the observation made by Malcolm Evans when giving evidence before the International Relations and Defence Committee of the UK House of Lords in October 2021, that much room existed to ‘ratchet up’ assertions of State regulatory power within the existing LOSC framework.4 With regard to climate change policies, the EU’s increasingly strenuous efforts to reduce the contribution made by shipping to GHG emissions have taken the form of an argument with the IMO, conducted in a legal idiom but that is in substance a clash over the politics of climate change.

Third, this focus on the EU is merited because the EU’s activity in these areas is of global systemic relevance. The EU has expressed a willingness to threaten to squeeze the IMO’s position as prime regulator in the area of maritime policy. The EU’s economic power and importance as a market for shipping makes this threat credible, with the consequence that EU law and policies are of interest internationally as they have the potential to both set standards and have effects beyond the EU.5

The article proceeds as follows. The first section explains what autonomous inspection robots are, and what kinds of inspection and cleaning tasks they can perform, or are likely to be able to perform in the near future. The second section outlines the EU legal framework concerning port State jurisdiction, its interaction with the prerogatives and obligations of States under the law of the sea, and with the Paris Memorandum of Understanding on Port State Control. The third section offers a truncated history of attempts to regulate and adequately enforce construction, safety and maintenance standards of merchant ships since the 1980s, focusing on EU acts and the specific problems associated with bulk carriers and oil tankers. The fourth section closely analyses provisions of EU legislation on port State jurisdiction that require the inner and outer structures of ships to be inspected, linking these requirements to capabilities of autonomous inspection robots. The fifth section examines the Commission’s ongoing work on a review of the PSC Directive, examining how autonomous inspection robots could support the aims pursued by this initiative. The possibility of new EU legislation mandating that ships entering Member State ports comply with standards prescribing maximum acceptable levels of biofouling is examined, drawing a comparison with such initiatives in other jurisdictions. The fifth section briefly concludes.

What Are Autonomous Inspection Robots?

The autonomous inspection robots referred to in this article comprise a system of multiple different kinds of robots operating cooperatively to inspect and potentially clean a large structure composed of metal plates, such as the hull of a medium or large ship. There are three primary categories of such robot. Micro aerial vehicles are small multi-propeller drones that can systematically move around a large vessel, providing visual feedback to an operator. Autonomous underwater vehicles are small submersibles that can systematically visually map the portion of a ship’s hull that is underwater. Finally, magnetic wheeled crawlers can attach to a steel plate surface and conduct acoustic based inspection of the surface above and below the waterline. By transmitting sound waves at the surface as they move slowly across it, these crawlers can measure the thickness of the steel, thus identifying points thinned by corrosion with significant accuracy. It is possible for all three categories of robot to work together, with several individual units of each kind transmitting data into a single augmented reality representation of a vessel, monitored by a human inspector. This vision, which is the object of the BugWright2 research project on which this article draws, is sketched in Fig. 1.

Figure 1
Figure 1

Drones, magnetic wheeled crawlers and submersibles working autonomously to visually and acoustically scan a ship while transmitting data to a human operator

Citation: The International Journal of Marine and Coastal Law 37, 3 (2022) ; 10.1163/15718085-bja10097

Source: C Pradalier, ‘Autonomous Robotic Inspection and Maintenance on Ship Hulls and Storage Tanks’ (BugWright2), Description of the Action, EU Horizon 2020 grant agreement No. 871260, used with permission

Drones, submersibles and crawlers of these kinds are currently most commonly operated remotely by a dedicated human operator, without making autonomous decisions about their own navigation or about the surfaces they inspect. However, significant research effort is currently being dedicated to developing inspection systems composed of robots that can navigate autonomously, while decisions about defects identified are taken by a human operator. It is not unrealistic to imagine that in the near future a greater level of autonomous operation may be attained, with teams of robots making independent decisions in order to synchronise their movements around a vessel, while using large stores of data from past inspections to make further decisions about defects identified on the vessel being inspected.

In the near future, the most holistic use of all three categories of inspection robot, represented in Figure 1, could permit ship surveys and inspections that would ordinarily take place in dry dock to be undertaken at the quay, potentially even while a vessel is unloading and loading cargo. Depending on the type of vessel and the level of inspection being undertaken, drones, crawlers or submersibles might also be used independently of each other. For example, submersibles could conduct a visual inspection of the underwater portion of the hull of a fishing vessel, while drones could be well suited to conducting a visual inspection of the massive sides of a cruise vessel, or the outer hull and inner cargo areas of a bulk carrier. Where hull cleaning is the aim, a team of crawlers fitted with brushes can be deployed to systematically sweep the hull clean of organic matter. The advantage offered by these technologies is that they can make it easier to quickly and effectively examine and clean difficult to access parts of a ship’s outer and inner structure.

A Point of Intersection between EU Law and the Law of the Sea

This article focuses on ways such autonomous inspection robots could be used in the future by national authorities asserting port State jurisdiction in EU ports. Hence, the immediately applicable and overarching legal framework is provided by the PSC Directive, with its three implementing regulations.6 With this Directive, the EU has sought to harmonise how its Member States exercise prerogatives they enjoy as port States under the law of the sea.

The ability of port States to prescribe and enforce legal standards with respect to ships choosing to enter their ports follows from a concurrent reading of several provisions of the LOSC.7 Article 11 provides that outer parts of harbour works form part of the coast, making them part of the baseline and placing ports within internal waters; Article 8(1) specifies that waters landward of the baseline are internal waters; and, in stating that that the sovereignty of a State extends ‘beyond its land territory and internal waters’ to other specified zones, Article 2(1) makes it clear that States enjoy territorial sovereignty over internal waters.8 It follows from this pattern of provisions that States exercise prescriptive and enforcement jurisdiction that is territorial in nature over all ships, whether flying that State’s flag or not, while they are in port, subject to any agreements with other States that may limit such jurisdiction. As noted by Robin Churchill, this is also the position under customary international law, binding States with maritime ports, but that have not ratified the LOSC.9

This article addresses the broader concept of port State jurisdiction, as opposed to port State control. Erik Jaap Molenaar usefully clarifies the distinction between these concepts by noting that port State control is best understood by reference to the terms of regional memoranda of understanding (examined below) defining voluntary commitments among States Parties to undertake control inspections of foreign ships calling at their ports with the aim of verifying compliance with internationally agreed standards, and to take enforcement action with respect to those standards that is largely corrective in nature.10 Port State jurisdiction can be understood to encompass such control inspections, but to also include prescriptive and enforcement jurisdiction of port States over foreign flagged ships in their ports with respect to national or supranational legislation that may be more onerous than internationally agreed standards. A wider focus on port State jurisdiction is appropriate here because applications of autonomous inspection robots are envisaged that would support enforcement of international conventions, as well as applications that could support EU Member States exercising prescriptive jurisdiction over foreign flagged ships in their ports, for example, with regard to standards intended to safeguard marine biodiversity by prescribing minimum acceptable levels of biofouling.

Today, a consensus can be said to exist, in scholarship and as evidenced in State practice, that views port State jurisdiction as an increasingly important supplement to (though not a replacement of) flag State jurisdiction. It is a jurisdictional basis that is widely seen as supporting the assertion of relatively broad regulatory powers by port States over foreign flagged ships, and as an important tool with which to pursue the realisation of community interests such as the protection of the marine environment; the rigorous enforcement of construction, design, equipment and manning (CDEM) standards pertaining to ships; and measures relating to climate change mitigation.11 With respect to port State control, the sixth recital to the PSC Directive evokes the current widespread emphasis of the role of port States in enforcing international standards neglected by flag States:

[T]here has been a serious failure on the part of a number of flag States to implement and enforce international standards. Henceforth, as a second line of defence against substandard shipping, the monitoring of compliance with the international standards for safety, pollution prevention and on-board living and working conditions should also be ensured by the port State, while recognising that port State control inspection is not a survey and the relevant inspection forms are not seaworthiness certificates.12

The PSC Directive and the Paris Memorandum of Understanding

The PSC Directive has the effect of making binding on EU Member States the particular system for coordinating inspections undertaken based on port State jurisdiction established by the Paris Memorandum of Understanding on Port State Control (the Paris MoU). The Paris MoU, like other regional agreements coordinating port States’ undertaking of control inspections, is an agreement between States to coordinate inspections carried out by their national maritime authorities with the aim of enforcing international legal standards. First agreed to in 1982 between the then EU Member States and Norway, the Paris MoU now has twenty-seven Member States, including all EU Member States with seaports, the Russian Federation, Iceland, Canada and Norway.13 Concretely, such regional MoUs on port State control entail the administration of databases recording results of past inspections and assigning risk profiles to individual ships based on those records; they outline procedures and parameters for how many inspections States Parties should undertake, how those inspections should be conducted and what should be inspected; and they facilitate the coordinated refusal of access to ports in the MoU region for ships failing to satisfy inspection standards or take remedial action. The regional system of MoUs has been criticised for failing to make consistent inspection practices between different MoU regions, and between States in the same MoU region, and for its non-binding character.14

As noted above, the EU would appear to have solved this problem, binding its Member States by layering its PSC Directive atop the arrangements made within the Paris MoU, and linking the practical operation of the Directive, for example with respect to the assignation of ship risk profiles, to the methods established by the Paris MoU.15 With the international conventions enforced under the Paris MoU, the PSC Directive also coordinates Member States’ enforcement of EU maritime legislation.16 An exception made in the fortieth recital and in Article 3(1) of the Directive and related to MoU regions is addressed to France, permitting France’s remaining colonies, the ‘overseas departments’ listed in Article 299(2) of the Treaty Establishing the European Community (TEC), now Article 349 of the Treaty on the Functioning of the European Union (TFEU), to be exempted from the port State control system applied pursuant to the PSC Directive, due partly to the fact that some of these territories are parties to different regional MoUs, as well as due to their geographical distance from Europe.17

Regulating in Response to Disasters

Briefly recalling the background to this contemporary legal landscape spanning multiple regimes is worthwhile because it contains salutary lessons for attempts to regulate shipping today. The 1980s and 1990s saw a series of significant disasters involving oil tankers and bulk carriers. Bulk carriers are used to carry huge quantities of loose dry cargo like grain, iron ore, or fertilizers. These vessels came into use in the post-war period, but in the early 1990s a large number of bulk carriers were wrecked after suffering catastrophic structural failures, in some cases simply breaking apart in heavy weather. Once these vessels failed, they were frequently flooded and lost extremely quickly, with the consequence that all crew died.18 Research into the problem revealed that bulk carriers are subjected to particularly serious structural strains due to factors such as the loading and unloading of heavy, loose materials; the movement of unevenly distributed loose cargo; accelerated corrosion of metal plates composing the hull due to the chemical composition of these cargoes; design flaws; and the increased use of thinner, high-tensile steel plates.19 Age was also a central causal factor, with most of the bulk carriers lost in the early 1990s being over 20 years old.

Since the 1980s oil tankers had also been involved with some regularity in massive disasters that caused catastrophic environmental pollution, making up a considerable portion of total worldwide losses of ships.20 Concern in Europe at this trend had initially prompted the 1982 agreement to the Paris MoU. The 1999 breaking in two of the Maltese tanker Erika off the French coast and the 2002 wrecking of the Bahamian tanker Prestige off the Spanish coast prompted significant EU legislative packages focused on, among other topics, using inspections undertaken under port State jurisdiction to more vigorously enforce safety and maintenance standards with respect to foreign flagged vessels. Both the Erika and the Prestige had broken in two, were over twenty years old, and had been inadequately maintained and surveyed.21 A particular contributing factor to disasters involving tankers was the use of tankers of a single, rather than double hulled design.22 This prompted the EU to adopt a regulation accelerating the timetable specified by the 1973 International Convention for the Prevention of Pollution from Ships (MARPOL) for the phasing out the use of single hulled oil tankers.23

This spate of shipping disasters from the 1980s through to the 2000s, involving especially but not only bulk carriers and tankers, catalysed efforts to impose more stringent legal standards for the construction, maintenance and inspection of merchant ships. One important outcome of these efforts, which is of particular relevance to the focus of this article, were the 1993 Guidelines on the Enhanced Programme of Inspections during Surveys of Bulk Carriers and Oil Tankers adopted by the IMO Assembly, on the basis of which amendments were made to the International Convention for the Safety of Life at Sea (SOLAS) that entered into force in 1996.24 The Guidelines mandate enhanced survey procedures be applied to bulk carriers and tankers during the surveys prescribed by SOLAS, focusing on identifying corrosion, taking plate thickness measurements, how close-up surveys should be conducted, who is qualified to conduct such surveys and what documents ships must carry to demonstrate compliance with these requirements.25

Responsibility for ensuring compliance on the part of ship owners and operators with these legal instruments lies primarily with flag States. Those States will in turn ordinarily follow the longstanding practice of privatising the responsibility of actually conducting the required surveys by contracting private companies to do so – classification societies.26 However, the history of the development of these legal instruments shows that port States can also play a significant and at times crucial role in ensuring their enforcement. Australia’s tightening of port State inspections in the early 1990s in response to disasters concerning ageing bulk carriers at first resulted in a large movement of bulk carriers from the Pacific to the Atlantic, apparently by owners seeking to protect their substandard vessels from Australia’s more stringent inspection regime.27 Subsequently, wider enforcement of standards concerning safety procedures, construction, design and maintenance of bulk carriers and tankers, alongside the agreement of IMO level guidelines, raised standards worldwide. When taken by port States in an economic and geographical position to do so, unilateral enforcement measures like those of Australia can contribute to raising standards more widely, including by prompting activity through the IMO.28 The EU’s speeding up of the phasing out of single hulled oil tankers in the early 2000s is another example of unilateral (in this case, on the part of a regional body) regulation that went beyond internationally agreed standards and had the effect of helping to lift global standards.29

Writing in 2004 of the EU’s successive efforts to combat oil pollution resulting from disasters involving old, poorly maintained and surveyed oil tankers, Malgorzata Anna Nestorowicz summarised the situation in the following way:

Even if the recent years have seen an important development in monitoring and control of the maritime traffic on the international level, they can hardly catch up with the potential dangers that shipping brings about. The mechanism established by the IMO granting a flag state major prerogatives over its ships is not effective anymore. The ownership of the registered tonnage is largely concentrated in new flag states where the IMO conventions are either not uniformly adopted or, if adopted, not properly enforced due to insufficient controls of ships by the flag state authorities. Moreover, many of the IMO resolutions are not legally binding. This allows many substandard ships to continue to operate under one of the flags of convenience where controls are not too strict. Employing an old, substandard ship constitutes for many importers a major reduction in fixed costs.30

The EU’s efforts to harmonise how Member States assert port State jurisdiction, currently manifested in the PSC Directive, is yet another unilateral (regional) attempt to address this situation by better enforcing compliance with internationally agreed standards with respect to ships entering EU ports, as well as to enforce EU maritime legislation that goes beyond standards provided for in international conventions. This can be welcomed as a productive contribution to improving the safety of life at sea, the protection of community interests like the marine environment, and as a measure that reduces substandard shipping and removes a competitive advantage enjoyed by owners and operators that benefit from cutting costs by operating poorly maintained ships.31

From the truncated history of legal developments concerning ship construction, maintenance and inspection standards presented here, we can draw two significant lessons. First, as is often noted by commentators, an assertion of public regulatory power that may seem improbable today is often one disaster away from becoming an imperative and obvious priority of powerful actors keen to act and be seen to act. Second, these legal developments are often propelled through initial unilateral acts taken by powerful States or regional organisations. Departing from a perspective cognisant of these lessons, the following section examines the extent to which the employment of autonomous inspection robots could, or would, constitute an innovation in the operation of port State jurisdiction from the perspective of EU law.

Inspection of Ship Structures under Current EU Legislation on Port State Jurisdiction

The PSC Directive is the latest iteration of EU legislation on how Member States undertake inspections based on port State jurisdiction. In response to events, including those outlined in the previous section, it consolidates and moves the law further than previous legislation on the subject. As Vincent Power notes, the Directive embodies the fact that ‘PSC is best seen as an evolutionary regime’.32 The legal basis for the PSC Directive was Article 80(2) of the TEC, now Article 100(2) of the TFEU. Article 100(2) falls under Title VI, which sets out a framework for a common transport policy, and gives the European Parliament and Council the power to ‘lay down appropriate provisions for sea and air transport’. 33 The stated purpose of the Directive is ‘to help drastically reduce substandard shipping in the waters under the jurisdiction of the Member States’, and in scope it applies to ‘any ship and its crew calling at a port or anchorage of a Member State to engage in a ship/port interface’, with the possible exception of ports of French colonies noted above.34 Member States are required to ‘take all necessary measures, in order to be legally entitled to carry out the inspections referred to in this Directive on board foreign ships, in accordance with international law’, entailing national legislation be adopted by Member States to empower their competent authorities, and that those authorities be adequately staffed and equipped.35 The Directive requires Member States to refuse access to ports and anchorages in their jurisdiction where a ship fails to satisfy inspection criteria on several occasions and after specified time periods, and to detain any ship exhibiting deficiencies ‘clearly hazardous to safety, health or the environment’ until the deficiencies are rectified.36

A number of provisions of the PSC Directive establish a framework within which Member States’ competent authorities could choose to employ autonomous inspection robots when fulfilling their obligations to assert port State jurisdiction. The central point from the perspective of this article is that the Directive, and the Paris MoU on which it draws in significant respects, requires Member States’ competent authorities to inspect the inner and outer structures of ships in specified circumstances. Under the terms of the PSC Directive and the Paris MoU ships are selected for ‘periodic inspections’ at intervals determined by a system of assigning risk profiles to individual vessels. This selection also takes into account past performance of a ship’s flag State, the relevant recognised organisations (‘a classification company or other private body, carrying out statutory tasks on behalf of a flag State administration’), and companies responsible for operating a ship.37 Ships can also be subject to ‘additional inspections’ regardless of the time period since their last periodic inspection where ‘overriding or unexpected factors arise’.38 Such factors concerning ships include suspension or withdrawal from their class since their last inspection in the Paris MoU region; being the subject of a report or notification by another Member State; being involved in a collision on the way to port; or carrying certificates issued by a recognised organisation that is no longer recognised.

Having been selected for inspection, a ship may first be subject to an ‘initial inspection’, during which a Port State Control Officer (PSCO) verifies the ship is carrying documentation certifying compliance with international conventions relating to safety and security, as well as EU maritime legislation, checks whether deficiencies identified during a prior inspection have been rectified and assesses ‘the overall condition of the ship’.39 However, a ‘more detailed inspection’ may be conducted where there are ‘clear grounds’, after an initial inspection, to believe a ship does not meet the relevant requirements of a convention.40 Among the examples of ‘clear grounds’ specified in Annex V to the PSC Directive is: ‘Evidence from the inspector’s general impression and observations that serious hull or structural deterioration or deficiencies exist that may place at risk the structural, watertight or weathertight integrity of the ship’.41

A focus on the inner and outer structure of ships is also a component of a further inspection category, that of ‘expanded inspections’.42 Expanded inspections are carried out on ships of certain types with certain risk profiles. Among other categories, ‘passenger ships, oil tankers, gas or chemical tankers or bulk carriers, older than 12 years of age’ are prioritised for expanded inspections.43 Annex VII to the Directive specifies risk areas to be given particular attention, including a ship’s ‘structural condition’, ‘weathertight condition’ and ‘pollution prevention’.44 Commission Regulation No. 428/2010 of 20 May 2010 implementing Article 14 of Directive 2009/16/EC of the European Parliament and of the Council as regards expanded inspections of ships offers yet further detail concerning specific items that should be verified during an expanded inspection. The annex to this implementing regulation specifies that with regard to appraising a ship’s structural condition, the specific items to be verified during an expanded inspection referred to under Article 14(4) of the Directive include: for all ships, the condition of the hull and deck; and for bulk carriers and oil tankers, the verification of documentation certifying compliance with the Enhanced Survey Programme (discussed above), and examination of the condition of bulkheads, coamings and ballast tanks within the cargo area, with the possibility that at least one ballast tank may need to be inspected from the inside.45

Finally, a focus on inspecting the inner and outer structure of ships is also evident in the criteria on the basis of which a PSCO is required to make a professional judgment as to whether a ship should be detained. These criteria are referred to in Article 19(3) and listed (non-exhaustively) in Annex X, grouped by reference to the international conventions to which they relate. Alongside broadly delineated ‘main criteria’ concerning the general safety and ability of a vessel to proceed to sea, criteria of particular relevance for the purposes of this article include: under SOLAS, failure to carry out the ESP, which in turn could be a ground for a more detailed inspection as per Article 13(3) and Annex V; and under the 1966 International Convention on Load Lines, ‘significant areas of damage or corrosion, or pitting of plating and associated stiffening in decks and hull affecting seaworthiness or strength to take local loads’.46

The provisions of the PSC Directive highlighted here all require a PSCO to undertake some level of visual inspection of the outer and inner structure of vessels of all types. With regard to bulk carriers and tankers, visual inspection for structural defects is given added priority due to the particular risks associated with these vessels and their history of involvement in significant disasters, as outlined in the previous section. Drones or submersibles operating autonomously to identify structural defects could offer significant advantages in such scenarios. Submersibles offer the possibility of visually inspecting underwater parts of a ship’s hull with relative speed and without the use of divers. Drones also offer the possibility of inspecting difficult to access parts of massive vessels. The autonomous navigational capabilities of drones currently under development enable the systematic visual appraisal of enormous areas of steel plating in a way that a human eye would be unable to replicate. This level of methodical, systematic inspection conducted at relative speed would increase the likelihood of areas of plate corrosion, pitting and cracking being identified. Drones are also well suited to inspection tasks within the large internal compartments of vessel hulls, for example, the inspection of bulkheads in a bulk carrier.

One conclusion that can be drawn from the above analysis is that it would be possible for national competent authorities to use autonomous inspection robots to conduct inspections based on port State jurisdiction within the legal framework provided by the PSC Directive as it stands. Judgment as to how and in what scenarios such technologies may be useful would be a matter for the national competent authorities, and at the most immediate operational level for the PSCO undertaking a particular inspection, depending on the procedures established at national level. The professional judgment of the PSCO with respect to the best way to appraise whether a ship satisfies standards of relevant EU maritime legislation and international conventions is emphasised in the Directive.47 From a technical and operational perspective, the European Maritime Safety Agency (EMSA) could offer support and coordinate Member States’ adoption of autonomous inspection technologies. EMSA has the responsibility of supporting Member States’ with the aim of ensuring ‘the convergent and effective implementation of the port State control system’ by, among other tasks, assessing the port State control procedures established by individual Member States and managing the THETIS and SafeSeaNet databases, which record ships prioritised for inspection and the results of those inspections, and collate information on vessel movements to and from EU ports respectively.48

These new technologies can be viewed simply as new tools that can allow old inspection tasks to be completed in new, quicker and (it is hoped) more effective ways. However, they can also be viewed as technologies that alter the character of old tasks by making it possible to inspect in ways not considered feasible previously. The PSC Directive caveats the scope of detailed or expanded inspections on the basis of ‘practical feasibility or any constraints relating to the safety of persons, the ship or the port’.49 It may prove to be the case that the employment of autonomous inspection robots will change what is and is not considered safe and feasible in the context of inspections conducted under port State jurisdiction. With respect to feasibility, the speed offered by autonomous inspection robots may simply permit inspections to include more extensive and rigorous examination of ship structures than is currently possible through human, visual inspection. With respect to safety, one concrete example that may be noted concerns expanded inspections of oil tankers and bulk carriers. Notwithstanding the requirement under Article 14 of the PSC Directive read together with the annex to its implementing Regulation No. 428/2010 (examined above) that as part of an expanded inspection, the condition of bulkheads be examined in the case of bulk carriers and that ballast tanks within the cargo area be examined and possibly entered in the case of both bulk carriers and oil tankers, feedback from PSCO s suggests that in practice it is rare for a PSCO to enter cargo holds or tanks.50 The use of inspection drones could help to reduce this discrepancy between law and practice. As noted above, drones are well suited to inspection tasks within the large internal compartments of vessel hulls, for example, the inspection of bulkheads in a bulk carrier or of ballast tanks.

Possible Changes to EU Legislation on Port State Jurisdiction

At the time of writing in May 2022, a number of EU legislative proposals that could support the possible increased use of autonomous ship inspection robots under port State jurisdiction are at various stages of development. The most significant of these are the Commission’s plan to review and potentially revise the PSC Directive, and the ‘Fit for 55’ legislative package, so called because it aims to reduce EU net greenhouse gas emissions by at least 55 percent by 2030 compared to 1990 levels. The implications of each of these significant initiatives merit brief examination.

In October 2020, the Commission announced its intention to review the PSC Directive, after which a public consultation took place. The Commission is expected to publish a legislative proposal in the summer of 2022. Upon announcing its intention to review the Directive, the Commission published an Inception Impact Assessment outlining problems and policy options, on the basis of which it intends to develop a legislative proposal. One set of policy options, proposed on the basis of perceived problems with the functioning of the PSC Directive, envisaged requiring Member States to conduct ‘more substantive, ship based inspections’, concentrating ‘on operational issues rather than being just a document check’; charging EMSA with training PSCO s to be ‘more pro-active’ in their approach to safety, security and pollution prevention; supporting Member States that have difficulty fulfilling their inspection commitments due to limited resources, including with respect to staffing; and encouraging Member States’ to digitalise their inspection procedures, including by making provision for the acceptance of electronic certificates of compliance with international standards and preparing port State control procedures to accommodate autonomous shipping.51

From these proposed policy options, an impetus can be discerned in favour of moving towards more substantive inspection procedures, carried out in a uniform way by all Member States, which instrumentalise and adapt to greater levels of automation, of ships themselves and of their associated technologies. Review of the Directive aims to incorporate ‘new tools and political priorities’ into this legal framework.52 The autonomous inspection robots discussed here fit comfortably with this impetus and could contribute to the achievement of aims sought by revising the Directive, including the improvement of ‘maritime safety, security, [and] pollution prevention’.53

A second leitmotif of the Commission’s proposed policy options with respect to the PSC Directive is a focus on mitigating the shipping industry’s contribution to GHG emissions. The Inception Impact Assessment identifies as a problem the fact that the current inspection targeting system does not allow for emphasis to be placed on environmental aspects aimed at rewarding ‘greener’ vessels, and notes that environmental issues connected to decarbonising maritime transport ‘will have to be looked at from the enforcement perspective’.54 Review of the Directive is framed in part as a response to the European Council Conclusions endorsing the ‘Opatija Declaration’ of March 2020, the ‘EU Waterborne Sector – Future Outlook: Towards a carbon-neutral, zero accidents, automated and competitive EU Waterborne Transport Sector’, a declaration that instantiates a belief that digitalisation and automation, climate sustainability and the EU’s economic competitiveness are intertwined.55 This focus on ‘greener’ shipping is shaped by the broader context of the EU’s assumption of an increasingly active role with respect to regulating GHG emissions from ships and its vying with the IMO on this topic, as noted at the outset of this article. The ‘Fit for 55’ legislative package announced in July 2021 fits into the ‘European Green Deal’, the overarching initiative that aims to make the EU the first climate neutral continent by 2050, and contains a number of much commented upon proposals of relevance to shipping, including its inclusion in the European Emissions Trading System (ETS), a proposed FuelEU Maritime Regulation and the proposed Alternative Fuels Infrastructure Regulation.56

While at this stage the Commission’s vision of how a legislative proposal based on its review of the PSC Directive should practically connect to environmental goals pertaining to shipping is not clear, it could be suggested that one possible connection concerns biofouling. As noted above, accumulated organic matter on a ship’s hull significantly reduces fuel efficiency by increasing friction between the surface of the hull and the water. Cleaning such biofouling from a ship’s hull can result in a reduction in fuel consumption of 10 to 30 percent. This could be visualised as approximately half a swimming pool of heavy fuel being saved on a return trip across the Atlantic.57 The lower energy density of non-fossil alternative fuels means that maximising fuel efficiency will remain an important concern for non-fossil fuel burning vessels. Biofouling also risks the introduction to new habitats of alien invasive species. This is widely recognised as a serious threat to biological diversity, and the EU has adopted legislation (not limited to the maritime sphere) on alien invasive species, as well as a series of instruments focused on improving and protecting the quality of EU waters and marine habitats.58

One way to combat biofouling is by painting ship hulls with anti-fouling paints, although it is recognised that such paints do not completely prevent the accumulation of biofouling.59 Another option is to physically clean hulls, brushing them free of organic matter. While the EU has adopted legislation prohibiting the use of anti-fouling paints harmful to the environment, no EU legislation currently exists that prescribes acceptable levels of biofouling for ships entering Member State ports, or requiring national authorities to address biofouling in the context of inspections under port State jurisdiction.60 Such legislation can be found in jurisdictions outside the EU, for example in Australia, New Zealand, and in some US states.61 In certain Australian ports, for example, biofouling is an object of inspection, while the state of California has recently developed an inspection programme that will use remotely operated underwater vehicles to examine the hulls and difficult to access areas of vessels entering port to ascertain their compliance with state level mandatory biofouling regulations.62

In the context of revising the PSC Directive, the EU could address biofouling in a similar way, requiring Member States to inspect for acceptable levels of biofouling on ships entering their ports. Alongside inspection, cleaning hulls of biofouling can also be undertaken robotically. The magnetic wheeled crawlers described in the second section above can be fitted with brushes and can navigate autonomously across the entire surface of a large hull, brushing organic matter free above and below water. It is worth noting that if ships were cleaned in this way with sufficient frequency, biofouling could be eliminated completely and only gentle brushing would be required during each cleaning. This reduces the possibility that anti-fouling paints are brushed free along with organic matter and released into the marine environment. Given the EU’s focus on investing in port infrastructure to support decarbonisation aims under the ‘Fit for 55’ legislative package, resources could be committed to making such robotic cleaning systems available in ports.


This article has analysed the extent to which the aims pursued by EU legislation on port State jurisdiction – the improvement of ‘maritime safety, security, [and] pollution prevention’ – could be supported by the employment of autonomous inspection robots that are currently under development. Based on a close reading of the primary piece of EU legislation governing port State jurisdiction, Directive 2009/16 of the European Parliament and of the Council of 23 April 2009 on port State control, alongside the problems and policy options identified in the context of the Commission’s significant ongoing work on the revision of this Directive, these technologies could support the completion of inspection tasks conducted under the current version of the Directive in significant ways.

One conclusion that has been drawn from this analysis is that it would be possible for national competent authorities to use autonomous inspection robots to conduct inspections based on port State jurisdiction within the legal framework provided by the PSC Directive as it stands. The analysis undertaken here also suggests that autonomous inspection technologies could prove even more useful to Member States implementing a revised version of the Directive focused on more proactive, substantive inspection procedures that incorporate both automated technologies and sustainability and environmental protection aims to a greater extent than is currently the case. From the perspective of EU law, an appropriate way for the Commission to ensure Member States employ autonomous inspection robots would be through a new regulation implementing provisions of a revised PSC Directive that require physical inspection of ship structures, or through a revised version of Regulation No. 428/2010 implementing Article 14 of the PSC Directive.63 The purpose of such a regulation, directly effective in national law, would be to specify what means Member States should use to implement a particular requirement of the Directive. In this case, those means would be autonomous inspection robots.

As suggested above, mandatory minimum biofouling standards offer a logical point of intersection between sustainability and biodiversity protection aims, and ship inspection practices, which might profitably be addressed by the Commission’s revision of the PSC Directive. Mandatory minimum biofouling standards could also be laid down by means of a regulation, similar to the manner in which the EU prohibited the use of organotin compounds in anti-fouling paints used on ship hulls.64

The intersection between the construction and maintenance quality of ships and sustainability and biodiversity aims is significant. This will only become more so as regulators seek to pressure older fossil fuel burning ships out of the global fleet through more stringent enforcement of existing legal instruments, and potentially the introduction of new, higher standards. Increasingly automated enforcement procedures may play a significant role in this effort.


The research that resulted in this publication was conducted under the European Union Horizon 2020 funded project ‘Autonomous Robotic Inspection and Maintenance on Ship Hulls and Storage Tanks’ (BugWright2), grant agreement No. 871260. The author would also like to acknowledge the generous funding of the World Maritime University (WMU)-Sasakawa Global Ocean Institute by The Nippon Foundation.


For a conceptualisation of the concept of ‘responsible Port state’ see EJ Molenaar, ‘Port State jurisdiction: Toward comprehensive, mandatory and global coverage’ (2007) 38 Ocean Development and International Law 225–257.


Directive 2009/16 of the European Parliament and of the Council of 23 April 2009 on port State control (as amended), OJ L 131/57 [Directive 2009/16].


M Evans, ‘Formal meeting (oral evidence session) of the International Relations and Defence Committee of the House of Lords: UNCLOS: Fit for purpose in the 21st century?’ available at All websites accessed 10 March 2022, unless otherwise mentioned.


S Kopela, ‘Port-State jurisdiction, extraterritoriality, and the protection of global commons’ (2016) 47(2) Ocean Development and International Law 89–130, at p. 90; on the EU’s use of extraterritorial jurisdiction see J Scott, ‘Extraterritoriality and territorial extension in EU law’ (2013) 62(1) American Journal of Comparative Law 87–126 (cited in Kopela); see also J Leeuwen, ‘The regionalization of maritime governance: Towards a polycentric governance system for sustainable shipping in the European Union’ (2017) 117 Ocean & Coastal Management 23–31.


Directive 2009/16 (n 3). The Directive’s three implementing regulations are: Commission Regulation (EU) No 428/2010 of 20 May 2010 implementing Article 14 of Directive 2009/16/EC of the European Parliament and of the Council as regards expanded inspections of ships, OJ L 125 [Commission Regulation No 428/2010]; Commission Regulation (EU) No 801/2010 of 13 September 2010 implementing Article 10(3) of Directive 2009/16/EC of the European Parliament and of the Council as regards the flag State criteria, OJ L 241; and Commission Regulation (EU) No 802/2010 of 13 September 2010 implementing Article 10(3) and Article 27 of Directive 2009/16/EC of the European Parliament and of the Council as regards company performance, OJ L 241.


R Churchill, ‘Port State jurisdiction relating to the safety of shipping and pollution from ships: What degree of extra-territorialty?’ (2016) 31(3) International Journal of Marine and Coastal Law (IJMCL) 442–469.


United Nations Convention on the Law of the Sea (Montego Bay, 10 December 1982, in force 16 November 1994) 1833 UNTS 3; Churchill (n 7), at p. 444.


Churchill, ibid. Noting recognition of a State’s wide discretion in exercising sovereignty over ports within its territory under customary international law, see Molenaar (n 2), at p. 227. This view was stated by the International Court of Justice in Case concerning Military and Paramilitary Activities In and Against Nicaragua (Nicaragua/United States of America) (Merits) [1986] ICJ Reports 14, at 111.


Molenaar (n 2), at p. 227.


On jurisdiction to prescribe and enforce CDEM standards see Churchill (n 7), at p. 445–458; For an overview of international law debate concerning port State jurisdiction see the 2016 special issue of the International Journal of Marine and Coastal Law: C Ryngaert and H Ringbom, ‘Introduction: Port State jurisdiction: Challenges and potential’ (2016) 31(3) IJMCL 379–394. The more contentious aspects of this debate tend to concern States asserting jurisdiction over ships in their ports on jurisdictional bases that are extra-territorial in nature (such as with regard to discharges alleged to have occurred outside maritime zones of the State in question), or in ways that have, or can be argued to have, extra-territorial effects. See Kopela (n 5). On discharges outside the port State’s maritime zones, see Z Sun, ‘The Role of East Asian Port States in Addressing Ship-Source Pollution in Arctic Shipping’ (2022) World Maritime University [forthcoming publication]; Y Tanaka, ‘Protection of community interests in international law: The case of the law of the sea’ (2011) 15 Max Planck Yearbook of United Nations Law 329–375, at pp. 350–356. The territorial basis for assertions of port State jurisdiction addressed in this article can be considered sufficient, although some of these acts may be argued to have extra-territorial effects. Adopting a similar position see Molenaar (n 2), at p. 228. On this point, and considering the position of the European Court of Justice with regard to extra-territorial effects, see AN Honniball, ‘The exclusive jurisdiction of flag States: A Limitation on pro-active port States?’ (2016) 31(3) IJMCL 499–530.


Directive 2009/16 (n 3). This remained the view of the Commission as of its publication of an Inception Impact Assessment of the operation of the PSC Directive in October 2020: ‘Port State Control is considered the third line of defence against sub-standard shipping, the primary responsibility laying with the shipowner and the flag state (the state of registration of the vessel). However as some owners and some flag states have shown an inability or an unwillingness to correctly discharge their responsibilities PSC is seen as a very important enforcement tool. Ensuring compliance with international rules and standards by vessels calling EU ports promotes a level playing field between shipowners. In addition, increasing the quality of shipping in EU waters helps preventing big maritime accidents and its associated financial and environmental costs’. Inception Impact Assessment: ‘Port State control - Strengthening safety, security and sustainability of maritime transport’, DG MOVE.D2 – Maritime safety (2020) [Inception Impact Assessment].


Inception Impact Assessment (2020) (n 12). There are eight other regional MoUs: Asia and the Pacific –Tokyo MoU; Latin America – Acuerdo de Viña del Mar; Caribbean – Caribbean MoU; West and Central Africa – Abuja MoU; Black Sea region – Black Sea MoU; Mediterranean – Mediterranean MoU; Indian Ocean – Indian Ocean MoU; and Gulf region –Riyadh MoU. The United States Coast Guard maintain the tenth PSC regime. See IMO, ‘Port State control’ available at


A Graziano, MQ Mejia Jr. and J Schröder-Hinrichs, ‘Achievements and challenges on the implementation of the European Directive on Port State Control’ (2018) 72 Transport Policy 97–108, at p. 98, and criticism cited therein.


Directive 2009/16 (n 3), Recitals 9, 13, 14, 15.


Ibid., Article 1(a); Paris Memorandum of Understanding on Port State Control, Section 2, ‘Relevant Instruments’ [Paris MOU]; V Power, EU Shipping Law (3rd ed., Routledge, London, 2019) 1305.


Directive 2009/16 (n 3), Recital 40, Article 3(1); Consolidated version of the Treaty on the Functioning of the European Union, OJ C 326, Article 349 [TFEU].


‘Bulk carrier - Improving cargo safety’ [2007] United Nations Atlas of the Oceans available at


Ibid. High tensile steel can allow metal plates composing a ship’s hull to be thinner than mild steel. This has the consequence that corrosion becomes a structural threat more quickly.


MA Nesterowicz, ‘European Union legal measures in response to the oil pollution of the sea’ (2004) 29(1) Tulane Maritime Law Journal 29–44, at p. 31.


Ibid., at pp. 32, 39.


Double hull tankers are designed with two layers of metal plates separating the oil they carry from the seawater. Ibid., at p. 33, n 44.


International Convention for the Prevention of Pollution from Ships, 1973, as modified by the Protocol of 1978 relating thereto and by the Protocol of 1997 (entered into force on 2 October 1983), 1340 UNTS 61 [MARPOL]; Nesterowicz (n 20), at pp. 33, 35.


Guidelines on the Enhanced Programme of Inspections During Surveys of Bulk Carriers and Oil Tankers, IMO Resolution A.744(18) adopted 4 November 1993; International Convention for the Safety of Life at Sea (SOLAS), 1974 (entered into force on 25 May 1980), 1184 UNTS 2.


Relatedly, the EU has legislated to harmonise procedures for the safe loading and unloading of bulk carriers: Directive 2001/96/EC of the European Parliament and of the Council of 4 December 2001 establishing harmonised requirements and procedures for the safe loading and unloading of bulk carriers, OJ L 13.


For analysis of the position of classification societies within the field of global maritime governance drawing on Bourdieusian sociological concepts, see R Lillillour and DB Fernandez, ‘The balance of power in the governance of the global maritime safety: The role of classification societies from a habitus perspective’ (2021) 22(3) Supply Chain Forum: An International Journal 268–280.


‘Bulk carrier - Improving cargo safety’ (n 18).


Molenaar (n 2), at p. 226.


The United States had previously taken unilateral action to phase out the use of single hull tankers: Oil Pollution Act of 1990, 104 Stat. 484.


Nesterowicz (n 20), at p. 44.


Molenaar (n 2), at p. 226; Directive 2009/16 (n 3), Recitals 7, 16.


Power (n 16), at p. 1307.


TFEU (n 17).


Directive 2009/16 (n 3), Articles 1, 3(1).


Ibid., Articles 4(1), 4(2).


Ibid., Articles 16, 19.


Quoting ibid., Article 2(19) regarding recognised organisations; on selecting ships, Article 12 and Annex I; on risk profiles and frequency of inspections, Article 10 and 11 respectively; the Directive draws language and procedures from Annex 7 (risk profiles) and Annex 8 (on selecting ships for inspection), Paris MOU (n 16).


Directive 2009/16 (n 3), Article 12, Annex I.


Ibid., Article 13(1), Annex IV.


Ibid., Article 13(3).


Ibid., Annex V Part A(13).


Ibid., Articles 2(11), 2(12), 2(13), 14.


Ibid., Article 14(1).


Ibid., Annex VII.


Commission Regulation No 428/2010 (n 6), Annex Part A(a) and (b), Part B(b), Part E(a) and (b).


Directive 2009/16 (n 3), Article 19, Annex X, Points 3.2, 3.5.


E.g., ibid., Annex X, Point 1.


Ibid., Recital 10; Power (n 16), at pp. 1305–1306; Regulation (EC) No 1406/2002 of the European Parliament and of the Council of 27 June 2002 establishing a European Maritime Safety Agency, OJ L 208.


Directive 2009/16 (n 3), Annex VII; a similar caveat is found in Commission Regulation No 428/2010 (n 6), Recital 1.


I am grateful to the members of the BugWright2 ‘Senior Advisory Group’ for this observation.


Inception Impact Assessment (n 12), Part A and B; European Parliament, ‘Legislative Train Schedule: Review of the Port State Control Directive’ available at


Inception Impact Assessment (n 12), at Part 2.


Ibid., at Part A.




Council Conclusions on ‘EU Waterborne Transport Sector – Future outlook: Towards a carbon-neutral, zero accidents, automated and competitive EU Waterborne Transport Sector’ 2020.


Proposal for a Regulation of the European Parliament and of the Council amending Regulation (EU) 2015/757 in order to take appropriate account of the global data collection system for ship fuel oil consumption data COM/2019/38; Proposal for a Regulation of the European Parliament and of the Council on the use of renewable and low-carbon fuels in maritime transport and amending Directive 2009/16/EC COM/2021/562; Proposal for a Regulation of the European Parliament and of the Council on the deployment of alternative fuels infrastructure, and repealing Directive 2014/94/EU of the European Parliament and of the Council COM/2021/559.


C Pradalier. ‘Autonomous Robotic Inspection and Maintenance on Ship Hulls and Storage Tanks’ (BugWright2), Description of the Action, EU Horizon 2020 grant agreement No. 871260.


Regulation (EU) No 1143/2014 of the European Parliament and of the Council of 22 October 2014 on the prevention and management of the introduction and spread of invasive alien species, OJ L 317; Directive 2008/56/EC of the European Parliament and of the Council of 17 June 2008 establishing a framework for community action in the field of marine environmental policy (Marine Strategy Framework Directive), OJ L 164; on implementation of the MSFD Directive see R Derrig, ‘Report on Irish State practice on the law of the sea 2020’ (2020) XV Irish Yearbook of International Law (forthcoming publication).


Guidelines for the Control and Management of Ships’ Biofouling to Minimize the Transfer of Invasive Aquatic Species, IMO Resolution MEPC.207(62) adopted on 15 July 2011.


Previously, anti-fouling paints frequently contained organotin compounds, active biocides intended to prevent organisms from attaching to the hull, which had significant negative effects on the marine environment. In 2003, the EU legislated to prohibit ships bearing such anti-fouling paints from entering Member State ports, a unilateral regulatory act that is considered to have prompted enough States to ratify the International Convention on the Control of Harmful Anti-fouling Systems on Ships to ensure its coming into force in 2008: Regulation (EC) No 782/2003 of the European Parliament and of the Council of 14 April 2003 on the prohibition of organotin compounds on ships, OJ L 115 [Regulation No 782/2003]. On this see L Gipperth, ‘The legal design of the international and European Union ban on tributyltin antifouling paint: Direct and indirect effects’ (2009) 90 Journal of Environmental Management S86–S95


CJ Zabin et al., ‘How will vessels be inspected to meet emerging biofouling regulations for the prevention of marine invasions?’ (2018) 9(3) Management of Biological Invasions 195–208.


Ibid., at p. 199.


Commission Regulation No 428/2010 (n 6).


Regulation No 782/2003 (n 60).

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