Hi Jan,
Is there anything known about routing for cars over ferrys? I mean short ferrys routes over a river or over the Kiel-Channel like in my case. I tried several start an stop points that should cause the ferry to be the shortest and fastest way, but my garmin routes an other (much longer) way over the next bridge. The ferry is tagged with route=ferry, and I tried also with additional key motorcar=yes.
The attached patch can be applied to the new nod SVN branch (that supports routing from OSM files directly). The patch will make ferry routes routable. I haven't tested it, but it should work (famous last words). Make sure that the ferry route ways actually connect to the roads at each end of the ferry route. All feedback welcome. Cheers, Mark