Emniyetli gemi operasyonları için hata türleri ve etkileri analizi (FMEA)'ne dayalı risk değerlendirme modeli geliştirilmesi
Developing a dynamic risk assessment model based on failure modes and effects analysis (FMEA) for safety ship operations
Yazar: SERAP GÖKSU
Danışman: PROF. DR. ÖZCAN ARSLAN
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / Deniz Ulaştırma Mühendisliği Ana Bilim Dalı / Deniz Ulaştırma Mühendisliği Bilim Dalı
Derece: Doktora, 2021
Konu: Deniz Bilimleri = Marine Science ; Denizcilik = Marine ; Ulaşım = Transportation
Dizin: Deniz yolu taşımacılığı = Sea transportation ; Gemi emniyet yönetimi = Ship safety management

Özet:
Gemi operasyonları esnasında hem çevresel hem de insan kaynaklı riskler, beklenmeyen ve istenmeyen aksaklıklara sebep olabilmektedir. Gemilerde, risk değerlendirme faaliyetleri çoğunlukla her bir operasyon için sabit risk değerlendirme formları ile yapılmaktadır. Ancak gemi operasyonları esnasında görüş durumu, geminin konumu, operasyonun yapıldığı zaman dilimi, hava durumu, akıntı hızı, gelgit durumu, trafik yoğunluğu, seyir bölgesi, gemi türü ve geminin boyu vb. dinamik faktörler bu riskleri artırabilmektedir. Gemilerde operasyonel risk değerlendirme formları mevcuttur ancak risk değerlendirme formlarında, bu dinamik riskler yer almamaktadır. 
Bu tez çalışmasında, gemi operasyonlarındaki riskleri artıran dinamik faktörler tespit edilmiş, nicel olarak operasyondaki hangi değişkenlerin hangi riskleri ne kadar artırdığını incelenmesi için  deneyimli gemi adamlarına ön anket çalışması yapılmıştır. Daha sonra, oluşturulan bir uzman ekip ile dinamik risk faktörlerinin neden olacağı potansiyel hata türleri belirlenmiştir. Dinamik risk faktörlerinin değerlendirilmesi için Hata Türleri ve Etki Analizi (FMEA) yöntemi  kullanılmıştır. 
Belirlenen hata türlerinin ortaya çıkma sebepleri, bu hata türleri meydana geldiğinde karşılaşılan durumlar ve bu hata türlerinin operasyon esnasında tespit edilip edilemeyeceği uzmanlar tarafından değerlendirilmiştir. Klasik FMEA'daki hatalı ölçüm ve uzman değerlendirmelerinden kaynaklanan belirsizliğin ortadan kaldırılması için çalışmaya bulanık küme teorisi dahil edilmiştir. 
Yanaşma/kalkma/halat ve demirleme operasyonu vaka çalışması olarak belirlenmiş ve önerilen yöntemin geçerliliği ve uygulanabilirliği gösterilmiştir. Bu kapsamda, yanaşma/kalkma/halat ve demirleme operasyonlarındaki statik risklere dinamik riskler eklenerek, operasyona ait toplam risk değeri hesaplanmıştır. Uzman değerlendirmeleri sonucunda, klasik FMEA ve bulanık FMEA'nın çıktısı olan RPN ve FRPN değerleri belirlenmiş ve hata türleri önceliklendirilmiştir. Elde edilen RPN ve FRPN değerleri karşılaştırıldığında, yapılan öncelik sıralamalarında önemli ölçüde farklılık olduğu görülmüştür. 
Çalışmanın sonucunda, hesaplanan FRPN değerlerine göre, dinamik risklerin oluşturduğu potansiyel hatalardan hangisinin operasyon süreci için daha kritik olduğu hesaplanmış ve geminin emniyetini etkileyen olası risklerin kontrol edilmesi ve proaktif bir yaklaşımla bu risklerin etkilerinin azaltılması veya ortadan kaldırılması için kontrol önlemleri belirlenmiştir. 
Risklerin önceliklendirilmesi, bu risklerin doğru yönetilebilmesi açısından önemlidir. Sınırlı kaynak ve insan gücünün daha etkin yönetilmesi, yeni risklerin ortaya çıkmasını da önleyecektir. Böylece, risk kaynaklı maliyetlerin azaltılması ve sınırlı kaynak aktarımlarının daha verimli yapılması sağlanabilecektir.

Abstract:
Ships with which sea transportation activities are performed have great importance both in terms of life and property safety. Ships are exposed to risks that stem from the sea, either when they are moored or during their time at sea, stemming from the cargo or crew. Many recommendations and safety codes were proposed with the contracts related with the courses of ship, and crew, such as SOLAS, COLREG, MARPOL, STCW and MLC, which were prepared by relevant authorities to eliminate or reduce these risks. 
Although there are continuous developments in safety and technology, many ship accidents occur in systems open to external factors, such as ships, and loss of lives and property are experienced. For this reason, studies conducted on ship safety in the field of maritime research are the subject of continuous research; and various studies are conducted to identify the sources of accidents in ship operations and to avoid or reduce accidents. 
There are operational risk assessment forms on ships. Risk assessment activities are mostly performed with risk assessment forms, which provide quantitative evaluation of external threats and seafarers failures, including safety and failure data of the HSEQ Department in shipping companies. However, when the variety and dynamic nature of ship operations are considered, the condition in which the risks will constantly vary even for the same operation is overlooked. 
There are dynamic risks as well as static risks that stem from the nature of operations on ships. In the scope of this thesis study, the dynamic risks that affect the operational activities of ships were identified. Visibility, weather conditions, location of ships, current speeds, tidal status, the time of the operation, when the operation was performed, traffic density, and navigation zone were evaluated as the dynamic variables. The type of ship and the length of the ship were evaluated as the static variables. 
In this study, firstly, the dynamic factors increasing the risks in ship operations were identified, and with the survey, it was examined with the help of experts which variables in the operation increased which risks to what extent. Then, with the help of a team of experts, the types of potential failures caused by the dynamic risk factors were identified. The FMEA (Failure Modes and Effects Analysis) Method was used to assess the effects of the identified dynamic risks on failures. 
The FMEA Method was used to measure the risks according to dynamic variables for each specified operation. In this context, the dynamic risk factors were identified in ship operations; and the potential failure types, which these risk factors would cause, were identified. 
The FMEA Method was used to measure the risks according to the dynamic variables for each operation. In this respect, the dynamic risk factors were identified in ship operations; and potential failure types, which these risk factors would cause, were identified. The primary purpose of the study was to identify these risks before they appear, and ensure that quick actions are taken to control them. Preventing risks before they appear is of great importance in the safe execution of ship operations. The second purpose of the study was to notice the potential failure types before they become an unavoidable problem; and to take necessary regulatory and reducing measures. In this context, regulatory and reducing control measures were proposed as a result of the study. Controls must be performed systematically. For this purpose, brainstorming was done with the FMEA expert team that was created; and 25 failure types were identified for 8 dynamic risk factors. The probability, severity, and detectability of these failure types were examined and evaluated by the expert team. 
Then, the Fuzzy Logic Approach was integrated into the FMEA Method to overcome the disadvantages of the FMEA Method. The decision-makers evaluated each failure type based on risk factors by using linguistic terms instead of clear terms. 
Mooring/unmooring/rope and anchoring operations were determined as the case study; and the validity and applicability of the proposed method was shown. In this context, the dynamic risks were added to the static risks in mooring/unmooring/rope and anchoring operations; and the total risk value of the operation was calculated. According to the results obtained from the FMEA Method and the proposed approach, the failure types were prioritized in order of importance; and comparisons were made between the outcomes. According to the results, it was revealed that the ranking results that were obtained with the Classic FMEA and Fuzzy FMEA differed from each other.  
In this respect, there were no changes in the ranking of the first three failures. The top three failures that had the highest FRPN values were FM 3.2 (fatigue/individual failure), FM 2.7 (very strong wind), and FM 2.5 (extreme heat), respectively. Among all failure types, FM4.1 (low water) ranked the fourth. FM5.2 (increase/decrease in the speed of the ship) ranked the fifth in importance ranking. FM5.1 (effect on maneuvering) and FM6.2 (machine room and operations) failures that had the same FRPN values ranked the sixth. 
The risk priority approach that was proposed offers a systematic framework for risk assessment of failure types; and eliminates the weaknesses of the Classic FMEA. In this thesis study, it was shown that the developed risk priority model is more flexible, practical, and effective for evaluating and sorting the failure types in the context of uncertainty. When the FRPN values were calculated to conduct the operations in a safer and more reliable setting, corrective and preventive activities were proposed for each failure type. 
Determining possible effects of dynamic risks is very important for risk management systems in ship operations. The adequacy of the existing measures and the proposed additional measures can only be performed more effectively after possible effects of failure types are determined. In this way, we will be prepared for possible risks that may be faced during ship operations. For this reason, it is predicted that potential risks will be eliminated, and time, cost and labor will be saved. 
It is important to identify risk reduction measures and risks for safe completion of ship operations. It is expected that the proposed method serves as a proactive and self-renewing, useful tool for safety and risk management of ship operations. The present study included the Fuzzy Logic Method in the FMEA Method to ensure that stakeholders make rational risk-based decisions, to provide a basis to improve the safety of mooring, unmooring and port operations.