There are several docks where one can get on or off the boats, but the main one is in the center of Basel.
How to reach the boat dock
The main boat dock is called 'Schifflände'. It is located next to the bridge 'Mittlere Rheinbrücke' in the old town center. It can be reached in a 20-minute walk from the rail station Basel SBB, or in 10 minutes by tram.
The little ferries depart from 4 different locations in town. See their website for details.
Most boat rides are available from April to October. The schedule is limited on weekdays. There are usually just 1 or 2 rides per day, so check the timetables in advance. There are more cruises on Saturdays and Sundays.
Rhine ferry schedules
The ferries cross the river on all days and all year long. In summer season they're available until the early evening. In winter season the schedules are limited and ferries may operate in the afternoon only.