Monopulse HydroHex

History

The Monopulse HydroHex is a hybrid unmanned vehicle designed to operate both as an unmanned aerial vehicle and as an unmanned surface vehicle. The Danish-Lithuanian Monopulse developed the system around a configurable maritime platform that can fly to an operating area, land on water, and then continue its mission on the surface.

HydroHex combines vertical takeoff and landing with waterborne operation. Its demonstrated configuration carries an integrated sonar for examining objects beneath the water surface, while the developers state that the sensor can be replaced with other equipment according to customer requirements.

The platform is intended for search and rescue, inspection of civilian infrastructure, and military missions. Proposed military tasks include reconnaissance of rivers and lakes, assessment of routes for crossings, and detection of mines, improvised explosive devices, and other underwater objects.

Development and presentation

HydroHex was publicly unveiled in 2025. The Lithuanian Defence and Security Industries Association reported that Monopulse presented the hybrid unmanned aerial-vessel platform at DSEI on 10 September 2025. The announcement described HydroHex as a hybrid aerial and surface platform. Further information is available from the Lithuanian industry association.

Monopulse subsequently presented HydroHex at the MSPO international defence exhibition in Poland in 2026. The system shown there incorporated a hydroacoustic sensor and demonstrated the concept of transforming from an aerial vehicle into a surface craft.

Design

HydroHex is configured as a vertical-takeoff unmanned aircraft that can launch from a ship, from the shore, or from another suitable area of land. After reaching the mission area, it can land on the water and transition to surface operation.

During the transition to the surface mode, the motors and propellers rotate into a horizontal position. In this configuration, the propulsion system drives HydroHex across the water in the manner of an unmanned surface craft. This arrangement allows the same platform to use aerial mobility for deployment and waterborne movement for sensor work.

Sensor payload

The configuration displayed in 2026 carried an integrated hydroacoustic sensor with an approximate scanning range of 120 m. While moving on the water, HydroHex can use this sonar to examine objects beneath the surface. According to the developers, the sonar can be replaced with other equipment when a different payload is required.

Operating concept

The combined aerial and surface modes are intended to reduce the need to launch a separate boat for some inspection and reconnaissance tasks. HydroHex can fly from a suitable launch point, land on a river, lake, or other body of water, and then conduct a surface-based sensor mission.

For military use, the stated mission set includes reconnaissance of inland waterways, examination of potential crossing routes for troops and vehicles, and detection of underwater mines, improvised explosive devices, or other foreign objects. Civilian roles identified for the platform include search and rescue and infrastructure inspection.

Program status

HydroHex had reached the public demonstration and exhibition stage by 2025 and continued to be displayed in 2026. The available information describes the platform and its intended missions but does not establish operational service, production quantities, or confirmed military operators.

Specifications (HydroHex)

General characteristics

• Configuration: Hybrid unmanned aerial and surface vehicle
• Takeoff and landing: Vertical takeoff and landing, with water landing capability
• Surface propulsion: Motors and propellers reposition for horizontal waterborne movement
• Standard demonstrated payload: Integrated hydroacoustic sensor

Performance

• Overall operating range: 5 km
• Sonar scanning range: Approximately 120 m