Racine has a quarry. From what I hear, you'll want to pass on it. Definetely check on the Milwaukee charter situation. I've been on the Lender. It's slow, but roomy and comfortable. If you can dive the car ferry Milwaukee or the Prinz Wilhelm, that would definetely be worth your trip. If your willing to travel north to Black River Falls, check out Lake Wazee. It's an abandoned open pit iron mine that features submerged trees and fish cribs. Summer time viz there is about 25 feet unless you go below about 120 fow and then it gets a little better. Winter time ice diving is the best way to do that place. Travel tip for Black River Falls. Do the Best Western. You may pay a little more, but you will get a bar and a decent resturant in the bargin. The resturant choices in town are somewhat limited IMHO.
Jim