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Having the right spare part at the right time to the right place for ship maintenance to the minimal possible costs is an exigent management problem that maritime shipping companies face. This is especially challenging in bulk shipping where routes are not fixed, but subsequent port calls depend on spot market dynamics. Thus, spare parts allocation ahead in time is limited, but possible if failures rates of ship components and their timing can be foreseen, so that spare parts can be allocated to hedge against the risk of long waiting times and thus ship downtimes. Thus, monitoring the condition of components key to the ships performance is essential to the task. This can enable companies to significantly reduce operational costs of their fleet leading to a competitive advantage in a highly volatile market regarding demand and demand-driven freight rates. However, shipping companies seem far away from applying such methods due to various challenges ranging from data gathering and cultivating an understanding of data quality needs, adaptation to move from preventive towards predictive and condition-based monitoring, and the introduction and application of decision support tools for sourcing, spare parts allocation, and inventory management. In this paper, we investigate the current state of the art of maintenance and related spare parts logistics management for maritime shipping and discuss the application of methods to the bulk carriage market. We add practical knowledge from case companies and discuss how challenges can be overcome in providing guidelines for companies.

Problem. The estimation of voyage efficiency is vital for a shipowner who operates the vessels in tramp shipping on carriages of cargoes. Developing the methods of voyage efficiency calculations should be oriented on different aspect of voyage performance and the voyage costs are one of the most important components as they are the component of the efficiency evaluations. Goal. The goal of the paper is the improvement of the methodological base on the evaluation of the vessel's voyage efficiency using the cost-based approach. Methodology. The voyage costs are presented as three components: fixed operating costs, bunker costs and disbursement costs. The ways of their calculating show the dependence of the costs on the vessel's details such as fuel consumption, NRT etc. That was the reason to propose to calculate the vessel's voyage expenses on 1 tn of her deadweight as far as all the vessel's details largely depend right on her deadweight. Such indicator will show the vessel's voyage efficiency based on the costs on different voyage distances whatever the carried cargo as far that voyage costs don’t depend on the cargo being carried but on vessels particulars. In a certain sense, that is why, it does not matter for the shipowner, what cargo is proposed to be carried. To make it possible to compare the proposed indicator with freight rate (to include the income component of voyage efficiency if necessary) it is proposed to apply the vessel's deadweight utilization indicator. Results. The calculations were carried out for bulk-carrier of about 24000 tns of deadweight for voyage distances from 500 to 2000 nautical miles, and showed the adequacy and workability of the proposed method. Originality. Using the vessel's deadweight distinguishes the proposed indicator from other ones helping to evaluate the vessel's voyage efficiency for the shipowner whatever the cargo proposed to be carried. Practical value. The obtained indicator can be used in operating activity of shipping companies using the vessels in voyage chartering on carriages of cargoes. It can be applied as voyage expenses indicator of a particular vessel. The method is rather simple and flexible for revision for different vessels, voyage distances, bunker prices, port disbursements etc. In addition, it can be used as a freight rate idea during negotiations.

Purpose. The presented study aims to systematize the definition of the terms «demurrage» and «detention», which are used in the theory and practice of maritime transportations, but are characterized by different meaningful definition when used in liner and tramp shipping, which requires the need for a comparative analysis. Methodology. For the stated comparative analysis, the applied information sources allowed to determine the specificity of the terms «demurrage» and «detention» both at the scientific level and at the level of practical implementation. Findings. The authors proved that despite their synonymous character, the terms «demurrage» and «detention» have fundamental differences when used in transportation contracts for the vessels of liner and tramp shipping. Taking into account the specific conditions of these organizational forms of shipping, the terms, the meaningful interpretation of which are the object of the study, have a different object of accrual, the procedure for substantiating the value of the corresponding rates and the procedure for calculating the total amount. Originality. The authors for the first time carried out a study in the context of two forms of organization of maritime transport (tramp and linear) and established the semantic features of the marine terms «demurrage» and «detention». Practical value. The commercial practice of transport companies, in particular shipping ones, is closely connected with technical, technological, organizational, legal, economic and even linguistic issues. The last aspect concerns the role of the accuracy of understanding of the terms by the parties to the transportation contracts concluded by shipping companies (liner and tramp shipping) with counterparties, since it is the responsibility of a material nature that follows from them. Clear interpretation of the terms is crucial to prevent possible disputes regarding the relevant payments. Uncertainty, which is currently present in scientific publications and literary sources of practical nature, leads to a free interpretation and substitution of the analyzed terms with each other without a clear distribution of the parties' responsibility in different forms of shipping., Цель. Представленное исследование направлено на систематизацию содержания понятий «демередж» и «детеншен», применяемых в практике морских перевозок. Эти понятия характеризуются различным толкованием при их использовании в линейной и трамповой формах судоходства, что требует необходимости выполнения компаративного анализа. Методика. Для указанного анализа использованы источники информации, которые позволяют на основании современных научных методов определить специфику понятий «демередж» и «детеншен» как на научном уровне, так и на уровне практической реализации. Результаты. Авторы доказали, что несмотря на синонимичность понятия «демередж» и «детеншен» имеют принципиальные отличия при использовании их в договорах перевозки грузов судами, работу которых организовано в форме трампового и линейного судоходства. Учитывая специфические условия организационных форм судоходства, термины, содержательное толкование которых является объектом исследования, имеют разный объект начисления, порядок обоснования величины соответствующих ставок и порядок расчета общей суммы. Научная новизна. Авторы впервые провели исследование в контексте двух форм организации морского транспорта (трамповой и линейной) и установили семантические особенности морских терминов «демередж» и «детеншен». Практическая значимость. Коммерческая работа транспортных предприятий, в частности судоходных, тесно связана с техническими, технологическими, организационно-правовыми, экономическими и даже лингвистическими проблемами. Последний аспект касается точности понимания терминов сторонами договоров перевозки грузов – судоходными компаниями (линейной и трамповой организации работы) и контрагентами-грузовладельцами, – поскольку из значения этих терминов следует ответственность материального характера. Чёткое толкование понятий является решающим для предотвращения возможных споров относительно соответствующих выплат. Ведь неопределенность, присутствующая в научных публикациях и информационных источниках практического характера, приводит к свободной интерпретации и подмены анализируемых понятий друг другом без четкого распределения ответственности сторон в различных формах судоходства., Мета. Це дослідження спрямоване на систематизацію змісту понять «демередж» і «детеншен», які застосовують у практиці морських перевезень. Ці поняття наразі характеризуються різним тлумаченням відповідно до їх використання в лінійній і трамповій формах судноплавства, що потребує необхідності виконання компаративного аналізу. Методика. Для зазначеного аналізу використано джерела інформації, які дозволяють на підставі сучасних наукових методів визначити специфіку понять «демередж» і «детеншен» як на науковому рівні, так і на рівні практичної реалізації. Результати. Автори довели, що попри синонімічність поняття «демередж» і «детеншен» мають принципові відмінності відповідно до використання їх у договорах перевезення вантажів суднами, роботу яких організовано у формі трампового й лінійного судноплавства. Враховуючи специфічні умови організаційних форм судноплавства, терміни, змістове тлумачення яких є об’єктом дослідження, мають різний об’єкт стягнення, порядок обґрунтування величини відповідних ставок і порядок розрахунку загальних сум. Наукова новизна. Автори вперше провели дослідження в контексті двох форм організації роботи морського транспорту (трампової й лінійної) і встановили семантичні особливості морських термінів «демередж» і «детеншен». Практична значимість. Комерційна робота транспортних підприємств, зокрема судноплавних, тісно пов’язана з технічними, технологічними, організаційно-правовими, економічними і навіть лінгвістичними проблемами. Останній аспект стосується точності розуміння термінів сторонами договорів на перевезення вантажів – судноплавними компаніями (лінійної й трампової організації роботи) і контрагентами-вантажовласниками, – оскільки зі значення цих термінів випливає відповідальність матеріального характеру. Чітке тлумачення понять є вирішальним для запобігання можливих суперечок щодо відповідних виплат. Адже невизначеність, наявна в наукових публікаціях та інформаційних джерелах практичного характеру, призводить до вільної інтерпретації й підміни аналізованих понять один одним без чіткого розподілу відповідальності сторін за різних форм судноплавства.

Tedarik zincirinde %84'lük pay ile deniz yolu taşımacılığı en önemli taşıma modu konumundadır. Deniz yolu taşımacılığının taşıyıcı rolündeki temel aracı gemilerdir. Tankerler, kuruyük gemileri, konteyner gemileri gibi çeşitli tiplerde ele alınabilen bu araçlar ile 2016 yılında 4885 milyon ton dökme yük, 3631 milyon ton petrol ve kimyasal madde türevleri, 1726 milyon ton konteyner yükü taşınmıştır.Farklı ülkeler ve limanlar arasında kitlesel taşımalarda rol oynayan gemiler, denizyolu taşımacılığını en uygun maliyetli taşıma modu konumuna getirmektedir. Denizyolu taşımacılığı, dünya ekonomisinin etkilerinin ilk hissedildiği alanlardandır. Dünya ekonomisinin seyrine paralel hareket eden artan gıda ve emtia talepleri, artan taşıma gereksinimi doğurur. Artan taşıma gereksinimi, gemi taşımacılığı karşılığında alınan navlunlarda yukarı yönlü bir yönelmeye neden olur. Benzer şekilde azalan ticaret hacmi azalan yük trafiğini doğurur. Böylece belirli sayıdaki gemi filosu arasında yük bulma yüzünden daha sıkı rekabet ortamı yaratılır. Rekabet ortamı denizcilik işletmelerinin daha güçlü olmasını ve sürdürülebilir kılınmasını gerektirir. Sürdürülebilirlik, bir denizcilik işletmesinin işletme maliyetine bağlı olarak, hangi navlun değerlerine kadar çalışabileceğinin göstergesidir. İyi bir yönetim ile, sürdürülebilirlik çıtası yukarıya çıkartılabilir. Sürdürülebilirliğin önemli olduğu günümüz ticari yaklaşımında, gemi işletme firmalarında en önemli maliyet kalemini satınalma oluşturmaktadır. Bir denizcilik işletmesinde satınalma kaynaklı gemi işletme maliyetleri, %90 düzeylerine kadar çıkabilmektedir. Bu sebeple, bir denizcilik işletmesinin stratejik ve yönetsel adımlarla satınalma kaynaklı azaltacağı her maliyet unsuru sürdürülebilirlik seviyesini yukarı çekecektir. Gemiler, düzenli hat taşımacılığı ve trump taşımacılık olmak üzere iki prensibe göre işletilmektedir. Düzenli hat taşımacılığında genelde gemilerin bir sonraki limanının neresi olacağı, ekstrem durumlar olmadıkça yaklaşık olarak ne zaman bir sonraki limanında olacağı bellidir. Trump taşımacılıkta ise gemiler, nerede yük bulursa orada çalışır. Dünyada denizyolu taşıma gereksinimlerinin büyük bir kısmında trump taşımacılık yapan gemiler rol oynar. Trump çalışma, gemilerde belirsizlik doğurur. Belirsizlik yönetimsel anlamda karar vericilerin önünü görmesine, veriye dayalı yönetim anlayışı kazanmasına engel olur. Bu ise, denizcilik işletmelerinde tecrübeye dayalı yaklaşımların ağırlıklı olmasını sağlar. Bir geminin operasyonel hizmet akdi sırasında 42000 IMPA katalog, 35000 ISSA katalog ile tanımlanan ve bu kataloglarda yer almayan sayısını bilmediğimiz ürün yelpazesine ihtiyaç duyulmaktadır. Denizcilik işletmelerinde satınalmanın belkemiğini oluşturan bu ürün yelpazesi, artan liman sayısı ve bu limanların herbirinde farklı tedarikçi profili ile oldukça komplike bir sürece dönüşmektedir. Hangi limana gidileceği ve ne zaman varılacağı belirsizliği ile de bu karmaşıklık daha da içinden çıkılmaz hale bürünmektedir. Bu sebeple denizcilik işletmelerinde satınalma süreç yönetiminde, deneyime esas yaklaşımlara başvurulur. Satınalma birimine gemiden gönderilen talep listeleri, satınalma birimi tarafından şirket içi diğer birimlere iletilir. Gemiden gelen talepler; kumanya, slop chest, güverte malzemeleri, makine malzemeleri, kırtasiye malzemeleri, yayınlar, kimyasallar, emniyet malzemeleri, tıbbi malzemeler, temizlik malzemeleri, haritalar, yağ ve boya malzemeleri şeklinde 13 ana başlıkta incelenebilmektedir. Ürünler bu ayrıma göre şirket içerisinde birimlere iletilmektedir. Satınalma departmanınca diğer birimlere iletilen bu ürünlerin teknik yeterlilikleri ve talep miktarına ilişkin uzman tecrübelerine dayanarak, satınalma birimine bilgi aktarımı yapılır. Satınalma birimine alım yapılacak ürün miktarını veya alıma gerek var-yok şeklinde nihai kararını iletir. Satınalma birimi, bu birimlerden onay gelmesine istinaden onaylanan miktar ve ürün nezdinde tedarikçi arayışına girer. Denizcilik işletmeleri çok fazla ürün ve çok fazla liman seçeneğinde genelde birkaç tedarikçi-liman nezdinde bu satınalmayı yürütür. Satınalma birimi de ağırlıklı olarak bu tedarikçilerden fiyat talebinde bulunarak, en uygun tedarikçi seçimini gerçekleştirir. Tedarikçi seçimiyle gemi satınalma süreci tamamlanmaz. Gemi tedarik zincirinde ele alınan ve satınalma sonrası işlemleri gerçekleştiren çeşitli hizmet sağlayıcılar mevcuttur. Bu hizmet sağlayıcıları ile gemiye teslimata kadar ki süreç yönetilir. Bu hizmet sağlayıcılar; tedarikçiden ürünün teslim alınarak geminin geleceği limana veya geminin gelmesi beklenecekse gösterilen bir depo ya da antrepoya kadar ulaştıran lojistik firmaları, gerekli ise depo veya antrepo hizmeti veren firmalar, limana kadar getirilen ürünün teslim edilecek gemiye ulaşımını ve gümrük vb. işlerini takip eden gemi acenteleri, liman ya da terminalde değilde açıkta seyreden bir gemiye tedarik yapılacaksa gemi acente botlarıdır. Bu süreç başından sonuna kadar ayrıca satınalma ve gemi-acente koordinasyonunda takip edilir. Gemiden talebin alınıp, gemiye ürün teslimatına kadar ki geçen gemi satınalma döngüsü, denizcilik işletmelerinde mevcut işlerin yanısıra ek iş yükü meydana getirmektedir. Geliştirilecek bir strateji ile iş yükleri azaltılarak, karar desteği sağlanabilecektir. Bu amaçla tez kapsamında simülasyon-delphi tekniği-bulanık mantık hibrit yaklaşımı ile süreç ve maliyet iyileştirmesi sağlayacak Promag ismiyle anılan model önerisi geliştirilmiştir. Denizcilik sektörüne özgü geliştirilen ve satınalma sürecini ele alan ilk model olan Promag ile stok ve politika yönetimi kapsamlı bir şekilde ele alınmıştır. Sayısal verilere odaklanan stok yönetimi ile dilsel verilere odaklanan politika yönetimi bir araya getirilerek, satınalma sürecinde entegrasyon sağlanmıştır. Dinamik bir çevrede ve belirsizlik altında ticari faaliyetlerini sürdüren gemilerde, gemiye özgü stok kavramı ortaya atılmıştır. Gemiye özgü stok kavramında, gemilerin seyir süresi dikkate alınarak stok yönetimi için üç aşamalı geçiş formu dizayn edilmiştir. Bu geçiş formunda sırasıyla emniyetli stok, minimum stok ve kritik ürün değerleri tanımlanmıştır. Uygulamada farklı seyir geçmişine sahip tüm gemiler için bazı ürünlerde kritik ürün değeri tanımlanmışken, bu geçiş formu ile tüm ürünler için ve her bir gemi için ayrı birer aşamalı stok değeri elde edilmiştir. Bu stok değerlerinin elde edilmesinde Arena simülasyon programı ile kurulan stok yönetim modeline başvurulmuştur. Simülasyon programının çalıştırılması için bir tanker gemisi örneği seçilerek son 1 yıllık stok-satınalma verileri modelde koşturulmuştur. Hibrid model önerisinin politika yönetimi safhasında, satınalmayı etkileyen kriterler, alt kriterler ve alternatifler Delphi tekniğine başvurularak uzmanların katılımı ile tespit edilmiştir. Delphi tekniğinin son aşamasında sezgisel bulanık kümeye başvurularak her bir kriter, alt kriter ve alternatif için sayısal karşılıklar elde edilmiştir. Kriter, alt kriter ve alternatifler için bulanık birleştirme süreci takip edilerek, politika yönetimi için entegre model ortaya çıkartılmıştır. Politika yönetiminde entegrasyon sağlandıktan sonra, stok yönetimi için stok risk katsayıları tanımlanmış ve takiben politika yönetimi ile entegre edilmiştir. Böylece nihai Promag modeli elde edilmiştir.Promag modelinin validasyonu için gerçek verilere başvurulmuştur. Yine anılan geminin tedarik limanı, geminin geçirdiği denetler, lokasyon bazlı tedarik maliyetleri elde edilmiştir. Elde edilen veriler kumanya başlığını kapsayacak şekilde özelleştirilmiş ve yaklaşık 600.000 hesap ile Promag modelinde koşturulmuştur. Test bulguları, gerçekleşen değerlerle karşılaştırıldığında Promag modelinin stok yönetim kısmı ile maliyetlerde %7,43, stok miktarı gerçekleşen alım miktarı ile aynı kalmak üzere politika yönetimi stratejisi ile %62,98, hem stok hem de politika yönetimini kapsayan Promag modeli ile %70,41 azaltma söz konusu olmuştur. Kumanya için Promag modeli ile küçük tonajlı, 15 personele sahip bir gemide yılda 83869,7 TL iyileştirme sağlanmıştır. Maliyet yaklaşımının yanısıra satınalma ve diğer destekleyici birimlerin iş yüklerinde sistematik yaklaşımla ciddi düşüşler sağlanmıştır. The maritime transportation is the most important transportation mode with the 84% market share. The main transportation vehicles of this mode are ships which specialize with tanker, breakbulk, container ships etc. In 2016, 4885 million tonnes breakbulk, 3631 million tonnes petrol and chemical products and 1726 million tonnes containerized goods have been carried with these type ships.The maritime transportation is the most cost effective-transportation mode with the ships which play role in mass transportation between different countries and ports and, is one of the first affected components from world economic fluctuation. Increasing demands on commodity market lead to increase in transportation requirements as the parelel with course of world economy. The freight market links to supply-demand balance between ships and goods and, increasing level in transportation requirements cause to rise in freight rates or vice versa. In the shipping market, low volume of goods creates a fierce competition environment. Therefore, this environment requires a powerful and sustainable shipping companies. The sustainablity is the indicator of what is the lowest workable freight level for a shipping company depends on their operational costs. The shipping companies could crank their sustainability level up several notch with various management strategies. For this purpose, the shipping companies tend to decrease their operational costs and apply to several management strategies mainly focus on cost-reductive solutions. During the management of a ship, the most important cost element is procurement and it reachs up to %90 of overall ship operational costs. Hence, it could be say that the sustainability level will be rise when the each cost element which is interested in procurement of a shipping company decreases with the strategic and managerial steps. The ships have been managed in two main categories i.e. trump and liner shipping based on their working principle. In the liner shipping, the ships navigate within certain routes and fixed schedules and, their next destination and estimated time of arrival is clear without an unexpected event. In the trump shipping, the ships work where she find goods. The trump ships meet much of the world transportation requirements. The trump working is the main source of uncertainity in this type of ships. The uncertainity prevents the decision makers from data-driven management approach and creats an administrative impediments. Therefore, we face frequently with experience base approaches more than data-driven approaches in the shipping companies.The ships apply to 42000 products defined by IMPA catalogue, 35000 products defined by ISSA catalogue and other products undefined by any catalogue during their operational period. The management of these defined and undefined products which form backbone of ship procurement in shipping companies, could be complex process with increasing number of ports and suppliers from different countries. Especially, in the trump ship, unceartainty in the ship route and schedule make this complexity worse. The complexity in ship procurement forces shipping company to apply experience base-decision makers' subjective decisions. During the procurement cycle, the ships send the their purhase requisition list to purchasing department and then, the purchasing department distributes purchasing items to different departments. These requisition lists consist of 13 main classifications such as provision, slop chest, deck demands, engine demands, stationary demands, publications, charts, chemicals, safety materials, medicial demands, cleaning materials, oils and paints. The requisitions for each classification have been analysed different departments in shipping companies and purchasing department considers task sharing through sending purchasing items to departments. After the receiving requisitions lists include each product items and quantity by the relevant department, these departments approve, correct or reject each product items and quantity according to their technical competence and demand quantity based on decision makers previous experiences and then clue purchasing department in their final decisions and confirmations. The purchasing department search potential suppliers by considering approved quantity and items. However, the number of suppliers worked together is limited with several suppliers and delivery ports in shipping companies even if they have pretty much suppliers and port options. The purchasing department frequently make a request price list of each items from these limited suppliers and select best supplier. The selection of best supplier does not mean the purchasing proces complete and after selection of supplier, the various service providers perform the aftersales facilities. These facilities include to receive the goods from supplier and delivery to the ship in certain port or if the goods wait for ships, in certain warehouse until the ship arrives. In this period, the potential service providers are logistic companies, the firms give service in warehouse management, ship agent follows custom procedure in ports, and agent boats if the ship receives the goods during her navigation period. This supply chain process is also monitored by purchasing department of shipping company, both ship and agent coordination. The ship supply chain cycle from taking requisition list to delivery the ship generates additional workload in shipping companies as well as present workload. This workload could be decreased by developing a strategic approach and the it could be provided decision support to decision makers. For this purpose, author recommends a hybrid model called as Promag in this thesis. The Promag model integrates simulation, Delphi technique and fuzzy hesitant set in order to process and cost improvement of purchasing function. It provides comprehensive analysis of stock and policy management in shipping companies and, it is first model suggestion which address procurement process and speficially developed for shipping industry. In the Promag model, numerical analysis results of stock management and linguistic analysis results of policy management have been thrown together and, integration between different components have been provided in procurement process. In the ships, which engage commercial activities under uncertainity and dynamic environment, the term of stock which is intrinsic to a certain ship, firstly introduced with shipping literacy. In this term, dynamic three-way stock levels i.e. safety stock, minimum stock and critical product have been designed for effective stock management by considering ship port to port time periods. Although several shipping stakeholders define only a static critical value in the practice for overall ships even if they have different port to port time periods, this approach recommends different stock values for each item and ship which are continously reproduced under changing dynamics in ship environment. These stock values have been calculated with developing stock management model in Arena simulation package programme. 1-year stock-procurement data of a selected tanker ship have been run in this developed model. The results of simulation have been transformed into risk values between 0 and 1 interval by normalization procedure. The criteria, attributes and alternatives effect the purchasing decisions have been determined with partipication of the experts by applying Delphi technique in the phase of policy management of hybrid model suggestion. The same process have been followed to obtain numerical value of each criteria, attributes and alternatives by using fuzzy hesitant set in the last phase of Delphi technique. Finally, the fuzzy aggregation for criteria, attributes and alternatives has been completed in order to integrated model for policy management. Both stock management and policy management results have been integrated each other. Therefore, final procurement process management model (Promag) has been obtained.Real ship stock and purchasing data have been used in validation of Promag model. Supply ports, ship inspection dates and product prices based on each countries have been obtained from shipping company. The provision related data have been selected from these data lists and Promag model has been run with these data. The approximately 600000 different calculations were completed in Promag model. When the test results were compared with present values, we saw that it possible to reduce the cost 7.43% with only stock management process, the cost 62.98% with only policy management process on the condition same stock value with present values, and the cost 70.41% with both stock and policy management of Promag model. This means to possible save 83869.7 TL/year in the small tonnage ship which have 15 seafarers only for provision procurement. Besides cost-driven opportunies, this model has reduced workload of decision makers with systematic approach. 134

Purpose: This paper discusses the current state of routing and scheduling in tramp shipping, an important planning problem on the operational level in maritime logistics. The purpose is to report and compare the existing methods and to investigate possible future additions and improvements. Furthermore, an outlook on potential applications of machine learning for this optimization problem is given. Methodology: In this paper an extensive literature review of reports and journal papers on cargo routing in tramp shipping of the last seven years is conducted. The wide range of findings are categorized by the different considered characteristics. The results are analyzed and trends are pointed out. Findings: Optimization problems in tramp shipping differ in their main properties from liner shipping or classical vehicle routing problems. Thus, different approaches and implementations are required when developing or adapting existing optimization algorithms. The real-world problem is often limited in the optimization, so found solutions are improvements, but cannot fully reflect reality yet. Originality: This paper provides a comprehensive overview of tramp ship routing and scheduling. Although optimization of routing and scheduling in liner shipping is fairly well researched, the publications on tramp shipping are sparse in comparison. This leaves room for future research, as the findings for liner shipping and vehicle routing are not directly applicable to tramp shipping.

Η θαλάσσια μεταφορά εμπορευμάτων πραγματοποιείται από τις ναυτιλιακές επιχειρήσεις. Τα τελευταία χρόνια, λόγω των απαιτήσεων που έχουν προκύψει απ’ το διαρκώς μεταβαλλόμενο και δυναμικό περιβάλλον της ναυτιλίας, έχουν αναδυθεί δύο μοντέλα διοίκησης ναυτιλιακών εταιρειών, της tramp και liner ναυτιλίας. Τα δύο πρότυπα διοίκησης παρουσιάζουν διαφορές ως προς τα χαρακτηριστικά τους, τον τρόπο διοίκησης τους, την αγορά στην οποία δραστηριοποιούνται και γενικότερα ως προς την φιλοσοφία τους. Στην παρούσα εργασία, θα γίνει καταγραφή των χαρακτηριστικών του κάθε μοντέλου διοίκησης, των χαρακτηριστικών των αγορών στις οποίες δραστηριοποιούνται και τις μορφές ναυλώσεων τους. Στην συνέχεια, θα γίνει μία προσπάθεια σύγκρισης των δύο τύπων διοίκησης βάση των ιδιαιτεροτήτων τους και των διάφορων λειτουργικών ζητημάτων όπως σχεδίασης δικτύου μεταφορών, ταχύτητας πλεύσης, καταρτισμού δρομολογίων κ.α. Τέλος, θα χρησιμοποιηθούν οι οικονομικές καταστάσεις δύο εταιρειών (CMA CGM – Teekay Co), έτσι ώστε να γίνει μία σύγκριση του ποσοστού των επιμέρους δαπανών που καταλαμβάνουν επί του συνολικού κόστους., Shipping companies are in charge to transport cargoes through the sea. During the last decades, due to the turbulent and dynamic shipping industry, they are created two business models, Tramp and Liner Services. There are several differences between Tramp and Liner as in their features, in the way of the management and in the company philosophy. We are trying to mention the features of each business model, the features of Tramp and Liner market and how the vessels are chartered. Moreover, we will try to note the differences between the operating costs and the voyage expenses in each business model (Tramp-Liner) and we will use the financial statements of two shipping companies (CMA CGM – Teekay Co), in order to compare the percentage of each type of cost.

Shipping markets are dependent on international trade transactions that generate transport needs. These needs can dynamically change depending on global natural resources and commodity markets situation. The changes affecting shipping markets can also be caused by changes to the existing cargo flows and by establishing new ones in different geographies. It is anticipated that in the future shipping markets will change, visible by a decline in shipping in North America and Europe and an increase in Asia.

U radu se razmatraju horizontalni sporazumi o suradnji prijevoznih poduzetnika u segmentu pomorskog prijevoza. Najznačajniji horizontalni sporazumi prijevoznih poduzetnika u linijskoj plovidbi zasigurno su linijske konferencije. Linijske konferencije u mnogim su pravnim poredcima uživale određene oblike izuzeća od primjene prava tržišnog natjecanja, među njima je i Europska zajednica. Vijeće ministara je u rujnu 2006. godine usvojilo prijedlog Europske komisije za ukidanje izuzeća od primjene pravila tržišnog natjecanja na linijske konferencije koje djeluju na prometnim pravcima s EU. Ukidanje izuzeća stupit će na snagu u listopadu 2008. godine. To označava početak primjene novog, kompetitivnog pravnog režima u segmentu linijskog prijevoza. Kako bi se prijevoznim poduzetnicima olakšao prelazak na potpuno kompetitivni sustav, Komisija je u rujnu 2007. godine izradila Nacrt smjernica o prim jeni članka 81. Ugovora o osnivanju Europske zajednice na usluge prijevoza morem u kojima je najveću pozornost posvetila upravo horizontalnim sporazumima o suradnji prijevoznih poduzetnika u segmentu pomorskog prijevoza, sporazumima o razmjeni podataka među konkurentima u linijskoj plovidbi i pool-ovima u slobodnoj plovidbi. U svezi s horizontalnim sporazumima poduzetnika u linijskoj plovidbi, u Nacrtu smjernica navodi se kako razmjena podataka o količini, kapacitetu i cijeni između linijskih prijevoznika može proizvesti pozitivne gospodarske učinke u smislu povećanja učinkovitost pružanja usluga linijskog prijevoza, dok je razmjena podataka koji se smatraju trgovinski osjetljivima protivna pravu tržišnog natjecanja. U Nacrtu smjernica sadržani su i drugi naputci prijevoznim poduzetnicima u linijskoj plovidbi o tome u kojim će slučajevima razmjena podataka biti u skladu s pravilima tržišnog natjecanja EZ-a. Kad je riječ o pool-ovima, u Nacrtu se navodi kako, zbog njihovih različitih obilježja, svaki se pool mora analizirati zasebno kako bi se utvrdilo krše li se njime pravila o tržišnom natjecanju EZ-a te se daju podrobne upute o načinu provođenja te analize. U radu se razmatraju rješenja usvojena Nacrtom smjernica te prijedlozi i komentari zainteresiranih stranaka na koje se kritički osvrće.

This paper investigates the simultaneous optimization problem of routing and sailing speed in the context of full-shipload tramp shipping. In this problem, a set of cargoes can be transported from their load to discharge ports by a fleet of heterogeneous ships of different speed ranges and load-dependent fuel consumption. The objective is to determine which orders to serve and to find the optimal route for each ship and the optimal sailing speed on each leg of the route so that the total profit is maximized. The problem originated from a real-life challenge faced by a Danish tramp shipping company in the tanker business. To solve the problem, a three-index mixed integer linear programming formulation as well as a set packing formulation is presented. A novel Branch-and-Price algorithm with efficient data preprocessing and heuristic column generation is proposed. The computational results on the test instances generated from real-life data show that the heuristic provides optimal solutions for small test instances and near-optimal solutions for larger test instances in a short running time. The effects of speed optimization and the sensitivity of the solutions to the fuel price change are analyzed. It is shown that speed optimization can improve the total profit by 16% on average and the fuel price has a significant effect on the average sailing speed and total profit.

Οι συνθήκες αγοράς και το θεσμικό πλαίσιο όπως διαμορφώνονται στην ναυτιλία έχουν μεταβάλλει τη φύση της ναυτιλιακής δραστηριότητας και τη σύνθεση του κόστους των ναυτιλιακών αγορών. Ειδικότερα μία από τις μεγαλύτερες βασικές ναυτιλιακές αγορές που είναι η ελεύθερη φορτηγός ναυτιλία έχει διαφοροποιήσει πολύ τις δραστηριότητές της στον τρόπο που διεξάγει τη μεταφορική της υπηρεσία. Εκμεταλλευμένη τις οικονομίες κλίμακας, χρησιμοποιώντας μεγαλύτερα πλοία κατάφερε να μεταβάλλει τη δομή του κόστους της. Οι αλλαγές που έχουν συντελεστεί, αυξάνοντας τα κόστη τόσο της ελεύθερης όσο και της ναυτιλίας γραμμών, οφείλονται σε μια πληθώρα παραγόντων όπως το νέο θεσμικό πλαίσιο για την προστασία του περιβάλλοντος, οι νέες εργατικές νομοθεσίες, αλλά και η κρίση που διέρχεται η παγκόσμια ναυτιλιακή αγορά. Η νέα αυτή δομή του κόστους στην ελεύθερη ναυτιλία οδηγεί σε μια βιώσιμη ανάπτυξη και σε αλλαγές στον τρόπο με τον οποίο οι ναυτιλιακές εταιρείες αντιμετωπίζουν την μεταφορική τους δραστηριότητα., The formation of the market conditions and the regulations of the ocean shipping have altered the nature of the shipping activity and the composition of the cost of the shipping markets. In particular one of the biggest key shipping markets which is the tramp shipping has diversified its operations in the manner of conducting the shipping service. By using the economies of scale and using bigger vessels managed to change the structure of their costs. The changes made, which result to the increase of the costs of the tramp and liner shipping as well, are due to a various factors such as the institutional framework for the environment protection and the modern labor laws, along with the undergone crisis of the market. This new structure of the cost in the tramp shipping leads to a sustainable development which brings changes to the way shipping companies deal with their transport activity.

Η παρούσα διπλωματική εργασία έχει σκοπό να παρουσιάσει, να περιγράψει και να αναλύσει την κατάσταση, στα πλαίσια των συνεργασιών που υφίστανται ήδη καθώς και όσων τείνουν να δημιουργηθούν στη ναυτιλία τακτικών γραμμών. Ιδιαίτερα επιχειρείται η στοχαστική και οικονομική ανάλυση του φαινομένου δημιουργίας συμμαχιών - συνεργασιών μεταξύ των κορυφαίων εταιριών τακτικών γραμμών μεταφοράς εμπορευματοκιβωτίων. Μέσα από την ανάλυση της συγκεκριμένης αγοράς και των χαρακτηριστικών της, την θεωρητική αλλά και την χρηματοοικονομική μελέτη των συνεργαζόμενων εταιριών στη πορεία των χρόνων, καθώς και τα πλαίσια του ανταγωνισμού που τη διέπουν, την προσδιορίζουν και την οριοθετούν τις τελευταίες δεκαετίες, καταλήγουμε σε χρήσιμα συμπεράσματα, τα οποία αφορούν τόσο το παρόν, όσο και το μέλλον της συγκεκριμένης αγοράς., The present dissertation has the intention to examine, analyze and demonstrate in all the perspectives the liner shipping industry, within the partnerships that already exist and those tend to be created in liner shipping. Particularly attempts to analyze the phenomenon coalition - collaborations among the leading companies in container liner shipping from stochastic and economic point of view. Throughout the analysis of liner shipping industry and its special characteristics, the theoretical but also the financial study of cooperating companies in the course of years and the examining of the relevant ruling regulations concerning competition we can reach in exceptionally useful conclusions, regarding the present of that specific market and the future as well.

This paper presents a novel column generation algorithm for managing the logistics activities performed by a fleet of multi-parcel chemical tankers. In our procedure, for providing elementary routes, the conventional dynamic programming routes-generator is replaced by an efficient continuous-time MILP-slave problem. The performance of the decomposition method is evaluated by solving several examples dealing with the operations of a shipping company operating in the Asia Pacific Region. Computational results show that the proposed approach outperforms a pure exact optimization model and an alternative heuristic solution method reported in the literature. Fil: Coccola, Mariana Evangelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); Argentina Fil: Dondo, Rodolfo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); Argentina Fil: Mendez, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); Argentina

This paper is an effort to understand how the tramp shipping industry works, which is considered to work close to perfect competition model, where the atomicity, homogeneity and information transparency are evident. Many small shipping companies compete for a volatile and unpredictable demand. Despite there are some entry barriers to the market, these can be easily mitigated by the way this market works. Tramp shipping companies co-operate among them in pools, in order to bid for large contracts of affreightment, which otherwise, shipowners could not perform on their own. Tramp shipping pools raise competition concerns, and under the EU Competition Rules, these agreements shall be assessed on case-by-case basis in order to determine whether an agreement may jeopardise competition within common market. To do so, an assessment under Article 101 TFEU is required. Normally, tramp shipping pools created for the right purposes, do not entail competition restrictions. Conversely, those agreements that have a combined market share considerably high or involve hardcore restrictions, are prohibited under Article 101 (1). These agreements have three options: terminate their agreement; demonstrate that economic efficiencies brought by the agreement outweigh restrictions under Article 101 (3); and lastly and most appealing, try to restructure the agreement creating a full-function joint venture in order to fall under a more certain legal framework, the EC Merger Rules.

A tramp ship operator often has contracted cargoes that must be carried and seeks to maximize profit by carrying optional cargoes. Hence, tramp ships operate much like taxies following available cargo and not according to fixed route networks and itineraries as liner ships. Marine fuel is referred to as bunker and bunker costs constitute a significant part of daily operating costs. There can be great variations in bunker prices across bunker ports so it is important to carefully plan bunkering for each ship. As ships operate 24 h a day, they must refuel during operations. Therefore, route and schedule decisions affect the options for bunkering. Current practice is, however, to separate the two planning problems by first constructing fleet schedules and then plan bunkering for these fixed schedules. In this paper we explore the effects of integrating bunker planning in the routing and scheduling phase for a tramp operator sailing full shiploads, i.e. carrying at most one cargo onboard each ship at a time. We present a mixed integer programming formulation for the integrated problem of optimally routing, scheduling and bunkering a tramp fleet carrying full shiploads. Aside from bunker integration, this model also extends standard formulations by using load dependent costs, speed and bunker consumption. We devise a solution method based on column generation with a dynamic programming algorithm to generate columns. The method is heuristic mainly due to discretization of the continuous bunker purchase variables. We show that the integrated planning approach can increase profits and that the decision of which cargoes to carry and on which ships is affected by the bunker integration and by changes in the bunker prices.

U radu se razmatraju horizontalni sporazumi o suradnji prijevoznih poduzetnika u segmentu pomorskog prijevoza. Najznačajniji horizontalni sporazumi prijevoznih poduzetnika u linijskoj plovidbi zasigurno su linijske konferencije. Linijske konferencije u mnogim su pravnim poredcima uživale određene oblike izuzeća od primjene prava tržišnog natjecanja, među njima je i Europska zajednica. Vijeće ministara je u rujnu 2006. godine usvojilo prijedlog Europske komisije za ukidanje izuzeća od primjene pravila tržišnog natjecanja na linijske konferencije koje djeluju na prometnim pravcima s EU. Ukidanje izuzeća stupit će na snagu u listopadu 2008. godine. To označava početak primjene novog, kompetitivnog pravnog režima u segmentu linijskog prijevoza. Kako bi se prijevoznim poduzetnicima olakšao prelazak na potpuno kompetitivni sustav, Komisija je u rujnu 2007. godine izradila Nacrt smjernica o prim jeni članka 81. Ugovora o osnivanju Europske zajednice na usluge prijevoza morem u kojima je najveću pozornost posvetila upravo horizontalnim sporazumima o suradnji prijevoznih poduzetnika u segmentu pomorskog prijevoza, sporazumima o razmjeni podataka među konkurentima u linijskoj plovidbi i pool-ovima u slobodnoj plovidbi. U svezi s horizontalnim sporazumima poduzetnika u linijskoj plovidbi, u Nacrtu smjernica navodi se kako razmjena podataka o količini, kapacitetu i cijeni između linijskih prijevoznika može proizvesti pozitivne gospodarske učinke u smislu povećanja učinkovitost pružanja usluga linijskog prijevoza, dok je razmjena podataka koji se smatraju trgovinski osjetljivima protivna pravu tržišnog natjecanja. U Nacrtu smjernica sadržani su i drugi naputci prijevoznim poduzetnicima u linijskoj plovidbi o tome u kojim će slučajevima razmjena podataka biti u skladu s pravilima tržišnog natjecanja EZ-a. Kad je riječ o pool-ovima, u Nacrtu se navodi kako, zbog njihovih različitih obilježja, svaki se pool mora analizirati zasebno kako bi se utvrdilo krše li se njime pravila o tržišnom natjecanju EZ-a te se daju podrobne upute o načinu provođenja te analize. U radu se razmatraju rješenja usvojena Nacrtom smjernica te prijedlozi i komentari zainteresiranih stranaka na koje se kritički osvrće., The paper analyses horizontal cooperation agreements of shipping undertakings in the maritime transport sector. The most important horizontal agreements of liner shipping undertakings are certainly liner conferences. Liner shipping conferences have been granted some form of exemption from the competition rules in many jurisdictions, including the European Community. In September 2006 the Council of ministers adopted Commission's proposal to repeal the exemption from the EC Treaty's ban on restrictive business practices (Article 81st of Treaty) for liner conferences on routes to and from the EU. The repeal will enter into force in October 2008. This marks the start of a new competitive regime in the maritime sector. In order to ease the transition to a fully competitive regime, the Commission in Sept 2007 issued Draft guidelines on the application of Article 81st of the Treaty to maritime transport services in which it deals mostly with horizontal cooperation agreements of shipping undertakings in the maritime transport sector, information exchange agreements in liner shipping and pools in tramp shipping.

Linijske konferencije su u mnogim zakonodavstvima uživale određene oblike izuzeća ili imuniteta od primjene prava tržišnog natjecanja. U EU Vijeće ministara je 1986. godine donijelo Uredbu 4056/86 kojom se određivanje cijena i reguliranje upotrebe kapaciteta linijskih konferencija, uz ispunjavanje određenih uvjeta, izuzima od primjene čl.81 i 82. Ugovora o osnivanju Europske zajednice. Opravdanje za donošenje Uredbe 4056/86 temeljilo se na pretpostavci kako određivanje vozarinskih stavova i druge aktivnosti linijskih konferencija dovode do stabilnih vozarina, osiguravajući tako prijevoznicima pouzdane prijevozne usluge prema redovitom rasporedu. Međutim, u posljednje vrijeme imunitet linijskih konferencija je podvrgnut reviziji u nekoliko dijelova svijeta, jedan od njih je i EU. Komisijin prijedlog za ukidanje skupnog izuzeća za linijske konferencije rezultat je njenog trogodišnjeg istraživanja tijekom kojeg su održane mnogobrojne konzultacije s prijevoznicima i korisnicima prijevoza. Vijeće ministara je u rujnu 2006. usvojilo Komisijin prijedlog za ukidanje izuzeća od primjene pravila tržišnog natjecanja na linijske konferencije koje djeluju na pravcima iz i prema EU. Ukidanje izuzeća će stupiti na snagu u listopadu 2008. Vijeće je također ovlastilo Komisiju da primjenjuje pravila tržišnog natjecanja na kabotažu i slobodnu plovidbu, tako što je proširilo područje primjene Uredbe 1/2003, koja sadrži provedbena pravila tržišnog natjecanja. Kako bi se olakšao prelazak na potpuno kompetitivni sustav, Komisija će donijeti Smjernice o primjeni prava tržišnog natjecanja na pomorski prijevoz, u dogovoru sa svim zainteresiranim stranama. U radu se analiziraju recentne izmjene materijalno-pravnih i procesno-pravnih pravila tržišnog natjecanja, koji se odnose na linijske konferencije, kabotažu i slobodnu plovidbu, a na različite prijedloge i argumente zainteresiranih strana kritički se osvrće, Liner shipping conferences have historically been granted some form of exemption or immunity from the competition rules in many jurisdictions. In the European Union, the Council of ministers agreed on rules, in 1986, which exempt price-fixing and capacity regulation, under certain strict conditions, from Articles 81 and 82 of the EC Treaty. The justification for the Liner Conference Block Exemption Regulation 4056/86 was the assumption that rate-setting and other activities of liner conferences lead to stable fright rates, which in turn assured shippers of reliable scheduled maritime transport services. However, this immunity has been subject to review in several part of the world, including European Union. The Commission’s proposal to repeal the block exemption for liner conferences was the result of three year investigation by Commission during which extensive consultations with carriers and transport users took place. In September 2006 Council of ministers adopted Commissionʼs proposal to repeal the exemption from the EC Treatyʼs ban on restrictive business practices (Article 81) for liner conferences on routes to and from EU. The repeal will enter into force in October 2008. The Council also empowered the Commission to apply EC Treaty competition rules to cabotage and tramp shipping, by extending the scope of the competition implementing rules of Regulation 1/2003. In order to ease the transition to a fully competitive regime, the Commission will issue Guidelines on the application of the competition rules to maritime transport services, in consultation with all stakeholders. The paper analyses the reasons of the recent changes of the competition substantive-law regulations and competition implementing-law regulations regarding liner conferences agreements, cabotage and tramp shipping services. The different proposals and arguments of the stakeholders are being taken into consideration in a critical manner.

Çalışmada Türk tarifesiz filosunun navlun salınımlarına verdiği tepki ölçülmek istenmektedir. Regresyon analizi kulllanılmıştır. Türk tarifesiz filosunun, Dünya filosuna oranla daha çok dalgalandığı tespit edilmiştir. Buradan Turk tarifesiz filosunun, dünya filosuna göre daha çok rekabete açık olduğu ve risk barındırdığı sonucuna ulaşılmıştır. Her iki filonunda tam rekabetçi bir piyasada çalıştığı, araştırma sonuçları ile teyit edilmiştir. Türk tarifesiz filosunun ülke ekonomisine esas katkısının asıl görünmeyen kalemler bağlamında olduğu, özellikle Türkiye'de başlayan ve biten düzenli hat taşımalarında navlunları baskı altında tuttuğuna vurgu yapmıştır. Türk filosunun daha rekabetçi bir döneme girmesi muhtemeldir. Türk armatörlerine bu can sıkıcı durum karşısında başvurulabilecek tedbirler tavsiye edilmiştir. ABSTRACT This study aims to analyze the reaction of the Turkish tramp fleet against the overall oscillation in freights. In measuring the extent of this response, regression analysis has been deployed. The analysis has revealed that the fluctation of the Turkish tramp fleet has been higher than that of the world tramp fleet. The excess in fluctuation has raised an inference that the Turkish tramp fleet has been exposed to a tougher competitive and more risky environment. The relevant research has also revealed that both the world tramp fleet and the Turkish tramp fleet have struggled within a perfectly competitive market. The findings reached have emphasized the worthwhile contributions of the Turkish tramp fleet to the Turkish economy, particulary in terms of the invisible items and also in that it has established a strict control over the liner shipping freights, concerning the shipments loaded and discharged at the Turkish ports. Considering the likeliness for the Turkish tramp fleet to encounter a more severe competition, the study has put forward some proposals for the Turkish tramp owners to overcome any difficulties such a competition might bring about. VI 295

Maritime transport costs significantly impede international trade. This article examines why these costs are so high in some countries and quantifies the importance of two explanations: restrictive trade policies and private anticompetitive practices. It finds that both matter, but the latter have a greater impact. Trade liberalization and the breakup of private carrier agreements would lead to an average of one-third lower liner transport prices and to cost savings of up to US dollar 3 billion on goods carried to the United States alone. The policy implications are clear: there is a need not only for further liberalization of government policy but also for strengthened international disciplines on restrictive business practices. The authors propose an approach to developing such disciplines in the current round of services negotiations at the World Trade Organization (WTO).