Yup kneeboard. I believe they have them for rent. They usually only allow kneeboards on the big cable. I remember a few years back a guy was using a kneeboard off a long since gone ramp called "Big Red". I was wondering how he wasn't breaking his knees landing off it. Then he broke his kneeboard.
The water was pretty smooth in my profile pic because it was taken during the Slider Spectacular, when only one person's riding at a time. Unfortunately they don't have an island to cut down on chop like TSR.