That's horrible. It happened here in FL on the St. Johns river a couple months ago. A guy in a house boat left a hot plate on and woke up to find the boat engulfed in flames. Half the house boats in the marina burnt to a crisp - probably at least 20 vessels. Luckily no one was killed in this disaster either.
This happened at Lake Don Pedro here in California a couple of years ago. A pilot light left on a houseboat started it, and the houseboat was docked at the gas pumps.