With the christening of an autonomous underwater vehicle (AUV) of the type GREYSHARK in the new variant with fuel cell, two German medium-sized technology providers are offering a solution for a permanent maritime presence under water. In the presence of the Federal Government's Maritime Coordinator, EUROATLAS and EvoLogics presented a system that is set to fundamentally change the protection of critical underwater infrastructure through scalable automotive technology and weeks of endurance.

GREYSHARK Foxtrot: The automotive fuel cell as the key to permanent underwater presence

On 11 March, the Baltic Sea marina in Damp was dedicated to maritime safety. Dr Christoph Ploß, Maritime Coordinator of the German Federal Government, was informed about the latest generation of autonomous underwater systems. Another item on the programme was the christening of the first GREYSHARK Foxtrot, the first fuel cell variant, named „Franzi“ by the politician's assistant, Annika Einhorn. The small ceremony was more than just a classic ship christening. „Franzi“ could provide the answer to the demand for technological sovereignty of the increasingly contested space under water and on the seabed. During his visit, Dr Ploß emphasised that innovative systems such as GREYSHARK are essential for creating a complete underwater picture and detecting acts of sabotage on pipelines, submarine cables and offshore wind farms at an early stage.

The technological leap

1. 16 weeks of autonomy

During the sea trials in the Bay of Kiel in November 2025, the focus was still on the battery-powered "Bravo" variant (approx. 6.5 metres long, 3.5 tonnes). Sensor integration, autonomy and motor were on the checklist. Now „Franzi“ is starting its tests, in which the technical maturity of the fuel cell system will be put to the test.

The Foxtrot, which is around 1.5 metres longer than the Bravo version, marks a technological leap in several respects. The system utilises an emission-free hydrogen drive based on an industrially mature fuel cell from the automotive industry. It enables economical series production. And, according to the manufacturers, it offers unrivalled operating times of up to 16 weeks and a range of over 8,000 nautical miles at a speed of four knots. The flow-optimised bionic design does the rest. „Franzi“ and her sisters have what it takes to shift the established benchmarks in the AUV sector.

2. Strategic dimension: Seabed security and situational awareness

Against the backdrop of hybrid threats, manipulated pipelines and growing awareness of the dangers, permanent control of the seabed has become a strategic necessity. GREYSHARK conceptually closes the gap between short-range systems and expensive, strategic Extra Large UUVs (XLUUV). Equipped with high-resolution synthetic aperture sonars (SAS), the vehicle covers the seabed over several thousand square kilometres. With the help of AI, the fused data from various sensors is analysed directly on board and condensed into an integrated underwater image - a capability that was previously almost exclusively reserved for manned submarines with this level of endurance.

System-of-Systems

GREYSHARK does not operate in isolation. In addition to the main system, EUROATLAS and EvoLogics also presented smaller autonomous platforms in Damp, which are to be used as networked systems in the future. The interaction of several vehicles - supported by onboard edge computing and advanced underwater navigation and underwater communication - allows large sea areas to be monitored efficiently and complex missions to be carried out autonomously. This transforms the AUV from a tactical tool into a strategic component that can remain autonomously in operational areas such as the North Sea or Baltic Sea for months at a time.

A decisive factor for its utilisation is its integration into existing structures. GREYSHARK is able to summarise relevant information in such a way that it can be integrated into command & control systems in encrypted form via underwater communication in order to build up the situation picture - for example in the Rheinmetall Battlesuite. But also in other command and control systems such as North.io's True Ocean platform or even further up to the C4I system. This makes it possible to seamlessly transfer the data obtained into a common situation picture and distribute it in the sense of „multi-domain operations“.

GREYSHARK is backed by a powerful team: the EUROATLAS GmbH, EvoLogics from Berlin, the Fassmer throws and and Rheinmetall. Germany is thus catching up with the international leaders in the field of underwater robotics.

Comparison of established systems in the NATO environment (selection)

Text: Mergener / red. Schlüter