I'm building a small simple boat however im stumped as to what type of ply wood to use and the thickness. I want to be durable so i thought of 4x8x1/2 plywood but the closest lumber seller is lowes and they dont carry anything of that size. So i figured i'd go to 4x8x1/4 only thing is its OSB utility panel wood, the only problem i don't know what utility wood is, i know what OSB wood is just not utility. My next option would be 4x4x3/8 plywood sheathing.
So my question is which of those should i use or if i should use them at all?