From mine warfare to reconnaissance tasks, searching for submarines and countering enemy surface vessels – drones are increasingly marking their presence in the maritime domain.

An Italian underwater vehicle is lowered into the sea directly from a German frigate. It conducts reconnaissance of a key area of water, and the collected data is immediately transferred to the crew of an American military aircraft. Meanwhile, the drone concludes its mission on the deck of a French destroyer. This is a description that appeared some time ago on an official NATO website. Sounds like a wave of the future? Possibly. This is, however, what the Alliance is aiming at and the experts are certain that the role of unmanned vehicles will grow with every passing year – not only in the air and on land, but also in the maritime domain.

Ocean-Based Laboratory

In order to understand the dynamics of the processes taking place in the water, it is enough to observe Exercise REPMUS (Robotic Experimentation and Prototyping with Maritime Unmanned Systems), which has been organized for several years in Portugal. This year’s edition reached 2,000 participants. Most of the representatives came from NATO states, but partners from Japan, Australia, South Korea or Ukraine were also present.

Seamen had a chance to meet scientists and experts from defense companies. “The main aim of the exercise is to test and develop advanced maritime unmanned systems in a joint, international environment,” explains Cdr David Morgado, a spokesperson for the Portuguese Navy, one of the co-organizers of the event. Traditionally, Polish soldiers (troops of the 13th Minesweeper Squadron) also took part in REPMUS, and this time worked with the Gavia Autonomous Underwater Vehicle (AUV). Such equipment can be found, among others, in modern Kormoran II class mine countermeasure vessels, and is used to search for sea mines.

“We exercised in the Atlantic, near the town of Sesimbra,” says SubLt Marcin Kleparski, who commanded the Polish team. The missions began in the morning, and Gavia went into the ocean to search through a basin of 300x500 meters. The objective was to target the practice mines left by the organizers. “The vehicle operated at depths reaching 40 m. It recorded the images of the seabed which we then thoroughly analyzed,” explains Kleparski. The seamen picked out the so-called mine-like contacts, i.e. objects with mine-like characteristics, from the recording. Next, Gavia approached the objects again from various sides so that the seamen could sift out random indications. “The report from our operations was then sent to the task force command,” says Kleparski. The command also decided who would carry out the final identification of listed objects and indicated the way it should be done. In other words, it had to be determined if the found object was in fact a mine or only something very similar to it.

Sixteen teams from various states operated in Sesimbra. Every team had their own area to cover. When the task had been done, the team went on. “REPMUS is a fantastic opportunity to cooperate and share knowledge gathered through the years,” thinks Cdr Michał Dziugan, commander of the 13th Minesweeper Squadron. “Many countries use Gavia, but their experiences connected with its use are very different,” he adds. The Portuguese, for example, execute their daily mine countermeasures activities in the Atlantic, where the hydrological conditions are different than in the Baltic Sea. The two bodies of water differ in salinity, currents, in the way sound travels underwater. The ballast in the vehicle itself must be distributed differently before it is lowered into the water. The Danes, on the other hand, have equipped Gavia with an STM (Sonar Training Module), which produces sounds similar to those generated by a submarine. Consequently, the vehicle can be used to train operators of equipment intended for detecting such vessels. Other countries use Gavia for seabed high-resolution mapping. “Clearly, this reaches beyond the extent of tasks assigned to mine countermeasures forces, but it nevertheless shows the wide scale of capabilities of such vehicles,” emphasizes Dziugan.

Another important opportunity is direct contact with the representatives of scientific centers and the defense industry. “Before the start of the exercise, the participants declare what they would like to test, check, what tactical elements they plan to carry out. In doing so, they often cooperate with suppliers of individual components to optimize the system as a whole. We have already cooperated in this way with Teledyne, Icelandic company, a producer of Gavia, the Kraken company which supplies synthetic aperture sonars we use, the Polish Enamor company [a producer of ship electronics, navigation and automation systems, and above all Teledyne’s business partner], or the Gdańsk University of Technology (PG), with its specialists on underwater communications and communication protocols,” enumerates Dziugan. It was during one of the editions of REPMUS that the Poles had an opportunity to watch the operation of the T20 multibeam echosounder module, which can be used not only to search for mines but also to inspect underwater cables and pipelines. “At the time, we were thinking of procuring it, but we first wanted to check whether it was worth it,” recalls Dziugan. Ultimately, last year two Polish Gavia AUVs were equipped with T20 modules.

Not only mine-countermeasure specialists train during Exercise REPMUS. The operators of devices designed to search for submarines, counter threats on the sea surface and to conduct reconnaissance of key bodies of water also carry out their missions. Drones operate in the ocean, but also in the airspace above it. New solutions are tested in each of these segments. For instance, this year, near the Tróia peninsula, the Portuguese Navy launched a Gavia directly from a submerged Tridente-class submarine. Moreover, as the press office of the Portuguese Naval Forces informs, REPMUS 2024 was an occasion to unveil the Trator do Mar autonomous surface vehicle. The device can effectively locate and track submarines, using equipment such as a towed sonar. “Another breakthrough was the testing of an artificial, autonomous island that serves as a base for vehicles operating underwater,” explains Morgado. A year earlier, in turn, unmanned aerial vehicles produced by Connect Robotics took off from the coast and, using a precision landing system, sat on one of the ships, delivering to its deck rescue kits. After that, they were transferred back to land.

This is a highly significant example, because on top of introducing into service more and more advanced vehicles, the principal goal of NATO is to work on solutions that, if necessary, would allow for connecting such vehicles into an efficient and smoothly operating network.

War Impulse

“NATO no longer thinks only in terms of individual vehicles. The key issue now is using multiple platforms simultaneously,” explains Dziugan. To achieve that, they need to introduce some standardization, and, most importantly, solutions that will enable high-speed data transfer between multiple operators, platforms and command centers, in almost real time. The Alliance is trying to convince producers to aim just for that. “For the time being, the standard is still to task one vehicle, such as Gavia, to cover a particular route and register mine-like objects. After classification, another mission is necessary to identify those contacts. The next stage is destroying them. The bottom line is that each stage requires one vehicle. Soon enough, however, we might be able to have several platforms simultaneously searching for mines underwater. Having detected something, the vehicles will adjust their mission profiles, and one of them, acting as superior to all the others, will automatically assign them further tasks, such as identification of the object,” he adds. This applies not only to mine warfare.

During the 2018 NATO Summit in Brussels, the defense ministers of 13 states, including Poland, joined the NATO Maritime Unmanned System Initiative (MUSI). They declared to jointly advocate the development of unmanned systems that would help strengthen collective security in the maritime domain. Soon, five more states joined the initiative, and several years later MUSI was transformed into JCGMUS (Joint Capability Group for Maritime Unmanned Systems), which is now supervising the implementation of NATO’s Digital Ocean Initiative. “The program was launched in 2023. It aims to enhance NATO’s maritime situational awareness through coordinating activities undertaken at the level of member states and the Alliance itself. We want to conduct surveillance using multiple tools – from autonomous vehicles operating underwater, through surface and airborne systems, to satellites,” enumerates Simone de Manso of the North Atlantic Alliance headquarters press office. Exercise REPMUS, in turn, is to serve as an ideal testing ground.

Not only NATO is going in this direction. 2024 is the first year the European Defense Agency (EDA) has joined in the organization of REPMUS. Earlier, it implemented its own project aimed at exploring the possibilities of various types of platforms operating jointly while protecting key shipping routes. “15 European states and 43 various institutions were involved in the Ocean 2020 project,” says Lionel Sola, head of the communications team. The culmination of the project was an exercise organized in August 2021, during which three unmanned aerial systems, four surface drones and five autonomous underwater vehicles operated jointly for several days near the coast of Sweden. They were accompanied by several ships, a research vessel from Germany and a civilian aircraft equipped with a state-of-the-art radar. The participants used the information obtained from the COSMO SkyMed satellite and transferred the collected data to the European Maritime Operation Center (EUMOC) prototype. Poland was also part of the project – specialists from the Research and Development Maritime Technology Centre in Gdynia worked on solutions in communications, and during the final exercise the already withdrawn from service ORP Czajka minehunter operated on the waters of the Baltic Sea. “At the end of the project, the consortium responsible for its implementation made several proposals for further research,” says Sola.

The work on the development of unmanned maritime systems is accelerating, and the outbreak of a full-scale war between Russia and Ukraine has worked as an additional catalyst. The Russian invasion increased tensions in Europe – including the Baltic and the North Sea. The Kremlin has repeatedly indulged in provocations, and there have been at least a few incidents targeting critical infrastructure. Suffice it to mention the never fully explained damage to the Balticconnector gas pipeline and a telecommunications cable between Finland and Estonia, as well as unidentified drones circling over Norwegian oil platforms.

Maintaining control over sensitive bodies of water requires an ever-increasing number of resources, particularly as the area of interest for both NATO and its potential adversaries is steadily growing. In recent years, the rivalry between world powers has been increasing in the Arctic region, in connection with melting glaciers and easier access to natural resource deposits and northern communication routes.

The war in Ukraine has also shown that even relatively cheap and easy-to-produce drones can be extremely effective weapons against a much more powerful adversary. Surface unmanned vehicles, constructed on the basis of fast speedboats and fondly called Sea Baby by the Ukrainians, within several months have successfully damaged, among other things, the Crimean Bridge, a Russian Buyan-M-class missile corvette, as well as the Pawiel Dierzawin patrol ship. Sea Babies were initially capable of carrying an explosive charge of 800 kg and operating at 800 km, while the cost of building one slightly exceeded 200,000 dollars. In the newer version, the range of the drones has reportedly been increased to a thousand kilometers, and their carrying capacity to a ton. Moreover, as Reuters Agency has recently reported, some of the machines have been equipped with... Grad rocket launchers.

Meanwhile, Ukrainian constructors are relentlessly working to come up with more and more technologically advanced devices. For some time now, the Ukrainian army has been using Magura USVs, praised for their high maneuverability. In the summer, a prototype of Stalker 5.0, equipped with Starlink-compatible devices, was presented in Odessa. “Ukraine’s use of maritime autonomous systems in the Black Sea has significantly contributed to breaking the blockade that the Black Sea Fleet had tried to use against the country,” assesses Cpt (N) Rafał Miętkiewicz, PhD, of the Polish Naval Academy in Gdynia.

From Hugin to Kijanka

Combat maritime drones are not a Ukrainian idea, though. The world’s giants have been intensively working on such solutions for quite some time now. The US Navy, for example, is testing the Orca autonomous underwater vehicle, which might ultimately be armed with torpedoes or missiles. Turkish companies, on the other hand, have in recent years unveiled two assault surface vehicles – the Ulaq, equipped with guided missile launchers, and the Albatros-S kamikaze USV. One concept, taken into consideration by the Americans, for example, assumes using a swarm of drones to perform various tasks at sea – from conducting reconnaissance to striking enemy targets.

There are indeed multiple development directions for drones. “The main ones, in addition to mine countermeasures activities, are related to submarine search and combat and protection of troops,” believes Miętkiewicz. “Other developed concepts include those in which autonomous systems are to perform rescue and salvage, evacuation, hydrographic, and logistics tasks. It is still too early for robo-corvettes to appear within a decade. Nevertheless, seagoing combat platforms will be systematically integrated into combat teams,” he adds. Moreover, airborne drones, which are cheaper than helicopters and can perform at least some of their tasks, may soon become a permanent presence on board large ships.

Poland is also expanding its potential related to maritime unmanned vehicles. The Polish Navy primarily uses underwater vehicles designed for mine warfare. These include both fully autonomous devices (AUVs) and ROVs – remotely operated vehicles connected to the deck of a ship via a cable line or a fiber-optic cable. Most of them equip Kormoran II-class mine countermeasure vessels. The list is long and includes both vehicles from recognized global manufacturers and domestic designs.

Apart from the already mentioned Gavia, the Polish seamen also use Hugin by Norwegian Kongsberg. The vehicle is designed to search for, classify and identify mine-like objects resting on the seabed or placed underwater. It is equipped with three sensors: a side observation sonar, a multibeam echosounder and a camera. It moves autonomously, along a route assigned by the operator, and can descend to depths of up to a thousand meters (although there are no such depths in the Baltic Sea). The Navy also has Double Eagle Mark II vehicles (aboard the Kormoran prototype) and Double Eagle Sarov (on serial ships), developed by Swedish Saab. They can operate as both AUVs and ROVs, and depending on their configuration conduct search and mine warfare tasks. Ship crews can also neutralize dangerous objects using Ukwiał and Głuptak vehicles, which have recently been created owing to the ingenuity of the specialists from the Gdańsk University of Technology (PG). The former one is used to plant explosive charges, while the latter explodes itself near the target. Recently, several minesweepers have been equipped with vehicles of this type.

There are more examples to be mentioned, but it is worth emphasizing here that the vehicles assigned to mine countermeasure forces are versatile devices. Hugins with Pipe Tracking software, for example, can be used to monitor underwater critical infrastructure. The Polish Navy also has USVs that work for the benefit of its Hydrographic Office, conducting surveys of the seabed. The latest design is the autonomous DriX, acquired at the end of 2021.

The number of unmanned vehicles in the Polish Navy will soon further increase. One reason is that three new Kormoran IIs will enter the line. Apart from that, the Polish Navy is preparing to acquire Gavias, which will not be directly assigned to the aforementioned mine countermeasure vehicles. Ultimately, there are to be over a dozen such devices. The world’s second service center for vehicles manufactured by Teledyne has even been established in Gdynia.

There is more. According to the Navy Inspectorate (Inspektorat MW), the Polish Navy is continuing the work on acquiring several unmanned systems as part of the Combating Maritime Threats 2013–2022/2030 operational program. Among them are a surface mine-destroying vehicle (Kijanka) and an automated system protecting port and territorial waters, which is to include floating drones and electronic surveillance equipment (Ostryga). There are also Albatros 2 USVs and a possibility that short-, medium- and long-range drones will be procured for the Polish Navy. The former, due to their vertical takeoff capability, can operate from a ship deck. “As for the use of combat systems in the Navy, they will probably not replace the existing armament, such as missiles or torpedoes on ships and aerial vehicles. However, we are analyzing their capabilities,” admit representatives of the Navy Inspectorate. Combat drones could be used, for instance, as a so-called effector for the Ostryga system. In other words: such vehicles would be sent to vessels targeted by electronic surveillance systems.

Glimpse into the Future

For the time being, it is uncertain whether and when exactly all the mentioned projects will be implemented. Nevertheless, the Polish Navy is trying to follow the trends gaining popularity in the world. We are taking part in numerous international initiatives and projects organized within the framework of both NATO and EDA. “This way or another, there will be more and more unmanned systems in use. They are a good answer to the challenges of our time, including personnel shortages faced by armies all over the world. More importantly – by sending drones to execute particular tasks, we do not risk the lives of our troops or seamen as much,” says Cdr Dziugan.

Of course, increasing automation raises numerous ethical questions and concerns. It is worth considering, for example, how much should be permitted to vehicles that will make extensive use of artificial intelligence in the near future. Can a device, for example, completely autonomously decide to plant or set off an explosive charge? Either way, the progress in the field of unmanned vehicles seems unstoppable. The future belongs to drones.