EUR: Europe guards sea cables amid Iran War warship crunch

BLUF: The Iran war is forcing Europe’s navies to split resources between protecting undersea cables while providing security in the Mediterranean. Drones, sensors and pre-commercial early-warning systems could free up resources and strengthen deterrence by making it much harder for trouble-making vessels to deny responsibility and intent.

SCOOP: On Wednesday, the European Commission is due to propose a €100 million budget for AGILE, a new scheme for quick-turnaround defense tech projects, an EU official told The Arsenal. The budget is for 2027 and will be funded by existing defense programs, particularly the European Defence Fund.

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On 13 March, the prime ministers of Britain and Ireland signed a renewed security agreement, including naval cooperation to protect the undersea data cables that connect their islands to North America, as well as the power cables running between them.

Both countries’ naval forces have recently tailed suspicious vessels in their waters, particularly the Russian Navy’s Yantar (which Moscow says is a research ship) and submarines escorting it. Unlike in the Baltic Sea, there hasn’t yet been any suspected cable sabotage in British or Irish waters—but the threat has both countries on alert.

European navies have been patrolling the Baltic for threats to data and power cables since January 2025, as part of NATO’s Baltic Sentry mission. 

Now, the US-Israeli war against Iran is forcing some governments to shift naval assets away from the Baltic to secure the Eastern Mediterranean. France has redeployed its Charles de Gaulle aircraft carrier, for example, escorted by other European vessels such as the Dutch HNLMS Evertsen. Before its redeployment, the Charles de Gaulle was due to contribute to a few Baltic Sea missions, including Baltic Sentry.

“The large majority of the support for Baltic Sentry comes from the regional Baltic navies and nations,” so these redeployments don’t affect the mission, said Commander Arlo Abrahamson of the United States Navy, spokesman for NATO’s Allied Maritime Command (MARCOM). “Ships rotate in and out all the time,” he told The Arsenal. “The NATO group that’s been deployed there continues to be deployed.”

Nevertheless, Baltic Sentry is experimenting with uncrewed surface vessels (USVs) to free up naval resources, Abrahamson told The Arsenal. 

“We have uncrewed systems, for example, that are deployed in the straits of Denmark, that are providing us an additional sensor. That’s one less thing that our frigates would have to do in the area,” Abrahamson said. “They could be redeployed to, conceivably, other areas as part of the mission.”

“It’s not that we’re looking to replace crewed structures, like minesweepers and frigates,” Abrahamson told The Arsenal. 

“Sometimes there’s a misunderstanding that the goal is to just have uncrewed systems out there doing all this work with surveillance,” he said. “We want to have a combination of crewed and uncrewed systems—and we indeed have that now—but we're always looking for ways to enhance our operational experimentation in Baltic Sentry.”

Abrahamson declined to specify which USVs Baltic Sentry is experimenting with, but said it’s all mature technology. The mission is also using aerial drones—including the US-made General Atomics MQ-9 Reaper—as well as underwater remotely-operated vehicles (ROVs) launched from minesweepers, he said.

Defense tech firms such as Germany’s Helsing and Britain’s Kraken already produce military-grade maritime surveillance drones for naval forces. Earlier this month, The Arsenal wrote about how Helsing’s AI-controlled SG-1 undersea glider can detect and classify ships by their sound signatures.

However, there’s a limit to the military’s responsibility for the problem. “All of these cables and pipelines are built and maintained by private companies,” Emma Salisbury, associate fellow at the Royal Navy Strategic Studies Centre, told The Arsenal. “They have not only a responsibility, but an interest in making sure that they keep working.”

Moreover, like other forms of hybrid warfare, cable sabotage relies on plausible deniability. Identifying the ship that cut a cable can be difficult—and proving the crew’s intent even more so.

The EU, defense ministries and industry are backing research into early-warning technologies that civil actors could use to defeat that deniability, as well as supporting a quick response by navies and coast guards.

VIGIMARE is a €5 million EU-funded project to develop an AI system that can integrate data from sensors, satellites and the Automatic Identification System (AIS, a mandatory tracking system for sea vessels) to detect suspicious activity. 

While the project is largely civilian, Telespazio—a joint venture between defense giants Leonardo and Thales—is in the consortium. 

Suspicious behavior could be a ship turning off its AIS signal (a ‘dark vessel’) or dragging its anchor, said project coordinator Johanna Karvonen, a critical infrastructure specialist at Laurea University of Applied Sciences near Helsinki.

In the Baltic, “the authorities and the military will react very quickly if they get an alert that there's suspicious behavior in the vicinity of a cable,” Karvonen told The Arsenal. 

Letting the suspect ship know it’s being watched can have a deterrent effect. 

“There is a difference in the Russian calculation between sabotaging a cable where we don't know they've done it, versus sabotaging a cable where we can attribute that,” said Salisbury. 

For now, VIGIMARE is working with low-resolution satellite images from the EU’s Copernicus array, which only updates around once per day. 

The plan is to access more sophisticated commercial satellites for technical demonstrations of the system in the coming year, Karvonen said. One of the satellite companies she’s spoken to is Finnish-Polish unicorn ICEYE, she added.

The forthcoming VIGIMARE demonstrations will also take data from Distributed Acoustic Sensing (DAS), which uses pulses of light to detect tiny movements caused by acoustic vibrations. The goal is to use that acoustic data to discern objects from their sound signatures.

On 25 February, the Irish government’s Defence Innovation Challenge awarded a €1.8 million prize to Sea-Scan. Like VIGIMARE, it aims to effectively turn the cables into acoustic sensors by connecting them to land-based DAS equipment.

DAS has been used for decades, but not for this purpose: Converting the signals into maritime intelligence is new, said Marco Ruffini, Sea-Scan principal investigator and computer science professor at Trinity College Dublin.

“The problem is that the DAS just gives you a very large amount of signals that have to be interpreted,” Ruffini told The Arsenal. 

The range is limited by the fact that undersea cables were built for communications, not sensing, so they’re tightly packed and heavily insulated. 

“That stops a lot of vibration,” but laying a separate cable for sensing would increase the range, Ruffini said.

Ruffini estimated that with the current undersea cables, the system can detect ships within about two kilometers of a cable along an 80- to 100-kilometer stretch when measured from the sensor. 

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The European Commission is due to publish its proposal for a new defense tech program called AGILE tomorrow (Wednesday, 25 March), an EU official told The Arsenal. 

The official said AGILE will have a €100 million budget in 2027, drawing from existing schemes, particularly the European Defence Fund (EDF), an R&D program. The Arsenal has not seen the draft proposal.

The EDF budget for 2027 hasn’t been published yet, but it will carve up the roughly €1 billion or so left in its budget for 2021-2027. All programs in the EU budget are tied to this seven-year cycle.

For instance, there is already €20 million in the 2026 EDF budget for equity investments in small defense via the entirely separate European Investment Fund (EIF). That €20 million is the final installment of a €100 million contribution to the EIF spread out over 2021-2027. 

There is also €60 million allocated to research and development (€30 million for each) by defense SMEs.

Additionally, €6.2 million from this year’s EDF budget is committed to providing seed funding for 40 startups, under the EU Defence Innovation Scheme (EUDIS) Business Accelerator. 

Another €1.8 million in the EDF is reserved for business coaching of SMEs.

The Commission first announced it was working on AGILE in November, but it gave few concrete details. It said the program would be “a pilot instrument for rapid defense innovation.”

The scheme’s activities will include challenge calls, “with a time-to-result not exceeding 6-12 months,” the Commission wrote at the time. 

That time frame is much shorter than for projects supported by EDF, which can be years away from operational use.

When an undersea fiber-optic cable does get damaged, the break can usually be located using light pulses through the cable. But assessing the extent of the damage and planning the repair operation requires a visual inspection. 

“You have to bring the cable up to the surface to do the intervention,” David Barral, chief technology officer of Forssea Robotics, told The Arsenal. “That’s a big operation. Having a diagnosis of the cable state before bringing it to the surface would help.”

Even at the relatively shallow depths where Baltic Sea cables have been cut so far—no more than 100 to 150 meters—wireless communication with undersea vessels is virtually impossible.

Even at just a few meters’ depth, the only wireless signal that really works is acoustic, which has very little bandwidth, said Natàlia Hurtós, project manager at Iqua Robotics in Girona, Spain. 

“You cannot share images. I’m not talking about a stream of images. Just one image alone is a challenge,” she told The Arsenal. 

Acoustic systems are also often off-limits for military use, because adversaries can detect them, said Barral. 

Wired communications work, but they create drag, Barral said.

“At some point, the ROV can’t move anymore because it always fights against the tether,” he told The Arsenal. 

There are ways to reduce cable drag, but eliminating it entirely requires a fully autonomous system that can navigate without GPS and little to no communication with the surface.

Both Forssea and Iqua are working on autonomous systems, supplying undersea robots to a mix of civilian and military clients. They focus on modular systems that can be adapted to each mission—allowing for smaller, cheaper vessels instead of all-purpose systems typically used for deep-sea surveys.

Iqua has sold autonomous vessels to the Spanish Navy for mine-clearing missions, Hurtós said. Forssea supplies the French Navy—but it doesn’t tell the company what for, Barral told The Arsenal.

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