I’m not a boat-owner (mountains beat ocean, from my recreational point of view) so it hadn’t occurred to me to wonder what happens with their bodily wastes. Dumping them overboard would be the easy thing but that can cause obvious problems, especially close to shore. That’s a big reason, by the way, that New Hampshire does not allow anybody to sleep on board their boat in state waters – they’re worried about waste disposal into lakes.
Anyway, NH Public Radio must have wondered about this as well because they just a profile on the “Royal Flush” (their lede: “The boat could have only one name, right?”) which collects septage from boats in the harbor of the Piscataqua River.
You can read/hear the piece here.