The Bosporus

The Bosporus is the world's narrowest strait used for international navigation. The Bosporus at the nodal center of Istanbul, not only divide European from Asian Turkey (and the city of Istanbul from its hinterland in Anatolia) but also constitute an obstacle to the flow of surface traffic. Also called the Channel of Constantinople, the Bosporus unites the Propontis, or Sea of Marmara, with the Euxine, or Black Sea. According to the legend, it was called Bosporus from Io, who crossed it in the form of a heifer. At the entrance of the Bosporus were the celebrated Symplegades.

The word Bosporus, signifying literally Ox-ford, is traditionally connected with Io, daughter of Inachus, who, in the form of a heifer, crossed the Thracian Bosporus on her wanderings). By the ancients this name, signifying a strait, was especially applied to the Bosporus Cimmerius, and the Bosporus Tkracius. The totally unrelated kingdom of Bosporus was a long narrow slip on the south-east coast of the peninsula now called the Crimea or Taurida. There was anciently a Greek kingdom of the name of Bosporus, so called from the Cimmerian Bosporus, on both sides of which it was situated, the other Bosporus being distinguished as the Thracian Bosporus. The Bosporan kingdom is interesting as the first Hellenistic state, the first, that is to say, in which a mixed population adopted the Greek, language and civilization. It depended for its prosperity upon the export of wheat, fish and slaves, and this commerce supported a class whose wealth and vulgarity are exemplified by the contents of numerous tombs. When used without any adjective it now denotes the latter, which unites the Black Sea with the Sea of Marmora and forms part of the boundary between Europe and Asia.

Darius, king of the Persians, waged war on the Scythians, placed conjecturally about 515 BC. Over the middle of the Bosporus channel Darius constructed a bridge of boats on his expedition against the Scythians. This work was executed by Mandrocles the Samian, who was richly rewarded for his success. Niebuhr considers the passage of the Bosporus by Darius, on a bridge of ships, as historical. Some verses from the description of the passage of the Persian army over the bridge of Darius were cited from Choerilus by Ephorus, according to Strabo; but Naeke thinks that it is a mistake of citation for the bridge of Xerxes.

Darius then built a bridge across the lower Danube and crossed over into what is now southern Russia. The later narrative of his march by Herodotus is impossible and unintelligible, considered as history. The description of his march is rather to be looked upon as a fancy-picture, illustrative of Scythian warfare. The narrative of Herodotus regard to the Persian march north of the Ister seems destitute of all the conditions of reality. The Scythians, however, were unwilling to fight. To his great joy, Darius found that the Danube bridge had been preserved. He thus succeeded in making his retreat without loss or disaster.

The Scythian expedition of Darius is described by Ctesias, who recognises both the bridge over the Bosporus and that over the Danube, as well as the army of 800,000 men. He states that Darius destroyed the bridge over the Bosporus before his entire army bad crossed, and that 80,000 men, who were left behind, were killed by Scytharus, the Scythian king, who had pursued the Persians. This number agrees with the number of men who, according to Herodotus, were left under the command of Megabazus, in order to subdue Thrace. Ctesias adds that when Darius had passed the Bosporus, he burnt the town of Chalcedon, because the Chalcedonians had attempted the destruction of the bridge over the Bosporus, and because they had removed an altar which he had erected in memory of his first passage. He afterwards assigns the attempt of the Chalcedonjans to destroy the bridge as one of the reasons for the subsequent invasion of Greece by Xerxes.

Niebuhr, after analyzing the account of the march of Darius in Scythia, rejects it as fabulous ; ib. p. 157-8. “The expedition of Darius against the Scythians (he observes) is a remarkable instance of the phenomenon, that at an age so near to the historical times, so many things which are impossible and inconceivable are related as facts by a man of the greatest intelligence and judgment.'

The strait is defended by a series of strong forts, and by agreement of the European powers in 1841, confirmed by the Treaty of Berlin in 1878, no ship of war belonging to any nation shall pass the strait (or through the Dardanelles) without the countenance of the Porte. At the northern end lies the Golden Horn, one of the finest natural harbors in the world, on either side of which Constantinople is built. During the European War and the unsuccessful Dardanelles campaign (1915-16), the gauntlet of the Bosporus was run by British submarines which attacked Constantinople. The Montreux Convention was adopted in 1936 and guarantees the freedom of passage through the straits for merchant ships of all countries; both in peacetime and in wartime. However, the rules of passage of warships are different for the Black Sea states and others. For the warships of the non-Black Sea powers, significant restrictions on class and duration of stay have been introduced.

The Bosporus may be said to begin at Seraglio point on the European shore side, and the town of Skutari on the Asiatic shore, and to terminate at the entrance of the Black sea at the two capes, on which are built the lighthouses of Roumili and Anatoli. Its length from the sea of Marmara to the Black sea, including its numerous windings, is about 17 miles, the breadth varies from 4 cables to 11 miles, and the general direction is SSW and NNE. Like the Dardanelles, it resembles a river with abrupt and angular windings, the projecting points of which break the impetuosity of its stream, quiet its surface, and afiord shelter under their lee; the eastern part of the Bosporus, however, from Buyuk-dere to the Black sea is straight, and its general direction is NE. The depths in the stream is from 20 to 66 fathoms, over a mud bottom.

Both its shores are studded with magnificent palaces or painted houses, lightly built, and in a quaint and picturesque architecture. The European side is covered with them in its entire length, but on the Asiatic shore they are separated by rather longer intervals of space, and are everywhere backed by hills, whose rich vegetation admirably fills up this noble spectacle.

The swiftness of the currents, and occasional fogs, make navigation dangerous. There is a general flow of the Black sea water through the Bosporus, sea of Marmara and Dardenelles, to the Mediterranean, probably caused by the combination of three elements ; firstly, the prevalence of north-east winds in the Black sea ; secondly, the excess of water received from the large rivers over the amount lost. by evaporation, at some seasons; and thirdly, the difference of specific gravities in the two seas. Of these the wind has by far the greatest influence. There is in general a counter-current, setting under the surface stream in an opposite direction, namely, from the Mediterranean to the Black sea ; the under current seems to be dependent on the surface current, for, when the latter is slack, the under current is slack also. The current in the Bosporus is generally stronger in the afternoon than in the forenoon, and as the mornings are usually calm, and the north-east wind gains strength during the day.

Turkey is concerned that rising maritime traffic, especially of large oil tankers, presents a safety and environmental risk to this unique waterway, which bisects Istanbul and its population of 12 million. Oil transport has increased dramatically in recent years: from 60 million tons in 1997 to 134 million tons in 2003, and companies are using larger tankers. Turkish officials emphasize that traffic in the Straits is safe and they continue to work on safety improvements consistent with Turkey's obligations under the Montreux Convention.

However, by 2004 they warned that they were nearing the maximum safe capacity. For example, tankers over 200 meters face special difficulty managing the sharp curves and currents in the narrowest sections of the Straits, forcing them to routinely deviate outside the normal shipping channel. Turkey restricts these tankers to daytime transit and only in one direction at a time.

In 2003, Turkey took delivery of the Vehicle Traffic System (VTS), constructed by Lockheed Martin, which allows Turkish authorities to better monitor traffic and respond more quickly to accidents in the Straits. However, the VTS will not necessarily mean an increase in traffic, and may actually reduce traffic, because the authorities will be better able to enforce vehicle spacing and other safety regulations.

The congestion, when coupled with bad weather, resulted in expensive delays for oil companies and supply shortages for consuming country refineries. At one point in early 2004, 42 ships were waiting to enter the straits, with an average delay of 20 days, costing ship operators hundreds of thousands of dollars. These delays have led to a renewed interest in pipeline projects to bypass the Straits, which Turkey supports. The U.S. and Turkey have worked closely together to promote the development and construction of the Baku-Tbilisi-Ceyhan pipeline (to be completed at the end of 2004), which brought oil from the Caspian to the Mediterranean, bypassing the straits.