Quick easy fix... 3M 5200. It holds up super well if you dont want to do a full seal on the bottom of the boat with wetlander. Wetlander for sure will seal any leaky rivets. Been there done that, and I have 0 regrets putting all the work in to fix a boat with leaky rivets. If its just a couple and you dont want to go through all that though, ive also sealed holes in my bass boat with 5200 when my ladder pulled out and the holes are still sealed and going strong to this day. That happened ~5 years ago. 5200 is super thick, shouldnt drip, and it sets up nice. The only worry i would have is if you hit the bottom, jumping logs, going over sandbars, etc... it might need to be redone every so often. Very viscous sticky stuff. Sets up hard with just a slight rubbery feel. When i first found out about it, my friend who raced jet skis would carry it with him. In the event they were in a tournament and got a leak, this is what they used for a quick seal job to get to the next race and keep the hull dry.