Shipping Conditions Research Articles

Application of structural methods to assess the reliability of ship’s mechanical systems

At present, reliability indicators are of great importance at the design stages, during operation and in cases of extending the technical life. This is one of the reasons for choosing the research topic on the application of structural methods for evaluating the reliability of ship mechanical systems. The operational stage of the life cycle of ship’s mechanical systems is considered in the paper. Durability criteria such as service life, operating time, frequency of repairs are chosen as reliability indicators. In turn, work on the repair, maintenance or replacement of ship’s mechanical systems elements is carried out in accordance with the assigned regulations or in the case of an unforeseen failure. The comparison of event models of changes in the operating conditions of ship’s mechanical systems is carried out. To estimate the remaining resource in the form of graphs, events are shown by service life and operating hours, distributed by years. In order to improve the existing methods for assessing reliability, a set of elements of the average values of the residual resource and residual output is considered. The approach proposed by the authors for assessing both element by element and the entire ship mechanical system as a whole allows us to consider the residual resource from the moment of monitoring its technical condition to the transition to the limit state, to plan technical measures and prevent possible malfunctions. Three different time slices models corresponding to planned repairs and maintenance of systems, replacement of system elements and unforeseen accidents are considered in the study. The difference in the amplitudes of the calculated indicators of the ship’s mechanical systems reliability has shown that the closer the options between the maximum and minimum values are to the average, the more accurately the statistical indicators characterize this pattern. However, amplitude deviations can be used to apply fault risk assessment. This line of research seems to be important for ships in the Arctic navigation area, which are characterized by increased requirements for ship survivability.

Application of ship’s information system to control and monitor the technical condition of ship’s equipment

Failures and breakdowns of marine equipment that occur during the daily operation of ships can lead to major accidents, endangering the lives of the crew and passengers of ships, and also pose a threat to the environment. A project for using a ship information system to monitor the technical condition of ship power equipment in real time through integration with ship automated systems is presented in the paper. The implementation of the information system was carried out on the Handy Size dry-cargo vessel with a deadweight of 36,987 tons, during which an analysis of ship systems was carried out and sources for obtaining initial information were identified. These were AMS system (alarm monitoring system), technical control system of MAN 5S50ME-B “CoCoS” main engine condition, equipment on the navigation bridge (AIS, GPS, ECDIS, VDR). During the implementation of the project, a secure connection to the above-mentioned ship systems for collecting and processing information using the installed Dataloger computer with software was made. Channels for transmitting information to the shore through the satellite Internet and mobile communication systems using data coding and compression to reduce traffic volume were determined. The use of the implemented information system makes it possible to remove some of the routine tasks for the crew and the onshore technical service, to obtain more accurate information on the formation and control of maintenance tasks in real time.

Modern Types of Propulsion for Inland Waterway Transportas a Response to Contemporary Challenges in the Logistics Chain across Polish Seaports

This paper is devoted to the negative impact of transport activities. Every type of transport comes with negative effects on the environment, people’s health, and people’s comfort of living. Strategic papers from the European Union’s (EU’s) acts of law on national, regional, and local political levels have found that water transport is the future. The authors hypothesize that the increase in the use of inland waterway transport over the coming decades will provide an opportunity to increase the capacity of transport; however, without appropriate regulations regarding emission standards, the use of outdated water transport units will not allow us to achieve positive environmental effects. The authors, therefore, indicate good practices related to the use of shipping in conjunction with the use of modern types of propulsion. The literature review method was used to verify current knowledge about the impacts of water transport as well as to find possible alternatives. Moreover, a survey was conducted among experts—decision-makers in logistics companies operating in Polish seaports. The condition of ships, especially those used on inland waterways, needs to be improved, mainly in the aspect of emissions. Furthermore, a strategy should be prepared to include inland shipping as an ordinary part of the logistics chain in Poland, which seems to be a necessary and expected action, though it will bring only partial environmental benefits.

An Investigation about Stability in Waves of Large Pleasure Yachts

The IMO’s second-generation intact stability criteria (SGISc) have been applied to a set of seven megayacht units ranging from 40 m to 80 m. The application aims to evaluate their stability performance in a seaway. The assessment is based on two vulnerability levels, and the related criteria rely on the physics of the phenomena under investigation (dead ship condition, excessive acceleration, parametric rolling, pure loss of stability, and surf-riding). At the same time, SGISc provide methodological approaches to consider possible operational limitations related to the geographical area the vessel is meant to sail. Results of the comprehensive analysis carried out for the selected megayacht units are presented in term of limiting KG curves. Outcomes pointed out that inconsistencies among vulnerability levels still exist. Further comments about the relation of the investigated vessel typology and relevant operational profile have been reported. In addition, systematic analysis of the effect of the main design parameter on ship rules compliance has been carried out.

B-043 Thermal Evaluation and Field Study of Labcorp TrueThermTMpackaging System for Protecting Sub-Milliliter Blood Samples

Abstract Background Many diagnostic assays require temperature-controlled sample storage and shipment to ensure accuracy. Here we present, the Labcorp TrueTherm, designed for thermal-controlled shipment of small volume blood samples. The reusable TrueTherm combines a stainless steel vacuum bottle with a custom internal cold pack and insulating stopper. Users refrigerate the cold pack to protect against warm or cold temperature excursions. The whole system is relatively compact, measuring about 10in (25cm) in length, 3 inches (8cm) in diameter, and 2.5 pounds (1kg) in weight. Methods In order to evaluate thermal performance, the TrueTherm system was exposed to both ISTA-7D summer and winter conditions and internal temperature was recorded for 96hrs. Subsequently, venous blood samples were collected from n = 40 subjects, and immediately aliquoted into BD SST (Serum separator) Microtainers®. For each subject, sub-samples were subjected to centrifugal separation (provided by the Labcorp TrueSpinTM battery-powered centrifuge), serum removal, and 24hr insulated shipping on ice packs compared to a variety of 72hr cross-country shipping conditions with and without centrifugal separation and with and without insulated packaging (including TrueTherm) during August 2022. Results TrueTherm maintained temperature between 2 and 20C for 72hrs under simulated summer and winter conditions. Under actual cross-country summer commercial shipping conditions, both centrifugal separation and thermal control via TrueTherm expanded the number of valid analytes compared to unprotected whole blood (see Table 1). Conclusion The results suggest that TrueTherm is an effective system for protecting small blood samples from thermal extremes during extended shipping. Portable thermal moderation was complimentary with portable centrifugal separation to maximize stability of common analytes.

An efficient optimal hybrid SVELM based monitoring and forecasting the engine operations for safety standards

During the past years, the environmental and safety-based regulations have turned out to be more stringent, requiring more regulations on the ship's operation and condition for achieving most safety standards. Thus, timely, efficient, and accurate maintenance becomes more significant. The appropriate utilization of data can assist the shipping industry in obtaining improved efficiency and operational cost savings, greater safety, better crew rates, improved asset protection, and environmental protection. The most important objective of this study is to build up a novel technique that can synchronize collected data from different sensors on the ship and implement a scalable framework for identifying the early sign patterns of defective behavior in vessel operating conditions. Particularly, the novel technique investigated in the current study is based on a Hybrid SVELM-GOLF to evaluate time series directly from the dataset. The data smoothening, filtering, elimination of outliners and segmentation process are carried out in the preprocessing stage. Followed by preprocessing, the features are extracted for classification purposes. Here, a novel Hybrid Support Vector Extreme Learning Model based Grasshopper Optimization with Levy Flight (Hybrid SVELM-GOLF) technique is proposed to estimate the probability of cylinder condition (i.e. defective or healthy) in the ship. The simulation results display that the proposed hybrid SVELM-GOLF approach achieves a higher rate of prediction accuracy of about 96.2% as well as precision, recall, specificity and F1-score by 95.2%, 95%, 95.8% and 94.9% than other compared approaches. Thus, the hybrid SVELM-GOLF approach gains the higher capability to recognize suspicious patterns and localize defective regions.

Evaluation of a Compact, Portable Centrifuge for Separating Microvolume Blood Samples at the Point of Collection.

The increased demand for decentralized blood sample collection presents numerous operational challenges for diagnostics providers. Sample degradation including sample hemolysis due to time, temperature, and handling between collection and laboratory analysis leads to limited test menus and unreliable results. Here we introduce the lightweight, portable Labcorp TrueSpin™ for rapid point-of-care blood separation using commercially available microvolume blood collection tubes. The TrueSpin is a class I FDA-registered device designed for untrained users. The centrifuge runs on AA batteries and separates a blood sample in 5 minutes. Here we describe a series of studies evaluating sample quality and analyte stability in serum samples collected into gel microtubes and processed using the TrueSpin. Hemolysis, residual red blood cell concentration, sample volume, and serum-based chemistry analyte stability were evaluated. No significant difference was seen in hemolysis or residual red blood cell concentration in serum samples prepared by TrueSpin compared to the reference method. Additionally, capillary and venous blood samples separated using the TrueSpin and exposed to International Safe Transit Association 3A-simulated shipping conditions were shown to yield acceptable sample volume and quality for laboratory analysis. Finally, we show that many common serum-based chemistry analytes have limited (< 1 day) stability if uncentrifuged but improve to ≥ 3-day stability following TrueSpin separation and refrigerated or room temperature storage. These findings suggest that the TrueSpin is a simple and effective solution for remote sample separation and may enable broader test menus and increased test result reliability for decentralized sample collection pursuits.

Modelling of the availability for the ship integrated control system sensors

Innovative control systems regulate and adjust a lot of operational conditions of the modern ship’s functions. A comprehensive Ship Integrated Control System (SICS), for the operation of the propulsion plant, the power management of the auxiliary engines, the operation of the auxiliary machinery, the loading and unloading of cargo, the navigation, the management of maintenance and the purchase of spare parts is implemented in the paper. A strategy where preventive maintenance is carried out and different repair actions can be considered is proposed. The SICS is subjected to various levels of degradation, and if so, a repair process will be undertaken to restore the system to its full working state. The aim of the paper is to optimize the best strategy for the different sensors of the SICS where only maintenance actions are performed or only repair actions need to be carried out. The model is developed and applied to the sensors of a ship and the objective is to determine the optimal asymptotic availability, and in particular in the main propulsion plant of a Liquefied Natural Gas (LNG) carrier. The model is illustrated by a numerical example based on empirical data.

Pre-analytical handling conditions and protein marker recovery from urine extracellular vesicles for bladder cancer diagnosis.

Extracellular vesicles (EVs) contain a variety of biomolecules and provide information about the cells that produce them. EVs from cancer cells found in urine can be used as biomarkers to detect cancer, enabling early diagnosis and treatment. The potential of alpha-2-macroglobulin (A2M) and clusterin (CLU) as novel diagnostic urinary EV (uEV) biomarkers for bladder cancer (BC) was demonstrated previously. To validate the diagnostic value of these proteins in uEVs in a large BC cohort, urine handling conditions before uEV isolation should be optimized during sample transportation from medical centers. In this study, we analyzed the uEV protein quantity, EV particle number, and uEV-A2M/CLU after urine storage at 20°C and 4°C for 0-6 days, each. A2M and CLU levels in uEVs were relatively stable when stored at 4°C for a maximum of three days and at 20°C for up to 24 h, with minimal impact on analysis results. Interestingly, pre-processing to remove debris and cells by centrifugation and filtration of urine did not show any beneficial effects on the preservation of protein biomarkers of uEVs during storage. Here, the importance of optimizing shipping conditions to minimize the impact of pre-analytical handling on the uEVs protein biomarkers was emphasized. These findings provide insights for the development of clinical protocols that use uEVs for diagnostic purposes.

Investigation of Some Physio-Chemical and Microbiological Quality of Fresh Meat Sold Online

Aim: The research was carried out to draw attention to online fresh meat sales and the precautions to be taken in this area by determining some quality characteristics of fresh meat sold online. Materials and Methods: The pH values of the samples were determined using a digital pH meter and the temperature values were determined using an infrared sensor-operated immersion thermometer. The color values of the samples were determined by measuring the L*, a*, and b* color values with a Chromameter color measuring device. The total viable counts was determined in Plate Count Agar medium, coliform bacteria number in Violet Red Bile Agar medium, Staphylococcus spp. number in Baird Parker Agar medium supplemented with Egg Yolk Tellurite Emulsion using classical culture techniques. Results: The mean pH values of pieced, cubed and minced meat purchased online and customers were respectively 5.62/5.62, 5.64/5.70, and 5.81/5.84. The average temperature values of pieced, cubed, and minced meat purchased online and customers were respectively 11.35/11.1°C, 11.26/11.7°C, and 12.07/12.7°C. Total viable counts of pieced, cubed, and minced meat purchased online and customers were respectively determined as 5.69/5.09, 6.34/5.68, and 7.01/6.36 log10 cfu/g. Temperature values and microbiological results determined in both meat samples purchased online with cold chain and customers without cold chain were similar. Conclusion: In light of the results, it is thought that the temperature values, packaging forms, and shipping conditions of online meat should be more prominent in the reorganization of legislation.

On-site detection and laboratory verification of the presence of nerve agent biomarkers using dried blood spots

The analysis of biomedical samples is important for the investigation of the alleged exposure to chemical warfare agents. The present study aims to use dried blood spots for portable detection and laboratory verification of organophosphate poisoning. After in-vitro incubation of blood with Novichok A-230, A-232 and A-234 and sarin, a volume of 25 and 50 µL was spotted on a protein saver card. Subsequently, the dried spots were extracted and analyzed by a mobile cholinesterase test kit. In addition, butyrylcholinesterase (BChE) was isolated and digested by pepsin followed by analysis with liquid chromatography tandem mass spectrometry (LC-MS/MS). The fluoride-activated samples were analyzed by gas chromatography tandem mass spectrometry (GC–MS/MS) and LC-MS/MS. It was found that the CWA induced cholinesterase inhibition was remarkably stable in dried blood spots. Even after at least one month storage under ambient conditions, the same linear reduction was visible as function of nerve agent exposure. Additionally, nonapeptide adducts were identified by LC-MS/MS one month after exposure. Also, intact Novichok nerve agents and regenerated sarin were observed by GC–MS/MS. In addition to the stability of the sample, important benefits of the proposed method include the less invasive sample collection and safer and easier shipping and storage conditions. In conclusion, this study shows the feasibility of using on-site detection and state-of-the-art laboratory analysis of dried blood spots for unambiguous verification of nerve agent exposure.

Growth performance, feed utilization, and resistance to acute crowding of post‐metamorphic stage black sea bass Centropristis striata reared at high stocking densities in a pilot recirculating nursery

AbstractA reliable and cost‐effective source of fingerlings is essential for the successful commercial aquaculture of black sea bass. This study aimed to determine the effects of nursery tank stocking densities on the growth performance, feed efficiency, survival, tolerance to shipping, and biochemical quality of juvenile black sea bass. In two experiments, different stocking densities were compared for black sea bass at different stages of development. In Experiment 1, intermediate stage juveniles (1.27 g mean wt) were stocked at densities of 4.5 and 6.5 fish per liter of tank volume. Growth performance and biochemical quality were similar between the two density treatments. In Experiment 2, early post‐metamorphic stage juveniles (mean wt. = 0.524 g) were compared using the same stocking densities. While the fish reared at 4.5 fish/L were slightly larger, there were no significant differences in growth performance or biochemical quality between the density treatments. After both experiments, the fingerlings from each density treatment showed high survival rates under acute crowding and simulated shipping conditions. The study demonstrates that high NT densities of 4.5 and 6.5 fish/L did not negatively impact the growth performance and quality of black sea bass fingerlings, providing transport‐ready fingerlings in a relatively short period.

Conceptual scheme of intelligent vessel traffic control system with the human factor included

The subject of the research is the development of technologies for automated and automatic ship traffic control systems, which is of great importance in modern shipping conditions. At the same time, special attention is paid to intelligent control systems based on artificial intelligence methods, such as artificial neural networks, fuzzy logic, machine learning, evolutionary computing and genetic algorithms. As a result, integrated information navigation systems, which provide decision-making on all aspects of navigation tasks, primarily where reception, processing, storage and transmission of navigation information is required, are being created and widely used in practice. However, in such developments, due importance is not given to the human factor, namely, it is often not taken into account that the control system of a moving object is a man-machine and consists of a regulator, which includes a human operator (navigator). The inclusion of the navigator in the vessel control link leads to the need to simultaneously take into account the human factor and the characteristics of the vessel controllability, i. e. human and machine factors in their unity. In connection with the development of artificial intelligence, the concept of “human-machine symbiosis” is becoming increasingly relevant in the study of human-machine systems. The problem is that there is still no single point of view on this issue due to the lack of reasonable methods for taking into account the human factor in the process of controlling the movement of moving objects. The results of the theoretical research on the formalization of some aspects of human mental activity and their implementation in the conceptual scheme of an intelligent vessel control system are reflected in the paper. The results obtained may be of interest to specialists in vessel traffic control automation, artificial intelligence, the creation of intelligent control systems and navigation safety.

Prescriptive analytics for a maritime routing problem

Port state control (PSC) serves as the final defense against substandard ships in maritime transportation. The port state control officer (PSCO) routing problem involves selecting ships for inspection and determining the inspection sequence for available PSCOs, aiming to identify the highest number of deficiencies. Port authorities face this problem daily, making decisions without prior knowledge of ship conditions. Traditionally, a predict-then-optimize framework is employed, but its machine learning (ML) models' loss function fails to account for the impact of predictions on the downstream optimization problem, potentially resulting in suboptimal decisions. We adopt a decision-focused learning framework, integrating the PSCO routing problem into the ML models' training process. However, as the PSCO routing problem is NP-hard and plugging it into the training process of ML models requires that it be solved numerous times, computational complexity and scalability present significant challenges. To address these issues, we first convert the PSCO routing problem into a compact model using undominated inspection templates, enhancing the model's solution efficiency. Next, we employ a family of surrogate loss functions based on noise-contrastive estimation (NCE) for the ML model, requiring a solution pool treating suboptimal solutions as noise samples. This pool represents a convex hull of feasible solutions, avoiding frequent reoptimizations during the ML model's training process. Through computational experiments, we compare the predictive and prescriptive qualities of both the two-stage framework and the decision-focused learning framework under varying instance sizes. Our findings suggest that accurate predictions do not guarantee good decisions; the decision-focused learning framework's performance may depend on the optimization problem size and the training dataset size; and using a solution pool containing noise samples strikes a balance between training efficiency and decision performance.

Impact of relative humidity and temperature oscillations mimicking authentic storage during shipping on whey proteins powders properties

The impact of authentic storage conditions during shipping was tested on whey protein concentrate powders as environmental conditions heavily influence shelf-life performance. Most experimental studies are conducted at constant conditions of temperature and/or humidity whereas in real shipment conditions powders are often transported all over the world in ships which can experience vastly different temperatures and humidity with large amplitudes from day-time to night-time. Here, industrial whey protein concentrates and β-lactoglobulin powders were stored under cycled temperatures and relative humidity fashioned from authentic data collected on ships carrying dairy powders. Protein lactosylation and denaturation, browning index, particle surface and powder functional properties were measured in order to estimate functional and physicochemical modifications occurring close to authentic storage under shipping. It was observed that oscillation amplitudes tested had no impact on powders unlike the storage duration. The presence of residual lactose (1.5%) in the whey protein powder induced lactosylation during storage leading to particle surface hydrophobicity and surface elasticity increases whereas for β-lactoglobulin powders (depleted in lactose), transformation of initial lactosylated proteins into advanced Maillard products was observed with no particle surface impact. The rehydration was not impacted regardless of the storage conditions and powder chemical composition.

ANALISIS PENGARUH BILGE KEEL TERHADAP GERAK ROLLING KAPAL FERRY RO-RO DENGAN MENGGUNAKAN METODE STRIP-THEORY

Ships are a mode of transportation that is often used by the community as a link between the islands. People generally use the ferry as a mode of crossing in addition to the economical price but also comfort is still preferred. But in recent years, researchers have often heard cases of shipwrecks. Especially ship crossing accidents caused by overturned ships. Based on this, prevention is needed to reduce the number of ship accidents in the future. One of the keys that can be taken is to improve the technical analysis before the ship is designed. One such analysis related to the ship is seakeeping ship. The method used in this study is to use strip – theory method through OSM program. This method is one of the commonly used methods because it calculates the 3D model into 2D. The results showed the effect of the use of Bilge keel on the ferry Ro-Ro tested with conditions x0, x1, x2, and x3 on the condition of the stationary ship with a wave height of 1.5 m and heading 90 deg. The addition of Bilge keel is able to reduce the resonance of roll motion up to 58% in conditions of variation x1, 61% in variation x2, and 67% in conditions of variation x2. Therefore the installation of bilge keel has a significant effect on the rolling of ferry Ro-Ro.&#x0D; &#x0D; Keywords: Roll Motion, Bilge Keel, OSM.

Postharvest control of spotted-wing drosophila and blueberry maggot by low temperature conditions and fumigation with sulfur dioxide

Cold treatment and fumigation are widely applied approaches to disinfest storage pests after harvest of fruits, nuts, grains, and vegetables. Cold conditions can limit the development and survival of spotted-wing drosophila, Drosophila suzukii Matsumura, in fruit and fumigation of blueberries with SO2 may control blueberry maggot, Rhagoletis mendax Curran. In this study, we found that at least 21 d of 0.5 °C was needed for achieving 98.3% reduction in R. mendax making this unsuitable for pre-export disinfestation. The average concentration of SO2 in modified atmosphere packages with slow release SO2 pads was only 2.93 ( ± 0.37) µL L−1 held at 0.5 °C, too low for control of R. mendax. To develop a fruit treatment schedule that controls both pests, we first combined fumigation of 10,000 µL L−1 SO2 and CO2 at 6% v/v for 30 min followed by cold storage at 2 °C for 12 d or − 0.5 °C for 6 d to mimic shipping conditions. With short fumigation and long cold, R. mendax survival was reduced by no more than 4%, whereas D. suzukii was controlled effectively by cold in fumigated and non-fumigated conditions. However, fruit condition was negatively affected by SO2, so lower dosages were explored. 300 and 500 µL L−1 of SO2 with a longer exposure duration were applied at room temperature. These dosages successfully controlled R. mendax without damaging fruit quality. Survival of R. mendax to pupation was reduced by 58% and 61% after 2 d and 3 d fumigation at 22 ⁰C with 300 µL L−1 SO2, respectively. Fumigating infested blueberries at 22 °C with 500 µL L−1 of SO2 reduced pupation by 97% after 2 d and by 100% after 3 d. Fruit quality parameters were not significantly reduced by the low SO2 fumigation regimen on three different blueberry cultivars. Our data indicate that both insect pests can be controlled in harvested blueberries without loss of fruit quality by the combination of fumigation for 3 d at 22 ⁰C with 500 µL L−1 SO2, followed by cold storage. These results can inform export protocols for blueberries as part of a systems approach that combines in-field management and postharvest control programs.

Hydrodynamic Derivatives of a Ferry Ship Maneuvering in Deep and Shallow Water with Computational Fluid Dynamic Method

The mathematical model and hydrodynamic derivatives can be developed in the simulation program to investigate a ship’s maneuvering performance using numerical simulation. This research describes a study to investigate the hydrodynamic derivatives of maneuvering a ferry ship in shallow and deep water. Using virtual drift and rotating arm model simulated, the hydrodynamic derivatives for a ferry ship’s surging, swaying, and yawing motions were obtained through Computational Fluid Dynamics (CFD). The hydrodynamic derivatives of the ferry ship were analyzed from the model test data using the least-square method. This study investigated three conditions of the ferry ship with various water depth conditions. The simulation result indicated that the ferry ship’s water depth affected its maneuvering performance.

The impact of maritime service quality on employee satisfaction by seafarers rank: evidence from a global survey grounded on ERG theory

PurposeThis study aims to reveal the constituents of seafaring service quality (physical and social environment) and their effects on seafarer employee satisfaction (job satisfaction and turnover intention) and analyse any differences among seafarer ranks. Literature on service quality has overlooked the transportation sector and seafaring in particular.Design/methodology/approachSeafaring service quality is measured by the workplace environment constituted of physical and social environments. Two types of employee (job) satisfaction were explored: overall job satisfaction and turnover intention. This study is based on a unique, large survey based on the Existence-Relatedness-Growth (ERG) needs theory. An exploratory factor analysis revealed four physical environment factors (Ship conditions, Communication facilities, Nautical health and Living conditions) and four social environment factors (Social fit, Team cohesion, Ship company support and Intercultural environment). Multi-group regression analysis assessed the effects of seafaring service quality on employee satisfaction.FindingsThe social environment has stronger effects than the physical environment on job satisfaction but not on employee retention. Team cohesion has strong effects on employee retention, while social fit has stronger effects on overall job performance. Seafarer ranks showed significant variations. The physical environment matters for 2nd engineers' and cadets’ job satisfaction but not for ratings, masters and chief officers. Team cohesion is significant to master, chief officer, engineer and cadet ranks but not for junior officers and ratings. Social fit has stronger effects on overall job performance than employee retention, particularly for ratings, cadets, master, chief officer and chief engineer ranks. Ship company support has the stronger effect on overall job satisfaction among all workplace factors; this is also observed across all ranks.Research limitations/implicationsMotivation theories like the ERG theory can help understand service quality and employee satisfaction in the maritime sector; future studies should examine more behaviour variables/constructs from these theories.Practical implicationsMaritime companies can offer better services to seafarers, who are considered as key workers, by customising their interventions to specific seafarer ranks and developing a supportive culture that improves seafarer well-being.Originality/valueThis study examined the overlooked topic of maritime service quality based on a large-scale survey grounded on ERG theory and reveals how the physical and social environment has different effects on seafarer job satisfaction and retention.

Towards the declaration of the strait of Gibraltar as an environmental controlled area

The emissions from maritime transportation, both greenhouse gases and traditional pollutants, are harmful to the ecosystem and human health. The large quantities of these pollutants emitted by shipping in the Strait of Gibraltar could be reduced if the Strait was declared an Emission Control Area (ECA). Using the SENEM1 emissions model, this study aims to compare the current situation and a possible future situation as an ECA. Unlike other models, SENEM1 includes all the variables – both ship and external conditions - that influence the calculation of emissions. Comparing only the 2017 emissions from ships sailing in the Strait of Gibraltar with the designated ECA simulation, reductions of up to 75.8 % in NOx, 73.4 % in PM2.5 and 94 % in SOx were collected. It would be a wakeup call for the International Maritime Organization (IMO) and the governments responsible to recommend that the Strait of Gibraltar be designated an ECA zone.