After you put in a zip code and the map pops up, there is a line starting with "Listing Type". Move to the right to the "More" button. Under that pulldown you will find "Keyword" search box.
Put in "dock" or "sailboat" to get the list narrowed down to waterfront properties with docks. The term waterfront is too vague. It returns properties with marsh views and sunnie ponds.
1984 Monk 36 Hull #46
Currently moored in Englewood, Florida.