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A helicopter emergency flotation system can provide flotation capability after the helicopter accidentally falls into the water. To solve the problem of attitude change of a helicopter after landing in water, a numerical simulation was carried out on a light civil helicopter with a weight of 3.5 t. It was simulated in level 5 sea conditions, the traveling speed was 15.4 m/s, and the height of the lowest point of the hydrostatic helicopter from the water surface was 250-260 mm, with or without lift, with or without floats. Landing on the water can be done with either basic or elliptical floats and in three different postures. The simulation results show that equipping a helicopter with pontoons can significantly improve its overturning resistance and flotation capabilities, but the impact on a helicopter equipped with pontoons will increase. Landing a helicopter in the water at a certain elevation angle is beneficial to the stability of the helicopter. A helicopter with a basic pontoon is more stable when it lands in the water. The performance is higher than that of the ellipsoidal pontoon, but the pitch stability of the basic pontoon is lower than that of the ellipsoidal pontoon.

The number of recreational marinas has increased in recent years due to the growing demand for leisure boating. Recreational marinas are key points for the introduction of non-indigenous species (NIS), which are considered a source of biocontamination. However, there is scarce knowledge on the influence of environmental features on NIS fouling assemblages, especially regarding different salinity conditions. The aim of this study is to explore the effect of salinity on the structure of NIS fouling assemblages and biocontamination levels. Therefore, fouling assemblages associated with floating pontoons were studied in recreational marinas located in fully marine and brackish habitats on the Northern Portuguese coast. Twenty-four NIS were found, of which arthropods and bryozoans represented the most abundant taxa. Except for NIS abundance, univariate and multivariate analyses showed that NIS assemblage structure was shaped by salinity conditions. Thus, NIS richness and the ratio between NIS richness and total richness were significantly higher in marine than in brackish habitats. Similarly, consistently higher biocontamination levels were found in marine habitats, compromising their ecological status. Quantitative data provided here will be useful in the development of NIS management strategies. Thus, in Northern Portugal, efforts should be focused on marinas under fully marine salinity conditions because they harbor a greater number of NIS and, consequently, a worse ecological status.

The conversion of floating docks from single pontoon to multi pontoon is a beneficial alternative for shipyards to enhance the performance of the facilities owned. The objective of this research is to analyze technically and economically the conversion of single pontoon floating dock to multi pontoon. The results of calculations used the 2.2 Finite Element Method software was the amount of the stress at the floating dock after the conversion of 14.635 MPa is smaller than the permitted stress of 160 MPa. Besides that, the pump ballast filling capability after conversion is 54.16 minutes. The decrease in Ton Lifting Capacity (TLC) can be determined by the difference in the load that occurs in the floating dock. After the floating dock is converted using the same TLC, it changes from 2.07 m to 2.11 m. The freeboard height is >300 mm so it is still able to work on the same TLC. There are 4 stages at the production stage, making access to the pontoon, installing bulkhead and additional reinforcement, removing the pontoon, dismantling and installing the pump, and reconnecting with the sidewall. The analysis results found that the conversion costs was IDR 20,051,463,949, the economic analysis conducted also obtained savings for floating dock reparation costs of IDR 6,559,475,128 to IDR 4,143,346,112. When one pontoon is repaired, the rest of the pontoon can still be used and get an income of IDR 3,292,265,120 thus the total cost is IDR 851,080,992. Saving amounting to IDR 5,708,394,136 is used to pay off investment costs.

Most studies using cosmic‐ray neutron sensors (CRNS) for soil moisture estimation use high‐energy neutron monitor observations to correct for changes in incoming neutron intensity, but there is interest in over‐water CRNS observations and muon observations for such purposes. This study compares these approaches with a focus on observations from an over‐water pontoon‐based CRNS system. Pontoon and neutron monitor intensity comparisons showed similar responses with the best statistical agreement when neutron monitor observations were from locations of similar cutoff rigidity or when scaling for geomagnetic and elevational effects were applied. Comparison of historic variations in neutron monitor and muon detector intensity, and more recent observations from the pontoon, revealed temporal differences and weaker short‐term responses from the muon detector. Time‐delays in intensity correction for the pontoon and neutron monitors were observed during a Forbush decrease and through cross‐correlation analysis over the comparison period with delays likely a result of longitudinal differences. Pontoon neutron intensity exhibited slightly higher amplitudes over the study period. Some of this was related to periods of irregular water vapour distribution in the atmosphere where current humidity corrections appear insufficient. Application of intensity corrections to soil moisture estimates illustrated the increasing importance of accurate corrections with decreasing cutoff rigidity and increasing elevation. The impact of neutron intensity correction was greatest for wet soil conditions at low cutoff rigidity sites at higher elevations. Over‐water CRNS observations offer a means to correct CRNS observations with the advantages of being locally managed, locally applicable, and directly relevant to CRNS energy spectra.

Floating pontoons have played a supreme and indispensable role in crises and disasters for both civil and military purposes. Floating bridges and ferries are exposed to blast loadings in the case of wars or terrorist attacks. The protection effectiveness of sacrificial cladding subjected to a blast was numerically investigated. In this study, a steel ferry has been simulated and exposed to side explosions with different explosive charges at certain stand-off distances, according to military standards from NATO and American standard TM5. In this simulation, nonlinear three-dimensional hydro-code numerical simulation ANSYS autodyn-3d has been used. The results reported that the ferry could withstand a charge of 5 kg TNT at a stand-off distance of 1 m without failure. The main objective of this research is to achieve a design that would increase the capacity against the blast loading with minimal plastic deformation in the absence of any failure in the ferry. Therefore, an innovative mitigation system has been proposed to dissipate the blast energy of the explosion based on the scientific theory of impedance using sacrificial cladding. The new mitigation system used a specific structural system in order to install the existing pontoon structure without any distraction. The response, elastic deformations, plastic deformations and plastic failure of the ferry were illustrated in this paper. Furthermore, the results revealed that the proposed mitigation system could mitigate more than 50% of the blast waves. The new design revealed promising results, which makes it suitable for mitigating blast waves. Finally, the results were provided with a reference for the preliminary design and application of sacrificial cladding for structural protection against blast waves.

Over the years of existence of the oil and gas industry, increasing the efficiency of equipment at production facilities places increasing demands on operational reliability and durability. The use of aluminum alloys is due to a large range of its features and properties, one of which is the combination of high strength in combination with low density, sufficient corrosion resistance, good moulding ability by casting, pressure and cutting, the possibility of using aluminum parts in all kinds of structures by welding, soldering and other methods. It is important to bear in mind that aluminium alloys do not require regular corrosion coating during operation. It is all about the finest and extremely strong oxide film (0.00001 mm), which forms a reliable adhesion to the metal.

Floating ferries are used for both civilian and military purposes. This study concerned with a ferry composed of sixteen connected floating pontoons. This ferry is simulated and optimized to carry Military Load Capacity MLC70 (Tank load). Consequently to the increasing demand of evolution and cost optimization, the design optimization is performed in this paper to obtain the optimum minimum weight which minimizesboth the cost and the buoyancy factor. The simulation of the ferry is performed using the finite element program ANSYSsoftware. Furthermore, different grades of the structural steel, hybrid materials (steel stiffeners covered with aluminium plates) and aluminium alloy are incorporated in this study. Thesimulation is verified with both practical and mathematical results. The performance of the ferry is investigated. In addition to the design parameters, constraints and objective functions are determined. The optimum weight of the ferry is obtained, followed by a reduction in the buoyancy factor; accordinglythe capacity of the ferry can be increased. Comparison between the behaviour of the different ferries using different materials is operated considering stresses, deformations and weight. Conclusions and recommendations are then stated.

This paper presents the design of an electric amphibious vehicle with buoyancy provided by inflatable pontoons, referred to as the Electric Inflatable Pontoon amphibious vehicle (E-IPAMV). To investigate the effect of pontoon arrangements on resistance performance, maneuverability, seakeeping, transverse stability, and longitudinal stability of E-IPAMV, STAR-CCM+ and Maxsurf are used to solve the above performance parameters. A constrained space Latin hypercube experimental design is employed, using the lengths of the inflatable pontoons at five installation positions as input variables, and total resistance, steady turning diameter, maximum pitch angle, transverse metacentric height, and longitudinal metacentric height as output variables. A neural network model is then established and validated. Based on this model, NSGA-II is employed to optimize the pontoon lengths at the five installation positions, yielding Pareto-optimal solutions. Finally, considering project and manufacturing requirements, two optimized design schemes are proposed. Compared to the original design, optimization scheme 1 shows a slight reduction in seakeeping but improvements in other hydrodynamic performances. Meanwhile, optimization scheme 2 enhances all hydrodynamic performances. Specifically, in optimization scheme 2, maneuverability increases by the smallest amount, showing 23.43% improvement compared to the original design, while transverse stability sees the greatest improvement, increasing by 290.99% compared to the original design.

The offshore floating wind energy sector is poised for exponential growth in the coming decades. A pivotal challenge within this context is the imperative to substantially decrease the levelized cost of energy (LCOE) to enhance competitiveness. A significant proportion of these LCOE costs are attributable to the towing operations entailed in both the installation of assembled floating wind turbines and the maintenance of major components. Semi-submersibles, characterized by multiple columns and pontoons, represent the prevailing conceptual approach in the industry due to their versatility across varying water depths and their cost-effectiveness in terms of mooring and transportation. Towing model tests for the semi-submersible INO WINDMOOR floating wind turbine have been conducted in the Ocean Basin at SINTEF Ocean. The primary objective of these tests is to investigate critical aspects such as towing resistance and dynamic responses, including vortex-induced motion (VIM) and galloping. This paper presents the experimental set-up and initial findings from the model tests. Through comparative data analysis of selected cases, an enhanced and insightful understanding of the intricate fuid-structure interactions is expected to be achieved. Additionally, it highlights the identification of knowledge gaps and research imperatives aimed at expanding the towing operational criteria, with the ultimate goal of reduction of installation and maintenance costs.

Floating Photovoltaics (FPV) are renewable energy producing technological breaktroughs whic are suitable to circumtances of lakes across Indonesia. The core of this technology is the function of working transformers installed on the pontoons. An FPV with 145 Mwac capacity is designed to run on Cirata weir by utilizing pontoons with the length of 16.5 meters. The hydrodynamic response in the form of plane and rotation movements due to surrounding loads (including but not limited to wave, wind and sea depth data) calculated by using Response Amplitude Operator (RAO) concept. The wave period measured in meter from 0 to 180 ° incoming degree, the biggest translational response comes from pontoon i.e 0.986 (m/m) in sway direction, spread mooring is used to limit the pontoon’s movement. Using weighing concept, in operating condition Tension Mooring Line is obtained at the value of 1.67 for pontoon. While in extreme condition the obtained value is 2.5.