Nicholas, this lovely postcard is the same one I uploaded on the thread 'History of Piraeus port' where I asked if anyone could identify the two ships on the extreme left and right of the picture. I have my suspicions it could be Kalymnos on the left and what looks like the Lemnos on the right, but am sure one of you will venture a more accurate answer.
Thanks for sharing this beautiful postcard which I actually obtained on ebay very recently!
Henry.