I used to use the Goop products a lot until I observed that they harden and become brittle with age and then become less effective. Now I don't use them anymore.
The kit offered by Hobie to repair the rivets uses epoxy.
The best adhesive I've yet found is
3M Marine Adhesive Sealant 5200 Fast Cure. Do not confuse this with the more common
silicone sealant which is a good sealant but not a good adhesive.
3M Marine Adhesive Sealant 5200 is urethane based and one of the strongest and most durable adhesive/sealants available, especially for marine use. It remains flexible for years and is
far superior to Goop and most other similar products in every way.