Istanbul strait, in terms of the formation of the decay of a geological fault. The fault of the valley formed by the decay of our time about 8,000 years ago, along with the increase in the marine waters filled with water, the Black Sea and Marmara seas is estimated combined. Gradual decrease in the depth of the Bosphorus, from north to south, once the height at the southern entrance to constitute a barrier to the waters of the Marmara, but as a result of rising sea waters, this barrier strengthens the thesis has been exceeded. The Sea of Marmara and the Dardanelles were formed as a result of the decay of a geological fault.
Length 18 nautical miles from the Istanbul strait, about 33 kilometers long. Vary the width of the Istanbul Strait is. These wide, the narrowest point of the Bosphorus, between the Aşiyan-Kandilli 700 meters at its widest point between the Büyükdere-Beykoz 3500 meters. When it comes to the depth of the Bosporus average depth is 60 m. The deepest place, the 110 meters and prevent Kandilli. It is an important point in Turkey. Istanbul Strait depth increases towards the south to north. Rise from the bottom of the sea, such as a wall, reminiscent of the coast of the Bosphorus. For this reason, depth, despite a fall in towards the coast, in most places, the coasts, even has a depth of over 10 meters. For this reason, vessels, in the event of a malfunction failed to protect aspects of the routes that they lose as much as you can enter the interior of the houses groundings.
16.64 nautical miles of the throat length. So 30 834 m. The straight length (Rumelifeneri-Anadolufeneri straight distance between the Maiden’s Tower Seraglio): 29.900 km respectively. Width at the northern entrance (between Rumelifeneri-Anadolufeneri): 3328 m. The narrowest location: 698 m from the Kandilli nose nose-Aşiyan. At its widest point: Büyükdere Dark – 3420 m from Umuryeri. Average depth: 65 m. The deepest location: 110 m from the Kandilli Baby. 12.8 m in front of the shallow place Aşiyan. Bridges between the distance: 5514 m (Bosphorus Bridge and the Fatih Sultan. There are two bridges bearing the names of Mehmet Bridge. Fatih Sultan Mehmet Within the boundaries of Bridge Sariyer).
The other factor that make the course a challenge for large tonnage vessels, which flows along the Bosphorus. There are two main discharge from the Strait of Istanbul. First, the surface current that. Secondly, starting from the surface and the depth of 15 meters below the fullest extent permitted Dip current that can be effective to a depth of 45 meters. Surface run-off flows generally towards the Black Sea to the Marmara, on the contrary undercurrent flows through it. Not only the ship traffic in the Strait of Istanbul, the Black Sea waters fed by three major rivers, the only exit door. These three great rivers into the Black Sea, the Danube river, the Dnieper River and Don River. These three rivers feeding the Black Sea with fresh water continuously.
So much so that: if you discharge and surface evaporation of the Strait of Istanbul was not flowing, these rivers would rise up to 30 centimeters per year due to the Black Sea. Nevertheless, the Black Sea, the Marmara sea of water level is higher than 40 centimeters. Here are the main reason for the current of the Black Sea to the Marmara towards the surface, which is the difference between these levels. The higher the level of the waters of the Black Sea, the Sea of Marmara, which flows through the lower level. However, also called discharge stream. This discharge areas is stronger than the middle of the Bosphorus. Towards the south, especially from the Kandilli increases.
Surface stream that runs from north to south speed, the waters of the Black Sea to the mouth of the Bosphorus periods to be effective in filling the northern winds reach the highest level. Almost like a river flows into the waters of the Bosphorus during these periods. Speed, time is up to 7 knots’a. [Sea speed as the unit of measure used in the knots, the term refers to the speed in miles per hour. 1 knots, refers to the speed of 1 nautical mile per hour. Thus, one knots, approximately 1.85 kilometers / hour corresponds.] The discharge rate of the throat km / h if expressed in terms of the Bosphorus waters, discharge times of high, about 13 kilometers / hour flows from north to south. In normal times, this current is around 3-4 knots.
On the other hand, the Black Sea, salinity, constantly fed with fresh water and salt transport by surface run-off water, partly because of the low. Approximately two times saltier than the Black Sea to the Sea of Marmara. This is also the specific gravity of the Black Sea waters, waters is less than Marmara means. Salinity of the waters of the two seas, the salinity difference between the rate of the newborn, starting from the bottom at a depth of 15 meters previously mentioned the cause of stream.
However, the salinity difference between the two sea bottoms stream comprising what speed, nor flow, surface flow is not as great. The amount of water carried by surface run-off to the south, moved north with the undercurrent stream, about 2.5 times higher than the water. To give a figure, the surface of the water flow up and down with the Sea of Marmara carrying 300 cubic kilometers per year, which is in turn moved to the Black Sea by the undercurrent cubic kilometers of water is estimated to be approximately 125 per year. Examine in terms of speed, undercurrent, but can be up to 1-2 knots speed.
North winds, the Bosphorus fierce winds prevailing winds and currents, this is also a strong case. On the other hand, rarely, though, is effective in the southern winds and southwest wind from time to time, and we all know that: Istanbul city line, even if carriers winds southwest wind strong enough to cause the work to be canceled voyages. These winds, the waters of the Marmara Sea to the north stacks, and raise the water level up to half a meter at the southern entrance of the Bosphorus. In this case, the Bosphorus and the South orkoz called discharge regime change occurs when the counter current. This stream from time to time, flow rate and reached the north.
So you can reach 6-7 knots speed up orkoz discharge. The flow of the water from south to north [north discharge), the discharge from north to south (south discharge) is more dangerous. For example: In February of 1999, 100 thousand tons of crude oil from Spetses installed a giant oil tanker, the southbound direction in passing, to make a 90 degree turn at the point Yenikoy not able to make the turn due to severe southwest wind, drifted towards the opposite shore, and barely stopped in front of Rod . That occurred right in front of the fuel rod storage in this case, the threshold was converted to a huge win.
Fog in the Strait of Istanbul is one of the natural phenomena make it difficult to seyirini ship. Introduced in 1994 and amended in 1998 (revised) in accordance with the Turkish Straits Maritime Traffic Regulations, a shaft of visibility falls below the Bosphorus, one-way traffic allowed, falls below half-shaft of the traffic, both reciprocal direction is reversed. The reason is a narrow, winding waterway, the Strait of Istanbul, football authorities, fashion statement with the naked eye without visual conditions, just because electronic data with a view to the radar cruise ships simply can not do so, is the fact. Istanbul Strait average annual number of foggy days is 15 days. Within a month of the most densely foggy days of the month of April with an average 2.6 days. It is followed by the end of March with an average of 2.5 days. Istanbul Strait fog usually occurs in winter and spring.
There are sharp turns 80 degrees up to the Strait of Istanbul from place to place. 80-degree turns, most importantly, Yenikoy Cape. In a north-south axis, to the north at an angle of about 22 degrees, Istanbul Strait, in the 80-degree rotation of Yenikoy There are another 11 more return. Back to the narrow one that is in the front of their Kandilli, currents are high, looking towards the north of ships in a fearful dream.