Proje yönetiminde kısıtlar teorisi ve gemi inşaasında örnek uygulama
Theory of constraints in project management and  a model  application in shipbuilding industry
Yazar: SEZGİN KARABACAK
Danışman: YRD. DOÇ. DR. YALÇIN ÜNSAN
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Gemi İnşaatı ve Gemi Makineleri Mühendisliği Ana Bilim Dalı
Derece: Yüksek Lisans, 2015
Konu: Gemi Mühendisliği = Marine Engineering

Özet:
İşçilik maliyetlerinin yüksek olduğu ve bu nedenle maliyetler açısından uzak doğu ülkelerindeki tersanelerle rekabet etmekte zorlanan Türk tersaneleri, stratejik öneme sahip bu sektörde dışa bağımlı olmamak adına kriz döneminde çeşitli destek mekanizmaları geliştirerek gemi inşa sanayini canlı tutmaya çabalamışladır. Ülkemizde destek mekanizmalarının yetersiz oluşu kriz döneminde para akışı sıkıntısı yaşayan tersanelerin gemi inşa faaliyetlerini durdurmalarına neden olmuş ve pek çok tersane bakım, onarım ve tadilat çalışmaları ile ayakta kalmaya çabalamıştır. Krizle birlikte sektördeki rekabet gücümüz zayıflamış ve ülkemize karşı bir güvensizlik ortamı oluşmuştur.
Bu tezin ilk bölümünde sistemlerin ve proje sistemlerinin sürekli iyileşme ve performanslarını arttırma konusunda yeni bir yaklaşım getiren Kısıtlar Teorisi konusu ele alındı. Kısıtlar Teorisi, sistemlerin işleyişine bir zincir gibi bakıp, sistemin performansının zincirin en zayıf halkası kadar olduğunu ve sistemin genel performansının sadece bu en zayıf halkayı iyileştirmekle mümkün olacağını savunan metodolojidir.
İkinci kısımda ise Kısıtlar Teorisinin firmaların proje yönetim anlayışına getirdiği yeni yaklaşım olan Kritik Zincir Proje planlaması ve bu yeni proje planlama ve yönetim tarzının firmalara getirileri incelendi.
Gemi inşa sektörünün içinde bulunduğu durumdan çıkışının üretim sistemlerinde yapılacak değişikliklerin ölçülmesi gerektiğine vurgu yapıldı. Diğer sektörlerde başarılı bir şekilde uygulanan bu felsefenin gemi inşa üretim sistemine entegre edilmesine çalışıldı ve seri üretim yapan bir tersanenin global kriz öncesinde üretmiş olduğu gemilerin teslimatlarına ilişkin veriler kulllanıldı. Seçilen tersanenin seri üretime yatkın bir anlayışta olmasına dikkat edildi. Tersanenin üretim metodolojisi tanıtıldıktan sonra iş akışı ve yapacağı gemi tipine göre istasyon bazındaki verileri incelenmiş ve kritik zincir, proje ve besleme stokları hesaplandı. Hesaplanan bu veriler tersanenin üretim yaparken ki kaydedilmiş gerçek verileriyle karşılaştırıldı ve teorinin gerçekleşen bitiş zamanından daha başarılı sonuçlar ortaya koyduğu gösterildi.Böylece Kısıtlar Teorisinin Gemi İnşaat Proje Yönetimine uygulandığında firmaların elde edebileceği katma değere vurgu yapıldı.

Abstract:
Shipyards in Turkey with  inability to compete with far east countries due to high labour costs aim to produce several supportive mechanisms during the crisis period to keep this strategic ship building industry  alive with no dependence on foreign sources. Lack of supportive mechanisms in Turkey has resulted in closing of shipbuilding activities for those shipyards with cash flow problem and many shipyards has tried to survive through repair, maintenance and modification activities. Our competitiveness in the market has  been decreased and an unreliable market environment has been developed as a negative  result of the crises in Turkey. 
The first part of this thesis disccusses the Theory of Constraints posing a new approch on continous improvement and sustainable performance growth of project systems. Theory of Constraints is a methodology  that  the system process is seen as a chain where the performance is the weakest ring of the chain and general performance growth is only possible through the improvement in this weakest ring. Our aim and the targeted results by using the Theory of Constraints have been explained in detail. The related studies on this subject has been reviewed and mentioned by the literature survey.  
The second and third part analyses  The Critical Chain Project Planning as a new approach of Theory of Constraints on project management and the advantages of this new project planning and management style on firms. The safety tampon is described at the end of the project. The advantages and disadvantages of this application has been discussed in single and multiple projects. 
The forth part explains the main principles of the Theory of Constraints and what the theory ignores. It mentions the types of the constraints and how they can be resolved. The actions and followed processes change depending on whether the constraint is internal, raw material or in the market. The Theory of Complaints which aims system improvement as a whole is explained in 5 steps by Goldratt. The prupose of these 5 steps is sustainable improvement of the system by identifying and managing constraints of the system. The first step is to identify and define the constraints in the production environment. After the main constraint is known, the direction of the study is for system performance enhancement. 
The constraint of a company is not always internal. The disscussed point is that after a number of cycle the constraint will no longer exist in the system and get out of the system. Goldratt believes that the 99% of an organisation's constraints is political constraints. Thats why the explains how to manage these constraints. The easiest way of finding a constraint without any calculation is to examine the settlement of the in-process stocks within a system.  While improving the constraints, it is explained how to apply the reasoning processes and how the previous analyses and methods contribute on the reasoning processes.
A project is reaching out the aim and goal of the activities (high quality and on time delivery) with predetermined start and finish points under budget and time constraints. The project management is the usage of all tools and techniques simulatneously. The project management is a continous process, not a system with constant activities. It may seem that the multiple assignment in a project management prevents additional human resource and decreases the costs at the first side. However, this indeed causes delays in processes and project deliveries. 
The Critical Chain Project Management is the application type of the Theory of Constraints in project management.  The elements that differentiate the  Critical Chain from other project approaches  have been explained item-by-item. The relationship of methodologies other than Critical Chain (Ghannt, PERT , CPM) and their superiority between each other have been analysed and described. 
The exit from current market conditions of the ship building industry  depends on monitoring and measurement of the changes in production systems and processes.  The priorites of the market and the need for re-reviewing the marine policy and strategy of Turkey have been discussed. In our country there are a very limited number of shipyards that have the mass production process and apply project management system. It is aimed to integrate this philosophy into ship building industry just like the successful application in other industries and the data in this study  belong to ship deliveries's of a shipyard manufactured  before the global crisis with mass production. The used data belongs to 3 pcs 1900 TEU container ships during 2000s among the other mass produced ships. The  shipyard was strictly chosen for its mass production understanding. In the Theory of Constraints applications, a activity should start just after the previous activity ends.  The theory benefits from the station weight of each block in creating workflows. All tasks for a block ( dye, outfitting, equipments, etc.) should be finished and ready before the assembly of the blocks. It is predetermined to assemble which part in which station, because the workload balance is important for the stations. Workload is critical data that can be used with direct proportion in shipyard industry. 
A project plan is created after every sub-function by using %50 estimated finish date without adding the safety periods. Then  the safety periods have been added to the project ends. Feedstocks are placed to the end of the functions that sequentially connected to each other. At this point multitasking is avoided. Safety stocks are placed for the resources and it aims to prevent the problems related to the resources. The quantity of the tampon protects the project from uncertainities that lead to delays in project timing. Besides it also determines the level of the safety margin added to the project and also the total time of the project. While preparing the project tampons, the project managers can determine when to finish the tasks by asking the employees, but they do not make any pressure or mention any expectation on this.s
While working based on %50 finish date principle, the manegement definetely does not make any pressur to complete the tasks in shorter periods. Mutitasking is prevented and each employee is directed to finish only one task in a single time slot. Another cruitial point is not make any used resource or capacity conflict with each other. The manegement of a firms shoudl be aware of a very important situation: if they have a system working properly and with no failures, an idle employee with no current task does not mean that employee doing nothing. 
After the introduction of the production methodology of the shipyard, data has been analysed for each station depending on the workflow and type of the ship and then critic chain,project and stocks has been calculated. The calculated data has been compared to the actual data of the shipyard during actual production and it is seen that the theory ends up with more successul results than the actual completion time
In the end, it  emphasises the added value of the Theory of Constraints for  the firms applying the theory in ship building industry. Depending on the information retrieved from the project, the number of stocks have been decreased in parallel to the improvement rates. It also resulted in decrease of the operatinal costs in the same proportion. The improvemenst will let the firm to start the next project early than the other projects and finish earlier. It serves to a very important aspect of the industry: ontime delivery. On time or even early delivery to the customer will definetely change the mindset of the customers in a positive way. This kind of theorotical studies  are being efficiently applied in other sectors.  It will be beneficial if this theory is  adopted by the decision makers of the companies with mass production and applied accordingly. The main prupose and aim of the study is to create a structure in shipyard industry where the changes will be measurable and let the industry benefit from this data to have tangible values.