Flag Denmark Few countries are contributing as much as Denmark to Ukraine’s defence. A 7-meter (23 ft) underwater drone exhibited at the DALO Industry Days 2026 in Denmark on 19th-20th August is of particular interest. Unlike most new AUV (autonomous underwater vehicle) designs it is unambiguously low cost (around €50k) and geared to the expendable nature of modern drone warfare. This purposeful design is expected to be arriving in Ukraine later this year.

Denmark underwater drone AUV Shadowfin

The Shadowfin drone is designed and built by Danish company Søens Tech, which has a background in innovative Mechatronics technologies to support underwater infrastructure projects, especially in Horizontal Directional Drilling (HDD). The Shadowfin is thus, while innovative and unconventional, developed by engineers intimately acquainted with watery arena.

Among Western designs Shadowfin stands out as being engineered for truly low-cost warfare. Its hull is a simple fiberglass tube, and the thrusters are commercial off the shelf units. While this will limited its operating depth, it results in a very affordable platform.

Denmark underwater drone AUV Shadowfin Shadowfin on display at DALO Industry Day 2026. Photo Naval News.

Specifications (estimates)
Length: 7 meters
Diameter: ~0.5 m
Displacement: 1.5 tons
Payload: ~300 kg

The thrusters are unusual. Shadowfin uses two rim-drive pumpjets where the blades rotate around the outside of the rim, leaving the center where the axel normally is completely clear. This arrangement is increasingly available in commercial thrusters, but has yet to be widely seen in defence projects.

The rim-drive pumpjets appear to be an underwater-optimised type built by Copenhagen Subsea. Rim drive designs use the rim itself as the motor, eliminating the need for the complexity and moving parts of the hub. Passing electricity through the rim spins the ring directly, removing the need for a gearbox, drive shaft, or seals. This means that it should, in general, be quieter too.

Denmark underwater drone AUV Shadowfin Shadowfin on display at DALO Industry Day 2026. Photo Naval News.

The design features a tall, fixed mast which can house cameras and other sensors, as well as navigation and communications antenna. It is also proposed that it could include a short mast to allow an internal combustion engine in the hull, which would significantly increase endurance.

Shadowfin is intended to carry a 300kg payload, about the same as a heavyweight torpedo, enabling both ISR (intelligence, surveillance and reconnaissance) missions and direct strike. Soens Tech propose an improved version, Shadowfin Enhanced, armed with a MU90 Impact lightweight torpedo. This weapon is not used by Denmark but has been sold to Ukraine for use aboard their future Ada Class corvettes. Soens intend it to provide an anti-submarine warfare capability. Being low cost, it can also be used as a decoy or forward sensor node. We can therefore envisage a formation of Shadowfins with some drawing the target in while those behind are positioned to launch the torpedoes in response.

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