Deterioration in the performance of gas turbines is a well-known phenomenon occurring during their operation. The most important form is a decrease in the internal efficiency of the compressor and turbine due to fouling, which is the most significant deterioration problem for an operator. This article presents the effect of gas turbine fouling as a drop in airflow, pressure ratio, and compressor efficiency resulting in a reduction in power output and thermal efficiency. This resulted in a decrease in the nominal power of a gas turbine and an increase in the fuel consumption (heat rate). The fouling effects were described using the example of the MT30 marine gas turbine with a nominal power of 36 MW. The estimated profit loss during the operation of the gas turbine was within the range of 1–10% of the total fuel consumption cost. A 2% deterioration in the output of a gas turbine accounted for US$ 10,000–20,000 per year and 1 MW of gas turbine nominal power (according to marine fuel prices in 2019–2020) – this means at least US$ 300,000 annually for an MT30. Due to the low accuracy of fuel consumption measurements, another possibility was provided. The correlation between the gas turbine power deterioration and thermal efficiency was presented, which made it possible to estimate the increase in the specific and total fuel consumption when the nominal power deterioration is known. Two linear approximations were proposed to calculate increases in the annual operating costs for an MT30 due to fouling.

This article explores the use of ontology for semi-automatic marine vessel navigation and ship-to-ship communication to mitigate collision risk. Semi-automatic vessel communication is a step towards automatic communication for autonomous ships. Examples of how such communication can be used is discussed, based on a comprehensive analysis of selected marine collisions, with particular attention to the communication conducted on ships. The effectiveness of such communication was assessed and compared. The suggested solutions are based on the review of official reports from accident investigations. The novelties of this work include original ontologies and interfaces. Through this work, it could be possible to fully automate communication processes between ships. In future work, the research results in this work will be used to create a system of automatic communications for manned and autonomous vessels.

In this study, a functional diagram for an automatic sliding mode control system for a three-phase bridge buck current converter was developed. To achieve this, a simulation program was created in MATLAB/Simulink which analyzed the dynamic performance of the developed automatic control system, operating in the active rectifier and network current inverter modes. The results present the mathematical modeling outputs, along with the analyzed control algorithm and the automatic control system of the buck current converter evaluated.

The aim of this article is to present the results of research on solutions that can be implemented by the Gdynia Sea Port to allow it to obtain the title of a Green Port. The conducted research concerned a broad area, i.e., the identification of initiatives taken by seaports distinguished as Green Ports and other possible solutions consistent with the ideas of sustainable development. The article focuses on solutions for the Gdynia Sea Port, which, despite the implementation of many pro-ecological initiatives, does not have the official title of a Green Port. Seaports serve many modes of transport, but they are currently dominated by road transport. The activities of seaports located in urban agglomerations significantly contribute to the emission of air pollutants, noise, congestion, and other factors, which directly affect the health and quality of life of its inhabitants. The research process involved a critical literature analysis, the method of deduction, and a structured interview with representatives of the seaport in Gdynia. Based on the conducted research, areas important for obtaining the title of Green Port were identified, including increased investments in renewable and alternative energy sources, as well as a focus on the implementation of intelligent solutions.

Dear Readers, This is the last and fourth issue (No. 68) of our journal in 2021. This issue includes twelve articles by authors from research centers in Poland and abroad. The articles deal with diverse problems in the following branches of science: Civil Engineering and Transport, Environmental Engineering, Mining and Energy, Material and Mechanical Engineering, Economics, Management and Quality Science and Information and Communication Technology. The Civil Engineering and Transport section consists of five articles. The authors of the first paper found that the vessel stability criterion is not valid due to a turning maneuver and it needs a new approach. Further in the article, they claim that there are no accurate procedures and formulas to calculate the heeling moment due to the centrifugal forces as a function of time. This provided the reason for the authors to develop such a procedure, taking into account appropriate formulas to separate the heeling moment due to centrifugal force from the other heeling moments acting on the vessel during the turn. The second article elaborates on the effects of the international maritime safety requirements implemented over recent years. The authors studied the impact of these regulations on improving vessel safety in European maritime waters by analyzing accidents between 2014 and 2020. The analysis was based on the classification of accidents by their severity, type of vessel and the identified causes or contributing factors. The next study presents the new, fourstep approach to selecting the location of an LNG terminal, where the area concerned was the Adriatic Sea. The expert authors carried out a multi-criteria analysis of six locations for three different scenarios using the PROMETHEE method. The author of the fourth study notes that, in the development of vessel safety assessment methods, it is necessary to reach a balance between the accuracy of the results and their availability. This article describes the calculation of the theoretical hull in relation to the damage stability provisions set out in SOLAS 2020, ICLL 66/88 as amended in 2003 and MARPOL 78. The correlation between the required GZ properties and the actual vessel’s circle on a wave is presented. The study demonstrated the influence of GZ curve parameters on the ship’s circular motion. The last article in this section presents best practices for reducing private transport in selected European cities. Methods of source analysis, descriptive analysis and the method of inference made the analysis possible. As the analysis shows, for city administrators, it is a challenge to continuously search for new solutions to reduce traffic problems. In addition, it is noted that transport policy is a key tool for changing the public’s awareness of the ecological approach in the use of private vehicles in the city. There is one article in the Environmental Engineering, Mining and Energy section which is aimed at determining the impact of changes in the global economy on the evolution of the fishing fleet. An attempt is made to identify the most common type of vessels currently operating in the world fleet. The authors intended to determine the size and structure of the existing fishing fleet and, moreover, to find whether it is changing because of environmental transformation. The Material and Mechanical Engineering section consists of two articles. The first study discusses the existing and future regulations on the energy efficiency of vessels and methods for improving it. The authors compared the design and operating characteristics of slow-speed gas-fired main engines, conditions for liquefied natural gas regasification and the amount of waste cold. The second article deals with the problem of the long-term operation of hydromechanical fittings exposed to aggressive water. The author aimed to find the importance of water quality during the operation of wind power plants and geothermal power plants, especially hydromechanical fittings during long-term operation at the base of the Baltic Sea and geothermal power plants. In the Economics, Management and Quality Science section, we present a study that addresses an important and topical issue in supply chain management. The subject of the study centers on the uncertainty in supply chain operations. The authors’ objective was to create a catalogue of typological disruptions as an inherent component of supply chain management under the conditions of uncertainty. The overview leads to the conclusion that contemporary supply chain management requires at least an attempt to forecast the effects of uncertainty conditions, including the risk of disruptions. Three studies are presented in the Information and Communication Technology section. The aim of the first article was to evaluate the potential of using modern virtual reality (VR) and augmented reality (AR) to investigate passenger evacuation from vessels. The results of the study showed that there is excellent potential in the implementation of VR and AR technologies in navigation. The subject of the next two articles is unmanned aerial vehicles. It should be noted that the development of unmanned vehicles in transportation is gaining momentum, so it can be believed that the use of such vehicles will become commonplace in the near future. In the first study, the author notes that unmanned aerial vehicles allow relatively cheap and fast acquisition of high-resolution data for small areas, making it possible to produce not only an orthophotomap, a two-dimensional set of data, but also a three-dimensional cloud of points, which is the basis for obtaining a numerical terrain model. The study evaluated the effectiveness of algorithms used for the classification of terrain in photogrammetric point clouds and obtaining a correct NMT. Three algorithms were tested: Adaptive Triangulated Irregular Network, Progressive Triangulated Irregular Network and Multi-Scale Curvature Classification. The research included two test areas on natural coastlines. The author of the second article on unmanned aerial vehicles notes that low-altitude imaging enables rapid acquisition of high-resolution data for various objectives, especially for mapping. This article presents the mapping of a bridge and its warning signs, lighting and spans to create electronic navigation maps for inland navigation. The object of study was the Cłowy Bridge on the Regalica River in Szczecin. We hope that the presented studies will receive much interest, and it will inspire discussion and drive new research.

Dear Readers, We are pleased to announce the third 2021 issue (No. 67) of the Scientific Journals of the Maritime University of Szczecin. This issue features novel findings and perspectives in the following areas: Civil Engineering and Transport, Environmental Engineering, Mining and Energy, Material and Mechanical Engineering, Economics, Management and Quality Science, and Information and Communication Technology. The Civil Engineering and Transport section features two articles. The main research objective in the first study was to identify and propose new risk assessment tools. A maritime accident involving a Cosco Busan container ship that struck the base of the Delta Tower of the San Francisco-Oakland Bay Bridge in November 2007 was chosen as an example. An analysis of the factors that led to the accident was conducted, and the effects of the accident were outlined. On that basis, a risk analysis using mathematical and tabular values related to navigational risk in a specific navigation region was performed. Drones and their potential uses in the maritime sector by various entities, including ship classification societies, shipyards, and search and rescue (SAR) missions, was the subject of the second study. The benefits and limitations of drone implementation were highlighted, and a plan for the use of drones in shipping was presented. Projections of drone applications in the maritime sector in Poland, in the West Pomeranian Voivodeship and Pomeranian Voivodeship, were also made. The Environmental Engineering, Mining, and Energy section contains an article discussing waste treatment methods to identify the best method to reprocess (recycle) polyurethane (PUR). Glycolysis was concluded to be the most promising process for polyurethane waste management. The research material was produced by the glycolysis of scrap polyurethane foam. Based on the research, analysis, and testing, it was concluded that the most suitable reaction conditions for the recovery of polyols from scrap were: a temperature range of 170–190°C, alkaline pH, and an air atmosphere, which were the same for all samples. The Material and Mechanical Engineering section contains two articles. In the first study, the influence of the stern wedge length and height on hull drag and trim to glide in calm water was examined. For this purpose, liquid flow was simulated with Star-CCM+ software using a shifted mesh model and a turbulent k-ε model. The stern wedge sat below and near the stern perpendicular to the hull to facilitate moderate spread. To evaluate the hydrodynamic properties of the hull at different speeds, different wedge lengths of 0.2 B, 0.5 B, and B were investigated at two different heights of 5 mm and 10 mm. The trim angle, resistance, water surface elevation, porpoising, roster tail, and the stern and bow were computed and analyzed. The results showed that as the length of the wedge increased, the drag and trim decreased. It was also found that the best wedge for a vessel with the desired wake generation was one with a length of 0.2 B and a height of 5 mm. The author of the second study argued that the good quality of composite castings can be mainly attested by their user. In his research, he presented the casting defect porosity, with particular emphasis on the porosity in suspensions and saturated metal composites. The purpose of the study was to detect and analyze the porosity in composites using microscopic and sub-microscopic methods. Three articles are featured in the Economics, Management, and Quality Science section. The author of the first study shows that the increasing unpredictability of socioeconomic or biological changes (e.g., the SARSCoV-2/COVID 19 pandemic), the multidirectional nature of their impact, the variability of their intensity, and the uncertainty in estimating their potential impacts, made it difficult for supply chains to stably operate. This reality demonstrates the great unreliability of the classical economic measuring instruments and methodologies used in management and quality sciences. This observation sparked an attempt to produce a sample set of expectations for contemporary supply chains that are particularly appropriate for emerging market challenges in the form of threat and condition megatrends, including those illuminated during the SARS-CoV-2/ COVID-19 pandemic. The author suggests a holistic perspective on the nature of the supply chain system and its processes. The proposed approach, based on an interpretive (qualitative) research method enhanced by an idiographic nomothetic approach, is treated as a creative alternative that does not exclude other ways of perceiving the supply chain. The research subject of the second study was the relationship between the characteristics of consumer product demand and the profitability of the purchasing strategy, considering both the supply source and the transportation technology. A model was developed for two demand distributions (Gaussian and gamma), varying sales fluctuations, and changes in demand during delivery. Then, Monte Carlo simulations were performed by considering transportation costs, warehousing costs, capital costs associated with maintaining inventory, and lost sales costs. The simulation results showed that the higher the fluctuation and the lower the demand predictability, the more profitable the air freight and local deliveries. The calculated results further indicated that the strategy of outsourcing production in low-cost countries will, in many cases, become unprofitable if the production costs in such countries grow even marginally. Team coaching was the research problem in the third study. The goal was to present a team development process using the High Performance Team Coaching Model. The first part of the article characterized the theoretical essence of team coaching and the specifics of the team coaching process, along with the specific tools at each stage. In the second section of the article, the author explains the process for implementing the High Performance Team Coaching Model in business practice. The Information and Communication Technology section features a study on the use of artificial neural networks (ANNs) to solve image classification problems. SHREC (Automatic Ship Recognition and Identification) projects were used to classify and identify ships based on images obtained from CCTV cameras. The authors collected an image dataset of ships during the 2018, 2019, and 2020 video survey campaigns and utilized three pre-trained neural networks, GoogLeNet, AlexNet, and SqeezeNet, to explore the classification feasibility and then assess their quality. About 8,000 ship images were used, which were divided into seven categories: barges, special-purpose service vessels, motor yachts with motorboats, passenger ships, sailing yachts, canoes, and others. The authors compared the results obtained using neural networks to classify floating inland vessels. The articles in this issue show the continuous theoretical and practical inspiration of the authors, contributing to important and current scientific investigations. I encourage you to read these articles in the hopes that they will be of interest to you and that they will stimulate debate and inspire you to undertake research, not only in the discussed areas but also on an interdisciplinary level.

This article concerns the issue of the long-term operation of hydromechanical fittings during their contact with aggressive water. The aim of this analysis was to investigate the significance of the quality of water during the operation of wind power farms and geothermal power stations, especially hydromechanical fittings during long-term operation at the base of the Baltic Sea and geothermal power stations. This article presents the properties of water and their impact on hydromechanical equipment during long-term operation in marine and geothermal waters. The paper includes the analysis and evaluation of their impact. Additionally, the article describes important problems with the operation of wind power farms and geothermal power stations. The results of periodical analyses of southern Baltic marine water and thermal groundwater from “Geotermia Podhalańska” were evaluated and used as the basis for future research. Every negative parameter of water, known as its aggressiveness, adversely affects the basic materials of wind masts and pipelines, as well as the hydromechanical equipment in contact with marine and thermal water. The presented results show the necessity of controlling the water quality prior to the operation of geothermal water and building wind power masts in coastal marine water. Attention was paid to corrosion during contact with aggressive water with unprotected materials. This issue is rarely seen in the literature but is very important.

The shoreline is an important geographical zone, and knowledge of its accurate location can be crucial for coastal management and mapping. The ever-increasing number of aerial and satellite sensors is leading to research related to the development of new methods for the automatic extraction of the shoreline. Currently, there is a lot of research in this area with different research methodologies. In this paper, an analysis of shoreline extraction methods was carried out. Based on the analysis undertaken, current research processes in this field can be verified. This enabled the further evaluation of the research methodologies studied, including the identification of basic assessment elements for shoreline extraction accuracy. Practical aspects of this work include the ability to establish the correct methods to assess the accuracy of extracted shorelines for both research and production processes related to data extracted from remotely sensed images.

The aim of the article is to designate catalogues of typological disruption as an inherent element of supply chain management in the light of uncertainty conditions. By means of deduction, the typological characteristics of the disruption and the catalogue of management decisions were determined. In this way, the scope of theoretical knowledge based on the theory of risk and supply chain management was expanded by leading the discourse towards the location of the so-called the required uncertainty in the canon of obligatory components of management strategies. The article presents an overview discourse leading to the conclusion that contemporary supply chain management requires at least an attempt to forecast the effects of uncertainty conditions, including the risk of disruption.

Maritime and coastal areas are the lifeblood of many countries, being essential to their well-being. They provide trade routes, regulate the climate, and supply both organic and inorganic resources, along with energy, a crucial requirement for living and recreation. However, there are emerging disparities and barriers in terms of marine exploitation. On the one hand, existing and evolving technologies and knowledge allow better utilization of the sea, while on the other hand, the cumulative effect of human activity leads to conflicts of interest and to a deterioration of the marine environment. This article aims to consider the impact of changes in the world economy on the evolution of the fishing fleet, including the characteristics of vessels produced in consecutive years. We also attempt to determine the most common type of vessel presently operating in the world fleet. A number of external factors impact the organization and operation of the world’s fishing fleet, including economic, geographical, and political factors. The strength of each factor varies depending on the conditions in which the fleet operates. Also, we would also like to establish to what extent efforts aimed at energy demand reduction have affected the characteristics of the current fleet, determining the scale and direction of change, while also identifying any relevant constraints and limitations. The intention behind this paper is to discover the size and structure of the fishing fleet and whether it is changing as a result of environmental transformation. With this objective in mind, we have outlined a review of the literature and used statistical methods in order to carry out a comparative analysis of the size and structure of the world’s fishing fleet.

The aim of the article is to indicate the best practices used to limit individual transport in selected European cities. Due to the dynamically progressing urbanization processes and the related development of cities, the demand for transport services is increasing. Individual transport has become a significant problem, which contributes to the increase in road traffic in urban transport networks, causing congestion, which determines the increase in air pollution and noise emissions, road accidents and affects the health and quality of life of residents by limiting their mobility and transport accessibility . More and more often local authorities decide to implement traffic restrictions in cities, thus contributing to reducing the negative effects of transport. The methods of source analysis, descriptive analysis and the method of deduction were used to carry out the analysis. As indicated by the conducted analysis, the constant search for new solutions contributing to the reduction of transport problems is a challenge for city managers in the era of rapidly advancing urbanization processes. The implemented transport policy and the pace of implementing changes seem to be a key aspect in discouraging the society from using individual road vehicles in the city.

Unmanned aerial vehicle (UAV) technologies are becoming increasingly common, with ever-expanding applications. Low-altitude imaging makes it possible to quickly acquire high-resolution data for various objects, especially for mapping. This paper presents the mapping of a bridge and its notice marks, lights, and span to produce electronic navigation charts for inland navigation. The research object was the Clowy Bridge on the Regalica River in Szczecin, Poland. In order to carry out the research, two photogrammetric flights were made, and three sets of photos were created, from which orthophotos were developed. The research included the analysis of the orthophoto generation process, as well as quantitative and qualitative analyses. The results of the research demonstrated the possibility of using this type of data for mapping bridges to create electronic navigation maps for inland navigation.

Unmanned aerial vehicles (UAVs) allow relatively cheap and fast acquisition of high-resolution data for small areas, making it possible to produce not only an orthophoto, understood as a two-dimensional product, but also a three-dimensional point cloud, which is the basis for obtaining a digital terrain model (DTM). The use of high-resolution image and elevation data may allow accurate shoreline delineation in areas where such measurement is not possible with other methods and further use of these data, e.g. for the production of electronic navigation charts. The accuracy of the final product, the DTM, is significantly affected by the photogrammetric classification process of the point cloud and the correct separation of the ground class. The aim of this study was to assess the effectiveness of the algorithms used to classify ground in photogrammetric point clouds and obtain correct DTMs. Three algorithms were tested: Adaptive Triangulated Irregular Network, Progressive Triangulated Irregular Network, and Multiscale Curvature Classification. The study involved two test areas covering natural shorelines. Images acquired with a UAV on the X8 system and a Sony alpha camera with a mounted 15 mm wide-angle lens were used as data for the research experiment. Accuracy analysis of the developed models was performed using check points acquired by the GNSS-RTK method.

The purpose of this paper was to assess the possibility of using modern technologies, virtual reality (VR) and augmented reality (AR), to study the evacuation of passengers from ships. The evacuation of passengers fromships is usually studied from post-accident reports, laboratory or field experiments, and/or numerical modelling. Nowadays, with the rapid development of computer resources and wearable technology, evacuation canalso be studied using VR or AR. The methods used in this paper for such assessments included a literaturereview (tools like Web of Science, Scopus, and Google Scholar indexing platforms) and comparative strengths, weaknesses, opportunities, threats (SWOT) analysis. The results demonstrated the great potential for the implementation of VR and AR technologies within the shipping industry, similar to how they have already foundapplications in the research of pedestrian evacuation from buildings or open spaces. Finally, recommendationsfor their use in ship passenger evacuation are presented.

During the currently ongoing development of methods for assessing the safety of ships, it is imperative that a compromise between the accuracy of the results and the accessibility of obtaining results is reached. This paper shows the calculations of a theoretical hull against damage stability regulations as included in SOLAS 2020, ICLL 66/88 as amended in 2003 and MARPOL 78. The rules included in the currently valid regulations require certain righting arm curve properties from vessels before and after potential damage, which does not pose a high difficulty level to engineers. However, for many engineers and scientists working with these rules, it is unclear what kind of behavior (particularly roll motion) these righting arm curve parameters correspond. In this paper, a correlation between the required GZ properties and the actual roll motion of a ship in waves, as calculated with the well-established method proposed by the ITTC, is revealed, and a comparison of the results to the currently in use regulations as well as comparison between the methods themselves is made. The comparison reveals the impact of GZ curve parameters on the roll motion of the ship.