Bump ^^^ I am curious about this too as my Mom lives in Chicago and I keep threatening to make her buy a boat I told her we would bring the family more often. Maybe that's what killed it . . .
The Windy City Marina (300 N State St, Chicago, IL 60610-4814) and the River City Marina (800 S. Wells, Chicago, Ill) are both on the Chicago River. Lots of places to put in at the lake and then shuttle up the river.