Search Results (28)

Long-term continuous and reliable real-time ocean wave height data are important for climatologists, offshore industries, leisure craft users, and marine forecasters. However, maintaining data continuity and reliability is challenging due to offshore equipment failures and sparse in situ observations. Opposing interactions between wind-driven ocean waves generate acoustic waves near the ocean surface, which can convert to seismic waves at the seafloor and travel through the Earth’s solid structure. These low-frequency seismic waves, known as secondary microseisms, are clearly recorded on terrestrial seismometers offering land-based access to ocean wave states via seismic ground vibrations. Here, we demonstrate the potential of this by estimating ocean Significant Wave Heights (SWHs) in the Northeast Atlantic using continuous recordings from a land-based seismic network in Ireland. Our method involves connecting secondary microseism amplitudes with the ocean waves that generate them, using an Artificial Neural Network (ANN) to quantify the relationship. Time series data of secondary microseism amplitudes together with buoy-derived and numerical model ocean significant wave heights are used to train and test the ANN. Application of the ANN to previously unseen data yields SWH estimates that closely match in situ buoy observations, located approximately 200 km offshore, Northwest of Ireland. Terrestrial seismic data are relatively cheap to acquire, with reliable weather-independent data streams. This suggests a pathway to a complementary, exceptionally cost-effective, data-driven approach for future operational applications in real-time SWH determination. Full article

An air-lubricated planing hull with integrated air channels presents a transformative approach for enhancing marine vessel performance by significantly reducing hydrodynamic resistance. Within the framework of air-layer drag reduction research, the precise definition and optimization of geometric design parameters are critical, as they directly influence the formation and stability of the air layer and the hydrodynamic characteristics of the hull. Applying a fully parameterized modeling approach to the air-lubricated planing hull is highly relevant and pivotal for advancing systematic, performance-driven hull design and optimization in modern naval architecture. This study proposes a fully parameterized modeling method specifically designed for such crafts. The method utilizes B-spline curves to represent the planar projections of the primary hull contours and the sectional lines of key hull surfaces. The hull surfaces are fitted using non-uniform rational B-Spline (NURBS) surfaces, and the design parameters are smoothed according to the principle of minimum strain energy, leading to fair and smooth hull surfaces. A dedicated program is developed based on this method. It facilitates the rapid generation of smooth hull forms for an air-lubricated planing hull solely from design parameters without depending on parent hull forms. This approach provides geometric hull samples for optimizing the hydrodynamic performance of the air-lubricated planing hull. Full article

The wing-in-ground (WIG) effect occurs when air pressure is created beneath a craft moving close to the ground. The pressure created adds upwards lift, resulting in less need for propulsion for moving forward. Over the years, several companies in various countries have developed wing-in-ground crafts—marine vessels, looking like airplane, that operate using the ground effect. However, no commercial routes are currently in operation using such crafts. This article seeks to identify the critical factors that contribute to the successful commercialization of WIG crafts. The study is composed of a literature review, a company comparison and an analysis of one case study close to successful commercialization. The study indicates that the following actions are critical for the commercial success of a company engaged in WIG operations: engaging community, enhancing R&D, establishing a robust technological system and focusing on safety and compliance. It is also noted that technological readiness itself does not guarantee the successful implementation of WIG crafts on commercial routes. Full article

(1) Background: Additive manufacturing (AM), which has also become known as 3D printing, is rapidly expanding its areas of use in the marine industry. This study undertakes a historical development of AM in the marine industry. The study also criticises these developments to date and the future technological applications they will lead to, while considering the benefits for the industry and its segments. (2) Methods: This review followed the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and was registered in the Open Science Framework. The personalized search strategy was applied to Scopus, and Web of Science databases. The core emphasis was placed on two eligibility criteria throughout the evaluation process. Firstly, Criteria 1 sought to determine the paper’s relevance to AM. Secondly, Criteria 2 aimed to assess whether the paper delves into the implementation of AM or provides valuable insights into its utilisation within the marine industry. The risk of bias was analysed using a checklist of important parameters to be considered. (3) Results: In recent years, there has been a growing trend in studies related to the application of AM in the marine industry. While AM is widespread in industries such as automotive, aviation, and healthcare, it is relatively new for the marine industry. Almost only 5% of publications related to AM are related to the marine industry. There is a need for extensive research in many areas. It has been observed that classification societies and approval institutions, which largely drive the marine industry, have not yet taken AM into consideration sufficiently. (4) Conclusions: The studies show that AM is very promising for the marine industry. However, there are new studies at the experimental and theoretical level that need to be carried out to determine the right materials and AM methods to establish the quality control methodology and the necessary classification rules. This review also emphazises AM’s pivotal role in reshaping the marine industry, addressing the potential environmental and occupational safety effects of AM. Full article

Meroterpenoid-type marine natural compounds have attracted an increasing amount of attention due to their peculiar chemical structures and their potential for the development of therapeutically important probes. Within this group of substances pelorol stands out; it is a natural compound isolated from marine organisms with a unique structure and an interesting biological profile. In this article, we summarize and highlight the most interesting aspects of the synthetic procedures towards this compound, which have two common key steps. The first is the coupling of a drimanyl derivative with a compound derived from an arene. The second is a Friedel–Crafts cyclization which forms the C ring of the natural product. Despite the synthetic advances achieved so far, we consider that a more efficient synthetic procedures could be carried out, since their synthetic routes are difficult to scale up due to numerous reaction steps and the limitations imposed by the use of some reagents. In this article, we present a new and versatile retrosynthetic analysis of (−)-pelorol and analogs, which is highly desirable for their easy preparation and subsequent broad study of their biological activities. This is a retrosynthetic route that could improve those reported in the literature in terms of cost-effectiveness. Full article

This paper surveys the recent advances in dynamic positioning (DP) control for marine crafts. DP of marine crafts means that a craft can maintain a fixed position and heading, or move along a predetermined trajectory slowly without the anchoring system, using only its own thruster system to counteract ocean disturbances. The survey is by no means exhaustive but provides a survey of some of the major technological advancements in DP controller design over the years of research and development. Firstly, the model of marine crafts and some difficult problems in DP control are introduced including the impact of multiple source disturbance, unavailable velocity measurement information, resource conservation and performance optimization, destabilizing impact of faults and network security and compound multi-constraint restrictions. Then, the DP control schemes in recent years are summarized and classified in detail. Finally, some theoretical and technical problems are proposed, including online data-driven model-free control, man–machine combination intelligent control and composite hierarchical anti-disturbance control to guide future investigations. Full article

Due to increasingly stringent IMO and European Commission requirements for greenhouse gas emissions, the present study analysed the projected reductions in CO₂ emissions achieved by using methanol as an alternative fuel to power custom service operation vessels (SOVs) serving wind platforms in the Baltic Sea. Methanol is a relatively new fuel, approved for use as a safe marine fuel in the late 2020s. In these analyses, reference was made to the current interim guidelines, supplementing the IGF Code in the form of MSC.1/Circ.1621. The SOV type was chosen because of the current growing demand for these ships (the dynamic development of offshore wind power) and the lack of analyses of this type of small craft. The importance of assessing CO₂ emissions in this case is due to the specifics of the vessel’s operation in different modes, and thus the variable load on the propulsion system and the area of operation close to the coastline. A computational research method was used to evaluate CO₂ emissions, as well as the cost of methanol fuel, using current regulations and technical data. A comparison was also made between conventional MDO and LNG fuels. The first results of the analysis showed that methanol fuel is only competitive with MDO (a few-percent advantage) in terms of the average estimated index value EIV. Economically, it will require a higher investment, despite the favourable unit price of methanol compared to LNG and MDO. Full article

Beer brewing is a complex process that comprises many fundamental unit operations. Over the last few years, craft brewing has become very popular, and the number of small-scale commercial brewers has drastically increased. However, due to the use of traditional beer-making methods, energy utilization in craft breweries tends to be inefficient, resulting in poor sustainability. Therefore, there is a necessity for a holistic analysis on the energy profile of craft beer brewing to evaluate its environmental performance on a unit operation basis. In this study, a gate-to-gate life cycle assessment was conducted to analyze and compare the environmental profiles of craft beer brewing, including ale and lager, at commercial (microbrewery) and pilot scales. A process simulation model was developed to estimate the electricity and/or natural gas uses of each unit operation, including heating, mashing, boiling, whirlpool, cooling, fermentation, and maturation. The model accurately predicted the steam use for pilot-scale brewing and the electricity and gas bills of a microbrewery. The beers brewed at the microbrewery scale (21.5-barrel brewhouse) had 2–11-fold lower environmental impacts than those brewed at the pilot scale (1-barrel brewhouse), and lager beer generally produced 11–32% higher impacts than ale. The fermentation and maturation steps in brewing were the major contributors to global warming and terrestrial acidification, whereas the mashing step was predominantly responsible for marine eutrophication. This study provides craft brewers with a useful tool for identifying the hotspots of energy use in their processes and developing potential improvement strategies. Full article

For the marine industry, resistance reduction can reduce energy consumption and achieve protection of the marine environment. The use of air lubrication to reduce the resistance of ships is one of the most important ways. With this technology, high-speed air cavity crafts show immense potential as they can be utilized in various marine activities, such as emergency rescue, supply, and maritime security. Through experiments, this study presents an in-depth analysis of the effects of bubble chamber pressure and initial stern inclination on the resistance of high-speed air cavity crafts at different speeds. The results show that air pressure has a significant impact on resistance. It was found that as the speed of the ship increased, the resistance reduction effect became more prominent under the same pressure conditions. Moreover, the resistance tended to stabilize when the pressure reached a certain value. In addition to the air pressure, the longitudinal inclination does have an effect on resistance reduction. To achieve better resistance reduction, the initial stern inclination angle should be chosen appropriately. Furthermore, adjusting the angle with speed changes can optimize the resistance reduction effect. This experimental study provides critical support for conducting further research on high-speed air cavity crafts. The findings offer valuable insights into improving hull forms, guiding host selection, and assessing performance. Full article

This paper combines the piecewise Cubic Hermite (CH) interpolation algorithm and the weighted least square support vector machine (WLS-SVM) to improve identification accuracy for marine crafts built based on the characteristic model. The characteristic model is first used to describe the heading dynamics of marine crafts and is a superior model to the traditional response model in both accuracy and complexity. Especially in order to improve identification accuracy, a CH-based data preprocessing strategy is utilized to densify and smooth data for further accurate identification. Subsequently, the combination of the linear kernel function and the Gaussian kernel function is introduced in the conventional WLS-SVM method, which renders global and local performance improvements compared with the conventional WLS-SVM method. Finally, informative maneuvers composed of Zigzag and Sine are carried out to test the performance of the improved identification method. Compared to the conventional LS-SVM method based on the response model, the root mean square error of the proposed CH-MK-WLS-SVM method based on the characteristic model is reduced by an order of magnitude in the presence of sensor noise. Full article

The availability of the propulsion system is of primary importance to ensure safe and stable operations of marine crafts, both during transit and station keeping. Diminished propulsion efficiency could impair the ability of a vessel to maintain speed and course and possibly lead to a drifting craft. The waterjet’s propulsion efficiency is affected by several factors such as cavitation, erosion, vibration and noise emission. This paper addresses the design of a fault-tolerant thrust allocation algorithm able to maintain the seaworthiness of a twin-waterjet marine craft in the presence of a severe power loss in one of the waterjets. The proposed solution combines a load torque estimator with an optimization routine that accounts for the power limits when a waterjet is subject to a power loss. This prevents faults from quickly escalating into a complete failure of the waterjet due to excessive power demands. Two simulated case studies including zig-zag path following and sideways movements are presented to demonstrate the effectiveness of the fault tolerant control thrust allocation strategy. Full article

Export competitiveness is an important factor for national development and economic growth. The craft product market is one of the commodities with high growing value. Thus, many craft product companies are encouraged to export their products to foreign markets. This study aims to examine the strategies and competitiveness of exporting craft products. The sample of 400 respondents who completed the questionnaires represents people working in craft product export companies using marine transport in Thailand. The data analysis was conducted using structural equation modelling (SEM). The findings show that the niche differentiation strategy of craft products positively relates to export promotion competitiveness. Moreover, a niche differentiation strategy positively affects export performance. The results indicate that export promotion competitiveness partially mediates the relationship between niche differentiation strategy and export performance. This study contributes to the craft product export business using marine transport and helps the companies to improve their competitiveness and export performance. Full article

International trade is defined as economic transactions between countries worldwide. Promoting the export of craft products, which are valued products, is critical for international business as the sales growth increases worldwide. Moreover, the export of craft products has increased international trade and maximized economic value in the highly competitive global market. Therefore, businesses need to be promoted to increase their competitiveness. This study explores the impact of export promotion programs on export competitiveness and the performance of craft products. A self-administered questionnaire was used to correct the data. There were 400 respondents completing the questionnaires, who were working in craft product export companies using marine transport. The data analysis is conducted by using Structure Equation Modelling (SEM). The findings show that the export promotion program has a significant positive relationship with export competitiveness. A positive relationship between export competitiveness and export performance is also found. The results indicate that export competitiveness fully mediates the relationship between export promotion programs and export performance. The findings from this study contribute to craft product export businesses and provide a practical exporting approach. Marine transport is one of the critical international entry modes many companies use to expand businesses. It should be noted that shipping cost savings are related to export efficiency. Full article

Levels of boat traffic in coastal seas have been steadily increasing in many parts of the world, introducing pressures on marine wildlife through disturbance. The appropriate management of human activities is important not only to preserve wildlife, but also for the local communities that depend on ecotourism for employment and their economy. This study presents further insight into bottlenose dolphin (Tursiops truncatus) responses to boats in New Quay Bay (West Wales) within the Cardigan Bay Special Area of Conservation. This region is heavily dependent on wildlife tourism, and marine traffic is regulated through a long-standing Code of Conduct. Based on a long-term dataset spanning the months of April to October and the years 2010–2018, the study found that compliance to a code of human behaviour increased dolphin positive responses towards boats. Dolphin responses to individual named boats and to different boat types were examined in greater detail. Speed boats, small motorboats, and kayaks were found to break the code most often, resulting in higher rates of negative response by dolphins. Visitor passenger boats formed the majority of boat traffic in the area, and showed greater compliance than other general recreational crafts. Suggestions are made for the better protection of the coastal dolphin population, as well as the role that citizen science can play to help achieve this goal through working directly with wildlife trip boats and the recruitment of local observers. Full article

Fatigue analysis and life cycle prediction of a naval craft or a commercial ship are one of the most critical phases of structural integrity calculations. Many structural failures have occurred due to insufficient structural design, production methods, and inappropriate operational environmental conditions. As a result of the deterioration of the structural integrity, the occurrence of both vital and economic losses becomes inevitable. This paper emphasises the importance of fatigue and life cycle analyses at the early design phase since the fatigue phenomena are generally considered in the late design stages. In this study, fatigue calculations and life predictions were carried out by the Palmgren–Miner method. The wave rosette, also called long-term wave directionality, was used as the wave spectrum approach. Based on wave loads and accelerations, an FE analysis was carried out using the Maestro Marine Altair Partner Alliance (APA) software. The undamaged life prediction of the vessel was calculated based on different sea states and vessel speeds. A specific scenario, which was prepared based on the International Code of Safety for High-Speed Craft, was also analysed to compare the fatigue life of the vessel with regards to safe operating conditions for passengers and crew. In this study, the effect of sea states, environmental conditions, and materials used on the fatigue behaviour of the vessel are discussed and analysed. As a result of this study, the shortest and the longest undamaged life spans based on the loading scenarios are put forth clearly. Analyses and calculations prove that loading scenario 5 is the most effective scenario in terms of the undamaged life span of the boat. On the contrary, loading scenario 1 gives the shortest service life. The main reason behind this phenomenon is the relation between the fatigue endurance limit and load cycles. Full article