A friend helped me re do a jon boat several yrs ago and after cleaning we found some black tape 2 inch wide rolls that we cut for each rivet and or hole and it has been leak free for a long time. Started out a a stick steer but converted over to tiller with a 25hp on it that just sips the gas since I don't run it wide open much and installed a older foot opr trolling motor up front. Best one ever and only $50. Last winter same friend helped convert 16ft fish/ski over to nice wide open fishing boat. Ripped out windshield and controls, tiller steer new floor and patched many many rivets and leaks with same tape. The roll of tape is getting thin so we have been trying to find more for a while. After we cut the tape patchs to size we hit then with a hair dryer and have had no problems.