Wood - rots/turns to dust.
GRP (fiberglass) - blisters/turns to toulene.
Steel - rusts/turns to iron.
Aluminum - forms self-protective patina/survives...,
unless itz galvanic action at work.
Then, look out: "
Popcorning" - puffs of bauxite over small/bigger & bigger "cavities" in the hull. Proximity to nibral props will cause this.
Sorry, no Crest fixes this - just epoxy (Interlux 2001E).
Just watch out for the
dissimilar metals.
Thatz all.
Whew!