To get to Mainz I had booked 3 ICE's, changing in Nuremburg and Frankfurt am Main. I had neglected to book seat reservations. While riding on the first relatively short segment from Munich to Nuremburg, I was able to book seats on the much longer Nuremburg to Frankfurt segment via the DB website using the wifi available. It was fortunate because I got the last four seats available. What was funny was the electronic signs denoting seat reservations were not functioning and someone was in our seats when we boarded. They quickly moved when I showed them my reservation on my phone.
This second train came to a halt near Würzburg because of "fire service" activity on both sides of the track up ahead. It arrived in Frankfurt an hour late, causing us to miss the train to Mainz. We wound up arriving in Mainz an hour late and about a half hour later than the supposed embarcation deadline. The delay actually turned out to be a blessing. Instead of walking or taking a bus to the ship as planned, we decided to take a taxi. I gave the cab driver the address of the dock we had been given, where upon he asked "Arkona?" meaning the ship. The address we had been given was wrong; and he saved us having to search for the ship on foot after the hot, tiring train ride.