: So, I want to put some permanent flotation in the boat and am planning to use
: just regular old styrofoam. Can anybody tell me what kind of glue to use
: on that stuff?

Get some construction adhesive at your local hardware store. One brand is Liquid Nails, but there are many others. Check the side of the tube and it will say if it can be used safely on styrene foam insulation panels.

Why would you want permanent flotation in your boat? If you are covering the thing with canvas you'll have lots of trapped moisture which will accelerate rotting of the skin, and mold growth. You really want to be able to remove the flotation after paddling so you can get lots of air inside the boat to help it dry out. Consider carving a plug of foam you can chuck into the boat before setting out, and remove later. Or, go with airtight float bags. You can also use mesh bags with your solid foam in them. When you remove these, the open mesh lets air circulate around the foam so it can dry out.

PGJ