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70 Scientific Journals of the Maritime University of Szczecin, no. 70 / 2022



 

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  • Zhao, Jingzhou (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    This study examines the volatility of the forward freight agreement (FFA) time series in the dry bulk shipping market. Series pattern analysis is first performed to determine the volatility and the characteristics of the unique FFA price time series. It then applies the ARIMA-GJRGARCH model to the Capesize FFA time charter (C5TC) and specific voyage charter one-month contracts (C3, C5 and C7), creating long or short signals, which helps market participants with FFA trading or hedging. In this study, these signals are collected and used to calculate the profit and loss for a specific period. Finally, the model-based return results are compared with the common buy-and-hold strategy. The empirical result suggests that this methodology is effective in generating trading signals, especially in the volatile periods, providing traders with prompt warnings about imminent market shocks. The purpose of the study is to examine whether this volatility-focused method is efficient in modelling FFA time series, and it also provides a handy method that may help market players make more accurate predictions when volatile days arrive.
  • Bayraktar, Murat; Nuran, Mustafa (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    New systems are produced and developed to meet specific needs, and their reliability is the most important issue. In the maritime industry, evaluating failures in a ship’s propulsion system results in high costs and the loss of prestige for the company. Land/sea fleet employees need to detect and minimize the failures that may occur in ship propulsion systems in advance to ensure the continuity of the ships’ operations. In this study, the recorded failure data of four different ships belonging to a fleet in the last 10 years are used. Failures were examined as a whole since the ships have similar propulsion systems. The obtained failure data were grouped, and the average time to fix the failures was determined by the chief engineer and made suitable for reliability, availability, and maintainability (RAM) analysis. A suitable model was created for grouped failures by Isograph’s RWB software. As a result of the analysis of the propulsion system and its subsystems, the main engine of the ship was shown to have the best reliability. Furthermore, the most important components were the cylinders of the main engine as subsystems. This study highlights the components that are important to the reliability of a propulsion system. Thanks to the RAM analysis, improvements can be pinpointed on a ship’s propulsion system, which will increase the operations of the maritime industry. Reducing failures will further increase the confidence in maritime transport and strengthen its place among the modes of transportation. This study provides a valuable resource for academicians, experts, as well as companies working on reliability, availability, and maintainability in the future.
  • Gucma, Stanisław; Gralak, Rafał (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    This article indicates the development trends in the construction of offshore wind turbines worldwide, and the characteristics of existing and planned ships for wind turbine installation and maintenance; it presents an approach to design ports with their future operations in mind. Problem: The safety of navigation in port waterways is the basic restrictions for the construction of harbors (terminals) to handle ships used for the construction of OWT and for increasing their size. Navigational risk is a criterion of navigational safety assessment that allows its accurate estimation in port waterways. Method: The article presents the method for dimensioning port waterways for ships serving offshore sea wind turbine transport and construction. Furthermore, a method for determining the navigational risk of jack-up vessels navigating in port waterway areas is presented. Results: The authors have determined conditions for safe operation of these ships in restricted areas and defined the basic condition of navigational safety. The presented method of navigational risk analysis refers to the departure of a loaded ship carrying offshore wind turbine components in the presently designed port terminal in Świnoujście for handling offshore wind farm projects. Conclusion: These are universal methods that can be applied to the design of ports serving vessels that install offshore wind turbines in various types of waters.
  • Pawelski, Jan (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    The grounding of a 400-meter long container vessel, called Ever Given, in the Suez Canal blocked the busiest shipping lane, which is responsible for 12% of seaborne trade, for 6 days. Some shipping companies had to divert their vessels and they had to take a much longer route around Africa to reach European ports. The concerned shipping industry started to look for alternative sea route to the Suez Canal with lesser risk of blockage, without a need to go around Africa. Such routes, which connect the Pacific and Atlantic Oceans, exist in the Arctic and the warming of the global climate makes them more accessible over time but the assessment of their viability requires a multifaceted analysis based on available professional navigational publications, scientific papers, and knowledge of polar shipping realities. Several nautical aspects are taken into account with the purpose of choosing a polar route that is most suitable as an alternative to the Suez Canal. Three routes are under consideration. One of them is the Northern Sea Route in the eastern part of the Arctic Ocean, along the coast of the Russian Federation. The second route is the Northwest Passage through the western part of the Arctic, passing waters belonging to Greenland, Canada, and the United States. The third one passes near the North Pole, a prospective route that may become available for commercial shipping in the future due to Arctic ice shrinkage, and it is known as the Transpolar Route. Analysis of these routes unambiguously point to the Northern Sea Route as the only viable option. Most prospective alternatives to the Suez Canal are technically feasible with the new generation of cargo vessels and they are experiencing a growth in maritime traffic together with a steady development of associated infrastructure. The existing simplified analyses of the transit costs, assuming strait passage in polar waters without any course deviation and the additional fuel that is burnt to overcome increased friction during passage in ice, shows that under present conditions that the Suez Canal Route is still cheaper than any polar transit and, moreover, offers year-round availability. It cannot be ruled out that the upcoming warming of the Arctic climate, and a lowering of the transit tariffs by the Russian Federation may tip the balance in favor of the Northern Sea Route. Presented here is an analysis of the competitiveness of the Arctic Routes in comparison to the Suez Canal from the perspective of the mariner.
  • Nazemian, Amin; Ghadimi, Parviz; Ghadimi, Aliakbar (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    Hydrofoils are utilized as instruments to improve the hydrodynamic performance of marine equipment. In this paper, the motion of a 2D NACA0012 hydrofoil advancing in water near the free surface was simulated, and a mesh morphing-adjoint based optimizer was used to maximize its lift-to-drag ratio. Ansys-Fluent was used as a CFD solver, and a mesh-morphing tool was used as a geometry reconstruction tool. Furthermore, the Adjoint solver was applied to evaluate the sensitivities of the objective function to all solution variables. Defined control points around the geometry are design variables that move in an appropriate direction through shape sensitivity. The computational results were validated against available experimental data and published numerical findings. Subsequently, different hydrodynamic characteristics of the optimized hydrofoil were compared to those of the original model at different angles of attack of 3, 3.5, 4, 4.5, 5, 5.5, 6, and 6.5°, and optimized shapes were determined. It was observed that the shape of the optimized hydrofoil was totally dependent on the angle of attack, which produced different lift-to-drag ratios. It is also seen that among higher angles of attack at which improvement in the L/D ratio became steady, the drag coefficient was the lowest at 5°. Therefore, it can be concluded that the appropriate angle of attack for a hydrofoil installation on the ship hull is 5°. Further investigation was conducted concerning the evolution of shape optimization, sensitivity analysis, free surface elevation, flow characteristics, and hydrodynamic performance of the hydrofoil at a 5° angle of attack.
  • Idzior, Marek (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    In recent years, there has been an intensification of work on the autonomy of means of transport, which also applies to ships. Modern ships are already equipped with crew decision support systems and numerous diagnostic systems. Increasingly more systems are installed on ships that can operate without human integration. This situation leads to the development and use of fully autonomous ships. This overview publication briefly describes the main features of the construction and operation of autonomous ships, including some examples of structures already demonstrated in recent years. In summary, the author presents comments that provide a contribution to the discussion on the autonomy of means of maritime transport.
  • Kasyk, Lech; Pleskacz, Krzysztof; Kapuściński, Tomasz (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    The definition of dynamic areas of searching for shipwrecks, and/or the movement of pollution across waters of Szczecin Lagoon first requires the knowledge and specification of hydro-meteorological conditions across the area. This article compares wind parameters from various sources of meteorological stations located close to Szczecin Lagoon. The wind speed and direction were obtained from Ueckermuende, I Brama Torowa (Urząd Morski Szczecin), and Kopice (wind meter of Szczecin Maritime Academy). Wind direction data analysis was based on directional statistics methods and tools.
  • Falkowski-Gilski, Przemysław; Uhl, Tadeus (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    Thanks to the availability of mobile devices and the spread of broadband access around the world, the number of network users continues to grow. This has raised user awareness when it comes to the quality of content they consume. Many service providers and operators focus on monitoring QoN (Quality of Network) and QoS (Quality of Service) parameters, particularly those influenced by bandwidth and latency. However, for most end-users, quality is understood as the subjective QoE (Quality of Experience), a mixture of several individual factors. This paper presents a QoN evaluation, carried out under real-time operating conditions at a university campus, considering the overall performance of the cellular network. The study involved 50 mobile devices, i.e., smartphones, used by students during their typical activity throughout a week. The results were gathered on the eve of 5G, using a custom-built Android application. This application enabled the acquisition of valuable data about the wireless link, including download and upload speed, latency (pink), the ID of the serving base station, and type of cellular connection. This approach can be used to detect the strengths and weaknesses of back-end networks.

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