This is driving me nuts! For those of you over 30, you may know this one. The name or something to do with, "I'm up the River" or something close. It's a comedy about teams of river rafters racing up the river on a vacation and there is a seen with the big guy saying over and over "erwin, erwin, erwin, erwin" old school comedy river rafting movie probably around the early to mid 80's. Please help, I need this movie!

Up the Creek(1984)