A German project group led by ThyssenKrupp Marine Systems is developing the world’s largest submarine drone. A prototype will soon submerge and demonstrate the performance and versatility of the modular underwater vehicle.

Around a year and a half ago, the second phase of the “Modifiable Underwater Mothership” (MUM) project was started in Kiel with a grant from the Federal Ministry of Economics. This is an unmanned underwater vehicle that, with a modular structure, is intended to take on many different tasks in the civil sector for the exploration and use of the world’s oceans. Now the next two phases are imminent, in which an approximately 25 meter long prototype is to be built and tested. According to “Naval News”, the MUM should be larger than any other submarine drone known in the world.

The project is coordinated by ThyssenKrupp Marine Systems, other participants are Atlas Elektronik, EvoLogics, the University of Rostock and the Technical University of Berlin as well as Fraunhofer and the DLR Institute. The aim of the project is for the MUM to set the new standard for unmanned underwater work by early 2025.

To achieve this, the submarine has a modular design. This means that various modules can be combined in the fuselage in such a way that the MUM fulfills the necessary requirements for different missions. According to “Naval News”, the modules have the dimensions of 10 or 20 foot sea containers.

This is not new, there are other Extra-Large Uncrewed Underwater Vehicles (XLUUVs) designed for containers. But these are sized to accommodate the containers, according to author HI Sutton. The MUM, on the other hand, is built around the containers.

Another special feature of the German underwater drone is its “flatfish design”. That is, the submarine is much wider than it is tall. One benefit of this is increased stability when surfacing, Sutton writes. The MUM is not there to operate like a military submarine at periscope depth. It is either deep below the surface or has surfaced. In a video from ThyssenKrupp Marine Systems you can see that the MUM can be raised with both a flat and a narrow side.

Since the submarine is underwater regardless of the weather conditions, it can be used all year round. The two counter-rotating propellers of the MUM are driven by a fuel cell motor, which, according to the project description, means that it can not only operate independently for a long time, but can also be used in an environmentally friendly manner in ecologically sensitive underwater worlds. According to “Naval News”, the engine has a rated output of 80 kilowatts and is supported by a lithium-ion battery module for peak loads.

From mid-2024, the system will carry out application-related operations. Planned areas of application include offshore wind power plants, deep-sea mining and research. The MUM can, for example, take on transport missions, explore gas and oil fields, take core samples from the seabed with a drill or deploy probes.

Not only in view of the threat from Russia, surveillance and inspections of underwater cables are also likely to be on the future MUM to-do list. And although it is a civilian project, the Navy is certainly watching developments with great interest, writes HI Sutton.