Frank, thank you for your comments. I'm leaning toward the location you suggested because of the "downtown" in the card's description. Watson Island was not downtown though it was across from it.
Don
Frank Davis
20-Mar-2010 02:32
Don,
I believe that the "Downtown Yacht Anchorage" shown on the postcard is actually the seawall along the north bank of the Miami River. It extended east from in front of the Royal Palm Hotel, along the north bank of the river to the mouth of the river.