C'mon, Occam, let's not make it any less biodegradable than it already is. Think of the impact on our future generations, amigo.so - should he pull her back on land, let her dry out a bit, and then cover her with 3/8" glass and polyester? (I'd say epoxy as it's wood, but we know that's not in the budget)
say he builds a "pan" up to about 6" above the WL, and then uses waterproofing paint above that. Will it keep the water out long enough to go "full taco"?