Feb 14, 2025

A new video from Ukrainian electronic warfare and drone expert Serhii “Flash” Beskrestnov shows what looks like an entertaining toy: a quadcopter drone that lands on a pool of water, sinks, and then starts up its rotors and rises into the air again. It is hardly a unique or innovative capability, as we will see. the question is why someone who focuses tightly on the latest battlefield developments would highlight such a gadget.

As with many drones, this new toy might be more dangerous than it first appears.

Submersible Drones

The new drone looks like the latest incarnation of a long-running fad: ‘submersible aircraft’ or ‘flying submarines’ which can transition from air to underwater mode. There have been a surprising number of such machines over the years, dating back to the 1920s. Most never made it off the drawing board, and there are more examples in science fiction than real life. A few, like the Reid RF-1 from the 1960s, were actually built and operated. But design compromises mean that such craft are poor both as subs and aircraft – the RF-1 only flew about 75 feet.

The concept kept recurring though, including wild ideas like the U-Plan submersible jet fighter from Saab which could hide in fjords. This would have taken dispersed operations to a new level, but the sadly no hardware was built.

Submersible drones are more practical, though not much more. In principle multicopters can ‘fly’ in water as they can in air, and without the need for a pressurized capsule for the pilot, with the issues with weight and buoyancy that this brings, the design is much simpler. In theory at least a quadcopter can fly to a given location, dive underwater and operate in submarine mode. Of course water is much denser than air and the swimming speed is slow so batteries are rapidly exhausted.

Several submersible multicopter emerged in the 2010s, including the Naviator from Prof Javier Diez of Rutgers University. In 2015, Diez’ team received a grant from the Office of Naval Research (ONR) to continue the project with a view to developing a mine counter-measures drone, but this does not seem to have progressed.

Videos from China show similar concepts, though the specifications are not encouraging: this model looks good but the flight time is given as just 6.5 minutes. The Chinese Spry is sold as a waterproof buoyant drone but can go underwater (see video at bottom) and could remain there if it was made neutrally buoyant..

The U.S. Navy has made better progress with fixed-wing submersible drones, including the Flimmer and Flying Sea Glider in 2017. Again though the performance does not seem to have merited development beyond the prototype stage.

The technology has something in common with drones controlled by a fiber-optic cable. We know that it can work, prototypes have flown, but there was no application for it. That changed with fiber optic control last year as both sides in the Ukraine conflict started fielding FPV fiber drones because they are immune to radio-frequency jamming and detection. If Ukraine is developing submersible drones, maybe they see a particular niche for them.

The Butcher Bird

The Shrike is a well-established Ukrainian FPV model, named for the Shrike or Butcher Bird, known for leaving its prey impaled on thorns or barbed wire to eat later. It was one of the first to make the leap from being made by volunteers to manufacture under a government contract. In 2023, Minister of Digital Transformation and drone supremo Mykhailo Fedorov announced that more than 1,500 Shrike FPV drones had been ordered under his Army of Drones initiative. . A video from October 2023 showed 35 Shrikes hitting a Russian convoy and destroying eight tanks and four personnel carriers, and impressive strike rate.

This pedigree suggests that the submersion video is not the work of a drone hobbyist but may be something bigger.

According to Serhii Flash, the video shows a “Shrike (Special Edition)”. In a caption he notes that “The demonstration in the video is not as impressive as the sight of drones taking off from underwater in a lake,” suggesting that he may have seen this demonstrated.

Multicopters make poor submarines, but that may not be relevant. What matters is that the drone is able to land in water and remaoin hidden for a period of time.

As previously noted, Ukraine is increasingly carrying out ambushes with lurking drones. An FPV drone is landed beside a road or track used by the enemy and remains with its engines off until reconnaissance drones detect an approaching vehicle. The operator then activates the FPV and carries out an attack.

The new Special Edition Shrikes are not limited to lurking on the ground or on buildings where they might be detected. They can hide in lakes, ponds, canals or the many water-filled craters. That makes the task of checking a route for possible ambush drones far more challenging.

Ukraine has also recently started deploying FPV attack drones from its uncrewed speedboats. Special Edition Shrikes could be dropped off covertly in coastal areas, ready to be activated when Russian vehicles appear on the land or boats come near on the water.

Submersible drones may be a niche capability. But if the cost and complexity of making a drone watertight are relatively low, then, like fiber FPVs, they may proliferate rapidly. As with fiber drones, they look difficult to counter – unless hunter-killer submersible FPVs can be developed to seek them out…

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David Hambling

https://www.forbes.com/sites/davidhambling/2025/02/14/ukrainian-drone-can-hide-underwater-and-strike-from-the-deep