Actually Fiberglass Resin does rot, at least Polyester does. Not quickly (like wood), but it does. The Gel coat protects it from water intrusion. If the Gel coat is removed (digs/scratches) and the fiberglass is left exposed to water for long periods it can absorb water and eventually will "rot" and delaminate etc. It can also happen through Osmotic penetration by water through Gel coat (commonly called "blisters").
Not something drift boats/trailer boats really have to worry about.
[ 03-08-2004, 11:14 AM: Message edited by: Miss B Haven ]