Hey I found a way to fix those leaking rivets last summer. The boat in question was a springbok 14 ft. I was forever bailing and fixing till I got the idea.2 part epoxy, you know the small tubes. Sand and clean the area around the rivet(s) with alcohol, cut some circular pieces of shirt material ( the size of a loonie) Canadian hahaha, Half dollar piece. Cover the cloth as in doing fiberglass. Place it over the rivet and with a wet finger smooth out the bubbles. Let dry. Then require a spray can of asphalt undercoating and give it a shot to cover the patch. Extra coats may be added. This is the only thing that worked for me including JB weld.