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.

Computerized maintenance management systems (CMMSs) are software packages that support or organize the maintenance tasks of assets or equipment. They are found in the background of any ship maintenance operation and are an important part of maintenance planning, spare parts supply, record keeping, etc. In the marine market, there are a number of CMMSs that are competing fiercely to program a better and more modern program that will capture the market, which has been accompanied by published analyses and scientific papers. At the same time, the quality of the data entered into CMMS databases is questionable, a fact that has been ignored in practice and scientific circles; until recently, there were no published analyses and there was no way to measure the quality of the data entered. This article presents two proposals for improving the quality of CMMS databases and calculates their potential benefits. By implementing the first proposal, the evaluation methodology for the ship’s Planned Maintenance System database, between 10% and 15% of databases will have significant financial or safety benefits. This measure will also have an impact on more than 40% of the other databases that can also be improved. The second proposal will have a smaller impact of only 4%. The overall benefit of these proposals is to improve more than 60% of the databases and will result in a significant increase in safety or financial savings.

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 describes an evaluation methodology for ship’s Planned Maintenance System database based on the application of a newly created questionnaire and the analysis of the evaluation results received by the questionnaire. The evaluation results of several databases and the analysis of evaluation results are also shown in the paper. The main purpose of the paper is to provide a simple and useful tool for the evaluation of all ships’ Planned Maintenance System databases, which will enable users to examine the data in the database and discover the areas where the database and maintenance can and must be improved. The expected outcome of the described methodology for the evaluation of ship’s Planned Maintenance System database can be described as: - Evaluating ship’s Planned Maintenance System database- Performing ship’s Planned Maintenance System database diagnostics to indicate insufficiencies- Determining the area and mode for ship’s Planned Maintenance System database quality improvement and, consequently, overall improvement of the maintenance and reliability of ships’ systems,- Setting up a standard for the development and evaluation of computerized database for ship’s planned maintenance,- Determining problems which occur during database development and describing complexity of the development process.

Marine propulsion shafting systems are exposed to torsional vibrations originating from excitations in their prime movers and propellers. It is essential to analyse their steady state response in the earliest stage of ship design. The paper describes the implementation of SimulationX software based upon simulation modelling for these calculations. This software can be used either by the design office of the shipyard or by the classification society for verification within the plan approval phase. Some specifics of the input data preparation are briefly discussed. In addition, the simulation results depend on the modelling approach chosen. For these reasons, the real two-stroke Diesel engine ship propulsion system was chosen and several different models were implemented for system modelling. SimulationX calculation results are compared with those of two well-known and field-proven programs that use an analytical approach. Finally, the results are compared with the measurements performed on the actual newly built ship. Discussion reviews the selected SimulationX model, and its verification and validation in the case of engine cylinders with normal ignition.