The boat will be underpowered. The hull weight alone is 555 lb. Adding your weight, your child's weight, then gear you're going to be carrying, trolling motor, battery then fuel and live well full of water. Getting on plane will be very difficult if even possible. If you want something to putt around in then the 20 should be fine. I wouldn't go less than 30 but the more power the better I'd suggest the 40.
Jon boats can't handle rough water that well, especially if they are underpowered. Sure you can plan days around weather, but sometimes the weather doesn't cooperate. Or an emergency happens and you need to get back fast. I've owned 7 different jons 16ft and under over the course of 20 years. Been in bays, big lakes and rivers.
I rather have a riveted jon, they are lighter, easier to modify and require less max HP. But welded jons have their advantages as well. Good luck on your adventures fishing with your kid/kids. There isn't anything better imo.
Edited by Alumacraft 14 (09/01/17 08:11 PM)