Considering the Contel Koblenz in Koblenz?
A VT member wrote the following comment about visiting Koblenz:
Boat ride on the Mosel by dln6874
If you are on the Eurail pass, you can get on the K-D line from Koblenz to Cochem on the Mosel river for free. There is only one boat per day from Koblenz - at 0945, and it takes five hours to get to Cochem (only an hour by train tho), but it is a nice ride. Nice views along the river, and with the right company, time will fly by. You will see cute towns, churches, and ruins along the way. You'll pass a few locks, wineries, mountains. The boat also has a return trip back to Koblenze in the evening, but we took the train back since we had to go back to Holland that night.