Along the Esplanade, you will find a couple of small piers where you can rent a boat and use to explore the Traunsee at your own pace. Oddly enough, when we went, there were no boats, nor anyone at the stand. This could have been because it was Sunday. As in most of Europe, everything's closed on Sundays. Well, okay, not everything, but surely this.
Oh, they usually only take cash from what I hear. and a rental will run you between 5 and 12 Euro.
Equipment: Bring a pair of swim trunks in the event you get wet. Leave the long pants in the car.
One alternative to exploring the Traunsee is to do so on a sailboat. What better way is there if you think about it? Sailing on such a large lake, surrounded by mountains and hills, is an experience all should try, including myself. I hope to do so next time I'm in Austria during the summer.
Equipment: Contact the sail school for more information on required Equipment.