South Shore Marina is located just up river of of the last bridge on the Allegheny coming out of Pittsburgh, up river from the Boardwalk. It is a barge that is painted blue with an office built inside the barge.
The other one, I can't remember the name of it, is locatedon the Ohio just down stream of the Point, on the same side as Heinz field. It is 1 of 2 places to get fuel in the the Pittsburgh pool, and the cheapest.
If you are going to be in PIT the weekend of the 21st, there is a Poker Run sponsered by Fox Chapel Marina.
Hope the weather holds out for you, too bad I'll be at work and not out this weekend.