Merchant Vessels Research Articles

Availability of Automatic Identification System (AIS) Based on Spectral Analysis of Mean Time to Repair (MTTR) Determined from Dynamic Data Age

Good marine practice and proper operation of navigation, radio navigation, and radio communication systems are nowadays of key importance for marine navigation safety. This applies to merchant vessels and navy ships and effectively monitoring unmanned vehicles along a set route. Technological progress has contributed to developing equipment for ships and unmanned vehicles, which are fitted out with devices of the automatic identification system (AIS). One of the issues in AIS operation is limited-service availability, which manifests itself in the presence of incomplete data for the navigation parameters sent by radio, compressed in dynamic data messages. This results in the unusability of the system information for ships equipped with an AIS transponder. This paper aims to develop an AIS service availability model based on the mean time of incomplete navigation parameter occurrence in AIS data messages and to present the test results in the time and frequency domain using a mathematical method—Fast Fourier Transform. The study results refer to five basic navigation parameters and are indicative of a high service availability index—over 0.99 for three out of the five navigation parameters tested. Data recorded by a ship’s system receiver were the key source of practical knowledge concerning the limitations of AIS service availability. The experiment revealed interruptions in regular data inflow from navigation devices. In effect, a description was provided of a functional relationship based on a spectral analysis of the frequencies of the times occurring between service repair (time to repair—TTR), and the use of the model to analyze other variables was proposed.

Simulation Tool for Winter Navigation Decision Support in the Baltic Sea

This article presents a novel simulation tool for the analysis of winter navigation operations in the Baltic Sea in the context of the Finnish–Swedish Winter Navigation System (FSWNS). The aim of the tool is to simulate the performance of the FSWNS under various potential future operating scenarios and thereby support decision making in matters affecting the operation and development of the FSWNS, for instance, in terms of icebreaking resources and ice class regulations. To this end, the tool considers key performance factors and characteristics of the FSWNS, such as the prevailing ice conditions, the ice-going capability and other technical characteristics of the relevant merchant vessels, the availability of icebreaking resources, and the features of specific icebreaking operations (e.g., convoys). The tool would allow testing of several “what-if” scenarios, answering questions related to optimal engine power for safe, efficient, and environmentally friendly navigation and the optimal scheduling of icebreakers for effective and cost-efficient assistance missions.

A suggested climate service for cyanobacteria blooms in the Baltic Sea – Comparing three monitoring methods

Dense blooms of filamentous cyanobacteria are recurrent phenomena in the Baltic Sea, with occasional negative effects on the surrounding ecosystem, as well as on tourism, human health, aquaculture, and fisheries. Establishing a climate service is therefore suggested; including multi-method observations of cyanobacteria biomass, biodiversity, and biogeography, in correspondence to biotic and abiotic factors. Three different approaches were compared for determination of spatial and temporal variability and trends of the blooms; 1) microscopy-based long-term data, 2) satellite remote sensing, and 3) phycocyanin fluorescence mounted on a merchant vessel. Firstly, microscopy-based data on cyanobacteria biomass from the period 2000–2020 showed that the toxin producing genus Nodularia and non-toxic Aphanizomenon both had summer means of 15 µg C L−1, while Dolichospermum was less dominant with a mean of 8 µg C L−1. Some years also the Kattegat was affected by cyanobacteria blooms, likely transported here by ocean currents. Secondly, the satellite remote sensing time series for the period 2002–2020 indicated that near surface blooms were most frequent in the Northern Baltic Proper and that near surface blooms have increased in the Bothnian Sea, starting later in the season than in the Baltic Proper. The largest extents (i.e., total area covered) were observed in 2005, 2008, and 2018. Thirdly, phycocyanin fluorescence from a flow through sensor mounted on a merchant vessel was used as a proxy for cyanobacteria biomass and correlated to cyanobacteria biomass estimated by microscopy. However, the satellite remote sensing data on surface accumulations showed little resemblance to the data on cyanobacteria biomass based on water sampling and microscopy, interpreted as an effect of methods. Sensors on satellites mainly detect surface accumulations of cyanobacteria while the microscopy data was based on samples 0–10 m, thereby comprising a larger community. Data from satellite remote sensing of cyanobacteria was correlated to the phycocyanin fluorescence indicating that similar bio-optical properties are observed. Finally, results from a downscaled ocean climate model (NEMONordic) were used to produce future scenarios for temperature and salinity, which directly affects cyanobacteria blooms in the Baltic Sea, supposedly by increasing in abundance and change in species composition. Short-term forecasts can be used together with observations for early warning of cyanobacteria blooms, and we suggest an internationally coordinated cyanobacteria observation and warning system for the Baltic Sea area.

A study on international trend and Korean measures regarding Cape Town Agreement of 2012

ABSTRACT At the global level, regulations on the safety of ships are gradually strengthening. Comparing international regulations on the safety of merchant vessels and fishing vessels, fishing vessels did not have a relatively strong safety regulations compared to merchant vessels. However, the importance of fishing vessel safety is being emphasized internationally for various reasons, such as the increase in IUU fishing activities. The Cape Town Agreement of 2012 is a representative international convention on the safety of fishing vessels. Although it has not yet met the requirements for entry into force, but several member states, including the IMO Secretariat, continue to encourage the entry into force of the Agreement. For reference, the Republic of Korea is also preparing various fishery policies with the goal of ratifying the agreement in 2023. This paper briefly introduces international trends related to the ratification of the Cape Town Agreement. In addition, by reviewing the current status of preparations of the Republic of Korea for ratification of the agreement in general, essential preparation measures for smooth ratification and implementation of the Cape Town Agreement have been identified.

Effect of Post-Weld Heat Treatment on the Corrosion Resistance of Super Austenitic Stainless Steel

Seaborne transportation by merchant vessels amounts to more than 90% of the world’s trade volume and it represents about 20% to 30% of the materials generated by the combustion of the total fuel. The International Maritime Organization (IMO) has enforced the use of 0.5% or less low-sulfur fuel oil when operation in all since 2020, and the installation of a scrubber is considered the most realistic alternative in compliance with IMO’s new regulation. However, the desulfurization process unavoidably creates a corrosive environment, and corrosion from it is mainly concentrated on welded materials. To solve the corrosion problem in that area, post-weld heat treatment was applied on Super Austenitic Stainless Steel (UNS N08031) which is commonly used for scrubbers. Upon heat treatment at 1,160 °C or at a higher temperature after welding, microsegregation of welds and base metals was dissolved. As a result, elements were distributed equally and the corrosion resistance increased due to the formation of a uniform oxide film.

The Gradient-Boosting Method for Tackling High Computing Demand in Underwater Acoustic Propagation Modeling

Agent-based models return spatiotemporal information used to process time series of specific parameters for specific individuals called “agents”. For complex, advanced and detailed models, this typically comes at the expense of high computing times and requires access to important computing resources. This paper provides an example on how machine learning and artificial intelligence can help predict an agent-based model’s output values at regular intervals without having to rely on time-consuming numerical calculations. Gradient-boosting XGBoost under GNU package’s R was used in the social-ecological agent-based model 3MTSim to interpolate, in the time domain, sound pressure levels received at the agents’ positions that were occupied by the endangered St. Lawrence Estuary and Saguenay Fjord belugas and caused by anthropomorphic noise of nearby transiting merchant vessels. A mean error of 3.23 ± 3.76(1σ) dB on received sound pressure levels was predicted when compared to ground truth values that were processed using rigorous, although time-consuming, numerical algorithms. The computing time gain was significant, i.e., it was estimated to be 10-fold higher than the ground truth simulation, whilst maintaining the original temporal resolution.

The Case of M/S Józef Conrad and Law of Air Warfare During the Vietnam War

Abstract On the 20th of December 1972, the Polish-flagged merchant vessel M/S Józef Conrad, anchored in the North Vietnam port of Haiphong, was hit by an air-delivered projectile in the Linebacker ii air campaign, also referred to as the ‘Christmas bombing’. The attack caused both loss of life and health among Polish sailors, and destroyed the ship itself. In 2020, the Polish Commissioner for Human Rights submitted a formal petition to the executive branch of the Polish government, highlighting that despite the fact that the act was a violation of the iccpr and udhr, neither legal actions nor diplomatic efforts were later undertaken on behalf of the victims. The statement of the High Commisioner did not examine the bombardment from the perspective of the law of air warfare, which is a pivotal precondition to determine the wrongfulness of the act in the light of international law.

Shipping Decarbonization: An Overview of the Different Stern Hydrodynamic Energy Saving Devices

In recent years, research into ships has focused on reducing emissions, consuming less energy, and being more efficient. As a result, the maritime industry has been continuing in a green and sustainable direction. Improving the fuel efficiency of ships and the decarbonization of shipping are important issues to reduce fuel consumption and emitted Greenhouse Gas (GHG) amounts. Decarbonization in the shipping industry could be achieved through technical and operational strategies such as Energy Saving Devices (ESDs) to reduce the fuel consumption of new and existing ships. According to the makers, ESDs can optimize fuel efficiency by up to 15%. This paper reviews the current literature on stern hydrodynamic ESDs, which are mainly used on typical merchant vessels, i.e., bulkers, tankers, and carriers. A comprehensive review is carried out analysing the different available solutions for stern hydrodynamic ESDs, the working principles, the methods used for the design, optimization, and evaluation of the performance improvements, and the relevant issues of these specific ESDs.

Acoustic vector sensor analysis of the Monterey Bay region soundscape and the impact of COVID-19.

From February 2019 through January 2021, data were collected by an acoustic vector sensor moored on the seafloor at a depth of approximately 900 m just outside of Monterey Bay, California, near a major shipping lane off the California coast. Analysis of the vector sensor data has shown the ability to accurately determine bearings to merchant vessels at ranges up to 60 km. This paper examines the features of the low-frequency soundscape using spectral probability densities and evaluates directional features through vector intensity processing as well as coherent linear and adaptive processing of the vector sensor channels. Merchant vessel acoustic data were analyzed using the 1/3 octave band centered at 63 Hz. Over the period analyzed, a reduction in merchant vessel noise was observed between February and June 2020 relative to the same period in 2019, consistent with a reduction in vessel traffic due to the worldwide response to COVID-19. The directional features of the data evaluated through adaptive processing methods also suggest this reduction can be most clearly distinguished towards the south, where the shipping lane is limited to transiting vessels, rather to the north-northwest, where merchant vessels tend to congregate on approach into the San Francisco Bay area.

A novel quantitative and qualitative model for forecasting the navigational risks of Maritime Autonomous Surface Ships

Navigators, shipping companies, port authorities and government maritime bureaus are interested in understanding the navigational risks of Maritime Autonomous Surface Ships (MASS) in order to decide how to develop port facilities and make navigational safety regulations for MASS in the future. Unfortunately, so far there are no historical data of actual marine accidents of MASS. Most of the autonomous ship researches focused on small autonomous boats in the past, few discussed the navigational risks of large MASS. Therefore, this study proposes a novel model for forecasting objectively and quantitatively the navigational risks of MASS. Firstly, this study constructs an analytical hierarchy frame for forecasting the navigational risk of MASS. Secondly, a novel computing method is developed to integrate the subjective navigator judgment of MASS and objective actual marine accident data of crewed merchant vessels, and then to measure the navigational risk of MASS. The results showed that the navigational risk of mechanical malfunction accident is the largest when oceangoing at sea; the navigational risk of collision is the largest when entering/exiting a port. The findings could be given for a reference while making policies in the future.

Ammonia as Clean Shipping Fuel for the Baltic Sea Region

Abstract The international shipping industry transports about 90 per cent of the global trade volume and is responsible for only two per cent of the anthropogenic carbon dioxide emissions. Consequently, the shipping sector is considered as an environmentally friendly transport mode. Nevertheless, global shipping can also improve its environmental footprint. So that in recent years clean shipping initiatives have been placed on the political agenda with the implementation of the Sulphur Emission Control Area (SECA) and Nitrogen Emission Control Area (ECA) regulations and the Global Cap. The next target of the International Maritime Organisation (IMO) in the sequel of the Paris Agreement of climate protection is dedicated to reduction of the Greenhouse Gas (GHG) emissions by up to 50 % until the year 2050. The paper investigates and discusses the research questions to what extent ammonia can be used in Baltic Sea Region (BSR) to propel merchant vessels and how ammonia can fulfil future demands under technical, economic and infrastructural aspects to become the green fuel for the Baltic Sea Region (BSR) shipping industry. The study benchmarks the properties of ammonia as marine fuel against Marine Gas Oil (MGO) and Liquified Natural Gas (LNG). The research is based on secondary data analysis that is complemented by expert interviews and case studies, and the results are empirically validated by data that were collected during the EU projects “EnviSuM”, “GoLNG”, “CSHIPP” and “Connect2SmallPorts” that took place within the last four years in the BSR.

Importance and applicability analysis of the health and safety measures taken against the coronavirus disease on merchant vessels

The coronavirus (COVID-19) outbreak has affected seafarers worldwide. This paper demonstrates the measures taken to prevent the spread of the corona-virus on merchant ships and evaluates them in terms of importance and applicability. Contamination reducing measures were determined through expert opinion and literature review. While their importance values were calculated using the fuzzy analytic hierarchy process method in which the total integral value with optimism index was applied, the applicability levels were revealed using a fivepoint Likert scale. The imbalance in rest and working hours was clearly seen in the re-sults. Immune system pro-tective measures were the most critical measures; however, two of them have the lowest applicability val-ue among all criteria. They were followed by the measures taken through training, the measures to be applied in case of personnel showing disease symptoms, and the temperature measurement. In terms of the ship locations and ship operations, maintaining physical distance on deck at the port was found more critical. Its applicability level was slightly below average. This paper is the first study in the literature in which the measures taken to prevent the spread of the coronavirus pandemic on merchant ships were demonstrated in detail and evaluated with scientific methods in terms of importance and applicability. The research findings will help companies in the risk assessment process and contribute to the enhancement of the preparedness of the maritime industry for such situations by helping to protect the seafarers’ health and safety.

Selection of the Viable Merchant Vessel Type for Charterers and Shipbrokers During the Carriage of Hns Cargoes by Implementing Intuitionistic Fuzzy Topsis Method

Selection of the Viable Merchant Vessel Type for Charterers and Shipbrokers During the Carriage of Hns Cargoes by Implementing Intuitionistic Fuzzy Topsis Method

Structuring design information by analyzing ship specifications

When specifications for a merchant vessel are prepared, they are based on existing specifications, and specifications are repeatedly changed in response to the shipowner's requests. Since the components of a ship are complex and interrelated, there is a possibility that some specification items will be changed in accordance with certain specification changes, but the relationships among these specification items are not organized and often depend on the intuition and experience of skilled workers. In this paper, the relationship between specification items for the equipment part of a merchant ship design document is calculated using the Cramer’s coefficient of association and expressed as a network structure so that even a non-skilled person can efficiently create specifications. The related values between specification items were derived on two scales, the components and their attributes, and multiple calculation methods were considered. It was also suggested that clustering specifications in advance and collecting specifications with similar characteristics may enable more accurate calculation of the relationship between specification items.

Know your safety indicator – A determination of merchant vessels Bow Crossing Range based on big data analytics

Even in the era of automatization maritime safety constantly needs improvements. Regardless of the presence of crew members on board, both manned and autonomous ships should follow clear guidelines (no matter as bridge procedures or algorithms). To date, many safety indicators, especially in collision avoidance have been proposed. One of such parameters commonly used in day-to-day navigation but usually omitted by researchers is Bow Crossing Range (BCR). Therefore, this paper aims to investigate, what are typical, empirical values of BCR during routine operations of merchant ships, as well as investigate what factors impact this indicator and to what extent. To this end, a ten-year big dataset of real maritime traffic obtained from the Automatic Identification System (AIS) was used to provide statistical and spatiotemporal analyses. The results indicate that BCR is strongly related to the type of navigational area (open sea or restricted waters) but not with the dimensions or speed of ships. Among analyzed vessel types, passenger ships were noted as vessels that cross other bows at the closes ranges. Results of this study may be found interesting by fleet managers and developers of Maritime Autonomous Surface Ships (MASS). The former could utilize the results to provide revised operational guidelines for deck officers while the latter - propose an early-detection warning system based on empirical data for prospective MASS.

Numerical modelling and dynamic response analysis of a 10 MW semi-submersible floating offshore wind turbine subjected to ship collision loads

The number of installed offshore wind turbines is continuously growing worldwide in recent years. Offshore wind farms are generally located near the coast close to traffic lanes and are exposed to the risk of collisions from visiting and passing ships. Potential consequences of collisions may vary from local structural damage to the detachment of turbine nacelles and rotors, and even tower collapse and capsizing of the turbine platform, causing significant economic loss and fatalities.This paper investigates ship collision responses of a semi-submersible floating offshore wind turbine (FOWT), i.e. the OO-STAR floater with the DTU 10 MW blades, using the nonlinear finite element code USFOS. The OO-STAR floater is made of post-tensioned concrete designed by Dr. techn. Olav Olsen. The striking ships are selected to be a modern supply vessel of 7500 tons and a shuttle tanker of 150,000 tons, representing respectively service/coastal merchant vessels and large passing vessels. Modelling of the FOWT in USFOS is described in detail including the OO-STAR floater, the DTU 10 MW turbine blade, the turbine tower, and the mooring system. The modelled hydrodynamic loads include buoyancy loads and motion induced radiation loads using the Morrison equation. The effects of external waves and currents are assumed to be small and ignored in all directions. Eigenmode analysis of the turbine model is performed to verify the established model.Global collision response analyses of the FOWT were performed in both parked and operating conditions. The ship resistance is modelled as nonlinear springs in USFOS containing force displacement curves simulated in LS-DYNA. In operating conditions, wind loads are introduced including wind thrust loads and wind induced torque to rotate the turbine blades. The changes of upstream wind speeds and rotor/wake interactions during collisions are neglected. The results are discussed with respect to energy absorption of the ship and the FOWT, and structural responses of the FOWT including global motions, nacelle accelerations, tower clearance, tower vibrations, and responses of the mooring system.

A probabilistic model to evaluate the resilience of unattended machinery plants in autonomous ships

Over the next few years, digitalization and automation are expected to be key drivers for maritime transport innovation to be key drivers for maritime transportation innovation. This revolutionary shift in the shipping industry will heavily impact the reliability of the machinery which is intended to be operated remotely with minimum support from humans. Despite a large amount of research into autonomous navigation and control systems in maritime transportation, the evaluation of unattended engine rooms has received very little attention. For autonomous vessels to be effective during their unmanned mission, it is essential for the engine room understand its health condition and self-manage performance. The unattended machinery plant (UMP) should be resilient enough to have the ability to survive and recover from unexpected perturbations, disruptions, and operational degradations. Otherwise, the system may require unplanned maintenance or the operation will stop. Therefore, the UMP must continue its operation without human intervention and safely return the ship to port. This paper aims to develop a machine learning-based model to predict an UMP's performance and estimate how long the engine room can operate without human assistance. A Random Process Tree is used to model failures in the unattended components, while a Hierarchical Bayesian Inference is adopted to facilitate the prediction of unknown parameters in the process. A probabilistic Bayesian Network developed and evaluated the dependent relationship between active and standby components to assess the effect of redundant units in the performance of unattended machinery. The present framework will provide helpful additional information to evaluate the associate uncertainties and predict the untoward events that put the engine room at risk. The results highlight the model's ability to predict the UMP's trusted operation period and evaluate an unattended engine room's resilience. A real case study of a merchant vessel used for short sea shipping in European waters is considered to demonstrate the model's application.

Analysing the Performance of Ammonia Powertrains in the Marine Environment

This study develops system-level models of ammonia-fuelled powertrains that reflect the characteristics of four oceangoing vessels to evaluate the efficacy of ammonia as an alternative fuel in the marine environment. Relying on thermodynamics, heat transfer, and chemical engineering, the models adequately capture the behaviour of internal combustion engines, gas turbines, fuel processing equipment, and exhaust aftertreatment components. The performance of each vessel is evaluated by comparing its maximum range and cargo capacity to a conventional vessel. Results indicate that per unit output power, ammonia-fuelled internal combustion engines are more efficient, require less catalytic material, and have lower auxiliary power requirements than ammonia gas turbines. Most merchant vessels are strong candidates for ammonia fuelling if the operators can overcome capacity losses between 4% and 9%, assuming that the updated vessels retain the same range as a conventional vessel. The study also establishes that naval vessels are less likely to adopt ammonia powertrains without significant redesigns. Ammonia as an alternative fuel in the marine sector is a compelling option if the detailed component design continues to show that the concept is practically feasible. The present data and models can help in such feasibility studies for a range of vessels and propulsion technologies.

Are there differences between officers and ratings on merchant vessels concerning effort\u2013reward imbalance: a cross-sectional maritime field study

PurposeToday, measures to economise in the operation of ships can cause either an effort–reward imbalance or health impairments. The goal of this study was to assess the risk of effort–reward imbalance including overcommitment among officers and ratings on merchant vessels during their assignments and to evaluate lifestyle factors of seafarers as well as the health-promoting conditions on board.MethodsA study sample of 308 male seafarers was examined during a total of 20 sea voyages on German container ships (participation rate 91.9%).ResultsOnly 11 seafarers were identified as having an increased health risk of an effort–reward imbalance (ER ratio > 1). Officers tended to have a higher risk of an elevated ratio than ratings (4.4% vs. 3.1%) and also showed a significantly higher risk of an ER ratio above the median (58.8% vs. 41.8%; p = 0.022). Compared to land-based populations, the average overcommitment score of seafarers was high (17.9)—particularly among officers (20.3 vs. 16.5; p = 0.031). This corresponded to an elevated risk of overcommitment among officers compared to ratings (OR 2.14; 95% CI 1.78–2.37). This elevated risk remained significant after adjustment for age (OR 2.11; 95% CI 1.76–2.35) and job-related stressors.ConclusionAlthough an elevated risk of effort–reward imbalance was only observed in few seafarers, this study revealed a high prevalence of overcommitment particularly among officers. In the course of time, overcommitment can lead to mental exhaustion. Therefore, shipboard health-promoting conditions need to be optimised.

Work-family conflict and job stress among seafarers: the moderating role of job satisfaction

ABSTRACT Work-family conflict (WFC) is not only prevalent among seafarers but also may cause their job stress. The objective of this research is to investigate the relationship between WFC and job stress, examining the moderating role of job satisfaction, which plays in this relationship. A cross-sectional survey was conducted in Yangshan Port, Shanghai, China, from August to October 2019. Seafarers working on merchant vessels participated in the present study. Hierarchical linear regression analyses were employed to test the moderating role of job satisfaction. The results demonstrated that WFC was positively associated with job stress. Job satisfaction played a moderating role in the association of WFC with job stress. The findings show that job satisfaction was a crucial factor to reduce seafarers’ job stress. Managers should therefore enhance organizational investment and support in job satisfaction to reduce seafarers’ job stress.