I am planning on renting a car in Cologne, and then driving south as close to the river as possible to Koblenz and beyond. But now I am thinking of going to Koblenz another way and rent the car there. Obviously I can go by train. Can you see the river from the train? But, I was wondering, are there (as on the Thames in London and in Bermuda) 'water taxis' or river ferries, or other boats (not the River Cruise Boats) that one can board in Cologne and go to Koblenz on?