|This may come rather late for many, as most clubs are launched now. However, note for the future that West System G/flex Epoxy has maintained a smooth, gap-free joint for a full season and a lay-up (which I think stresses the forward part of the joint more than sailing).
Last spring, I found that a considerable chunk of filler had fallen from the joint. After the usual flailing around, I called Gougeon Brothers' tech support and asked their opinion. They said that one of their mob had had a similar problem with a different type of boat and everything seemed okay at that point, so I ordered some G/flex (it's not always available in stores). I cleaned the joint back to bare glass and bare lead and applied the G/flex.
G/flex Epoxy is thick, but it still runs over time, so I filled the joint and then wrapped the area with plastic wrap buttressed with cardboard, duct tape, a couple of 2x4 props, the kitchen sink and a few other items that fell to hand as a "form" to hold the epoxy in place. Next day, when the form was removed, I had a filled joint with negligible sag. A light sand, some VC-17 and we were ready for the Travellift.
C&C 27 Mk IV