Hi all,
I am planing to build a one man boat with foams. The power will be a minn Kota 28lb trolling motor. From Lowes and Home depot, I found two kind of foams, the white foam sheet and blue foam sheet.
This boat is design for one man only, max load 200lb. I weight 138lb. I don't have a trailer, so this boat will has two removable floats that I can put inmy back seat. The whole idea is about portable.

Now the question is which foam should I choose? The foam sheets will be cut and Horizontaly sandwich together to form a float. Should I choose the white foam(cheaper), or the blue foam(expensiver)?

The extruded blue foam is easier to work with. It hotwires very well and sands much better than the EPS (expanded polystyrene), the white beaded stuff. The Eps will break down faster and unless it's well sheathed it will loose beads forever. I've always used extruded for all my projects, boat or plane. Though eps works pretty well as a wing core for a low stress wing that's going to be sheeted with balsa.

If you have the tools, you could strip build a boat, like a wood strip canoe, using blue foam strips covered with fiberglass cloth. You can even use water based poly to "seal" the cloth instead of more expensive epoxy resin. Or you could go lower tech and just chunk out the foam sponsons and paint them. Wont be as durable or as pretty, but they'll still float. A tip you may know is to use scraps of whatever foam you're using to "sand" with. Instead of using sandpaper, just use a block of foam to shape your foam! Works really well.
Have fun...

Thank you for all these tips