I remember this slide and have been on it at Riverside Park back in the early 90's, I am almost 100% sure it was called RipTide. I don't recall being on your knees but remember the hard plastic raft which I beleive you sat on with your knees up holding onto the side handles. I remember if you didn't skim across the bottom you wiped out & got soaked. Somewhere I have old video footage of this slide, if I can ever find it I'll post to this thread Cool ride to bring up, I had forgot about that section of slides!