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As computational fluid dynamics has matured to the point where it is widely accepted as a key tool for ship hull form design, development of simulation-based design (SBD) has been strongly motivated in the past decades. Although many successful demonstrations of SBD were presented, most cases just deal with minimization of total resistance with a formulation of single-objective optimization problem. Once the interest is in minimization of ship-scale delivered power or effective power, issue related to accuracy of the simulation appears critical in many cases, which yield unconvincing results to hull form designers. The method we propose in this paper aims at overcoming the issues. Instead of just counting on predicted power from the simulation and solve a single-objective optimization problem, we first introduce variable decomposition approach to decompose a target ship performance function into terms including embedded parameters, then formulate and solve a multi-objective optimization problem (MOOP). Any scheme to solve MOOP can be applied. In the following, an overview of the present approach is given and results are presented and discussed through comparison with available experimental fluid dynamics data and detailed analysis of flow and integral parameters. The effectiveness of the present approach is also discussed.

Steels are preferred in the building of commercial ships because they can be easily welded and supplied. Although it varies according to the parts of the ships, it is known that high-strength steels are preferred especially in bulb and side coatings where relatively high strength is desired during the building process. In the process of welding these steels, mostly gas and submerged arc welding are used. On the other hand, studies continue for the use of the new generation friction stir welding (FSW), which is known to have many advantages over existing welding methods, in the shipbuilding process. The formability of the welded plates in the construction process of the ships is extremely important to give the necessary form to the ship. On the other hand, post-weld formability properties are of great importance for determining the strength and elongation values in wave crests and wave troughs to which ships are exposed during navigation. In this context, in this study, relatively high-strength AH32 shipbuilding steel was joined with FSW and the formability behavior of the welded region was investigated comparatively by experimental, finite element analysis and artificial neural network methods. As a result of the studies, it was determined that the strength values in the weld zone of the steel joined by FSW increased compared to the pre-weld and the formability behavior did not deteriorate. In addition, it was determined that the results of finite element analysis and artificial neural networks were extremely consistent with the experimental data, and it was determined that the models created in the study would give close results to the real results even without experimental studies.

Ship classification in SAR images has attracted much attention by researchers. In this paper, a SAR target classification method for three commercial ships (container ships, bulk carriers and oil tanker) is proposed by analyzing their scattering features. Firstly, the ship slice is preprocessed to obtain the binary image, from which the density features can be extracted, which describing the ship scattering point distribution. Finally, the support vector machine (SVM) classifier is applied to classify these three types of commercial ships. The experimental results show that the classification accuracy of structure feature and strength feature is low, while the proposed density feature can reach 80% for three types of ships. The combination of structure features and strength features with density features can improve the classification accuracy. Combining the three features has the best classification performance.

Shipping faces challenges of reducing the dependence on fossil fuels to align with the international regulations of ship emissions reduction. The maritime industry is in urgent need of searching about alternative energy sources for ships. This paper highlights the applicability of harnessing wind power for ships. Flettner rotors as a clean propulsion technology for commercial ships are introduced. As a case study, one of the bulk carrier ships operating between Damietta port in Egypt and Dunkirk port in France has been investigated. The results showed the high influence of the interaction between ship course and wind speed and direction on the net output power of Flettner rotors. The average net output power for each rotor will be 384 kW/h. Economically, the results reveal that the use of Flettner rotors will contribute to considerable savings, up to 22.28% of the annual ship’s fuel consumption. The pay-back period of the proposed concept will be 6 years with a considerable value of levelized cost of energy. Environmentally, NO x and CO 2 emissions will be reduced by 270.4 and 9272 ton/year with cost-effectiveness of $1912 and $55.8/ton, respectively, at annual interest rate of 10%.

The introduction of Maritime Autonomous Surface Ships (MASS) into the maritime transport sector has significantly accelerated, as illustrated by the growth of project prototypes and by academic research throughput. While the MASS race accelerates, motivated by recent discussions in the IMO, there are still critical barriers and considerable challenges awaiting the materialisation and integration of MASS into the maritime sector. This study reviews the literature and builds homogeneous clusters in relation to MASS drivers and opportunities, including barriers and solutions. The results show that many benefits will result from MASS, while at the same time there are still many barriers that may hinder the full integration of MASS into commercial ships and oceangoing vessels. Though some solutions and recommendations were discussed, it is suggested that the barriers are taken into consideration in all project prototypes and research, and by policy makers. Identification of drivers, opportunities, and barriers serves as a holistic tool for port policymakers, designers and builders (of project prototypes), and managers. The results envision the current and future needs of MASS in line with the transition toward smart and automated industry. Academically, the study enriches scholarly discussions on MASS while the clusters can be cross-pollinated in further empirical investigation.

Niche areas of ships, such as lateral thruster tunnels, sea chests, and propellers, are often hot spots for the accumulation of biofouling organisms, a potential source of aquatic invasive species. Yet, the relative importance of different niche areas is poorly resolved, in terms of both total surface area and the associated biota (i.e., the species of organisms and their abundances). To address this information gap, a method was developed to estimate the extent of various niche areas in the global fleet of 120,252 commercial ships active between 1999 and 2013. The total niche area for these vessels was estimated to be 32,996 × 10 3  m 2 , representing approximately 10% of the total wetted surface area (WSA) available for colonization by biota. Considering the portion of niche areas relative to the total WSA, it was highest for passenger vessels (27%), followed by tugs (25%), and fishing vessels (21%), with niche areas representing a small portion of the WSA for bulk carriers and tankers (7–8%). Examining the different types of niche areas, thruster tunnels had the greatest total extent (10,189 × 10 3  m 2 ), representing a disproportionately large contribution (>50%) of the total niche area for passenger vessels and tugs compared to other vessel types. This result, combined with the use and cleaning of thrusters, may render them “super-hot spots” of biofouling. The uneven distribution and extent of niche areas across vessels has implications for transfers of organisms and management strategies to reduce invasions associated with the surfaces of ships.

Each year, commercial ships emit over 1.67 Tg of particulate matter (PM) pollution into the atmosphere. These ships rely on the combustion of heavy fuel oil, which contains high levels of sulfur, large aromatic organic compounds, and metals. Vanadium is one of the metals most commonly associated with heavy fuel oil and is often used as a tracer for PM from ship exhaust. Previous studies have suggested that vanadium-containing PM has impacts on human health and climate due to its toxicological and cloud-formation properties, respectively; however, its distribution in the atmosphere is not fully understood, which limits our ability to quantify the environmental implications of PM emitted by ships. Here, we present data obtained from a Particle Analysis by Laser Mass Spectrometry (PALMS) instrument on the NASA DC-8 aircraft during the 2016–2018 Atmospheric Tomography Mission (ATom) and show that ∼ 1 % of the accumulation mode particles measured in the marine boundary layer of the central Pacific and Atlantic oceans contain vanadium. These measurements, which were made without targeting ship plumes, suggest that PM emitted by ships is widespread in the atmosphere. Furthermore, we observed vanadium-containing ship exhaust particles at altitudes up to 13 km, which demonstrates that not all ship exhaust particles are immediately removed via wet deposition processes. In addition, using laboratory calibrations, we determined that most vanadium-containing ship exhaust particles can contain up to a few weight percent of vanadium. This study furthers our understanding of both the chemical composition and distribution of PM emitted by ships, which will allow us to better constrain the climate, health, and air quality implications of these particle types in the future. We note that these data were collected prior to the 2020 International Maritime Organization (IMO) sulfur regulation and stand as a reference for understanding how ship emissions have evolved in light of these regulations.

Recent global trade disruptions, due to blockage of the Suez Canal and cascading effects of COVID-19, have altered the movement patterns of commercial ships and may increase worldwide invasions of marine non-indigenous species. Organisms settle on the hulls and underwater surfaces of vessels and can accumulate rapidly, especially when vessels remain stationary during lay-ups and delays. Once present, organisms can persist on vessels for long-periods (months to years), with the potential to release propagules and seed invasions as ships visit ports across the global transportation network. Shipborne propagules also may be released in increasing numbers during extended vessel residence times at port or anchor. Thus, the large scale of shipping disruptions, impacting thousands of vessels and geographic locations and still on-going for over two years, may elevate invasion rates in coastal ecosystems in the absence of policy and management efforts to prevent this outcome. Concerted international and national biosecurity actions, mobilizing existing frameworks and tools with due diligence, are urgently needed to address a critical gap and abate the associated invasion risks.

The challenge of achieving net-zero carbon emissions in the shipping sector is a pressing issue that is yet to be fully overcome. While new fuels and technologies hold promise for the future, they are not currently viable solutions on a large scale in the short-term. One strategy that is being considered as a way to reduce CO2 and CO emissions in the immediate future is carbon capture technology. Additionally, the possibility of a carbon tax being implemented in the future further strengthens the case for the adoption of this technology, which is already quite mature and in use in industries, although it has yet to be developed in the maritime sector. In this paper, the authors start from the definition of carbon capture technology to provide a technical overview of the solutions that are currently available to the maritime sector. Given the absolute innovation of such systems for application on board ships, the authors studied their installation and developed appropriate schemes to illustrate the feasibility of integration of these new technologies on board. Furthermore, the authors highlight the different levels of technological readiness of the proposed systems based on their potential for implementation on board commercial vessels.

Short sea shipping involves transporting passengers and cargo between European ports and coastal countries bordering Europe on enclosed seas. Challenges include aging fleets and environmental concerns, but efforts to reduce emissions are in progress through the use of low-sulfur fuels, hybrid and electric vessels, and improved energy efficiency. This study focuses on emissions from international short shipping routes between Mytilini and Ayvalik, using standardized emission factors to calculate CO 2 , SO 2 , NO x , PM, and HC emissions. The research aims to bridge knowledge gaps and provide insights into these emissions, identifying the main commercial ships on the route, analyzing their emissions, and discussing the findings. Overall, six ships completed the route, consuming an average of 60 L of fuel per hour per 100 HP, depending on factors like speed and total load. Notably, NO x emissions are the highest, followed by sulfur oxides, with values exceeding 12.9 and 3.5 tons, respectively. As anticipated, cruising is the shipping practice with the highest energy footprint, amounting to 695 MWh. An essential discovery is that hoteling plays a significant role in energy consumption and emissions, accounting for 152 MWh out of the total 881 MWh consumed across all shipping practices. The potential adoption of hydrogen as a fuel holds the promise of substantial reductions in greenhouse gas emissions, enhancements in air quality, and noise pollution mitigation.