M_Boats: Removing stubborn clamcleat

I'm changing out the foresail halyard clamcleat on the cabin-top of my M17. Man, that baby is on there. Removed the bolts/nuts, but she no want to move. I hesitate to pry because it's so well seated I'm afraid a chunk of 'glass will come up too. Any suggestions on how to get this thing loosened up? The careful application of heat? Some kind of solvent? Suggestions appreciated. Tom t _/\_