Leisure Boat Research Articles

Leisure Boat Design: A Comprehensive Study of the Shape and Dimension Effects on Hydrodynamic Performances

Leisure Boat Design: A Comprehensive Study of the Shape and Dimension Effects on Hydrodynamic Performances

Development of Low-Pressure Die-Cast Al-Zn-Mg-Cu Alloy Propellers Part II: Simulations for Process Optimization.

With the increasing demand for high-performance leisure boat propellers, this study explores the development of high-strength aluminum alloy propellers using the low-pressure die-casting (LPDC) process. In Part I of the study, we identified the optimal alloy compositions for Al-6Zn-2Mg-1.5Cu propellers and highlighted the challenges of hot tearing at the junction between the hub and blades. In this continuation, we developed a coupled thermal fluid stress analysis model using ProCAST software to optimize the LPDC process. By adjusting casting parameters such as the melt supply temperature, initial mold temperature, and curvature radius between the hub and blades, we minimized hot tearing and other casting defects. The results were validated through simulations and practical applications, showing significant improvements in the quality and structural integrity of the propellers. Non-destructive testing using X-ray CT confirmed the reduction in internal defects, demonstrating the effectiveness of the simulation-based approach for alloy design and process optimization.

Estimating hydrodynamic performances of the designed leisure boats: a study considering hull shape and dimension variations

Abundant marine natural resources make Indonesia have potential in the field of marine tourism. Karimunjawa is one of the regions that still relies on marine tourism as the main sector in supporting the economy. Unfortunately, the existing modes of marine tourism transportation are dominated by traditional ships that have low performance, safety, and comfort. Therefore, infrastructure development is needed by developing a leisure boat design that has stability and good ship movement so that tourists are comfortable and safe on the trip. This study focuses on optimizing the hydrodynamic characteristics of leisure boats with variations in hull shape and hull dimensions adjusted to the characteristics of waters in Karimunjawa. The research was conducted by designing and analyzing 16 variations of hull models based on 5 reference ships. The regression approach is carried out on the dimensions of the reference ship to obtain variations in ship dimensions, then variations in hull shape include deep v, shallow v, flat bottom and round bottom. Each model variation is tested for resistance, stability, and seakeeping to determine the hydrodynamic performance of each model. Multi Attribute Decision Making (MADM) calculations are carried out afterwards to get the best tourist hull design. Then a sensitivity analysis was carried out on each variation to determine the influence of variations in dimensions and hull shape. The results showed the Deep V D model as the best model based on MADM calculations and hull shape variations had a significant influence on the hydrodynamic performance of the ship. It is hoped that this model can help the development of safe and comfortable tourist boats in accordance with the characteristics of the waters in Karimunjawa.

Development of Low-Pressure Die-Cast Al-Zn-Mg-Cu Alloy Propellers-Part Ⅰ: Hot Tearing Simulations for Alloy Optimization.

Recent advances in the leisure boat industry have spurred demand for improved materials for propeller manufacturing, particularly high-strength aluminum alloys. While traditional Al-Si alloys like A356 are commonly used due to their excellent castability, they have limited mechanical properties. In contrast, 7xxx series alloys (Al-Zn-Mg-Cu based) offer superior mechanical characteristics but present significant casting challenges, including hot-tearing susceptibility (HTS). This study investigates the optimization of 7xxx series aluminum alloys for low-pressure die-casting (LPDC) processes to enhance propeller performance and durability. Using a constrained rod-casting (CRC) method and finite element simulations, we evaluated the HTS of various alloy compositions. The results indicate that increasing Zn and Cu contents generally increase HTS, while a sufficient Mg content of 2 wt.% mitigates this effect. Two optimized quaternary Al-Zn-Mg-Cu alloys with relatively low HTS were selected for LPDC propeller production. Simulation and experimental results demonstrated the effectiveness of the proposed alloy compositions, highlighting the need for further process optimization to prevent hot tearing in high Mg and Cu content alloys.

Leisure Boat Concept Design: Study on the Influence of Hull Form and Dimension to Increase Hydrodynamic Performance

The tourism sector contributes significantly to the economic growth of the community and the country. Labuan Bajo has the potential for marine tourism, which is famous for foreign classes. The separation of the islands in Labuan Bajo requires transportation to support tourist activities to tourist destinations. One type of transportation to support the needs of marine tourism is leisure boats or recreational boats. The leisure ship must have standards of comfort, security for passenger safety, and efficient operational costs. It is necessary to have infrastructure in the form of a leisure ship that functions optimally, so research on the hull’s hydrodynamic characteristics is essential. This research aims to observe the influence of hull form variables and primary size on the hydrodynamic characteristics of the ship. The research method was the simulation method to determine the response of the hull model variation to the environmental conditions tested. Simulation testing using Maxsurf software based on resistance, stability, and seakeeping criteria. The MADM method analysis results showed that the Deep V Hull model variation had the highest score of 0.787. In the sensitivity analysis calculation, the hull form variable significantly affected resistance and stability testing with R square values of 0.6008 and 0.5930. Meanwhile, the size variable had more influence on seakeeping testing, especially roll motion, with an R square value of 0.4081.

Powering and Resistance Analysis of the 49 Meter Leganta Ship for Maritime Tourism in the Riau Islands Province

Prediction of ship resistance is the main factor in determining the main engine power. Prediction of resistance and powering of the Leganta 49 meter leisure boat is carried out on the Software Resistance software which is based on empirical calculations of Holtrop and Fung. By knowing the estimated ship resistance, an estimate of the power required to be able to operate optimally during the voyage is obtained. testing with a maximum speed of 21 knots on the Holtrop method gives a predicted result of the total resistance calculation RT of 664.2 kN with the required power of 8969.57 kW. Meanwhile, the Fung method gives a predicted result of the total resistance calculation RT of 624.4 kN with the required power of 8431.83 kW.

Developing Hull Design Based on the Hydrodynamic Criteria: An Application for Leisure Boats as a Tourist Facility

Developing Hull Design Based on the Hydrodynamic Criteria: An Application for Leisure Boats as a Tourist Facility

Environmental DNA survey indicates arrival of quagga mussel in Ticino River basin

The quagga mussel Dreissena rostriformis bugensis is an invasive species that has recently spread to Western Europe, causing major impacts on aquatic ecosystems and human activities. We considered lakes Lugano and Maggiore (Ticino River basin, Italy and Switzerland) to be at high risk of colonization due to leisure boat traffic from already-colonized lakes. We performed an environmental DNA based survey to detect any quagga mussel invasions in these lakes as early as possible. The results of the survey confirmed the presence of this species in the lakes and support the use of molecular approaches for the early detection of invasive mussels.

Methods for the detection and characterization of boat paint microplastics in the marine environment

Microplastics in the marine environment have been the focus of intense research recently, however little attention has been given to boat paint sources, despite its direct influence on the marine ecosystem. This is largely due to the lack of established analytical methods. Microplastics from boating sources may originate from antifouling paints on the underwater body, surface coatings on the top sides, deck, and superstructure, as well as plastic parts of the boat construction. Their release can occur during construction, operation (leisure boats and commercial ships), service, and maintenance, from the materials themselves or used chemicals (e.g., abrasive detergents). Most importantly, boat paint microplastics containing biocides, such as the metals copper and zinc, and particles containing tin (residues from old or current use of tributyl-tin ship hull paints) should raise higher concern on potential environmental impacts. This study aims to provide practical insight on methods for the quantification of boat paint microplastics in marine waters and provide a baseline survey on their occurrence. Sampling and analysis methods are applied on case studies, i.e., marinas on the Swedish coast. A multi-method approach for identifying and characterizing boat paint microplastics based on visual and chemical characteristics is presented. In general, the measured content of biocide-containing microplastics was remarkably high in all marinas, with concentration levels of copper-rich particles >10 μm between 400 and 1400 particles per L. Given that biocide paint particles are manufactured to be toxic, it is particularly important to take into account field measurements in future environmental status assessments. This work underlines the importance of monitoring data in the action work between relevant authorities and stakeholders.

BoatNet: automated small boat composition detection using deep learning on satellite imagery.

Tracking and measuring national carbon footprints is key to achieving the ambitious goals set by the Paris Agreement on carbon emissions. According to statistics, more than 10% of global transportation carbon emissions result from shipping. However, accurate tracking of the emissions of the small boat segment is not well established. Past research looked into the role played by small boat fleets in terms of greenhouse gases, but this has relied either on high-level technological and operational assumptions or the installation of global navigation satellite system sensors to understand how this vessel class behaves. This research is undertaken mainly in relation to fishing and recreational boats. With the advent of open-access satellite imagery and its ever-increasing resolution, it can support innovative methodologies that could eventually lead to the quantification of greenhouse gas emissions. Our work used deep learning algorithms to detect small boats in three cities in the Gulf of California in Mexico. The work produced a methodology named BoatNet that can detect, measure and classify small boats with leisure boats and fishing boats even under low-resolution and blurry satellite images, achieving an accuracy of 93.9% with a precision of 74.0%. Future work should focus on attributing a boat activity to fuel consumption and operational profile to estimate small boat greenhouse gas emissions in any given region.

A case study for 3D scanning-based quantitative quality control during key stages of composite small craft production

Composite small crafts are manufactured in a job-shop system that prioritizes delivery times and creates various small-scale products using flexible equipment and worker operations. The process involves layering composite materials onto a mold to form the product through molding. Three intermediate stages must be completed before the final product, including mock-up, mold, and small craft. The stability and performance of the small craft rely on the accuracy of the mock-up and mold production. However, repeated molding can cause deformation and worker skill level affects product quality, leading to inconsistent results. This study aimed to improve the quality control of composite small crafts in leisure boat shipyards. We propose developing a high-precision digital shape model using 3D scanning of intermediate products such as the ship body frame, finished mold, and shaped hull of the FRP small craft to enable quantitative quality control and identify shape deviations.

Towards the development of smart weather routing systems for leisure planing boats

Weather routing (WR) systems are widely adopted in the maritime transport since safety of goods and saving of fuel are crucial for shipping companies. However, the need of protecting the local coasts and reducing CO2 emission is making WR attractive even for the market of leisure boats, especially if comfort and safety are also accounted. In the present study, a prototype of a WR system is presented. The developed tool implements the Dijkstra’s algorithm to find the fuel-optimal path while ensuring comfort and safety. A computationally efficient digital twin of a planing boat, based on a 2D+t model and a powertrain mapped model, has been implemented for the estimation of the fuel consumption and the evaluation of vertical accelerations. The methodology for the acquisition of online weather data is presented, together with the strategy for the assessment of comfort and habitability. The application of the WR tool in a typical path of the Tuscan Archipelago shows improvements in fuel usage and comfort even in moderate weather conditions. The influence of each weather variable on fuel efficiency is assessed, highlighting the requirement of an accurate dynamic modelling. Criteria for the graph design are also outlined, showing a wrong estimation of comfort and fuel usage in case of low-definition graphs. The paper proves the potential and the effectiveness of the developed tool, moving toward a greener and more comfortable navigation in local seas.

Metal and PAH loads from ships and boats, relative other sources, in the Baltic Sea

The Baltic Sea is a sensitive environment that is affected by chemical pollution derived from multiple natural and anthropogenic sources. The overall aim of this study was to estimate the load of metals and polycyclic aromatic hydrocarbons (PAHs) from shipping and leisure boating, relative other sources, to the Baltic Sea and to identify possible measures that could lead to major reductions in the loads of hazardous substances from maritime shipping and leisure boating. The use of copper-based antifouling paints, and operation of scrubbers in open loop mode, were the two most dominant identified sources of hazardous substances to the Baltic Sea. Open loop scrubbers accounted for 8.5 % of the total input of anthracene to the sea. More than a third of the total load of copper can be reduced if copper-free antifouling paints or other biocide-free antifouling strategies are used on ships and leisure boats.

Mosquito surveillance in maritime entry ports in Miami-Dade County, Florida to increase preparedness and allow the early detection of invasive mosquito species.

Invasive mosquito vector species have been inadvertently transported to new areas by humans for decades. Strong evidence supports that monitoring maritime, terrestrial, and aerial points of entry is an essential part of the effort to curb the invasion and establishment of invasive vector mosquito species. Miami-Dade County, Florida is an important operational hub for the cruise ship industry and leisure boats that routinely visit nearby areas in the Caribbean, and freight cargo ships transporting goods from Miami-Dade to Caribbean countries and vice versa. To deal with the increasing public health concern, we hypothesized that mosquito surveillance in small- and medium-sized maritime ports of entry in Miami-Dade is crucial to allow the early detection of invasive mosquito species. Therefore, we have selected 12 small- and medium-sized maritime ports of entry in Miami-Dade County with an increased flow of people and commodities that were not covered by the current mosquito surveillance system. Collection sites were comprised of two distinct environments, four marinas with international traffic of leisure boats, and eight maintenance and commercial freight cargo ship ports. Mosquitoes were collected weekly at each of the 12 collection sites for 24 hours for 6 weeks in the Spring and then for 6 additional weeks in the Summer using BG-Sentinel traps. A total of 32,590 mosquitoes were collected, with Culex quinquefasciatus and Aedes aegypti being the most abundant species totaling 19,987 and 11,247 specimens collected, respectively. Our results show that important mosquito vector species were present in great numbers in all of the 12 maritime ports of entry surveyed during this study. The relative abundance of Cx. quinquefasciatus and Ae. aegypti was substantially higher in the commercial freight cargo ship ports than in the marinas. These results indicate that even though both areas are conducive for the proliferation of vector mosquitoes, the port area in the Miami River is especially suitable for the proliferation of vector mosquitoes. Therefore, this potentially allows the establishment of invasive mosquito species inadvertently brought in by cargo freights.

Model based optimal management of a hybrid propulsion system for leisure boats

The strict emission standards for port approach and coastal navigation, and the fuel-saving requirements, in the marine sector, are pushing the manufactures to consider more advanced and alternative propulsion systems.In this context, this study deals with the design and management of an innovative hybrid thermal-electric propulsion system. The evaluations are referred to the case study of a leisure boat, which is used for passenger transportation in tourist areas. Experimental tests are carried out on single components, with a particular focus on re-calibration of the thermal engine, for its homologation and optimal use in the proposed hybrid architecture. The identification of proper management strategies is performed on the basis of a boat simulation model, which is set up starting from experimental data and characteristics of components. In this regard, an optimization procedure, based on the use of genetic algorithms, is performed in order to set the parameters of onboard energy management strategies and pursue the double objective of extending battery pack cycling life and reducing exhaust emissions. The obtained simulation results highlight the benefits of the proposed architecture showing sensible improvements in comparison with a traditional ICE based configuration. The methodology proposed in this paper enables reliable evaluations and preliminary optimization of energy management strategies, with a drastic reduction in experimentation time and general costs.

The role of marinas in the establishment and spread of non-indigenous species in Baltic Sea fouling communities

The study included the sampling of 12 marinas across six areas of the Baltic Sea with settlement plates and scraping of submerged structures to assess the role of marinas in the spread of non-indigenous species (NIS) via biofouling. 15 NIS were detected in the marinas and secondary spread of previously introduced NIS was detected in five out of six sea areas. Salinity and sea area significantly affected the composition of the fouling assemblages. Settlement plates appeared as the more efficient sampling method over scraping, while the seasonal analyses revealed that the monitoring effort should span over the summer and early autumn in the south-eastern, central, and northern Baltic Sea. The present findings indicate that marinas contribute to the spread of non-indigenous fouling organisms, and there is an increasing demand for the monitoring of marinas and stricter regulations regarding the biofouling management of leisure boats in the Baltic Sea.

Modelling copper emissions from antifouling paints applied on leisure boats into German water bodies

Copper-containing antifouling paints (AFP) are widely used for leisure boat maintenance. Cu emitted from AFP into German surface water bodies has been suggested to be a significant source of heavy metal pollution, threatening water quality. We developed two scenarios to model Cu emissions from AFP applied on leisure boats on national scale, which allow identifying regional hotspots. The top-down approach (scenario A) was based on a previous study on national AFP consumption, while in the bottom-up approach (scenario B), median and interquartile range of Cu release rates depending on salinity conditions were considered for emission estimation. Both scenarios clearly highlighted the locally high emission pressure on inland waters in popular watersport regions, identifying these as requiring intense protection. Scenario B generally predicted lower Cu emissions (sea: 11.05–25.53 t a−1, inland: 14.15–34.59 t a−1) than scenario A (sea: 22.53 t a−1, inland: 47.97 t a−1). To evaluate their relevance, scenario results were compared to emissions modelled with MoRE (Modelling of Regionalized Emissions), which is used as reporting tool on substance emissions by Germany. According to scenarios A and B, the emission from AFP accounted for 13 % and 4–9 % of the total Cu emissions into inland waters in 2016, respectively. Scenario results were similar or higher than other emission pathways such as industrial direct dischargers. Thus, we consider Cu emissions from AFP as a significant pathway to be included in the MoRE emission inventory. We recommend scenario B for implementation as it allows a more flexible adaptation for future modelling.

Study on structural design and analysis of 18 ft CFRP leisure boat

The purpose of this study is to develop a lightweight design model for an 18ft leisure boat. The existing leisure boat is manufactured using glass fiber-reinforced plastics (GFRP) material and the hand lay-up process. Carbon fiber-reinforced plastics (CFRP) was applied to the new design to reduce the boat’s weight, while an automated tape laying machine was applied to the lightweight boat’s manufacturing process to increase boat manufacturing productivity. The newly designed CFRP model is 25% lighter than the existing GFRP model. It was confirmed that the newly designed lightweight hull has sufficient structural integrity compared to the existing hull through the structural integrity evaluation by the FEA.

Examination of the Mechanical, Corrosion, and Tribological Behavior of Friction Stir Welded Aluminum Alloy AA8011

Aluminum alloy AA8011 is emerging as a promising material for modern engineering applications in which improved tensile strength, hardness, corrosion-resistance, and wear-resistance of materials are required. Typically, AA8011 alloys are utilized in air-conditioning ducts and heat exchanger fins in ships, leisure boats, luxury vessels, workboats, fishing vessels, and patrol boats. However, the conventional welding of AA8011 is a challenging procedure. In this context, this paper focuses on the development of an effective solid-state welding methodology for AA8011 alloy welding. The AA8011 alloy was friction stir welded by varying the tool rotation speed, traverse speed, and shoulder diameter. The microhardness, tensile strength, joint efficiency, elongation, corrosion rate, and wear rate of the friction stir welded specimens were compared with the base material. Fractography analysis was conducted after the tensile test and surface morphology analysis after corrosion and wear tests, using scanning electron microscopy. The compositional elements in the corroded and worn section of the specimens were analyzed using energy-dispersive X-ray spectroscopy. Based on the joint efficiency as a primary constraint, the optimum process parameters for friction stir welding of aluminum alloy AA8011 have been established as follows: tool rotation speed of 1200 rpm, tool traverse speed of 45 mm/min, and tool shoulder diameter of 21 mm.

Biopollution by Invasive Marine Non-Indigenous Species: A Review of Potential Adverse Ecological Effects in a Changing Climate.

Biopollution by alien species is considered one of the main threats to environmental health. The marine environment, traditionally less studied than inland domains, has been the object of recent work that is reviewed here. Increasing scientific evidence has been accumulated worldwide on ecosystem deterioration induced by the development of massive non-indigenous population outbreaks in many coastal sites. Biopollution assessment procedures have been proposed, adopting criteria already used for xenochemical compounds, adjusting them to deal with alien species invasions. On the other hand, prevention and mitigation measures to reduce biopollution impact cannot always mimic the emission countermeasures that have been successfully applied for chemical pollutants. Nevertheless, in order to design comprehensive water-quality criteria, risk assessment and management strategies, based on scientific knowledge, have been developed in a similar way as for chemical pollution. The Mediterranean Sea is a well-known case of alien species invasion, mainly linked to the opening of the Suez Canal. Non-indigenous species have caused well-documented changes in many coastal ecosystems, favoured by concomitant changes induced by global warming and by the heavy load of nutrients and pollutants by various anthropogenic activities. Naval commercial traffic and leisure boats are among the most active vectors of spread for alien species inside the Mediterranean, and also towards other ocean regions. The scientific evidence gathered and summarized in this review suggests that effective management actions, under a precautionary approach, should be put in place in order to control introductions of species in new areas. These management measures are already established in international treaties and national legislations, but should be enforced to prevent the disruption of the dynamic ecological equilibria in the receiving environment and to control the direct adverse effects of alien species.