If a lure is working somewhere in the spread, run multiples of the same lure. Change the divers to something that is already working. When my divers aren't hitting, I work them and change them up every 20-30 minutes. Another thing I'll do is to keep letting them out farther too. Don't get stuck on a pre-planned spread. That is Ok to start the day but don't stick with it if you are marking fish and not hitting fish. I don't like to tow lures that aren't catching fish more than 1 hr tops. If it don't go, it's getting changed.