French company Kahe Nautic launches low-cost K600 semi-submersible drone for more than 65 maritime missions.

French manufacturer KAHE Nautic unveiled its K600 semi-submersible naval drone at Euronaval 2026 in Paris, introducing a €5,900 unmanned vehicle engineered for over 65 maritime applications. Developed by Motion Concept Group SAS in Lacanau to address French military requirements, the 15 kg modular platform integrates dual POD 600 electric thrusters, a 100 kg payload capacity, 10-hour low-speed endurance, and a 10-meter maximum operational depth for coastal surveillance and underwater infrastructure inspection. Operating at Technology Readiness Level 4, the company targets a 300-unit pre-series production and TRL 7 qualification by September 2027.

The inexpensive, modular K600 semi-submersible drone enters a naval market increasingly concerned with persistent maritime surveillance, underwater infrastructure protection, mine detection, and the deployment of unmanned systems in large numbers (Picture source: Kahe Nautic)

On November 3, 2026, French manufacturer Kahe Nautic unveiled the K600 semi-submersible drone at Euronaval 2026 in Paris, introducing an unmanned vehicle intended for underwater inspection, naval surveillance, acoustic detection, and coastal infrastructure protection. Developed in Lacanau, Gironde, the K600, priced at €5,900, measures 0.8 × 0.8 × 0.8 m, weighs 15 kg unloaded, and can carry 100 kg of mission equipment, equivalent to 6.67 times its unloaded mass. Its two POD 600 electric thrusters deliver 1,200 W and 30 kgf of thrust, enabling a maximum speed of 6 to 8 knots, one hour of operation at maximum speed, and up to ten hours at continuous low speed.

The vehicle can navigate with its hull beneath the waterline and its communications antenna exposed, or immerse completely to a maximum depth of 10 m. Kahe proposes seven mission categories encompassing more than 65 potential applications, with interchangeable sensors, batteries, and cargo modules, to allow the same vehicle to undertake different assignments, including coordinated drone operations. The K600, part of a three-model family that also includes the K1200 and K2400, remains at Technology Readiness Level (TRL) 4, with a 300-unit pre-series and TRL 7 qualification targeted for September 2027. The K600 originated from requests by French military operational units already using Kahe Nautic's electric thrusters, allowing the company to reuse components from its recreational marine propulsion business to make its entry into the unmanned naval vehicles market.

Related topic: Norway's Eelume S replaces traditional mine hunting vessels with fully autonomous underwater drone

Operating through Motion Concept Group SAS in Lacanau, Kahe is led by president Quentin Liévoux, chief operating officer Aude Blandineau, and co-founder Christian Ollier. After five years of research and development, commercial sales began in 2023, and the company has since sold more than 16,000 propulsion products across seven countries, principally for paddleboards, kayaks, small boats, and snorkeling equipment. Four patents cover its modular electric propulsion technology; Renault is also among its industrial partners, while additional industrial partners and financing are needed to increase production. The K600 itself combines two POD 600 thrusters with a new semi-submersible hull, modular equipment compartment, navigation electronics, and communications equipment.

Each commercial POD 600 produces 600 W and 16 kgf, weighs 4.5 kg including its battery, and uses a 420 Wh battery rated to retain 70% capacity after 500 charging cycles. No French armed forces procurement contract for the complete drone has been confirmed. The K600's two POD 600 thrusters deliver a combined 1,200 W and 30 kgf of static thrust, equivalent to 294 N, while the 1,200 Wh battery operates at 25.2 V, corresponding to 47.6 Ah. The battery and its enclosure have an IPX8 protection rating, with a five-hour charging time and field-replaceable batteries planned for military use. At the full 1,200 W propulsion rating, nominal battery energy lasts one hour before auxiliary consumption, corresponding to 6 to 8 nautical miles at maximum speed or 3 to 4 nautical miles outbound if an equal-distance return is required without reserve.

How electric propulsion is a key factor of range and endurance

Ten-hour endurance instead requires average consumption of no more than 120 W, assuming all nominal capacity is usable. A continuous 30 W sensor consumes 300 Wh over ten hours, leaving 900 Wh for propulsion and electronics, while a 60 W payload consumes 600 Wh, leaving only 60 W average power for everything else. Thus, endurance depends directly on sensor consumption, battery reserves, and propulsion demand rather than speed alone. A sonar requiring continuous electrical power, for example, would logically reduce the energy available for movement unless its operation were intermittent or additional batteries were installed. The K600's semi-submersible hull is intended to keep most of the vehicle beneath the waterline, with only the communications antenna and sensor mast exposed, reducing its visible surface area while retaining radio and GPS reception.

Its 0.8 m cubic envelope represents a bounding volume of 0.512 m³, although actual displacement depends on hull geometry and cannot be calculated from the external dimensions alone. Carrying the advertised 100 kg payload increases combined mass to 115 kg, but the under-hull compartment can accommodate optical cameras, 360-degree imaging systems, night-vision equipment, microphones, hydrophones, imaging sonar, and mission-specific sensors. The vehicle can reportedly immerse completely to 10 m, where the surrounding water produces an additional hydrostatic pressure of 98 kPa in freshwater, equivalent to 0.98 bar above surface pressure, restricting inspections to shallow infrastructure. Kahe also specifies operation in freshwater, saltwater, rivers, and coastal waters, with swell up to 2 m, equivalent to 2.5 times the vehicle's bounding height, while its electric propulsion is intended to reduce cavitation and wake.

How the K600 combines semi-submersible navigation with autonomous operations

The K600 combines remote control, waypoint navigation, autonomous operation, and coordinated missions through a mast-mounted radio antenna, GPS, and proposed 5G and Starlink connectivity. Its 30 to 40 km radio range applies to calm-water operation with the antenna exposed, not full immersion. An antenna 1 m above sea level has a geometric horizon of 3.6 km, while a 30 m shore antenna increases combined line-of-sight distance to 23.2 km before atmospheric refraction. As a full immersion could logically interrupt ordinary GPS and radio reception, Kahe is already developing a submerged navigation solution for its K600 semi-submersible. Programmed routes, station keeping, heading hold, reverse movement, low-speed depth control, mission recording, and resumption after interruption are among the proposed functions.

Furthermore, shared missions and real-time reassignment could allow several drones to monitor separate areas, but the number controllable by one operator and resilience to communications loss remain undisclosed. Emergency surfacing, low-battery alerts, optional locator beacons, and a possible self-destruction function are also included among the proposed safety and recovery capabilities. Kahe Nautic has divided the K600's proposed applications into seven mission families, covering underwater search, rescue, infrastructure inspection, hydrography, long-endurance carriage, surveillance, and coordinated multi-drone operations. Search missions would employ imaging sonar and hydrophones to locate submerged objects or investigate acoustic contacts.

What missions could the K600 perform for naval forces and coastal security?

Rescue configurations could carry flotation equipment or release a buoy toward a casualty, while infrastructure inspection would involve underwater cameras and side-scan sonar examining harbor walls, bridge foundations, moorings, and accessible ship-hull sections, potentially reducing the need to deploy divers for every preliminary examination, provided the structures remain within the 10 m depth limit. Hydrographic configurations could carry conductivity-temperature-depth probes and water-sampling modules to measure salinity-related conductivity, temperature, and depth, parameters relevant to water characterization and underwater acoustic propagation. Long-endurance carriage would use interchangeable batteries, cargo modules, and solar charging, with several hours to several days of standby or drifting operation proposed.

Surveillance configurations could combine thermal cameras, hydrophones, sonar, and radio relays to monitor harbor approaches, naval berths, and restricted coastal waters. Finally, coordinated operations could distribute different sensor packages among several vehicles, allowing optical, acoustic, and environmental measurements to be collected simultaneously from separate locations. At an advertised price of €5,900 excluding VAT, the KAHE K600 could be a competitive option in the small naval drone market, particularly if its proposed autonomous navigation, semi-submersible operation, and modular payload capabilities are validated.

Could the Kahe K600 compete with more expensive underwater drones?

Its specifications include two electric thrusters delivering 1.2 kW, up to ten hours of low-speed endurance, a maximum operating depth of 10 m, a 30-40 km radio link, and a claimed payload capacity of 100 kg. By comparison, commercially available underwater inspection drones such as the Blue Robotics BlueROV2 (which is priced around €4,934 and €5,308) and the Chasing M2 Pro (€5,499) are similarly priced but rely on tethered operation, although they can reach depths of 100-300 m and 150 m, respectively. The wider K-series strengthens this potential price advantage.

For €7,900, the larger K1200 increases propulsion power to 2.4 kW, battery capacity to 2.4 kWh, thrust to 40 kgf, and payload to 300 kg, with a 30 kg unloaded mass, a 20-hour low-speed endurance, and operation in 3 m swell. The K2400 increases these figures to 4.8 kW, 4.8 kWh, 60 kgf, 400 kg, 60 kg, and 40 hours, respectively, with open-sea operation proposed. Kahe targets 300 pre-series K600s and TRL 7 in September 2027, K600 series production and K1200 qualification in 2028, and K2400 production in 2028 to 2029. Both larger models remain at TRL 2, but the three vehicles cost only €59, €26.33, and €31.50 per kilogram of payload capacity, excluding mission equipment.

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Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, South Korea, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.