The Turkish Straits - Bosporus 17 nm, Sea of Marmaris 110 nm, Dardanelles 37 nm
My last piece about the Luwians and Troy’s big harbor made me wonder when sailors learned to navigate the Bosporus and the Dardanelles. As we know, a surface current flows from north to south at a speed of ca. 2.0 – 2.5 kn/h (Bosporus) and 1.0 – 1.5 kn/h (Dardanelles). Cruising against such strong currents is challenging, specifically in the confines of the narrow straights. But at one point ancient mariners discovered that a sea anchor would drag their vessel north. A strong and even faster bottom current flows from the Aegean to the Black Sea. It is amazing that people found out.
Replica of the Type of Ship build during the Time of the Trojan War
The two currents results from the difference in salinity between the Mediterranean and the Black Sea. Due to the inflow of large volumes of fresh water from the rivers Danube, Don and Dnieper, the salinity in the Black Sea is only at 17 grams per liter. It reaches 40g in the eastern Mediterranean. Thanks to precise satellite measurements we also know that the surface of the Black Sea is 30cm higher than the Aegean. As the lighter water flows from the Black Sea, it is compensated by saltier and heavier water from the Mediterranean.
The Slipway for sea-going Vessels carved into the Cliffs near Troy - it gave access to the Port
If Troy really had the big harbor recent research suggests, then the use of sea anchors must have been known to its bronze age citizens. It is difficult to imagine the construction of Troy's large port if the Dardanelles and the Bosporus were not navigable. Could not find a good research paper on the subject. The answer may be circumstantial. We know that proper anchors (iron or stone) came only into use by the 6th century BC. Before that, ancient mariners used buckets filled with stones, gravel or sand to keep their ships in place. These buckets would grab onto the mud or sand on the sea floor and were called “teeth” in Greek. It may well be that the ancient mariners found the bottom current by accident simply by anchoring their vessels.
A Sea Anchor for a modern Sail ship - today used to stabilise vessels in heavy seas
The two currents actually reflect the history of the straits. As the Anatolian mountains were folded, a barrier between the European Plate and the Mediterranean was created. The Caspian and the Black Sea became landlocked lakes, fed by giant rivers from the ice shields to the north. During the ice age, as water got tied up in glaciers, sea levels around the globe retreated by more than 100 meters. The Bosporus land barrier was low though. The hills never reached the height of the Anatolian mountains.
Course of the Bosporus, Sea Floor and the 2 Currents
There is now evidence that the Black Sea actually overflowed during the last deglaciation when the Fennoscandian Ice Sheet started melting. Sedimentary and stratigraphic evidence from the Caspian basin indicate a large increase in Black and Caspian Sea levels around 17’000 to 10’000 BC. Between 16’000 and 14’000 BC the Black Sea overflowed. The inflow of large volumes of fresh water caused a noticeable drop in the eastern Mediterranean’s salinity. It must have been a giant river that poured through the straits.
The Melting of the Fennoscandia Ice Sheet (red) caused the Overflow of the Black Sea
The idea that both Bosporus and the Dardanelles could be ancient rivers occurred to me in the past. The Bosporus looks similar to the Rhein river where it carves through the Taunus Mountains. As the ice sheets got thinner, the overflowing stopped. From 14’000 to 6’800 BC there was a land bridge linking Europe to Asia which could be crossed on dry foot. The Bosporus is on average 65 meters deep, but shallower on the southern side with only 13m and 18m respectively.
Detailed Bosporus Sea Floor Map before and after 6'800 BC when the Black Sea was filled
At the end of the last Ice Age when the big ice caps and glaciers disappeared, global sea levels rose back again. For a while, the land bridge held but it was eventually breached by 6’800 BC. In a giant waterfall, salt water from the Mediterranean poured into the Black Sea. Within a short time period, the surface of the Black Sea doubled displacing the people living on the coast. The experience must have been traumatic for the farmers on the northern shores. The Sea of Azov which is so prominent these days due to the war in the Ukraine, was created through these floods. Scientists believe today that the filling of the Black Sea is the basis for the many flood myths we find in all Middle Eastern societies. The story of Noah and his arch fits perfectly well.
Black Sea Sea Floor - the Northern Shores and the Sea of Above were arable lands
If the two straits were not navigable in both directions, the impact on world history might have been large. The territory of today’s Ukraine may never have become the world’s bread basket, the Vikings would not have used the Dnieper as trade route, not founded Kyiv and not brought Christianity to the Ukraine. Russia might have remained a sleepy region for the rest of history. Speculating about alternative history is a waste of time though. Sticking to the facts is more interesting. Ancient mariners discovered the bottom current and sea anchors. Troy and Constantinople owe their existence to these discoveries.
Constantinople and its Surroundings in 16th Century - by Petrus Gyllius (1490 - 1555)