My Home Despot sells a plywood called "Multiply" by Weyerhauser. It's a 1/4in. underlayment that is far superior to any luan. It's pale and ugly and only comes in half sheets but well made. Waterproof glue and thick verneers. I've made bulkheads from it,paddle blades a cockpit rim and yes, even a complete boat. It can really take a wallup. Coat it with epoxy,glue it in and forget about the 'glass. $10 a half sheet.
Charlie

: Lauan is pretty porous stuff--I'd prefer to cover it with light glass if
: possible...or get a lot of epoxy on it--mix in a tiny bit of xylene or
: acetone in the first coat for good penetration---and apply it outdoors.