I agree that daggerboards go in a slot and centerboards pivot, but there are always exceptions and inconsistencies. Many scow classes have bilge boards. Since the boats are designed to be sailed heeled they put a board on each side of the boat that will be the lowest point when heeled at the optimum angle and the board is vertical in the water at that heel angle. In addition the board has toe in to reduce leeway. All the classes I'm familiar with use pivoting boards.
http://144.92.9.188/hoofers/sailing//Manuals/The%20Scow%20Manual.htmThere are also leeboards. Most of the examples of these that I've seen or read about are pivoting. I believe that I've seen lee daggerboards on smaller boats where you would just have one blade that you move from one side of the boat to the other.
http://en.wikipedia.org/wiki/LeeboardJohn
