This coming weekend will be the event "Kurs Haithabu"(website available in English), a meeting of lots of old (reconstructed) viking ships and boats at (or near) Haithabu, North of Germany. They are expecting 22 vessels with 350 persons of crew, so it is going to be one big event.
And how do you get 22 ships to Haithabu? You sail them, of course. Only that's not so easy with fog and the electronic navigation off due to lack of battery power - so one Polish ship had to get some help from German sea rescue boats on its way to Haithabu. (It's a German article, but it has a pic, too.) They got stranded on a sand bank in the fog and had to be towed off - but will continue their journey as planned after drying themselves (and, presumably, re-charging that battery).