İstanbul Boğazı'ndaki gemi kazaları ve arızalarının analizi
Analysis of ships' accidents and defects at İstanbul Strait
Yazar: CANER GÜRSOY
Danışman: PROF. DR. YASİN ARSLANOĞLU
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / Deniz Ulaştırma Mühendisliği Ana Bilim Dalı / Deniz Ulaştırma Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2021
Konu: Denizcilik = Marine
Dizin: Boğazlar trafiği = Strait traffic ; Deniz kazaları = Maritime accidents ; İstanbul Boğazı = Bosphorus

Özet:
İstanbul Boğazı geçiş yapacak gemiler için 12 keskin dönüşü ve değişken akıntı rejimi ile en dar yerinin 698 metre olduğu, derinliğin ise 30 metre ile 110 metre arasında değiştiği dünya üzerindeki zorlu doğal dar su yollarından bir tanesidir. Tarih boyunca gemilerin İstanbul Boğaz geçişi sırasında karıştıkları bir çok kazaya tanık olunmuştur. Bunlardan bazıları ise maalesef insan hayatı, sağlığı ve çevre için büyük facialar ile sonuçlanmıştır. 
Dünya üzerindeki uluslararası doğal boğazlar incelendiğinde konu boğazlara hakim devletlerin kıyılarını koruma amaçlı olarak geçiş yapacak gemiler için çeşitli önlemler aldıkları görülmektedir. Hatta bazen Messina Boğazı için İtalyan hükümetinin yaptığı gibi altına imza attıkları 1982 Uluslararası Boğazlar Sözleşmesi'ne dahi ters düşecek bazı kararlar alındığı bile görülmüştür. İtalyan hükümeti çevre koruma hassasiyeti ile 50.000 gros ton üzeri tanker ve tehlikeli yük taşıyan gemilerin Messina Boğaz'ından geçişini yasaklamış ve 15.000 gros ton üzeri tüm gemiler ile çevre kirletici yük taşıyan 6.000 gros ton üzeri gemiler için ise kılavuz alma zorunluluğu getirmiştir ki bu karar daha önce de belirtildiği gibi İtalya'nın taraf olduğu uluslararası sözleşmelere de aykırıdır.
İstanbul Boğazı ise 2019 yılı itibari ile son 5 yılın gemi geçişlerini baz aldığımızda yıllık ortalama 42.258, günlük olarak 115 geminin geçiş yaparak yoğun bir şekilde kullandığı uluslararası ticaret için önemi yüksek doğal bir boğazdır. 6 Kasım 1998 yılında yayınlanan 'Türk Boğazları Deniz Trafik Düzeni Tüzüğü' ve 'Deniz Trafik Düzeni Uygulama Talimatları' ile 30 Aralık 2003 tarihi itibari ile aktif bir şekilde çalışmaya başlayan gemi trafik hizmetlerinin tahsisi gemilerin İstanbul Boğaz geçişlerini öncesine oranla daha emniyetli bir hale gelmesini sağladığı açıktır. 2005 yılı itibari ile İstanbul Boğazı içerisinde 13 gemi kazası meydana gelmişken bu sayı 2017 ve 2018 yılları için 2'ye 2019 yılı için ise 1'e düşmüştür. İstanbul Gemi Trafik Hizmetleri verilerine göre 2004 yılından bu yana boğaz içerisinde yaşanan gemi kazalarında azalma görülse de halen daha emniyetli bir İstanbul Boğazı için alınması gereken tedbirler bulunmaktadır. 
Türk Boğazları Deniz Trafik Yönetmeliği ve Uygulama Talimatına göre İstanbul Boğaz geçişi için tüm uğraksız gemilere önemle kılavuz kaptan tavsiyesinin yapılması yanında romorkör refakati alması zorunlu kılınan ya da tavsiye edilen gemiler vardır. Bu kararları özetlemek gerekirse nükleer güçle yürütülen, nükleer yük veya atık taşıyan, tehlikeli ve/veya zararlı yük veya atık (IMDG Kod-7) taşıyan gemiler, LNG gemileri, 150 metre üzeri LPG gemileri, 200 metre üzeri tüm tanker ile 250 metre üzeri tüm gemilere hem kılavuz kaptan alması hem de romorkör refakati zorunludur ya da istemesi önemle tavsiye edilmektedir. Ayrıca 150 metre üzeri tüm gemilere de kılavuz kaptan alması yine önemle tavsiye edilmektedir. Bu tavsiyeler uyarınca da gemilerin kılavuz kaptan alma oranları kıyaslandığında belirtilen sınıflara dahil gemiler ile boyu 150 metreden uzun gemilerin genelde tavsiyelere uydukları görülmektedir. Bu tavsiye kararlarının gemiler tarafından uygulanmasının ne kadar önemli olduğunu görmek için 2020 yılı içerisinde yaşanan iki ayrı kazaya yakın durumun incelenmesi bile yeterli olacaktır. Sadece 2020 yılı içerisinde iki adet 250 metre üzeri büyük tanker İstanbul Boğazı geçişi sırasında makine arızası vermiştir. Bu iki gemi de refakatindeki romorkörlerin acil müdahelesi ve üzerlerindeki kılavuz kaptanların tecrübesi sayesinde herhangi bir kazaya imkan vermeden emniyetli demir sahasına çekilerek götürülebilmişlerdir. 
Bu çalışma içerisinde bulunan veriler ışığında diğer kaza tiplerine oranla çatma ve çatışma kazalarıyla İstanbul Boğazı içinde ve çevresinde daha çok karşılaşıldığı görülmüştür. Hatalı seyir ise bu kazaların yaşanmasında en öncelikli sebep olarak karşımıza çıkmaktadır. İstanbul Boğazı içerisinde yaşanan kazalara bakıldığında ise hatalı seyir sonrası ikinci en önemli sebep ise gemi arızalarıdır. Ayrıca yaşı ilerlemiş ve liman devleti kontrollerinde başarısız olmuş gemilerin de İstanbul Boğazı içerisinde meydana gelmiş kazalar içerisindeki oranının çok yüksek olduğunu görmekteyiz. 
Ahırkapı demir sahası içerisinde yaşanan kazaların tüm kazalara oranı ise %50,1 ile çok yüksek seviyededir. Bu sebeple bu bölgede yaşanan kazalar için ayrı bir çalışma yapmak gerekmiş ve klasik AHP yöntemi kullanılarak deniz trafik operatörleri ile risk değerlendirme çalışması yapılmıştır. Yapılan çalışma sonucunda 'B' demir sahasının demirleme için en riskli bölge olmasının ve gemiler ile kurulamayan ya da eksik kurulan iletişimin bu bölgede meydana gelen kazaların en büyük sebepleri olarak ortaya çıktığı görülmektedir. Diğer sebepler de bu çalışma içerisinde Ahırkapı demir sahası özelinde ayrılan bölümde ayrıca irdelenmiştir. 
Yapılan çalışma sonucunda elde edilen veriler ve konu ile ilgili deniz trafik operatörleri, kılavuz kaptanlar ve gemi kaptanları ile yapılan mülakatlar sonucunda 'Türk Boğazları Deniz Trafik Yönetmeliği' ve 'Uygulama Talimatında' bulunan gemi geçişleri için belirlenmiş tedbirlere ek olarak Montreux Boğazlar Sözleşmesi'ne de aykırı olmayacak şekilde alınabilecek ek tedbirlerin neler olabileceği çalışmanın sonuç bölümünde maddeler halinde sıralanmıştır.

Abstract:
İstanbul Strait is one of the challenging natural narrow waterways in the world where the narrowest point is 698 meters and the depth varies between 30 meters and 110 meters, with 12 sharp turns and variable current regime for ships passing through the strait. Throughout history, many accidents have been witnessed in which ships were involved while passing İstanbul Strait. Unfortunately, some of these have resulted in great disasters for human life, health and the environment.
When the international natural straits around the world are examined, it is seen that the states dominating the subject straits have taken various measures for the ships that will pass their coasts for protection. It is even seen that they sometimes made some decisions against international conventions, like the contradiction of Italy for the Strait of Messina against 1982 International Straits Convention which the Italian government signed under. With its environmental protection sensitivity, the Italian government banned the passage of tankers and ships carrying dangerous goods over 50,000 gross tons through the Messina Strait and necessitated taking a pilot for all ships over 15,000 gross tons and the ships which is over 6.000 gross tons carrying dangerous cargo for their passages.
Also, İstanbul Strait is a very important natural waterway for international trade, which is used extensively by an average of 42,258 vessels per year and 115 vessels per day, based on the ship passages of the last 5 years as of 2019. It is clear that the allocation of vessel traffic services, which started to operate actively as of 30 December 2003 with the 'Turkish Straits Maritime Traffic Regulations' and 'Maritime Traffic Order Implementation Instructions' published on November 6, 1998, made the vessels passages safer than before for İstanbul Strait. While there were 13 ship accidents in the İstanbul Strait as of 2005, this number dropped to 2 for 2017 and 2018 and 1 for 2019. Although there has been a decrease in ship accidents in İstanbul Strait since 2004 according to Istanbul Vessel Traffic Services data, it is not sufficient yet to make İstanbul Strait safer. 
According to the Turkish Straits Maritime Traffic Regulation and Application Instruction, there are also ships that are obliged or recommended to be accompanied by a tugboat in addition to the advice of a pilot for all non-call vessels for the İstanbul Strait passage. To summarize these decisions, ships propelled by nuclear power, carrying nuclear cargo or waste, carrying dangerous and / or hazardous cargo or waste (IMDG Code-7), LNG ships, LPG ships over 150 meters, all tankers over 200 meters and all over 250 meters, it is compulsory or highly recommended to request both a pilot and escort of a tug boat. In addition, it is highly recommended that all ships over 150 meters should take a pilot. According to these recommendations, when the rates of vessels taking pilots are compared, it is seen that the subject vessels generally follow the recommendations. In order to see how important it is to implement these recommendations by ships, it will be sufficient to examine the situation of  2 near miss reports in 2020. Only in 2020,  two tankers over 250 meters had a machine failure during their passage of the İstanbul Strait. Thanks to the emergency response of the accompanying tugboats and the experience of the pilots, these two ships were able to be taken to the safe anchorage area without any accident.
In the guide of the data found in this study, it has been observed that allision and collision accidents are more common in and around the Istanbul Strait than other types of accident. Incorrect navigation appears as the primary reason for these accidents. Looking at the accidents in the İstanbul Strait, the second most important reason after incorrect navigation is ships equipments' failures. In addition, we see that the ships which are older ages and taking low success at the port state controls have big rate in these accidents. 
The ratio of accidents to all accidents in Ahırkapı anchorage is very high with 50.1%. For this reason, a separate study was required for accidents in this region and a risk assessment study was carried out with vessel traffic operators using the classical AHP method. As a result of the study, it is seen that the "B" anchorage area is the most risky area for anchoring and the biggest reasons for the accidents occurring in "B" are the inadequate communication or failure in communication with the ships involved in the accidents. Other reasons were also examined in this study.
In addition to the measures specified in the 'Maritime Traffic Regulations For The Turkish Straits ' and the 'Application Instruction', additional measures and recommendations do not violate the Montreux Straits Convention are listed below by utilizing from the obtained data and the interviews made with vessel traffic operators, marine pilots and ship masters. 
The reason for the measures taken in the current regulation seems to be due to the magnitude of the damage to be caused in the event of a risk, rather than the factors that increase the risk for safe Istanbul Strait vessels' passages. However, factors that increase the occurrence of risk must also be addressed. For this reason, a certain risk assessment should be applied for each vessel that will pass through the İstanbul Strait and this assessment should be included the ship's age, ship type, ship length, depth and air draft, ship tonnage, dangerous cargo transportation, vessel success in port state controls, ship master experience etc. for İstanbul Strait. 
Although there are checks that are requested from the ships before the passage of the Turkish Straits, it is also understood that the ship may not declare it if the ship is lacking after these checks, especially by the pilots who have been given many reports of the gyro and electronic malfunctions. For these reasons, the success of ships in port state controls should be closely monitored and additional measures should be taken in proportion to their success. 
Incorrect maneuver is in the first place among the reasons of accidents occurring in the İstanbul Strait with 56.9%. The main measure to be taken to prevent accidents resulting from incorrect maneuvers is to increase the number of ships that taking a pilot. Even if the non-call vessels passing through the İstanbul Strait are not obliged to take a pilot in accordance with the Montreux Straits Convention, the rates of taking pilots are increased since 2004 step by step due to the regulation recommends to take pilot and the following of this situation by vessel trafic service regularly. However, the number of ships refusing to take a pilot is not few. It is not right to allow that ship to pass the İstanbul Strait under all weather and sea conditions even if the ship does not request a pilot after recommendation of the authorities. If a ship, which is highly recommended to take a pilot after her risk assessment, still does not receive a pilot, the appropriate weather and sea conditions for the passage of this ship should be determined and only allowed this vessel to pass the strait under these weather and sea conditions.
The second leading cause of ship accidents in the Istanbul Strait is defects with 34.7%. The most important of these defects are machine and rudder malfunctions. Even if it is not possible to carry out inspections for every call or non-call vessel that will pass through the İstanbul Strait, the calling vessels could be subjected to additional inspections at the port or anchorage area in Marmara Sea, where including detailed checks of critical equipment, especially machinery, rudder and gyro equipment. 
Vessels having communication problems with vessel traffic service due to insufficient English or any other reason should be obliged to take a pilot. When the accidents inside or outside the İstanbul Strait are examined, effective communication with the ship before or after the accident or near miss event ensures the prevention of the accident or the consequences of the accident are overcome. The fact that the pilot is on the ship significantly increases the efficiency of the communication. 
For LPG tankers of 150 meters and above, it is required to accompany a tugboat as well as a pilot. However, when the data of 2019 is examined, it is seen that the rate of taking pilot for LPG tankers below 100 meters is only 6.4%. For LPG tankers over 150 meters, the reason for the recommendation taking a pilot and tugboat escort is that the damage caused by such ships as a result of an accident is worse than other types of ships. Again, it is understood from the data that ships under 100 meters are generally more likely to be involved in accidents than other length classes. The damage caused by any LPG tanker after being involved in an accident in the İstanbul Strait will be great regardless of the size of the ship. In the guide of all these data, it is necessary to oblige that LPG tankers below 150 meters should get at least a pilot in the regulation for the passage of the İstanbul Strait.
Passage records of ships passing through the Türkish Straits are readily kept. According to these records, ships that make more than a certain number of incorrect maneuvers, incorrect navigation, regulation violation or TSS (Traffic Separation Scheme) violation should be included in this class even if they are not classified as risky ships and should oblige to take pilot for their passage. Also, the names of the ship masters who pass the Turkish Straits are recorded by the VTS, these records can be followed in more detail, and for ship masters who have not passed the Turkish Straits before or who have made their last strait passage for a certain period of time, even if the ship class is not in the risky group, should evaulate as a risky ship.
When the visibility in the strait decrease below 2 nautical miles, measures are taken for vessels passage in the Turkish Straits according to the Regulation. When it reaches 1 nautical mile, it is allowed only one way traffic, and when it is below 0.5 nautical miles, the strait is completely closed to traffic. The visibility limit of 2 nautical miles should be the limit to stop the passages for the vessels which not taken pilot for passage. 
The amount of passage through the İstanbul Strait of vessels with deep draft and over 200 meters increases every year periodically. Although the tugboat is escorted for safe passage of these ships, additional tugboat reinforcement may be required in situations close to an accident or accident. For this reason, additional tug stations should be established near the difficult turning areas of the İstanbul Strait and areas where accidents frequently occur, as shown in this study.
Also the following solution suggestions are listed in order to ensure safety at the south of Istanbul Strait and especially at the Ahırkapı anchorage area;
The first reason for accident in Ahırkapı anchorage area is related to insufficiency of 'B' anchorage area. Increasing the waiting times at anchor from 48 hours to 168 hours in accordance with the regulation published on 15.08.2019 in a way that increased congestion of this area. VTS send the vessels which stay at 'B' anchorage area more than 48 hours due to the congestion occurs to Küçükcekmece anchorage area till their supply will be ready, when their supply will be ready at 'B' anchorage area they will back to 'B' anchorage area again. These extra compulsory ships moves also increase the accidents risks in this area.In this reason, the sectors of the Ahırkapı anchorage area should be studied with all details and new sectors should be determined which can be seen conclusion part of this study. 
Anchoring in the Ahırkapı anchorage area with a pilot may be compulsory, especially for ships over a certain size and ships carrying dangerous goods. Compulsory pilotage service to the anchorage area for ships that will supply or receive service in these regions does not violate the Montreux Straits Convention.
Especially in front of Ahırkapı anchorage area, dense vessel traffic occurs during the hours when the strait traffic is closed from the north and opened from the south. In case of an increase in ship traffic in this area and its vicinity, other ships in Marmara, which are moving to this region, may be delayed and their arrival to the anchorage area may be delayed. Also in cases of south westerly strong wind or dense fog where the visibility decreases, the ships may not be allowed to proceed or leave the anchorage area in the region.
Determining separate areas within the anchorage areas in a way to facilitate the anchoring of large ships according to ship lengths will facilitate the anchoring maneuvers of especially large ships and reduce the accidents risks. Any ship that will maneuver in Ahırkapı anchorage area, having communication problems with VTS or other ships also increases the risk factor. For this reason, a ship experiencing communication problems for whatever reason should not be allowed to proceed to the anchorage area or anchor without a pilot.