If you use anti-fouling bottom paint and either a) live in a region where it's pleasant to dive and scrub your hull, or b) can pay a service to do it for you, either way it's only a once a month thing, and a haul out ever couple of years. Although I can't speak to steel hulls, with fiberglass water can get into the fiberglass causing blisters that have to be ground out and epoxied in, which is precisely as annoying and expensive as it sounds.