By Olha Hembik | 2025-10-16

WARSAW -- Russia is testing a sea drone tethered by fiber optics, a new weapon aimed at countering Ukraine's naval drones and challenging its hold on the Black Sea.

The unmanned boat, developed by the Ushkuynik research center in Veliky Novgorod, is slated for combat trials with the Black Sea Fleet, according to the state news agency TASS.

The new drone could serve as a kamikaze vessel, a launch platform for FPV drones or a countermeasure against Ukraine's naval drones.

Ushkuynik previously introduced a fiber-optic first-person view (FPV) drone known as the "Prince Vandal of Novgorod."

Ukraine, meanwhile, has led the way with systems such as the Magura and Marichka, which have destroyed high-value targets at sea without risking crews and can carry weapons including antiaircraft systems and machine guns.

Coiled fiber drone

Developers say the drone carries a coil of protected fiber-optic cable. Small but heavy, it "immediately sinks and lies on the seabed, and the coil unwinds" on launch.

Defense Express noted in September that the cable is far heavier than those used in FPV drones, where the fiber is just a "glass thread." But for sea drones, "weight is less critical," the outlet said, since they can carry dozens of kilograms of cable. Routing the line along the seabed likely "decreases the chance that it will be broken by another vessel."

The drone's weight and size remain undisclosed. Militarnyi, after analyzing available video, called the craft "small and clumsily made" with its center of mass shifted toward the rear. The outlet also said the range "probably does not exceed 100 kilometers [62 miles]," limiting its use to coastal areas.

Cable limits

Military analyst Mykhailo Zhirokhov said cable length sharply limits the range of fiber-optic sea drones, which lose signal once the coil runs out.

"On the front line, the range of an aerial fiber-optic drone is 30–40 kilometers [19-25 miles], and that's normal. When you're talking about the sea, a maximum coil of 50 kilometers [31 miles] is too close to the shore," he told Kontur.

Zhirokhov said such drones could strike port infrastructure but lack the reach to hit ships at sea.

Defense Express noted even a light drone could carry FPVs to launch attacks on cities such as Mykolaiv, Odesa or Kherson from occupied coastal areas.

Intercepting Ukrainian naval drones headed for targets like Novorossiysk or Sevastopol would also force operators to move dangerously close to shore, Zhirokhov said. He concluded the drones are most likely limited to coastal patrols.

Patrol use

Military communications expert Serhiy Beskrestnov called fiber-optic drones "a solution for specific tasks," telling Kontur that "every crew should have one" for situations where operators must confirm a target or overcome electronic warfare.

Fiber optics are resistant to interference and jamming, providing more stable control -- an advantage at sea, where drones must operate in deep water or heavy waves.

Defense Express noted, however, that range remains a major limitation.

"For effective operations, naval drones would need to cover tens or even hundreds of kilometers," the outlet wrote, adding that without relays or boosters, even 100 kilometers "is optimistic."

The cable, analysts said, also compensates for weak satellite antennas on the Ushkuynik drone.

Still, Defense Express warned the technology "cannot be ignored," since it "could be scaled up over time."

Key advantages

The key advantage of fiber-optic drones is reliable control, since they are immune to radio interference, jamming and detection, according to a Ukrainian service member with the call sign Magician from the AlterEgo Rbns UGV unit.

"I can imagine how a fiber optic drone works in the water. It probably operates very well because nothing hinders it, while underwater there is no way the fiber will snag on anything," he told Kontur.

Beskrestnov said performance depends largely on the coil.

"The correct selection of cable thickness, the technology of its rewinding device and the features of the physical operation" determine effectiveness, he said.

Beskrestnov added that Ukrainian specialists demonstrated fiber-optic drone flights in 2022, but the concept drew little interest and later stalled. Russia then adopted the technology in Kherson.

"Unfortunately, this is the trend of the whole war: we’re the first to come up with something but they scale it faster," he said.

Zhirokhov noted technology often shifts between sides.

"It's practically impossible to determine who was the first to have some weapon or tactical methods," he said, adding that Ukraine rejected a proposal to develop fiber-optic drones three years ago because of cost.

"It was exactly the same with sea drones," Zhirokhov said. "This isn't about some huge technological breakthrough. It all depends on who brings it to fruition first."