How do you separate the keel from the hull on a 1978 tide craft fiberglass fish and ski boat?

I'm not certain about your specific model of boat, but on most fiberglass hulls, there is a rubber bump or rub rail above the waterline. If you pull off the rubber center piece, you will find either rivets or screws that will allow you to pry the hull apart once removed. Please note that I have seen info stating that some hulls may warp after removing the top, so this should probably only be done as a last resort.