Charge air cooling is essential for the efficient operation of marine diesel engines. This work presents the results of research on the characteristics of long-range heat transfer surfaces for marine diesel engines. Elliptical and flat-oval tubes were considered. This study was carried out using mathematical models that consisted of the equations for energy conservation, motion, continuity, and state. The RSM turbulence model was used to close the system of equations. To solve the resulting system of equations, the RANS approach was used, which was implemented in the software package Code Saturne with a free license and the SimScale cloud service. The mathematical model was verified by comparing the model results with the experimental results obtained using a prototype heat-exchange surface of a charge air cooler at a test bench. The discrepancy between the theoretical and experimental heat transfer coefficient α was ≤ 8.3%. An estimate of the compactness of smooth elliptical and flat-oval tube banks compared with round ones was carried out. A 19.6% increase in compactness was obtained for elliptical tubes and 17.5% for flat-oval tubes. Based on the profiled finning surfaces, it is possible to improve their thermohydraulic characteristics by up to 40% when using them together with elliptical tubes compared with round ones and up to 26% when using them with flat-oval tubes.

In Europe, at the end of the 20th century, the growth of marinas followed the rapid development of recreational marine activities. This trend has now slowed and today the creation of new marinas or the extension of existing marinas is less common, mainly due to the enforcement of protective environmental regulations. As the port sector is facing some major sustainability challenges, like tackling the pollution generated from port activities, the “green port”, or “green marina”, concept has now become a requirement. Both types of nautical ports, public ports and private marinas, share the same responsibility to achieve management standards. The term “green port” in practice describes the responsible behavior of all stakeholders in the port’s business, with a focus on the long-term vision towards the sustainable and climate-friendly development of the port’s infrastructure. This paper aims to confirm the adequacy of multi-criteria analysis (MCA) for the evaluation and introduction of energy efficient mobility options in nautical ports. Within the paper, a multi-criteria based model for energy- efficient mobility selection is presented. This model is tested on two Croatian private marinas and obtained results indicating the most suitable action for both. The output of the model showed that by far the best energy- efficient solution was the installation of electric charging stations (ECS) for cars. The presented model can assist decision-makers in port authorities and marina administrations in planning and finding the best scenario for the development of energy efficient systems and services.

Abstract This paper examines the factors affecting the performance of VTS operators. A general review of the human factor as a determinant of navigational safety is presented. The elementary nature of the system and its structure are defined, and the ability of a VTS operator to perform planned tasks within a specified timeframe and in a specific manner is analyzed. A reliability assessment scheme is proposed, which is based on the interpretation of factors affecting the VTS operator’s efficiency. The effective performance of VTS operators, along with the specific nature of the maritime environment and reliability of the vessel traffic management support, are key determinants in the process of ensuring the reliability and security of the entire system.

Presented are regulations concerning the operation of passenger ships (with particular emphasis on Polish ferries) designed to increase maritime safety the SOLAS Convention, established in 1974 and codified in 2002, codifies these regulations, and the International Maritime Organization mandates additional regulations, created in response to a rapidly increasing number of maritime disasters. The analyses described herein were based on restrictions established for the “Jan Śniadecki” and “Mikołaj Kopernik” ferries. Safety of ro-ro units, which also typically have a significant number of people on board, was also analyzed. Also included in the study were ship operational- limitation characteristics with respect to structure, unsinkability, and stability of machinery and electrical equipment, fire protection, operational requirements, and rescue measures and devices, along with their purpuroses. Safety management consists of taking appropriate actions to prevent or minimize the effects of an accident or a disaster and is assessed on the basis of calculations and experience gleaned from analogous cases. Safety management can proceed if a problem has been thoroughly assessed. The potential risk of negative consequences with respect to the safety of the transport process as a whole must be considered, and the safety of the whole must not be risked for that of a particular part of it. A safety management decision can be made when its necessity is not in doubt. A problem is assumed to have only one solution. The effectiveness of the previously used method should be carefully assessed before proceeding to the next method. Security management is not easy and requires much professional knowledge and experience.

In this paper, a special configuration for the huge multipurpose machine tool of “travelling column” type was investigated by the finite element analysis. Internal degrees of freedom of a bulky system consisting of the ram, stock, column, sledge and bed, were implemented by the hydrostatic guides. A simulation of coupling two assembled columns into the portal structure was completed. The results of this work showed that temporal joining raises the spindle static rigidity by 1.39–1.91 times depending on the direction (mostly longitudinal – along the X-axis). The simulation also revealed the robustness of a whole-machine resonance pattern (11.7–39.0 Hz) to “column–to–portal coupling”. Eight types of eigenmodes were analyzed for frequency intervals from 0 to 80 Hz. A decrease by 2.9 times of the resonance peaks of a frequency response function was observed in the case of a portal structure creation. In case of columns-to-portal transition, stable cutting just at resonance frequencies (resonance overriding) becomes allowable. Overall, the “Portal” structure is recommended for intermittent cutting machining by raised high spindle unit at frequencies below 40 Hz.

The hydrodynamic performance of trimaran hulls has been previously investigated for optimum performance in calm water, but there is still a limited understanding of its motion response; therefore, a CFD-based numerical approach was developed and applied on a trimaran hull in the presence of regular and irregular waves. To validate the CFD method, a comparison was conducted using both experimental and 3D panel method data. In this study, two different turbulence models were surveyed, and the SST Menter k-Omega (k-ω) turbulence model was shown to be a more accurate model than the realizable k-Epsilon (k-ε) model. The different features of the proposed numerical model include the implementation of an overset mesh method, unique mesh plan refinement, and wave-damping region. The discrepancy between the experimental data and the results of other seakeeping calculation methods have always been problematic, especially for low-speed strip theory and 3D panel methods, but good consistency was observed between the proposed CFD model and experimental data. Unlike potential-based or conformal mapping seakeeping analysis methods, the effect of nonlinear waves, hull shape above the waterline, and other ship dynamic phenomena were considered in this CFD application. The proposed CFD method reduces the simulation time and computational efforts for ship motion calculations.

Dear Readers, I am pleased to present the fourth 2020 issue (No. 64) of the Scientific Journals of the Maritime University of Szczecin. This issue contains the research results and views of the authors of seven articles that are compiled into three subject groups: Civil Engineering and Transport; Mechanical Engineering; and Economics, Management and Quality Science. The Civil Engineering and Transport section begins with an article that examines the relationship between the occurrence of failures in selected types of buses and the time of their occurrence using the public transport of Lublin as an example. The second article presents the current state of research on the technical, legal and administrative problems that need to be solved in order for unmanned ships to be used widely by society. There are four papers in the Mechanical Engineering section. The first paper presents a numerical study of the hydrodynamic parameters of a modified hourglass-type FPSO (Floating Production, Storage and Offloading) ship with different geometric parameters. The second paper evaluates the atmospheric composition after degassing and ventilating a ship’s cargo tank after a washing process with reference to the entrance and its visual inspection The author of the third article presented methods of joining (welding and sealing) single-polymer composite materials in a hot air stream. The last study in this section determined the vibration- activity parameters of a hermetic harmonic drive to evaluate a gearbox in terms of its manufacturing quality and wear-related deterioration. The third section, Economics, Management and Quality Science, contains one article. The article synthetically presents the process of financing investments related to the construction and purchase of ships, presenting, among other things, the concept of shipbuilding cycles and the relationship between the shipbuilding industry and the shipping market. The articles presented demonstrate the authors’ continuing practical inspiration and contribute to interesting scientific inquiry. I am aware that the presented articles are only a modest expression of these ideas, but believe that they will provide a basis for reflection, discussion, and broader research. dr

This paper discusses the problem of atmosphere composition assessment related to entrance and inspection of a vessel cargo tank after washing, gas-freeing and ventilation. A correct assessment of the atmosphere before an entrance into the cargo tank or other enclosed spaces is a basic condition for the possibility of safe crew working. An assessment of the flammability hazard, presence of toxic or dangerous gases for human, and the oxygen concentration should be completed. In this regard, the ship-owner should prepare adequate procedures before an entrance, during work, and in emergency situations. The officers responsible should perform an assessment onboard the vessel their decisions are crucial for the safety of successive operations. A proper assessment of oxygen concentration in the air into the cargo tank or an enclosed space after the measurement is one of the primary problems which should be properly interpreted. This concerns such situations when the measured oxygen concentration into the tank reaches the value over 22% and below 20.6% of volume (mole) contribution (v/v). Air temperature in the 5–25°C range may create additional threats. This manuscript clarifies the controversial information included in manuals concerning the safety of entrance into enclosed spaces on vessels and the ship-owners procedures concerning the safety precautions for preparing, entrance, protection, and work inside the cargo tanks.

The aim of this study was to examine the relationship between the occurrence of selected types of failures and the time and season of their occurrence in public transport buses in the city of Lublin. The analysis was carried out for buses operated in the Municipal Transport Company within the past 3 years. The chi-squared analysis showed that during operation, there are significant differences between the failures and the annual season, but there are no differences between the frequency of failures and the time of day.

This paper presents a numerical investigation of the hydrodynamic performance of a modified sandglass-type FPSO (Floating Production, Storage and Offloading) with different geometrical parameters. The influence of the roll damping plate on heave and pitch motions of the FPSO was studied in regular waves. To estimate the hydrodynamic performance and utilize the results on the design stage of the FPSO, the boundary element method (BEM) was used. Furthermore, the hydrodynamic performance of two cylindrical and sandglass-type FPSOs under the same conditions was compared in different waves. Five sandglass-type FPSOs with dissimilar inclination angles were utilized with the constant draft. The effects of different inclination angles, including various radii of water-plane part of the floating object on hydrodynamic responses and wave forces applied to the FPSO, were investigated, and presented here. Numerical results were compared against published experimental data of a sandglass-type model, and good agreement was achieved. Based on the simulation results, a conclusion that a sandglass-type FPSO with the inclination angle of 35 degrees proposes proper hydrodynamic performance in both heave and pitch motions for all ranges of wave frequencies was reached. In addition, as it was predicted, the effect of heading sea on a sandglass-type FPSO was significant compared to other wave directions. Finally, by adding a damper plate to the floor of the platform, its hydrodynamic performance is improved. For numerical analysis of the modified FPSO, three different damper sizes are used to investigate its effect on the reduction of the pitch motion amplitude in waves.

Unmanned, remotely or autonomously ships are the fastest growing new technology in maritime transport in recent years. The design of unmanned vessels envisions clean, emission-free electric propulsion. The costs of building physical models and target vessels are high, but the expected benefits are generating increasing interest in such vessels. This article presents the current state of research in the field of unmanned ships and the technical, legal and administrative problems that need to be solved in order for these ships to be used by the general public.

The aim of the article is a synthetic presentation of the complex process of financing investments related to shipbuilding and purchase. The first part presents the concept of shipbuilding cycles and the relationship between the shipbuilding industry and the shipping market. The paper then reviews the concepts and literature related to the shipbuilding industry, shipbuilding financing, and ship purchase. Lastly, the current state of the shipbuilding market is described. The results of the analysis indicates possibilities of financing the purchase of new vessels including mortgage bonds.

Dear Readers, I am pleased to announce the publication of the third edition (63(135)) of the Scientific Journals of the Maritime University of Szczecin in 2020. This edition contains the findings and opinions of the authors within thirteen articles, which are grouped into six fields: Civil Engineering and Transport, Environmental Engineering, Mining and Energy, Electrical Engineering, Mechanical Engineering, Economics, Management and Quality Science, and Information and Communication Technology. The Civil Engineering and Transport section begins with an article in which the authors provide an FMECA for a thermal deburring machine of a Slovak company to develop an efficient maintenance policy. The second article also covers maintenance issues by addressing freight cars used in railway transport. The authors used railroad car operation, maintenance, and failure data to establish a methodology to calculate the probability of failure and thereby determine the risk levels in the rolling stock maintenance policy. The author of the third article noted that the continued growth of transport systems and the extensive activities related to the system user safety require the development of methods to assess how the extension or upgrading of road infrastructure impacts road safety. The author aimed to develop an assessment concept that will form part of a comprehensive methodology for analyzing the operational reliability of transport systems. Conceptualized in the article is an assessment of the impact of road infrastructure on road safety that refers to the GAMAB and Road Safety Impact Assessment methods reported in the literature. The concept is based on a comparative analysis of the state of road infrastructure before and after expansion or upgrades, based on publicly-available data. The last article in this section deals with digitization, one of the most urgent modern determinants of economic activity. The authors consider the digitization of transport as a tool for achieving the European Union’s policy objectives set out in the Digital Single Market Strategy for Europe. For railway transport, digital innovation is necessary to increase its competitiveness, and one of the tools for the digital transformation of the railway is the fifth-generation of wireless communication systems (5G). The purpose of this article is to show the advantages of 5G deployment for railway operators. It describes unique flexibility in the allocation of 5G network resources, depending on the existing needs of rail traffic. The Environmental Engineering, Mining and Energy section contains study, that elaborates on the modern technologies used for the production and utilization of methanol. Particular attention was paid to technology for energy storage in the form of “renewable” methanol generated from hydrogen produced using renewable surplus energy or from captured CO2. The paper presents a methanol production and treatment plant and a methodology for assessing the plant efficiency. The Electrical Engineering section contains two studies. The first article demonstrates that an electricity- and-power system is affected by various types of power quality disturbances, which have a detrimental effect on generators, transformers and electrical appliances. At the same time, the authors noted that some 6 Scientific Journals of the Maritime University of Szczecin 63 (135) of the most harmful disturbances in power quality are voltage subharmonics, and the study describes the effect of voltage subharmonics on power losses and the heating-up of an induction motor. The second article presents methods for analyzing the power characteristics of generator sets with vector control of an asynchronous squirrel-cage machine. These methods facilitate analyses of the power characteristics of generator sets with field-oriented control (FOC) and direct torque control (DTC). The Mechanical Engineering section also contains two studies. The authors of the first article presented an analysis of possible variants of a handling terminal system by considering the factors of the current development of the Russian transport system. Their considerations were directed at identifying the rationale and possible issues related to the lack of human presence in the technological process of an inland container terminal. The control system of a mini crane is reported in the second study of this section, which analyses a system employing a programmable logic-controlled exoskeleton. The Economics, Management and Quality Science section presents three articles. The first examines the impact of exchange rate movements on international trade. The authors point out that various studies prove that the impact may vary between different sectors and countries. In the fishing industry, this relationship was not widely studied; therefore, an analysis was undertaken in this respect. Using the Emirmahmutoğlu and Köse causality test, the authors examined whether exchange rate fluctuations in certain countries affected fish production. The authors of the next study considered the most important problem in recent months, COVID-19. As we have already seen, the pandemic is a strong determinant, not only of social life, but the economy as well. Recognizing the strong impact of COVID-19 on different spheres of our lives, the authors analyzed the impact of the coronavirus pandemic on the oil market. The authors of the third study in this section, assuming that the management process analysis allows the detection of weaknesses and strengths, analyzed the production line management processes. To this end, they created a queuing model for a production line and analyzed its performance and reliability. The attempted modelling was used to determine whether queuing theory can be used to mod-el processes in production lines. In the last section, Information and Communication Technology, the authors evaluated the tracking performance of the GOOSE platform and compared it to a reference receiver. The quality and performance were analyzed using raw measurements of three signals, GPS L1CA, L2CM and L5. The data were processed with the “zeroEdit” module of the TUB-NavSolutions software. In conclusion, the presented articles address a wide range of contemporary problems that can initiate theoretical and empirical scientific research. We are aware that the problems are described only to a modest extent, yet we hope that the articles will inspire further research and considerations.

This study was designed to determine the vibroactivity parameters of a hermetic harmonic drive. A specially-prepared test bench was used to measure the normal velocity of vibrations and acoustic pressure generated by the unit. Piezoelectric sensors were applied to measure the characteristic values on the body of the prototype. In selected sections of drive, we determined the effective values of acceleration ae and frequency f. For the same points, the effective values of vibration velocity Vc were determined for the corresponding frequencies. The findings presented in this paper enable the assessment of a toothed gear in terms of the quality of its workmanship and wear-related deterioration, which are very important due to the characteristic work of this special drive

I am pleased to present the fourth 2020 issue (No. 64) of the Scientific Journals of the Maritime University of Szczecin. This issue contains the research results and views of the authors of seven articles that are compiled into three subject groups: Civil Engineering and Transport; Mechanical Engineering; and Economics, Management and Quality Science. The Civil Engineering and Transport section begins with an article that examines the relationship between the occurrence of failures in selected types of buses and the time of their occurrence using the public transport of Lublin as an example. The second article presents the current state of research on the technical, legal and administrative problems that need to be solved in order for unmanned ships to be used widely by society. There are four papers in the Mechanical Engineering section. The first paper presents a numerical study of the hydrodynamic parameters of a modified hourglass-type FPSO (Floating Production, Storage and Offloading) ship with different geometric parameters. The second paper evaluates the atmospheric composition after degassing and ventilating a ship’s cargo tank after a washing process with reference to the entrance and its visual inspection The author of the third article presented methods of joining (welding and sealing) single-polymer composite materials in a hot air stream. The last study in this section determined the vibration- activity parameters of a hermetic harmonic drive to evaluate a gearbox in terms of its manufacturing quality and wear-related deterioration. The third section, Economics, Management and Quality Science, contains one article. The article synthetically presents the process of financing investments related to the construction and purchase of ships, presenting, among other things, the concept of shipbuilding cycles and the relationship between the shipbuilding industry and the shipping market. The articles presented demonstrate the authors’ continuing practical inspiration and contribute to interesting scientific inquiry. I am aware that the presented articles are only a modest expression of these ideas, but believe that they will provide a basis for reflection, discussion, and broader research.