The Mebo II was originally the Dutch freighter, "Silvretta," built in 1948 by De Groot en van Vliet, Slikkerveer. It had a weight of 630 tons and a length of 186 feet. In 1969, it was bought by Edwin Bollier and Erwin Meister, renamed and converted into an offshore radio station at the same shipyard where it had been built. It was famous for its dramatic art nouveau color scheme.
From 1970-74, it broadcast as Radio Nordsee International (RNI) from international waters four miles off Scheveningen, the Netherlands. Transmissions were on AM medium wave (max105kW), shortwave (2x10kW) and FM (1 kW).