You can dive off the Boardwalk in the city of St. Clair. The current isn't too bad there (about 3 mph), vis can be as good as 25-30 ft all the way down to 1 ft. You will want to be a little overweigthed so you can "crawl" along the bottom. The seawall has ladders every so often so getting out is not a problem. Be sure to bring a dive flag that you can tie off to the ladder (you don't have to pull it along with you). You should "giant step" off the wall and then desend down the wall and "crawl" upstream for the first half of your dive. I usually stay less than 35 feet deep so you don't go into the shipping channel. When you reach the halfway point you should go to your left (while facing up-stream) and work your way back to the wall where you can surface and drift back to your starting point (Flag). You should not surface away from the wall (lots of boats and more current on the surface) and if you should get disoriented all you have to do is stop and face up-stream and go to your left to find the wall. There are some fish (tons of goby's, perch, walleye, smallmouth bass, sheephead) and other items (bottles, and other things people have benn tossing in for the last 200 years). If you have any questions pm me and I will try to answer them.