From what I recall from a couple visits to the Air Force Museum, they were mostly used for bombardier and navigator training. I don't think they were ever used by an operational unit, but I might be mistaken about that. They could easily have been used for anti-submarine patrols, but I think they were relegated to training and some cargo hauling.
Of course, you're on sensory overload in Dayton, so I might be mistaken, and won't argue if someone can prove otherwise.