Stress fractures and some cracklling sounds ARE normal, but should be minimal - something like bending a pair of fiberglass skis. Our club fleet of six boats lasted through three years of HARD use, going out Mondays through Fridays from mid-April to late October, being sailed by High School sailing teams as well as in the eight week standard summer Junior Sailing Program, with frequent capsizings. Three-year old boats showed some stress fractures, and were getting tired, so we replaced them this year. Not three week-old ones. The Club 420 was developed specifically to be tougher than the fragile International 420. From your description it sounds like you may have one of the latter hulls, with perhaps a club rig stuck in it? A centerboard can be bent from having two heavy guys standing on it to right the boat, but it shouldn''t warp on its own. Boards aren''t made of wood any more, and even then, they used to use plywood because it was so stable. Is seems like a detailed conversation with your 420 salesman would be in order, as well as an inspection of other boats (both older and newer) to compare wear & tear with yours.