The multi-ARPA (MARPA) system is a conceptual navigational decision-support tool intended to support the Officer of the Watch in complex ship-encounter situations, especially when several surrounding targets must be assessed simultaneously. In its original form, MARPA classifies candidate ship courses and target collision potential mainly by using predefined closest point of approach (CPA)/time to closest point of approach (TCPA)-based thresholds. Although such thresholds are operationally simple, they do not directly account for vessel dimensions, encounter geometry, uncertainty of navigational data, or the remaining maneuvering capability of a ship. This paper proposes a theoretical and analytical framework for improving MARPA hazard classification by replacing static CPA/TCPA-based heuristics with criteria derived from the ship domain and its safety-related sub-areas: the navigationally dangerous area, the critical area, and the collision zone. The proposed approach preserves the original operational structure of MARPA, including the direct hazard module and the indirect hazard module, but changes the meaning of the input hazard classes. Candidate ship courses and target collision potential are classified according to the predicted relation between the target trajectory and the domain-based safety areas. The analytical verification shows that domain-based classification changes MARPA output in several distinct ways. In the direct hazard module, the predefined scenarios produced higher, lower, and equivalent domain-based classifications when compared with static CPA/TCPA-based classification. In the indirect hazard module, the modification affected the class of direct hazard, class of course hazard, class of speed hazard, CMPH, and degree of indirect hazards through target geometry and through the course or speed change required for a target to violate the collision zone, critical area, navigationally dangerous area, or the ship domain. The collision zone provides the highest hazard class, a direct geometric meaning that refers to the possibility of physical contact rather than to an arbitrary CPA value. The practical advantage of this modification is that MARPA output can indicate not only that a course or target is hazardous but also which domain-based constraint is responsible for the classification. This study is theoretical and analytical in nature; full simulator-based, automatic identification system/radar-based, and onboard validation are identified as a necessary stage for future work.

Industrial infrastructure in coastal environments is exposed to particularly demanding operating conditions that can significantly affect the durability and reliability of metallic structures. Environmental factors characteristic of coastal zones, including high humidity and the presence of airborne salts containing chloride ions, accelerate corrosion processes and contribute to the progressive degradation of structural components. Such degradation may influence not only the physical condition of materials but also the operational stability, safety, and maintenance requirements of industrial systems. For this reason, corrosion-related damage should be considered within a broader framework of quality management and infrastructure safety rather than solely as a materials engineering issue. This paper proposes a conceptual framework for analyzing corrosion-related degradation in metallic structures operating in coastal environments, using a disturbance coding approach inspired by methodologies from safety science. In the proposed perspective, corrosion processes are interpreted as sequences of disturbances affecting system stability, while inspection procedures and maintenance interventions are treated as adaptive actions aimed at restoring operational reliability. The introduction of a structured coding scheme for identifying and documenting degradation-related events enables a more systematic monitoring of structural disturbances and supports decision-making in maintenance and quality management processes. The proposed framework integrates knowledge from corrosion engineering with safety-oriented system analysis and introduces structured coding logic linking disturbances, degradation signals, and adaptive maintenance actions. This approach may contribute to more effective monitoring and management of industrial infrastructure operating in aggressive coastal environments.

The paper presents a discussion of sonar target positioning in side-scan surveys. Practical experience shows that, regardless of layback uncertainty and vessel position error, an additional along-track component of uncertainty is observed during the processing of side-scan sonar data. This component is assumed to result from a delay in sonar data acquisition. It can be a significant issue because it is included in the calculation of the final target position during sonogram georeferencing and contributes to the overall horizontal linear uncertainty along the sonar track. This paper includes a theoretical analysis of the problem as well as empirical calculations based on real measurements. The aim is to investigate the magnitude of this additional error and, in the future, propose methods to reduce it while identifying its possible causes. The paper uses the recommended method for determining the final position of an object on the seafloor and proposes this method as a tool for calculating the total horizontal linear error along the sonar track.

This study investigates post-stall damage identification and vibration characteristics of the AMT Olympus micro gas turbine following a compressor surge event. The engine, primarily used for UAV propulsion, experienced rotor damage and increased imbalance during acceptance testing under steady-state conditions. Experimental diagnostics included measurements of rotational speed, vibration levels at compressor and turbine bearing planes, pressure, and temperature. The results reveal a significant increase in vibration amplitudes correlated with rotational speed. A spectral analysis identified rotor rubbing phenomena and imbalance signatures, providing insight into damage progression. This study highlights the diagnostic value of steady-state vibration monitoring for early fault detection in micro gas turbines and recommends limiting operational speeds to below 88% of the maximum allowable rpm during testing to ensure safety. Additionally, design flaws in the starter clutch system have been identified, suggesting improvements to future engine reliability. These findings contribute to enhanced engine health monitoring and maintenance strategies for micro-class turbine engines in UAV applications.

The maritime transport industry plays a key role in global trade and is also a significant emitter of greenhouse gases. Although literature on maritime decarbonization, regulations, technological change, and fragmented supply chains exists, it does not yet offer a tool that fully integrates these interrelated issues and has been empirically tested. The present study proposes and tests a multidimensional maritime transport transformation scale that covers supply chain disruptions, sustainability challenges, and carbon emission reduction initiatives. Forty-eight items across four constructs were developed from a literature review and piloted with 55 maritime and supply chain professionals. The results revealed that the instrument has high internal consistency (Cronbach’s α = 0.963), a sampling adequacy value of 0.608, and a theoretically derived four-factor model that explains 53.13% of the total variance. The scale shows preliminary reliability and structural validity, offering a robust tool for future maritime sustainability research and evidence-based decision-making

This paper presents the results of a study aimed at improving the accuracy of the recently published SATUFER method for estimating the dilution level of lubricating oil with diesel oil. It used the measured value of oil kinematic viscosity and known reference values of kinematic viscosity at the same temperature for fresh lubricating oil and diesel oil fed to the engine. This method was based on the REFUTAS algorithm for the analytical determination of the viscosity of a mixture with known mass shares and viscosities of the components. The correction factor K used in the formula estimating the concentration of diesel in the lubricating oil was Pareto optimized in the range 0.0–1.0 to minimize the value of the maximum absolute fitting error, δmax, and maximize the coefficient of determination, R2 , determined for the function estimating the degree of dilution of the lubricating oil with diesel relative to a known reference value. The analysis used a dataset of kinematic viscosity values for blends of SAE 30 or SAE 40 viscosity grade lubricating oil with B7 diesel oil at concentrations of 0, 1, 2, 5, 10, 20, 30, 40, 50, 75, and 100% m/m diesel oil in the blend at temperatures of 40, 50, 60, 70, 80, 90, and 100 °C. For each mixture, an estimated dilution level was calculated using the SATUFER method, and the result was presented with a known reference value. The results of the analysis for the assumptions presented in this article indicated that the initial value of the K-factor for further analysis was K = 0.53 instead of the initial value of K = 0.80 adopted in the REFUTAS method, which was the basis for the proposed and developed SATUFER method.

The seakeeping performance of ships is a critical factor in ship design, influencing both safety and efficiency. This paper examines the effect of two stern shapes (i.e., transom and canoe) on the response of the heave and pitch motions of a ship. The original U-shaped stern is redesigned into a curved shape by adjusting the longitudinal and transverse control points of the hull. The curvature starting point is positioned at 0.04L from the stern perpendicular toward the bow. After designing and constructing the modified model, the response amplitude operator (RAO) of the heave and pitch motions for regular waves in a towing tank test is analyzed under three different speeds and six wave frequencies. The results reveal that the transom stern shows slightly higher heave RAO values than the canoe stern, while demonstrating improved performance in pitch motion. Overall, the canoe stern exhibits a 5–15% reduction in total motion response compared with the transom stern.

The coastal zone is a very dynamic area, hence the need to monitor changes occurring within it. The aim of this study was to use video monitoring along the Polish coast of the Baltic Sea to analyze changes in beach width depending on the hydrodynamic conditions prevailing in the analyzed period. The research was conducted from October 20, 2022, to July 31, 2023. Snapshot images were collected in Jarosławiec. The measurement of beach inundation in the collected images was made using the FIJI is just ImageJ program, designed for image analysis. This research included the analysis of three issues: (1) change in beach width (2) statistical analysis of hydrological data and (3) correlation between beach width and hydrological parameters. Analyses showed that the greatest beach inundation occurs in winter and spring. The height of a significant wave was usually equal or less than 2 m. The dominant direction of waves was west. Most often, the maximum sea level during storms reached from 510 to 540 cm.

This article presents a preliminary method for selecting a standard bulk carrier intended for the loading and transportation of polymetallic nodules in the Clarion–Clipperton zone. The selection process is driven by key operational parameters, including the ship’s deadweight tonnage (DWT), the number of required bulk carriers, the loading time, and the annual fuel consumption. The mathematical models are developed for each parameter as a function of DWT, and a composite objective function is formulated to balance these criteria. The optimization task is performed using the Solver add-in within Excel. The results indicate that bulk carriers with a DWT between 12,000 and 24,000 tons are suitably aligned with the selected parameters, with optimal values depending on the prioritization of operational factors. Accordingly, handysize bulk carriers may be considered appropriate for the transportation of nodules from the Clarion–Clipperton zone to the discharge port.

This paper presents the electromagnetic design and evaluation of a low-voltage permanent magnet-assisted synchronous reluctance motor (PMaSynRM) intended for a compact underwater thruster in USV applications. The study addresses a propulsion motor required to operate at 3000 rpm and 0.6 N m under a maximum direct-current (DC) supply voltage of 14 V, with a rated phase current of 15 A (peak) and a short-time overload capability of 30 A (peak). Following a review of electrical machine topologies used in compact underwater propulsion, PMaSynRM is adopted as the target machine topology for a constrained low-voltage thruster drive. The design procedure focused on the electromagnetic sizing of a 24-slot, 4-pole machine under strict voltage and geometric limitations, including the selection of the main dimensions, winding configuration and rotor structure. A finite element analysis (FEA) was then used to evaluate magnetic saturation, shaft torque, torque ripple, efficiency and loss distribution under rated and overload conditions. The results show that the designed machine meets the required operating point, while the application of a stator skew reduces torque ripple with only a slight reduction in average torque. The highest efficiency is obtained in the vicinity of the rated operating region, whereas the overload operation is limited by increased magnetic saturation. At a rated current, copper losses dominate the loss balance, while core and excess losses remain significantly lower. The results indicate that PMaSynRM is a viable design option for compact low-voltage underwater thruster drives subject to strict voltage and space constraints.

Physical risk factors on ships are physical hazards arising from the working environment that threaten the health and safety of seafarers, and the assessment of the risks arising from these hazards is very important for sustainable maritime transportation. With this in mind, this study aims to analyze physical risk factors such as noise, thermal comfort conditions, static electricity, vibration, pressure, lighting conditions, weather conditions, and radiation on ships with the AHP and Fine-Kinney methods. According to the findings of this research, slippery floors, radiation, and noise are the most common physical risk factors that personnel working in the ship environment are exposed to. As a result of the weighting made by the analytical hierarchy process (AHP) method, the effect of these factors on occupational health and safety is found to be higher than that of other factors. Risk scoring performed with the Fine-Kinney method revealed that these factors were mostly at risk levels that “require precautions” or “require urgent intervention.” The findings show that physical risk factors affect not only employee health but also operational efficiency and long-term maritime safety. In this context, it is of great importance for ship operators to prioritize and evaluate these risks for the goal of sustainable and safe maritime transportation. In addition, the obtained findings provide important data for improving ship design processes, ergonomically reorganizing working conditions, and systematically monitoring risks.

This cross-sectional observational study evaluated the prevalence and determinants of metabolic syndrome (MetS) among 1432 seafarers aboard 76 trade vessels in the Red Sea. Data collection involved onboard examinations and remote or email-based protocols, encompassing anthropometric, biochemical, and lifestyle assessments. The prevalence of MetS was 27.8%, with higher rates among officers (33.5%) than among ratings (24.8%). Central obesity (81.3%) and elevated blood pressure (72.4%) were the most common components. Multivariate analysis identified age of 40 years or older, officer rank, and physical inactivity as significant predictors. Based on these findings, a novel three-phase maritime health framework is proposed, integrating digital screening, artificial intelligence (AI)-driven risk stratification, and continuous telemedicine monitoring. This model addresses operational challenges in surveillance compliance and aligns with the shipping sector’s digital transformation, providing a predictive and preventive approach to chronic disease management at sea.

Maritime autonomous surface ships (MASS) introduce operational paradigms for which no standard GUI designs or established operator roles currently exist. Conventional usability testing (UT) methods involving users are predominantly qualitative, limiting the precision of evaluations. While experienced system designers can partially compensate for this limitation, in the contexts of MASS—where operational conditions and operator roles are unprecedented—their experience offers less guidance. This underscores the need for UT methods that can efficiently support makers in developing and adapting schemata that remain well aligned with those of MASS operators. Leveraging recent advances in eye-tracking, this paper presents a conceptual UT method—a maker–user schemata alignment analysis—designed to support the research and development of GUI design for MASS. A proof-of-concept demonstration using scripted interactions illustrates how the method can reveal differences between makers’ and users’ schemata and quantify the extent of these divergences. The conceptual demonstration suggests the potential of the proposed method in providing both qualitative and quantitative assessments of maker–user schemata alignment, establishing a foundation for rigorous, human-centered evaluation frameworks as operational MASS systems are developed.

The risk management process in an organization consists of several stages, during which various methods, techniques, and tools are used. Their selection depends on the specifics of the company and the possibility of their application, given the current space-time conditions and the possession of specific resources. The most popular tools are SWOT analysis, brainstorming, and methods of studying the environment, etc. Sometimes, however, in a more complicated situation in an organization relating to the occurrence of risk, these methods may prove insufficient. They can be supported by solutions based on the Haddon model, which is based on several important factors discussed in detail in three dimensions: before a given event (risk), during its duration, and after the event. The main objective of this paper is to discuss the Haddon matrix tool that can be used in the risk management process at the stage of both risk identification and response. The paper also focuses on the practical application of the Haddon matrix for frequently occurring risks in an organization. Moreover, the application of the Haddon matrix for one of the risks occurring in a selected production company is presented.

This study evaluates the quantitative effects of laser cladding technology on the refurbishment of valve cages and exhaust valves in a Deutz TBD645 internal combustion engine. Laser powder cladding with Inconel 625 alloy is applied to GGG40 cast iron, and process parameters are optimized to minimize Fe dilution. The method enables low dilution, a homogeneous crack-free microstructure, reproducible valve seat geometry, and stable surface roughness after machining. Quantitative results indicate that laser cladding reduces unit repair costs by 70–80%, while total overhaul expenses decrease by 40–60%. For exhaust valve refurbishment, yearly savings of EUR 125,000–200,000 are achievable for fleets repairing 50–80 components per year. Despite process costs of EUR 250–383/kg, economic benefits remain strongly positive due to reduced downtime and extended component lifetime. The results confirm that laser cladding is an effective method for marine engine overhauls, delivering measurable economic benefits and supporting circular economy objectives in line with IMO 2030 and EU Green Deal targets.