I've seen Supercats upgraded to racing conditions from almost nothing - hulls, beams, mast and bad rudders. At that price yours could be a bargain.

Take a good look at the rudders to check if the blades rotate easily, they get tight with age. To verify if the hull was abused, look at the keel, the beam/hull attachments and the gudgeons - mainly.

Good luck,
Luiz