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The aim is to evaluate the importance of developing and adopting the maritime spatial plan in a present situation characterized by competing uses of the marine environment and its resources. The authors applied qualitative research method based on direct observations, authors’ previous experiences and research, official documents, literature surveys and current research reports on the subject. The drafting and adoption of a maritime spatial plan with its accompanying strategic environmental assessment requires the involvement of experts, scientists, economic sectors representatives, and the public. The principles for good practice maritime spatial planning aimed at achieving environmental targets are presented, whereby focus is placed on land-sea interactions. Global coverage of the marine area by maritime spatial plans is constantly increasing, but the Republic of Croatia is lagging behind, it having as yet not adopted the maritime spatial plan for its sea. Analysis is made of the pressures on the Adriatic Sea and its eastern coasts, pointing to significant aspects to be contemplated holistically in drafting the maritime spatial plan which should be a prerequisite preceding any planning of economic activities along the coast, on sea surface, its column, sea bottom, and subsoil. In conclusion, maritime spatial planning should be seen as a mean for supporting healthy, productive, and rich biological resources in the sea, which are themselves vital for true economic well-being and that of the coastal communities.

The marine litter issue has been identified as one of major threats to marine ecosystems due to its environmental, economic, safety, health and cultural impacts. Marine litter is any persistent, manufactured or processed solid material discarded, disposed of or abandoned in the marine and coastal environment. It also consists of materials transported into the marine environment from land by rivers, drainage or sewage systems or wind. The presentation analyses the obstacles in resolving marine litter issue in the sea, the quantities and composition of marine litter, its sources, emphasizing the threat of plastics. It elaborates the approach to circular economy and waste management and presents proposals for circular flow of discarded resources. Analysis is made of how the United Nations Sustainable Development Goals and European Union Marine Strategy Framework Directive and other acquis address marine litter and of the quality of national waste management plan in the Republic of Croatia in respect of its approach to marine litter, as well as the efficiency of their implementation in Croatia where the Adriatic Sea is subject to substantial pressure from marine litter. Marine litter to a great extent mirrors waste management problem on the land. Also, considering the large number of pleasure craft and their ability to approach unspoilt secluded beaches and islands, these are regarded as a significant contributor to the marine litter problem. The aim of marine litter management is to ensure the prevention of discarding the waste into marine environment, of handling the waste in a way that it gets into marine environment and coastal area, the replacement of products harmful to marine environment, as well as the removal to the greatest possible extent of the existing quantities of marine litter in marine environment applying environmentally-friendly methods. The authors strive for sustainable and more resilient societies in line with circular economy where the value of resources is maintained in the economy for as long as possible.

Continuous efforts in marine industry are directed towards increasing energy efficiency and reducing environmental impact of ships. These efforts target mainly large ocean-going vessels. Due to higher power of their installed engines, their emission are higher as well. Small vessels in comparison produce lower emissions, but they should not be neglected. To fulfil this aim the holistic approach can and should be applied because it allows identification of the “weak link” in the ship power system. The analysis in this paper shows how inappropriate gear box ratio selection can deteriorate the operation of the propulsion system leading to lower efficiency and hence higher required power, fuel consumption and emissions.

The description of sound as a form of energetic pollutant is very complex as is also its impact on aquatic life. Human activities causing continuous and implosive underwater noise, such as marine traffic, maintenance of ships, coastal tourism, marine research, military, offshore energy platforms, generation of ocean energies and construction operations are expected to increase. The paper analyses current approach to minimise the impact of underwater noise and limit its emissions, examines regulatory approach and discusses the possibilities to control this type of pollution in order to ensure the preservation of natural underwater soundscape. The timely implementation and further development of the European Marine Strategy Framework Directive and its provisions related to underwater noise is of exceptional importance for the Adriatic Sea, which is facing increasing pressure from various industries generating underwater noise.

Continuous efforts in the marine industry are directed towards improving energy efficiency and reducing the environmental impact of ships. The strategic document in Croatia focusing on that topic is the Operational Programme for Maritime Affairs and Fisheries of the Republic of Croatia. Based on this Programme different measures are funded from the European Maritime and Fisheries Fund (EMFF). In this paper a special focus is put on measure I.20 Energy Efficiency and Climate Change Mitigation. Through this measure the installation of new diesel engines in fishing vessels is co-financed from the EMFF. The main requirement is that the power output of the new engine is lower than that of the replaced one. This paper discusses pros and cons of such approach, provides an insight in the technical characteristics of the current fishing fleet, and proposes improvements regarding the environmental policies in the marine sector.

Due to demanding IMO regulations on the ship EEDI, increased attention has been brought to the research of Energy Saving Devices (ESDs). Such devices offer an easy, fairly reliable and relatively cheap gain in a conservative shipbuilding industry where the applications of alternative sources of power are still at the initial phase. However, there is still no full insight for all ESD shapes and their correlation to ship operational profiles. This study aims to assess the direct impact of the currently most reliable ESD (the circular duct) on the EEDI and gas emissions. Unfavourable non-uniform inflow on the propeller plane is a known cause for generating vibrations and noise, but is also accountable for significant propeller efficiency losses. By measuring the propeller characteristics during the self-propulsion experiments in model scale, the influence of the ESD can be estimated on the full scale ship power demands. In this study two types of engines are compared and the reduction in power delivered from the main engine to the propeller shaft with the ESD employed is shown. The decrease in the final main engine power needs is used to further estimate the lowering of the gas emissions (carbon dioxide) and EEDI at minimum ship design modifications.

In the current practice, ship design is generally approached with the aim of keeping building-cost at the minimum, often forcing low-cost designs and low value-added market solutions. This is particularly true for small- size passenger vessels designed for short-sea shipping which are usually built by small shipyards which cannot sustain high costs of innovation and investments in education and research. In addition, unlike other transport modes, vessels are generally produced in small series and the investment cost has a strong impact on the initial vessel cost. Therefore, ships are often based on previous concepts and designs with essentially no modernization, thus leading to poor energy efficiency improvements, high vessel life-cycle costs and significant environmental impact. The new regulations in shipping sector demand energy efficiency improvements, but the stakeholders lack in providing support in achieving these requirements. In order to increase competitiveness, changes are required not only in individual stages of a shipbuilding process, but integrally throughout the production process. Conventional design and production paradigm can be changed by developing a modular concept in ship design. The aim of this paper is to determine the potential to reduce environmental pollution from ships and thereby the externalities by applying modular concept for small passenger ships in the Mediterranean. This new concept for a high-efficiency passenger vessel class can facilitate the design process, reduce the initial cost of more technologically advanced vessels by allocating innovation costs to units in a much larger series, and thus prove as a viable and sustainable alternative.

Studija obuhvaća analizu prethodne i trenutno važeće regulative za plovila unutarnje plovidbe u Republici Hrvatskoj i odabranim stranim zemljama (prema javno dostupnim podacima), s naglaskom na uvjete i načine oslobađanja od plaćanja trošarina na energente, te odgovarajuću komparativnu analizu. Obrađeni su podaci o floti unutarnje plovidbe, dostavljeni od naručitelja, pri čemu su plovila grupirana u odgovarajuće kategorije prema namjeni i tehničkim značajkama. Na temelju dostavljenih podataka, provedena je statistička obrada deklariranih podataka o potrošnji goriva i usporedba s dodijeljenim/odobrenim količinama. Prema tehničkim podacima flote i eksploatacijskim režimima predviđena je stvarna potrošnja goriva analiziranih plovila, odnosno referentne vrijednosti s obzirom na gospodarski učinak. Naposljetku, dan je fizikalno utemeljeni prijedlog korekcije postojećih kvota za oslobođenje od plaćanja trošarina.

In this paper, the noise predictions on board ro- ro passenger ship and self-propelled cutter suction dredger are performed, by means of the general noise assessment software Designer-NOISE which is based on the hybrid Statistical Energy Analysis. All typical noise sources in ships (main engine, auxiliary engines, propeller, HVAC, exhaust system, etc.) as well as the non-typical ones in the latter case (sand moving through the pipelines, winches, dredging pumps, etc.) are taken into account. The prediction is based on vessels drawings and noise source properties, both provided by the shipyard. The A-weighted noise levels are evaluated in the frequency range from 63 Hz to 4 kHz. From the regulation viewpoint, BV Guidance Note NI-174-DNC and IMO Resolution A.468 (12) were applied and conclusions on the ship noise performances are drawn.

Noise prediction on board Ro-Ro passenger ship with a capacity of 145 cars and 600 passengers has been performed by means of the hybrid Statistical Energy Analysis (SEA). A general commercial noise analysis software Designer-NOISE is used. Basic issues related to noise on board ships are described, with particular emphasis to regulatory framework. An outline of the used software is presented together with ship technical data and noise source overview. Noise model is described in details and results are presented for selected compartments both without and with sound insulation. In addition to standard noise prediction output, a sensitivity analysis of noise levels with respect to some design parameters (wall thickness, insulation type and thickness, etc.) has been performed. Finally, conclusions on noise performance of a ship are drawn.

This paper deals with the novel design methodology of modular passenger ships aimed for operation in the Mediterranean Sea. It actually outlines aims and methods of an ongoing long-term competitive Installation research project funded by the Croatian Science Foundation (CSF) which is based on the modular concept enabling the change of the ship production paradigm from the classical all-in-one approach to a parallel manufacture of different components by highly specialized producers and a final assembly done by the local shipyard. The target vessel is considered as made of independent modules which can be combined together to achieve different characteristics in terms of ship dimensions, carrying capacity, operability, comfort, fuel consumption and energy efficiency. Within the project, an analysis of the market needs and of the corresponding ship requirements is being performed for different navigation regions in the Mediterranean Sea. Then, the preliminary concepts based on that analysis are being proposed, while the final concepts will be developed taking into account all important aspects of ship design: resistance and propulsion, seakeeping, structural aspects, ship habitability, simplified manufacturing processes as well as environmentally friendly energy solutions. Through this project several optimized modular passenger vessels will be proposed depending on the selected design criteria sets. In this sense it is expected that the project will result in a number of concepts fitting to the market needs with reduced production costs, higher level of comfort for crew and passengers, reduced fuel consumption as well as lower environmental impact.

This work discusses techno-economic aspects of implementation of modular concept in the design framework of small passenger ships intended to satisfy rigorous environmental criteria together with ordinary design requirements. As indicated, the procedure is based on the modular concept enabling the change of the ship production paradigm from the classical all-in-one approach to a parallel manufacture of different components done by highly specialized producers and a final assembly done by the local shipyard. This approach has the ambition of achieving a design of a modular passenger vessel concept which goes beyond the simple payload criteria. It is structured in a way that enables the development of a set of solutions which cover a quite wide range of applications in short-sea shipping. The target vessel is considered as made of independent modules which can be combined together to achieve different characteristics in terms of ship dimensions, carrying capacity, operability, comfort, fuel consumption and energy efficiency. There are several advantages in such a wide set of combinations. The first immediate consequence is that, due to the flexible and easy adaptation of the concept to different requirements of passenger ships, each component can be produced in larger lots, justifying an improved design and making it cost effective. Also, the modularity allows a parallel production of the modules. This can change the approach to the production from local, small size, shipyards, which build the vessel in a sequential way, to highly specialized and large business size industries that manufacture the modules in large numbers and deliver them to for the final assembly. This investigation is a part of long- term project, where at first an analysis of the market needs and of the corresponding ship requirements is being performed for different navigation areas, which is actually a main subject of this presentation. Then, the preliminary concepts based on those outcomes are being proposed, while the final concepts will be developed taking into account all important aspects of ship design: resistance and propulsion, seakeeping, structural aspects, ship habitability, simplified manufacturing processes as well as environmentally friendly energy solutions. Through this project several optimized modular passenger vessels should be proposed depending on the selected design criteria sets. It is expected that the investigation will result in a number of concepts fitting to the market needs with reduced production costs, higher level of comfort for crew and passengers, reduced fuel consumption as well as lower environmental impact.

The Energy Efficiency Design Index (EEDI) is a technical measure introduced by International Maritime Organization (IMO) with a goal to improve the energy efficiency of ships. Attained EEDI value of a ship has to be lower than the Required EEDI determined by the EEDI reference line, which represents world fleet average for a certain ship type corrected by an appropriate reduction factor. Although in last several years total number of ultra large container ships (ULCS) significantly increased, for the time being their presence in the world fleet is not taken in to account properly in the Required EEDI formulation for container vessels. Consequently, in most cases it makes existing EEDI criteria relatively irrelevant for the design of ULCS, while at the same time the EEDI criteria could be difficult to meet in case of smaller container carriers. In this paper several issues related to EEDI assessment for container vessels is discussed. First, recent advances in container ship design and operation are outlined. Secondly, the effect of ship size on the EEDI requirements is analysed. Third, the existing baseline formulation is updated with new ULCS data available in the IHS Fairplay database. Further, ship speed (slow steaming) influence on EEDI is considered, and as a potential step in more fair comparison of vessels within the certain type, EEDI reference surface is offered. Since in the container transportation business most of the parameters are expressed per TEU, here EEDI performance with respect to capacity in TEU is shown. Finally, importance of EEDI in the overall design procedure for container carriers is addressed.

Transportation sector, including maritime transport, exerts significant environmental impact. Public procurement as a policy strategy instrument which applies to the purchase of transport means, construction of infrastructure and the provision logistic services in supplying the goods, services and executing of works must integrate environmental considerations in the contract award procedures. The aim of this paper is to propose an environmental life- cycle costing (LCC) method that could be used to assess integral environmental impact of different marine power systems, including integrated and hybrid power systems, for the purpose of public procurement. While conventional LCC is based on four categories to be assessed e.g. investment, operation, maintenance and end-of-life disposal expenses, the environmental LCC method also takes into account the external environmental costs. This method is universally applicable and provides a fair basis for evaluating ships energy efficiency and environmental impact. The authors advocate clean and energy-efficient maritime transport ensuring effective implementation of environmental policy objectives and targets and emphasize the role of public authorities and entities in fostering the inclusion of environmental externalities in calculation of LCC.

Suvremena rješenja u razvoju brodskih energetskih sustava (BES) zasnivaju se sve češće na integriranim energetskim sustavima (IES), čija je glavna značajka centralizirana proizvodnja ukupno potrebne količine električne energije korištenjem raznovrsnih pogonskih strojeva i uređaja, primjena elektromotornih propulzijskih sustava i visoki stupanj utilizacije otpadne toplinske energije. Sadašnje normativne metode za ocjenu energetske učinkovitosti i ekološke prihvatljivosti BES-a temelje se na Projektnom indeksu energetske učinkovitosti (eng. Energy Efficiency Design Index – EEDI) koji je definiran kao relativni omjer između ekvivalentne emisije CO2 i pripadajućeg gospodarskoga učina broda. Iskustvo u primjeni EEDI-a pokazuje da nije primjenjiv za IES-e. U sklopu ovoga doktorata analizirana je povezanost različitih parametara koji utječu na energetske i ekološke značajke različitih konfiguracija IES-a. Na temelju te analize definirana je metodologija pomoću koje se u brodograđevnoj praksi može valorizirati indeks energetske učinkovitosti i ekološke prihvatljivosti (eng. Index of Energy Efficiency and Environmental Eligibility – I4E) različitih konfiguracija BES-a (uključujući IES-e). Primjenom I4E na flotu ro-ro putničkih brodova pokazano je da je integralni utjecaj brodova s IES-ima na okoliš manji od brodova s konvencionalnim BES-ima. Modern approach to the marine power system design is more often based on integrated power systems. These systems are characterized by the centralized production of the electrical energy from different prime movers, application of the electrical propulsion system and a high utilization factor. Current regulations introduced Energy Efficiency Design Index (EEDI) as a technical measure to increase ships efficiency. The methodology of EEDI calculation is based on the relative CO2 emission from ship power system and on the benefit for the society. This methodology is not applicable for integrated power systems (IPS). Hence, the analysis of different parameters influencing ship energy efficiency and overall environmental impact is performed. A new model is defined that can be widely used to evaluate the ships energy efficiency and environmental impact through the Index of Energy Efficiency and Environmental Eligibility (I4E). By calculating the I4E for a fleet of ro-ro passenger ships it has been observed that ships with IPS have lower overall environmental impact than ships with conventional power systems.

It has been five years since the inclusion of chapter 4 to MARPOL Annex VI and the introduction of the International Energy Efficiency Certificate (IEE Certificate). To obtain it, every ship has to satisfy the Energy Efficiency Design Index (EEDI) requirements. It requires that for every new ship the Attained EEDI has to be calculated and not higher than the Required EEDI calculated as a function of capacity. For most ship types the deadweight (DWT) proved to be appropriate measure of capacity, but not for ro-ro passenger ships. The capacity for these ships can be defined by several parameters besides DWT, like: GT, lane meters, number of cabins, number of passengers etc. All these parameters indicate primarily the volume the ship can transport, and not the mass. But two years ago, the EEDI was modified in order to include the ro-ro passenger ships. Even though many studies concluded that the DWT was not appropriate measure of capacity for ro-ro passenger ships, the definition of the Required EEDI based on the DWT was still adopted. Also two new correction factors fjRoRo and fcRoPax were included in the calculation of the Attained EEDI. Their role was to ensure at least some level of statistical correlation when applying the EEDI for the current ro-ro passenger ships fleet. Even though the current approach has some limited statistical correlation, it does not evaluate fairly ships capacity. In this paper the current ro-ro passenger ships fleet is analyzed and a new approach is proposed in which the capacity is defined in GT. This would then allow a fair comparison between different ro-ro passenger ships.

Piston rings are essential parts of all modern internal combustion engines and their properties significantly affect the engine reliability and exploitation life. Roles of a piston ring are: sealing the engine combustion chamber, minimization of the frictional losses against the cylinder liner, evenly distribution of oil along the cylinder liner and transfer of the heat from the piston. This paper deals with the strength assessment of a compression ring of a two stroke crosshead marine diesel engine in the mounting procedure. Namely, during the mounting the ring should be expanded by the appropriate device, which can cause significant bending moments and consequently plastic deformations. The aim of the paper is to examine selected available methods for the strength assessment of a ring to improve its mounting procedure. Two approaches are used to calculate the stress levels, i.e.: energy approach based on the 2nd Castigliano's theorem as well as widely used commercial FEA tool employing four-node solid elements. Based on the obtained numerical results family of curves determining allowable ring deflection with respect to the ring diameter and its width are drawn.

This paper deals with the application of integrated power systems in small passenger ships. Namely, integrated power systems were up to now mostly used in naval and large passenger ships, primarily for financial reasons. However, despite their complexity, such systems allow for much more versatility and their application in small passenger ships seems to be advisable in the context of environmental issues. Environmental aspects of maritime transportation are discussed, the needs for environmentally-friendly ships in the Adriatic Sea are elaborated and a review of actual IMO Regulations is provided, pointing out the effects of introducing new fuel-efficient and electrified ships. Different power systems of a ferry operating in the Adriatic Sea are analyzed in detail, with particular emphasis on gas emissions. Direct mechanical propulsion system and integrated power system in real operating conditions are considered and some advantages and drawbacks of both are examined. Finally, discussion of the results is presented and valuable conclusions are drawn. It should be mentioned that selection of proper power system, based on a holistic approach, can significantly reduce environmental pollution without affecting ship operational characteristics.

U cilju poticanja razvoja suvremenih tehnoloških rješenja koja doprinose poboljšavanju energetske učinkovitosti i unapređenju zaštite okoliša IMO Rezolucijom MEPC.203(62) donosi izmjene MARPOLa, Prilog VI. Izmjene stupaju na snagu 1. siječnja 2013. godine, a odnose se na obavezu uključivanja pravila za utvrđivanje i kontrolu energetske učinkovitosti u nacionalna pravila registara, kojima se propisuje obavezna primjena Projektnog indeksa energetske učinkovitosti (EEDI) i Brodskog plana upravljanja energetskom učinkovitošću (SEEMP). Kao dokaz ispunjavanja tih zahtjeva, brodu se izdaje Međunarodni certifikat energetske učinkovitosti (IEEC), koji postaje obaveza za sve brodove u međunarodnoj plovidbi čija je nosivost ≥ 400 GT. Namjera uvođenja tih mjera je povećanje energetske učinkovitosti broda korištenjem projektnih i operativnih mjera te smanjenje emisije stakleničkih plinova.

International Convention for the Prevention of Pollution from Ships (MARPOL), Protocol-Annex VI has been changed by IMO by the Resolution MEPC.203(62) with particular aims to improve energy efficiency and reduce environmental pollution. The above mentioned rules prescribe Energy Efficiency Design Index (EEDI) assessment as well as Ship Energy Efficiency Management Plan (SEEMP). Although the general expression for ships EEDI calculation seems to be very simple, there are still too many questions and doubts that should be answered prior to its wide and inevitable application in the ship design. This is especially pronounced in the case of Ro-Ro and Ro-Pax ship types. By introducing this criterion in their design procedure, there is a risk of affecting the main design parameters of the vessels in such a way that in the future it could be almost impossible to fulfill them. The paper deals with the possible modifications and adjustments of the proposed methodology, with particular emphasis on Ro-Pax ships. The general formula for EEDI calculation is analyzed term by term and properly commented, and also considerations on some parameters that should be taken into account, at least in the author's opinion, are given.

U cilju poticanja razvoja suvremenih tehnoloških rješenja koja doprinose poboljšavanju energetske učinkovitosti i unapređenju zaštite okoliša IMO Rezolucijom MEPC.203(62) donosi izmjene MARPOL-a, Prilog VI. Izmjene se odnose na obavezu uključivanja pravila za utvrđivanje i kontrolu energetske učinkovitosti u nacionalna pravila registara, kojima se propisuje obavezna primjena projektnog indeksa energetske učinkovitosti (EEDI) i brodskog plana upravljanja energetskom učinkovitosti (SEEMP). Dosadašnje iskustvo u primjeni formule za odreñivanje EEDI-a pokazuje da je potrebno prilagođavati vrijednosti i dopunjavati broj utjecajnih faktora ovisno o tipovima brodova i o njihovim specifičnim projektnim i eksploatacijskim značajkama. U radu su analizirani nedostaci primjene trenutno važeće (strukture) formule za odreñivanje EEDI-a. Za ro-pax brodove su posebno analizirani parametri za koje se smatra da značajnije utječu na vrijednost EEDI-a, a proizlaze iz različitih specifičnih projektnih i eksploatacijskih značajki tih brodova.

Osnovni ciljevi razvoja modernih brodskih energetskih sustava su povećanje energetske učinkovitosti i pouzdanosti te ispunjavanje kriterija ekološke prihvatljivosti. Kriterij ekološke prihvatljivosti je posebno izražen kod putničkih brodova, trajekata, brodova za unutarnju plovidbu, itd. gdje problemi utjecaja na okoliš postaju sve važniji projektni kriterij. U članku je prikazan idejni projekt hibridnog energetskog sustava višenamjenskog putničkog broda, koji se sastoji od dizelskog motora, gorivnog članka i baterije kao izvora električne energije. Za tipične režime plovidbe odabranog broda određena je energetska bilanca. Uz analizu energetske učinkovitosti i ekološke prihvatljivosti, zaključno su istaknute prednosti i nedostaci predloženog rješenja u odnosu na klasične izvedbe brodskih energetskih sustava sa smjernicama za daljnja poboljšanja.

U radu su analizirani zahtjevi kojima ulja za brodske motore moraju udovoljiti. Posebna se pozornost posvetila, ne samo općenitim zahtjevima kojima trebaju udovoljiti sva industrijska ulja, već i specifičnim zahtjevima zbog korištenja ulja u uvjetima sagorijevanja teških ostatnih goriva s povećanim udjelom sumpora i vanadija. Dana je i ekonomska usporedba troškova plovidbe na destilatno i na ostatno gorivo. Razrađen je i osnovni princip rada sustava za podmazivanje, a priložena je i shema sustava za podmazivanje s opisom i određivanjem bitnih karakteristika pojedinih komponenti. Prikazana su brojna poboljšanja konstrukcije motora koja su potaknuta željom za usavršavanjem procesa izgaranja i potpomaganja sustava podmazivanja. Ukratko su prikazane i metode kontrole viskoznosti ulja.

U priloženom su radu opisane izvedbe sustava hlađenja brodskih motora. Tipično se brodski motori hlade morskom vodom u protočnom sustavu, ili slatkom vodom u središnjem sustavu hlađenja. Prikazane su sheme obje izvedbe sustava hlađenja s objašnjenjem funkcija pojedinih komponenata. Analizirani su i problemi koje morska i slatka voda stvara u cjevovodima broda, a uz to su i objašnjeni načini zaštite od korozije. U radu je napravljena usporedba prednosti i nedostataka protočnog i središnjeg sustava hlađenja., The attached paper describes the cooling systems of marine engines and their schemes with an explanation of individual components of different cooling systems. Problems caused by seawater and freshwater in the ship's pipelines alongside methods of corrosion protection. The paper contains a comparison of systems with advantages and disadvantages of direct and central cooling systems.

U radu se daje uvid u osnovne zadaće i značajke propulzijskih podsustava te je ukratko opisana njihova povijest razvoja. Osnovna zadaća porivnog sustava je stvaranje sile poriva potrebne kako bi se brod gibao zadanom brzinom – plovio. Rad prikazuje metodologiju proračuna porivnog sustava broda. Za stvaranje poriva potrebno je na brod ugraditi propulzijski sustav koji se sastoji od tri podsustava: pogonskog stroja, prijenosnika snage i brodskog propulzora. Završni rad prikazuje kako promjena pojedinih dijelova i zahtjeva propulzijskog sustava utječe na rad ostalih propulzijskih podsustava, te je prikazano kako promjena prijenosnog omjera reduktora utječe na porivni sustav broda., The paper provides insight into the basic tasks and features of propulsion subsystems and briefly describes their development history. The basic task of the propulsion system is to create the propulsion force necessary for the ship to move, or sail, at a given speed. The paper presents the calculation methodology of the ship's propulsion system. In order to generate thrust, it is necessary to install a propulsion system on the ship, which consists of three subsystems: the propulsion engine, the power transmission and the ship's propulsor. This paper also shows how the change of individual parts and requirements of the propulsion system affects the operation of other propulsion subsystems. Lastly, it is shown how the change in the transmission ratio of the reducer affects the propulsion system of the ship.

U ovome radu analizira se ciklus parno – turbinskog postrojenja i svih elemenata koji tvore taj sustav. Nastavno na postupni porast povećanja broja stanovništva u svijetu, ukazuje se na važnost termoelektrana te se prikazuje gradnja i značaj same TE Plomin. Nakon toga prikazuje se općeniti parno – turbinski ciklus te je detaljno objašnjen putem T-s i h-s dijagrama. Ukazuje se na prednosti i nedostatke takvog procesa te je izračunata korisnost cijeloga ciklusa kao i korisnost samoga kotla. Potom se opisuju glavni elementi koji tvore sustav TE Plomin poput sustava mlinova, generatora pare, parne turbine, kondenzatora kao i postrojenja za odsumporavanje i postrojenja za obradu otpadnih voda kojima se bitno utječe na zaštitu okoliša. Zatim slijedi prikaz značajki termoenergetskog postrojenja te analiza i mogućnost poboljšanja samog postrojenja., This paper analyze the cycle of the steam – turbine plant and all the elements that form that system. Because of the progressive increase in the number of world´s population, this paper indicates the construction of the thermal power plants and its importance. More precisely the thermal power plant Plomin. Furthermore, it is presented and explained the general steam – turbine cycle by T-s and h-s diagrams. The advantages and disadvantages of such a process are point out, as well as the usefulness of entire cycle and the usefulness of the boiler itself. Further more, there are described the main elements that build the Plomin thermal power plant system. In other words the mill system, steam generator, steam turbine, condenser and the desulphurization plant, as well as the wastewater treatment plant which has significant impact on environmental protection. Overall are presented the features of the thermal energy plant as well as analysis and possibility of improving the plant itself.