A new degaussing facility at Kiel that will help make German warships "invisible" to magnetic mines should be completed by 2022.
The German defence ministry said the €54 million (US$63.7 million) investment would make it the biggest and most modern facility of its kind in northern Europe.
It will be able to treat ships up to 180 metres long and 25 metres wide.
It is technically impossible to erase a ship's magnetic field, but degaussing cancels the ship's magnetic distortion and helps avoid triggering magnetic mines.
Royal Dutch Navy ships will also be treated there as the Netherlands is also contributing financially to the project.
Once completed, the facility will be operated by the German technical centre for ships and naval weapons, the Wehrtechnische Dienststelle für Schiffe und Marinewaffen (WTD 71).
It will be the third degaussing facility built in Kiel since 1946.