Accidental Risk Analyses of the Istanbul and Canakkale Straits

Maritime transportation plays an important role in the world. Commercial transport and navy are international maritime activities in different countries. Thanks to the role of straits and channels, these activities can be easier and faster, Turkey has a crucial importance on it because of importance of geographical location. The Turkish Straits are a series of internationally significant waterways connecting Mediterranean Sea and Black Sea. They consist of the Canakkale Strait, the Sea of Marmara, and the Istanbul Strait, all part of the sovereign sea territory of Turkey and subject to the regime of internal waters. They are conventionally considered by the boundary between the continents of Europe and Asia. Because of this geographical importance, all kinds of huge sized vessel activities and high volume cargo transportation always keep going in this waterway. On the other hand, the more maritime activities grow the more accident risks increase. So, can be examined the accident risks on Istanbul and Canakkale Straits and can be assessed risk analysis for them. In the context of the study, one can see general information of the Turkish Straits and the regulatory regime. In addition, tables are applied for vessel movement in the Turkish Straits by years in detail in order to sense variation of the vessel. Risk analyses may also be described in sections with many variables. This paper outlines ship accidents and the risk analysis of ship accidents is applied and resulted for the Turkish Straits. The last chapter concerns the Vessel Traffic Service (VTS) System in the Turkish Straits.


Introduction
The Mediterranean Sea and the Black Sea region is one of the busiest waterways in the world, despite covering less than 1% of the world's oceans. This region accounts for around 16% of the global shipping activity by number of port calls, 10% by vessel deadweight tonnes and 8% of the global fleet underway at any given point. Although considered a safe and environmental form of goods transport, the impacts from maritime traffic are recognised as an anthropogenic threat to cetaceans in the Mediterranean Sea and the Black Sea [1].
The Turkish Straits are among the busiest waterways in the world. On average, there are about 43,000 vessels for non-stop passing from the Turkish Straits every year and 65% of them are less than 150 metres in length over all and these vessels generally do not require pilot assistance for strait passage. There is also a very high volume of small ferries, fishing boats and pleasure crafts crossing the Strait of Istanbul. Beside these, navy fleets which are a member of the Black Sea countries and the Turkish Navy constantly use the Turkish Straits.

Istanbul Strait
The Istanbul Strait is about 18 nautical miles in length and just 700 metres wide at the narrowest point. It contains several significant turns, which can serve to obscure oncoming traffic, and require course

Vessel Movements in the Turkish Straits
According to the data from the last 13

Risky Zones in the Turkish Straits
A complex and versatile traffic flow is seen in the Marmara Sea. Marine traffic within the Marmara Sea is summarized as follows: The vessels entering the Turkish Straits from the Aegean Sea or the Black Sea and passing through without interruption. These vessels proceed without stopping at the Sea of Marmara. The ships coming from Çanakkale mostly wait for drift in the anchorage or the south of the islands in the Ahırkapı port for the entrance of the Istanbul Strait.
Vessels coming from the Aegean Sea or Black Sea to the Turkish Straits and in the Ahırkapı port area in Istanbul, must provide personnel exchange, technical services stay in the port within 48 hours or less in order to not slowdown their passage.
There is a traffic in the Marmara Sea generally in the direction of the Traffic Separation Scheme. In addition to this situation, the traffic in the entrance and exit of the Istanbul Strait anchorage area is chaotic due to the heavy vessel traffic. There are also passenger ships and ferryboat lines running perpendicular to the traffic line in the Marmara Sea.
One of the most critical and intense regions of the Marmara Sea is the Ahırkapı anchorage area, the southern entrance of the Istanbul Strait. In parallel with increasing ship traffic in this area in recent years, sea hazards have also increased. Local traffic, which combines both sides of the strait, which is the scene of an average of 120 non-stop ships per day, is also increasing compared to the growing population.
There are lots of narrow zones and sharp turning points in the Turkish Straits. Beside these, pilot embarkation and disembarkation points are risky zones because of the restricted vessel maneuvers [5].

Vessel Accidents and Analyses
Turkish Straits are such dangerous waterways because of the tanker and dangerous cargo traffic. So, risk of accident and pollution is quite high and intolerable. When was analysed the vessel accidents that took place between January 2004 and April 2017, 70% of the accidents occurred in Ahırkapı region because of vessel dredging, bad weather, and heavy anchorage.
Statistics show that the accidents in the Turkish Straits are mainly due to the following causes [6]: sailing without pilot, heavy weather situation, heavy vessel traffic, technical deficiency, defects of vessels, current regime with complex and day-to-day variability, sharp turnaround areas, breach of Traffic Separation Scheme.
As the Turkish Straits, one of the world's most dangerous waterways, are exposed to intensive tanker traffic, the risk of accidents and pollution in the Straits is high. When the dangerous cargo carried by the vessels is added, the environmental dimension of the marine accidents becomes important agenda. In a large-scale, heavy accident in the marine straits can caused natural disaster and can influence millions of people for very long period, also historical and cultural heritages can be demaged [7]. Especially, if the oil pollution to be formed in Istanbul Bosporus cannot be intervened, the possibility of intervention will be difficult because of the expansion of the area, when it is opened in the Sea of Marmara.
More than 70 people died in the Independenta and Nassia events, and the Independenta tanker accident has been passed down as one of the world's largest tanker accidents. One of the recent accidents was the Volganeft 248 tanker accident. Russian flagged tanker named Volganeft 248 was split into two and leaked about 1500 tons of fuel-oil because of the severe lodes in the accident [8].
There are lots of wrecks in Turkish Strait and can be seen figure 1 and list for dangerous wrecks as below. Accident statistics which occurred after Traffic Separation Scheme (TSS) and Vessel Traffic Service (VTS) are given in table 3 and table 4 interval from 1st January 2004 to 1st April 2017 [10].
According to these accident data, there were totally 347 ship accidents during the last 13 years. The majority of accidents happen due to navigation errors. Only 44 of these accidents occurred in the vessels with pilot. All other accidents due to navigation errors happened in vessels without pilots.
Briefly, a total of 78 people lost their lives in ship accidents because of collision, fire, grounding, engine failure, steering failure, oil leakage, drifting, manoeuvre board and navigational mistakes in the last 13 years in the Turkish Straits.

Turkish Straits Vessel Traffic Service (TS VTS)
The Turkish Straits VTS was established in accordance with applicable national laws and international rules and regulations in order to improve the safety of navigation, protection of life, environment, and property in the Turkish Straits by using the latest technology [11].
Marine Traffic in the VTS delineated area is monitored by using Radar, ENC, AIS, CCTV and VHF equipment such as VHF R/T, DSC and DF. VTS also receives information from various sources on anticipated vessel movements, hazards to navigation, aids to navigation and any other information of interests to VTS participants [12].
The Turkish Straits are among the busiest waterways in the world. On average 55,000 vessels transit the Straits every year and 80% of these are less than 150 metres in length. There is also a very high volume of small ferries, fishing boats and pleasure craft crossing the Strait of Istanbul.

Conclusions
In this study, the definition of the Turkish Straits is done from the point of view of its legal status and international agreements. The Turkish Straits are the only waterway in the world surrounded by a state all around the world and a critical water with an intense ship movement.
As a result of this study, it can be seen that ship traffic in the Marmara Sea is mostly proceeded in traffic separation scheme. Apart from this, there are passenger ships and ferryboats, which operate vertically to the traffic separation. The riskiest area is Sector Kadıköy, which includes the Ahırkapı and Kartal anchorage areas and separation, the southern entrance of the Istanbul Strait and the Haydarpaşa Port. Safety distance and overtaking positions of vessels should be well monitored in the traffic separation scheme, short tracking distance and close overtaking positions should be avoided. It has been determined that one of the main reason of the accidents is, that the safe follow-up distance is not kept.
Especially, as the reported sea accidents in the Marmara Sea and Istanbul Strait were examined, 153 of the 240 sea accidents in the last 13 years took place in the Ahırkapı anchorage area. Of these, 139 accidents were clashes, collision and grounding. This situation showed that there is a heavy vessel traffic at the Turkish Straits with anchorage areas. Anchorage areas must be extended or new anchorage areas must be created. Besides, times of supply operations to non-stop passing vessels must be reduced. Pilotage must be compulsory for all dangerous cargo vessels and all vessels over 150m. All vessels including local traffic must stand by all the time in related sector of channel and must immediately answer sector calling.