I would skip on Dänholm / Stralsund, far away from anything.
Baltic Side, Kieler Förde: http://www.sporthafen-schwentine.de/
Small yard, nice people. I guess the phone
number might be out of date (Harbor Master changed like a year ago). But email
. or just call the hotel
, they will know how to reach the harbormaster. Hotel in Kiel am Hafen / Kiel Pension / Übernachtungen - Hotel Am Segelhafen | Kiel
And it doesn't freeze over bc of the river outlet next by.
Or Hamburg (actually Harburg, but thats pretty close). Behind the locks, so no tides.
is not that common in germany
(but at least legal
since two years or so), so you'll probably have to ask around a bit. If you end up in Kiel drop me a line, I've got some friends there you'll definitely want to meet...