After a long time of not committing anything to OSM (exept interested people maybe) I took the time here on Fehmarn in Lemkenhafen to learn some more mapping.
Following osm.wiki/DE:Segler i firstly try to add correct coastline at least near the harbour, then add facilities in the harbour and finaly maybe some more streets/ways in Lemkenhafen.

Hope all works out,
Ralph.