We demonstrate and verify, by the use of both synthetic and real wave data, a newly developed capability of short-time phase-resolved wave prediction based on incoherent X-band marine radar measurements. An inversion algorithm is developed to convert X-band radar sea surface measurements into the phase-resolved wave field and the associated wave spectrum based on the linear gravity wave theory. The

The purpose of this paper is to present a simple least squares technique for identifying a ship’s linear sway-yaw manoeuvring coefficients and drag-area parameters in current and wind, using measured data. These coefficients are required inputs to a standard three-degree-of-freedom manoeuvring model. The identification method employs the BFGS algorithm which avoids direct computation of the Hessian

High-Performance Marine Craft (HPMC) occupants are currently being investigated for various psychophysical impairments degrading work performance postulating that these deteriorations are related to their occupational exposures. However, scientific evidence for this is lacking and the association of exposure conditions aboard HPMC with adverse health and performance effects is unknown. Therefore, the

Turning Maneuverability is an important hydrodynamic performance of the wave glider, which can realize the position keeping, path tracking and steering obstacle avoidance in a reliable way. The influences on the maneuverability of the relevant parameters of the rudder are analyzed by using the Computational Fluid Dynamic (CFD) method in this paper. Through the analysis, the conclusions that the optimal

Speed optimisation is an important energy efficiency practice, which can bring good economic and environmental benefits. The methodology of the speed optimisation and dynamic programming of ships are firstly investigated. With the total fuel consumption as the objective function and main engine speed as the decision variable, a novel multi-stage speed optimisation model of ship is then developed based

Following the updated global sulphur emission cap from 1 January 2020, shipowners are facing an increasing cost burden to comply with the new regulation in a tough shipping market. This research compares the lifespan costs of three main alternatives, all of which can satisfy the 2020 global sulphur emission regulation. A lifespan cost analysis model is built considering several cost items across the

Working conditions of High-performance Marine Craft (HPMC) occupants are inherent with shock and vibration. Therefore, HPMC occupants are usually investigated believing that their psychophysical health and performance are negatively affected by exposure to these conditions. However, the association between the regular occupational vibration exposures of HPMC occupants and the deterioration of their

This research proposes two optimization models to deal with the berth allocation problem. The first model considers the berth allocation problem under regular vessel arrivals to minimize the flow time of vessels in the marine container terminal, minimize the tardiness penalty costs, and maximize the satisfaction level of vessels’ operators on preferred times of departure. The second model optimizes

Trimaran hull forms have been very attractive in the past decade. Hydrodynamic performance of trimaran ships is influenced by sidehull arrangement. The present study was intended to construct a surrogate model for better understanding of the hydrodynamic performance of a trimaran ship. Accordingly, seakeeping and resistance of an inverted-bow trimaran were considered as objectives of a simulation-based

CO2 emissions during ship building, maintenance, and scrapping are not be involved when defining Energy Efficiency Operational Indicator (EEOI). However, these CO2 emissions can only show its value during operation phase of ship life. In order to evaluate the effect of CO2 emissions during ship building, maintenance, and scrapping on energy efficiency, a real time EEOI definition was put forward, a

An enclosed space poses a serious risk to workers since its atmosphere can be oxygen-deficient, polluted or contain flammable and/or toxic gases or vapours. Hence, it is important to keep in mind that an enclosed space should not be entered unless it is absolutely necessary. However, many processes often need the worker to be present in an enclosed space. At this point, great attention should be paid

Air cavity drag reduction is one promising method for reducing power consumption of ships. Its current practical applications are rather limited, owing largely to the fact that air cavity size and shape change drastically in response to variations in ship attitude, motions and speed, as well as sea conditions. This study explores how deployment of moveable hydrodynamic actuators near the air cavity

With the development of the shipping industry, the number of ships at sea has increased significantly. According to the statistical data, oblique ship collisions are much more frequently happened than that of head-on ship collisions. However, there are less researches on oblique ship collisions than those of head-on ship collisions. The responses of hull structure during oblique collision scenarios

While ship emissions are incomparably less in comparison to land units, the threat of the world’s population and certain regions are in a serious danger due to 70% of these emissions occur in areas up to 400 km from the coast and on certain maritime routes. The formation of ship emissions strongly depends on the dynamically varying travel conditions and it is important to identify the emissions in

The water temperature in the ocean varies according to its depth and generates a thermocline layer. An internal wave can be excited by an object moving near the thermocline layer because the density changes owing to the water temperature. The internal wave propagates and interacts with the surface wave. This study aims to investigate the internal wave propagation in a two-layer stratified flow, generated

The accurate assessment of long-term extreme responses of floating-structure mooring system designs is important because of small failure probabilities caused by long-term and complex ocean conditions. The most accurate assessment would involve considering all conceivable sea states in which each sea state is regarded as a stochastic process and performing nonlinear time-domain numerical simulations

The oscillating water column (OWC) based wave energy devices require a turbine for the conversion of wave energy to electrical energy. Customarily, Wells and impulse turbines have been widely accepted for this energy conversion. However, the damping (i.e. the pressure drop developed based on volume flow rate) induced by the turbine significantly influences the performance of the OWC. The present study

Offshore facilities are exposed to the risk of accidental damages caused by fire, explosion, dropped objects, extreme environmental events and vessel collision poses a big threat to the safety and operation. During any lifting work, either from a supply vessel to the installation or from within the installation or plant itself, there is a potential danger when objects are being lifted for a dropped

Deep-sea Cone Penetration Test equipment (CPT) and In-Situ Sediment Acoustic Measurement System (ISSAMS) driven by hydraulic penetration system are the important equipment for in-situ detection of seabed sediment. The problems, such as poor position following precision and weak load disturbance rejection performance of the actuator in the hydraulic penetration system are common in the working process

The uncertain dynamics and environmental impacts in collision avoidance planning are always the key issues of autonomous navigation for unmanned surface vessel, due to the strong interactive ability and learning ability of deep learning, the combination of CNN and LSTM provide relevance and memory characteristics, which can extract the potential influence features of collision avoidance and correlation

The article addresses how the wave power in shallow water can be estimated based on available wind and wave statistics for a deep water ocean area. The average statistical properties of the wave power in shallow water expressed in terms of the mean value and the standard deviation are presented. Results are exemplified by using long-term wind and wave statistics from the same ocean area in the Northern

Multiple co-axial heave plates of uniform geometry are attached to offshore platforms for inducing damping and added mass. These effects generally decrease the magnitude of the dynamic response of the platform under applied environmental excitation forces. When spacing between heave plates is decreased the damping and added mass performance are altered due to their strong vortex interaction. A new

Cavitation occurs on objects that move underwater at high speeds, and it is accompanied by an increase in hull vibrations, a reduction in propulsion performance, and an increase in noise that is important for warships and submarines. Of the various types of cavitations, tip vortex cavitations (TVC) are the earliest occurring and are considered the most important in terms of cavitation inception speed

Safety problems may occur to the jack-up rig when it is installed near the old footprint. In this study, three-dimensional large deformation finite element simulations using the Coupled Eulerian–Lagrangian (CEL) method have been carried out on the spudcan–footprint interaction problem. The correctness of the CEL method is verified through comparison with existing centrifuge tests. Uniform and non-uniform

This paper presents the vibration analysis of stiffened plates with initial imperfections, using both conventional and super finite element methods. Von Karman theory was utilized so as to formulate the plate element. Eccentricity of the stiffeners is also taken into account and they are not limited to be placed on nodal lines. Consequently, any configuration of plate and stiffeners can be modelled

Deep learning has attracted the attention of many researchers for structural health monitoring. However, it is difficult to use most of the deep learning-based techniques to detect damage throughout the life cycle of a large or inaccessible structure, especially a ship. Few studies have focused on hull stiffened plate crack damage detection. We propose such a method based on deep learning using a convolutional

Wave force acting on a circular flexible plate in the presence of a vertical surface-piercing flexible porous membrane is examined under the hypothesis of linear water wave theory. A semi-analytic solution is developed employing the Fourier-Bessel series expansion method along with the methods of separation of variables and least-squares approximation. To keep the outer flexible membrane at a desired

This paper examines the influence of oblique perforated baffles on the sloshing dynamics of rectangular liquid storage tanks. The analysis presented accounts for sway induced hydrodynamic forces and entropy generation. Internal liquid free surface oscillation is modelled by the volume of fluid method. The effect of baffle geometric parameters, orientation and porosity on loads is examined and numerical

Flow noise originating in the turbulent boundary layer (TBL) often severely limits the performance of towed sonar array. Therefore, it is necessary to predict this noise for the design of an efficient towed array. This paper presents large eddy simulation methodology to establish the TBL properties and wall pressure fluctuations on a 12 m long towed array with length to diameter ratio of 1200 in the

The effects of the geometrical parameters on the hydroacoustic characteristics of the flow over rectangular, square and circular cylinders are investigated by numerical analyses and experiments. The numerical simulations are carried out by using a hybrid method which combines RANS with FWH equation. In order to validate the numerical results, the hydroacoustic measurements are also performed for the

In the present study, gravity wave interaction with a series of submerged artificial permeable reefs is analysed within the framework of linearised water wave theory. For wave past porous walls of the artificial reefs, a quadratic pressure drop is assumed to account for the wave energy dissipation due to the changes in wave height. The physical problem is handled for a solution using a numerical model

In this study, a series of sloshing model tests were conducted for type-C tanks, particularly to observe the effects of the inner bulkhead and rings. In regular pitch motion, the internal flow by swash bulkhead and rings located inside the tank was observed. The frequency range near the resonance frequency was checked at filling heights of 70%, and sloshing-induced impact pressures were investigated

The use of composite materials patches for the reinforcement of steel structures attracts particular interest. Due to their high strength, light weight, and high fatigue and corrosion resistance, composite patches represent a versatile reinforcement solution. In this paper, the reinforcement of steel beams with CFRP patches is examined. Large scale tests of “H” and “square hollow” cross section steel

Impacts from falling objects can pose a major risk of failure for offshore pipelines. Appropriate protection measures are required to reduce this risk. To achieve this goal, a risk-based integrity model is proposed. Based on the surrogate model of genetic programming, the finite element analysis is cooperated with the probabilistic method to consider nonlinear effects on the failure probability. The

The study of an integrated energy system is presented in this article that will cover all types of energy loads (mechanical, electrical, thermal) on a Very Large Crude Carrier (VLCC) with the maximum technically possible and economically feasible exploitation of fuel energy, thus reducing the operating cost and environmental footprint of the ship. There may be a large variety of configurations, design

Safety analysis and prediction of a marine structure is a very important field which has received attention from many scientists. Prof. R. Ajit Shenoi has made significant contributions in investigating various issues in this field. In this invited paper of recollection nature, a philosophical attitude is taken to re-examine some fundamental issues about the safety of marine structures with a purpose

Drilling is one of the costliest and risky activities in oil and gas industry due to complexity of interactions with downhole formation. Cyclic loads while drilling cause the initiation and growth of cracks in oil tubulars. This phenomenon, known as fatigue, results in permanent reduction of the failure-free service envelope of a certain tubular. Further, most of the drill string failures are triggered

As underwater missions become more and more complex, novel underwater manipulators with better performance are demanding. Soft underwater manipulators are judged to be the development direction and expected to have better performance in safe and compliant interaction with the target in underwater operations such as biological sampling. This paper provides an overview on the state-of-the-art of both

This study conducts a practical application of shipboard operation human reliability analysis (SOHRA) to a crankshaft overhauling operation of a general cargo ship at dry-docking period. The SOHRA approach includes error producing condition (EPC) and general task type (GTT) parameters to consistently calculate the human error probability (HEP) values of operation steps. In this case, a comprehensive

Investigation of the energy harvesting from deep water waves by using flexible piezoelectric eel in a controlled environment is studied. Energy harvesting potential is examined as a function of streamwise distance from the fixed cylinder and spanwise gap along with the cylinder at different wave conditions. Output voltage and eel flapping behavior are dependent on cylinder vortices caused by local

The fatigue of structural details of ships is of great importance in the maritime industry as they can lead to cracks which can jeopardize structural integrity. The hopper knuckle is among the most vulnerable areas in a ship with respect to fatigue damage. Analysis of the hopper knuckle has become mandatory for tankers in the Class Ship Rules and in the International Association of Classification Societies

This study considers the evaluation of ship operational performance in real sea states using a time-domain approach. The current seakeeping-maneuvering coupling approach consists of two modules. First, in the seakeeping module, the time-domain three-dimensional Rankine panel method is applied to compute wave-induced forces and resultant ship motion. To validate this module, the computational results

A submerged flexible mound breakwater can be employed for wave control in shallow water as an advanced alternative to the conventional rigid submerged designs. This study presents a flexible breakwater with an innovative geometry based on model experimentation. Experimental studies were performed to compare the wave energy dissipation by the flexible mound and rigid structures, over a range of test

Search and rescue craft have to endure the toughest conditions to save lives at sea. The design, resourcing, operation and support of a search and rescue fleet requires state-of-the-art technology and an ability to react to and exploit cutting edge research and foment future research agenda. This article reviews the unique relationships that exist between the Royal National Lifeboat Institution and

The ignition of ammonia in aqueous solution was simulated in a two-stroke compression ignition engine model. Zero-dimensional chemical kinetic calculations were used to estimate the ignition timing of fuel air mixtures in homogeneous charge compression ignition and diesel combustion modes. The fuel consisted of a 25% m/m aqueous solution of ammonia and pure ammonia for comparison. Ignition was studied

Autonomous underwater vehicles play an essential role in geophysical data collection, deep water mining, seafloor mapping, ocean exploration, and in many other related activities starting from military to scientific applications. A detailed understanding of hydrodynamic characteristics will lead to better design, better control, and optimal path planning of autonomous underwater vehicles in the deepest

The hydrodynamic loads of a disk impacting pure and aerated water are investigated experimentally and numerically. Experiments are performed on a rigid disk with different aeration levels and focus on the spatial and temporal pressure distribution. Drop tests are conducted by a specially designed apparatus to prevent the variation of velocity during the slamming period. A specially designed bubble

Accurate evaluation of the underwater radiated noise under the snorkel operating condition is critical as submarines are frequently exposed to danger under this condition. In this article, the procedures of an integrated simulation to estimate the flow-induced noise considering the submarine operating condition are described. These procedures evaluate both the bubble noise from breaking waves occurring

An efficient model predictive control design for ship autopilot, which is a representative marine application, is proposed based on projection neural network in this article. Ship motion control at sea exhibits the characteristics of large inertia, strong nonlinearity, and large delay; furthermore, it is frequently influenced by the external disturbances, leading to a complex uncertain problem. In

In this study, a three-dimensional discontinuous Galerkin isogeometric analysis framework is presented for the analysis of composite laminates. Non-uniform rational B-splines are employed as basis functions for both geometric and computational implementations. From a practical point of view, modeling with multiple non-uniform rational B-spline patches is required in many different applications due

The overall bearing capacity of a jack-up rig under horizontal load is conducted using finite element models that consider the deck–foundation–soil interaction. In these models, the simplified horizontal load acts on the deck and increases until the platform loses its stability. The effects of the self-weight of the platform W and load direction α on the ultimate horizontal bearing capacity Hult are

For numerical simulations of ship hydrodynamics in high Reynolds number, near-wall grids with high quality are essential to accurately predict the flow field and shear stress. This article proposes a discrete-forcing immersed boundary method to simulate moving solid boundaries in turbulent flows. The technique will efficiently remove the requirement of high-quality body-conforming grids and also preserve

The purpose of this article is to analyze the towing operation problem and towage incomes of the Kaohsiung port in Taiwan, and then propose feasible improvement alternatives for making tugboat operations more smooth and efficient, solving the problem of port congestion, and enhancing the port’s navigational safety. First, by analyzing 23,336 sets of actual data of merchant vessels entering/exiting

Jack-up platforms are commonly found in the costal or offshore environment for offshore oil and gas recovering. Pile legs are the main component of jack-up platform, which support the whole platform and suffer from the ocean environment load. Topology optimization method is proposed in this article to find an optimized shape for the leg by maximizing its structural stiffness, with the purpose of providing

Precisely assessing risk associated with critical and complex engineering systems operating in an environment with high amount of uncertainty is extremely difficult. Taking proper decisions to reduce risk level depends on how accurately the risks associated with the system are assessed. Risk assessment and safety modelling of complex systems were studied using various tools such as crisp sets, Bayesian

This article presents a metocean modelling methodology using a Markov-switching autoregressive model to produce stochastic wind speed and wave height time series, for inclusion in marine risk planning software tools. By generating a large number of stochastic weather series that resemble the variability in key metocean parameters, probabilistic outcomes can be obtained to predict the occurrence of

The harsh marine environment is a significant threat to the safety of floating structure systems. To address this, mooring systems have seen widespread application as an important component in the stabilization of floating structures. This article proposes a methodology to assess the reliability of mooring lines under given extreme environmental conditions based on artificial neural network–Bayesian

Subsea umbilical cable is an important link to transmit power and signals in subsea production system, often lasts for tens of kilometers in deep-sea projects. It is expensive, bulky, and inconvenient to transport. In this article, a compact, low-cost umbilical cable electrical simulator is proposed, which can be equivalent to the real umbilical cable in power transmission characteristics and can adjust

Due to the increasing pressure from stricter environmental regulations to reduce emissions in shipping, the maritime industry has been striving for finding more effective measures. Existing measures are often not enough to comply with new regulations. Among various alternative measures, it is not easy for decision-makers (shipowners and operators) to choose the most suitable alternative measure as

In this article, selecting an appropriate mooring system for the spar platform of a wind turbine consisting of chain–cable–chain is investigated based on a meta-heuristic method. A boundary element software is applied to hydrodynamics analysis, and the numerical results are verified by experimental results. According to the characteristics of the experimental mooring system, an appropriate chain is