The reliability of marine propulsion systems depends on the reliability of several sub-systems of a diesel engine. The scavenge air system is one of the crucial sub-systems of the marine engine with a turbocharger as an essential component. In this paper, the failures of a turbocharger are analyzed through the fault tree analysis (FTA) method to estimate the reliability of the system and to predict the cause of failures. The quantitative method is used for assessing the probability of faults occurring in the turbocharger system. The main failures of a scavenge air sub-system, such as air filter blockage, compressor fouling, turbine fouling (exhaust side), cooler tube blockage and cooler air side blockage, are simulated on a Wärtsilä-Transas engine simulator for a marine two-stroke diesel engine. The results obtained through the simulation can provide improvement in the maintenance plan, reliability of the propulsion system and optimization of turbocharger operation during exploitation time.

This paper estimates the exhaust gases emissions from ships in the international marine traffic in the port of Zadar. The emission results refer to the pollutants such as nitrogen oxides (NOx), sulphur oxides (SOx), particulate matter (PM), volatile organic compounds (VOC) and greenhouse gases such as carbon dioxide (CO2). The methodology that has been applied, so called “bottom-up” approach, uses detailed data on ship’s characteristics (engine power, the load factor, fuel type, the emission factor) and time spent cruising and hotelling. The estimated inventory for the port of Zadar includes overall marine traffic from the passenger and cargo terminals. The exhaust gases emissions have been divided into three ship’s activities: cruising in the reduce speed zone, hotelling (at berth) and manoeuvring. The results (tons/year) have shown that approximately 80% of total emissions come from passenger ships and 20% from cargo ships.

This paper presents a method of adjusting and designing the maintenance scheme for the high-pressure fuel pumps of a slow-speed two-stroke marine engine, MAN 6S70MC-C. The maintenance database for the marine fuel system was obtained from the planned maintenance software, and covered a period of 11 years. During this period, 29 failures occurred that required corrective actions. Our methodology includes failure mode analysis, risk analysis, reliability calculation and maintenance interval adjustment. Each failure is described using a failure mode analysis, based on a combination of the mode and cause of failure. The objective of this study is to recommend a new preventive maintenance interval based on the exponential reliability results and the analysed maintenance data. The initial maintenance plan for each fuel pump was set to 8,000 running hours, whereas in the modified plan, it is recommended to set this to 4,000 hours. Our results show an increase in the system reliability from 60% to 95% when the new modified maintenance plan is applied. In addition, the results and the recommended initial maintenance schedule are validated based on three similar types of engine with the same fuel pump system. The new maintenance approach can reduce the risk of component failure, which will lead to increased reliability of the fuel pump system and the optimisation of maintenance costs.

The paper estimates the exhaust emissions of marine traffic in the port of Šibenik. The results of the analysis were obtained by including the following gaseous pollutants: nitrogen oxide (NOX), sulphur oxide (SOX), particulate matter (PM), volatile organic compounds (VOCs) and carbon dioxide (CO2) as greenhouse gas. In order to gain results and estimate the emission of harmful gases in the port of Šibenik, the passenger and the cargo throughput were taken into account. The activities of the ship during which the exhaust gases are emitted into the atmosphere are slow cruising in the reduced speed zone, manoeuvring and hotelling. The “bottom-up” method used in the emission estimation takes into account the ship’s engine power, engine load factor, fuel type, the emission factor, time of cruising and time hotelling in the port of Šibenik. The results of the analysis have shown that approximately 70 % of total emissions come from passenger ships (cruise ships) and 30 % from cargo ships.

Increasingly stringent environmental requirements for marine engines imposed by the International Maritime Organisation and the European Union require that marine engines have the lowest possible emissions of greenhouse and harmful exhaust gases into the atmosphere. In this research, exhaust gas emissions were measured on three Ro-Pax vessels sailing in the Adriatic Sea. Testo 350 Maritime exhaust gas analyser was used for monitoring the dry exhaust gas concentrations of CO₂ and O₂ in percentage, concentrations of CO and NO_x in ppm and exhaust gas temperature in °C after the turbocharger at different engine loads. In order to compare and validate measured values, exhaust gas measurement data were also obtained from a Wartsila-Transas simulator model of a similar Ro-Pax vessel during the joint operation of the engine room and navigational simulators. All analysed main engines on three vessels had complete combustion processes in the cylinders with small differences which should be further investigated. Comparison of on board measured parameters with simulated parameters showed that significant fuel oil reduction per voyage could be accomplished by voyage and/or engine operation optimization procedures. Results of this analysis could be used for creating additional emission database and data-driven models for further analysis and improved estimation of exhaust gasses under various marine engine conditions. Additionally, the results could be useful to all interested parties in reducing the fuel oil consumption and emissions of greenhouse and harmful exhaust gases from vessels into the atmosphere.