I stare at how beautiful those shiny white hulls glide through water........and forget about trimming the sails!If Gelcoat is absorbent then water does permeate through it,waxing must in someway reduce water tension so that its not absorbed and it also must deter any foreign matter found in the water to stain the hulls. On our beach a hobie 17 circa 1996 has sat and for the three years I've known it the cat has never been in the water now there are glycol blisters all over whatever touches the sand. Another reason to use or move your boat once in a while or at least wax it.Is a painted hull another story? DSYC