In my previous entry I mentioned that I was surprised that the Bosporus was so twisty. Here is a picture I cribbed from the internet. According to the web site it is the second busiest strait on the planet with an average of 48,000 vessels per year. 132 ships a year, not counting all the public transportation ferries, the Bosporus cruises and fishing boats. During the commute hours, the strait is virtually covered with ferries between the European side of the city and the Asian side with its suburbs. They do a delicate little dance with all the tankers and cargo ships.
On the surface, the current usually flows from the Black Sea towards the Sea of Marmara. At depth, the current flows in the opposite direction. The Montreux Convention Regarding the Regime of the Turkish Straits of July 1936 treats the strait as an international shipping lane with Turkey retaining the right to restrict the naval traffic of non-Black Sea nations. Wonder who regulates the commercial traffic using all those radar stations.
The most recent scientific theory says that when the Aegean finally broke through the straits to the Black Sea, it constituted Noah's Flood and sea floor cores and exploration of the sea bottom seem to support the theory. The time frame is right.
In the picture, just where the strait begins, there is a long narrow indentation to the left. That is the Golden Horn and Istanbul is on both sides of it with the old city on the peninsula jutting out on the Sea side of the Horn.