I have a Feelfree Lure 2 that I use a lot for my family fishing trips. It has a small leak that I can't find. I dry it out routinely through the summer and after a trip on the river I can hear water sloshing inside. I would like to find the leak but am struggling how to find a small one like this. There are scratches in the hull from normal use but I don't think those are the problem. I suspect a small crack along a seam somewhere.

The crazy part of me is thinking about dry ice in the hold and watching for smoke. I am a little concerned about it over pressurizing and causing myself more problems.

Any ideas that work for something like this??