Dr. Willard Bascombe, in his book "Wind , Water, and Waves" (?) calls these vehicles ducks also. I read the book about twenty five years ago so I do not remember what that acronym was for. Interesting reading for anyone living on the coast.
These are still in use here in northeastern North Carolina, but I haven't seen any with For Sale signs on them.
I have a 1969 VW bug that can go some of the places that these can go but is a lot easier to park.
Have fun,
Tom