In 1965-1967 six seagoing tugs of the Wangerooge class were built for the German Navy as part of 1960 shipbuilding program:
In 1978 Juist and Baltrum were modified to diver training vessels:
In the same year Langeoog was rebuilt into a minelayer/lightship:
In 2002 Norderney was transferred to Uruguay as ROU 23 Maldonado:
More info:
English wiki,
German wiki