We recently purchased a 1990 26S. This past weekend we noticed that the chainplate where the forestay attaches to the hull has slipped. The cover plate has broken loose revealing that the chainplate has moved 1/4" to 1/2" aft. There are no apparent stress fractures or cracks in either the deck or hull and the chainplate appears secure. I can't be sure if this has just happened or was a pre-existing condition. Any thoughts about the severity of the issue and necessary repairs will be greatly appreciated.