Wood 101, todays subject BC Exterior plywood
BC is the grade of the plywood not what type of wood it's made from. The higher the grade, the less knots and voids the wood will have. In this case BC means that one side of the plywood is B grade and the other side is C grade. So one side will be prettier than the other. :mrgreen: A = no knots/splits and it's smooth/sanded B = knots with holes/splits filled and it's rough/unsanded C = knots holes/splits and it's rough/unsanded D = don't even go there, max allowed defects. The grade can also affect the strength of the wood since a C grade would have knots/holes/splits, it's obviously going to be weaker as a result of those defects. Exterior in the grade refers to the glue used to bond the layers of the plywood together. A glue that will not break down in moist environments was used in this case so it gets the Exterior rating for use outdoors. Of course you're most likely going to be using pine plywood for your boat project but you can go with a hardwood like oak, birch, or walnut if you really want to blow some bucks. :lol: