They can best be described as floating mobile homes on barge hulls or pontoons, aluminum, steel..occasionally fiberglass...anywhere from 40-100', some two stories high, with price tags up to a $ million for some...as little as $25k for used. You only have to google "houseboats" to see em. You'll definitely want to google "All Gore's houseboat"...it's a million $$ tin can that he named BIO-SOLAR I (which most people have shortened to "BS I"...it's in a marina near Nashville. There are some trailerable ones 25-27'...and these little "cottage" models have been around for a while. They're quite useful as offices on sales docks as well as weekend waterfront rentals for people who have no intention of leaving the dock.

Unfortunately the typical houseboat owners doesn't have a clue that he owns a VESSEL...he's quick to tell anyone who'll listen that he sees no point in paying $12.95 for that electrical switch or fuel system part (most houseboats on inland lakes and rivers have gas engines and gensets, btw) that has "marine" on the label when he can get the same switch at Home Depot for $6. As a consequence the great majority of marina fires on inland lakes and rivers--at least those in the south--are started by a houseboat.