Wikipedia
A car-boat is a boat or marine vessel built from, or powered by, an automobile chassis and engine. They have recently become well known in the United States media for being the vehicle ridden by a number of Cubans who have attempted to emigrate to the United States by water. The term taxi-boat has also been used for a car-boat built from a taxi.
Another example of a car-boat is the Aquada; earlier examples of this "car-boat" have been around since the 1950s.
By far the largest current manufacturer is Tim Dutton, who has been producing Amphibious Cars since 1989. Over 250 have already been produced. Current models include the 4wd Surf and 2wd Reef. Previous versions of these Amphibs have been used to cross the English Channel twice.