Large Container Research Articles

Numerical investigation of interaction between propulsion system behaviour and manoeuvrability of a large containership

In actual operation process of a ship, the engine-propeller-hull is an integrated system with internal coupling effects, and thus there is a close interaction between the diesel engine propulsion system operation conditions and the ship manoeuvring motions. The propulsion system can experience large power fluctuation during manoeuvring, with considerable torque increase with regard to the stabilized value in straight course. However, the diesel engine propulsion system behaviour and ship manoeuvrability are usually studied separately as they are considered to belong to different disciplines. Thus, it is difficult to reflect the actual operating characteristics of the propulsion system and ship manoeuvring motion under coupled conditions in actual operation. To investigate the interaction between the propulsion system behaviour and the manoeuvrability of a large containership, this paper proposed a multi-disciplinary ship mobility model capable of coupling the marine diesel engine model and the ship manoeuvring model. In the engine model, the mean value modelling approach was adopted to simulate the two-stroke marine diesel engine considering the fact that it can capture the performance of the engine sub-systems including scavenging receiver, exhaust gas receiver, turbocharger, etc. In the manoeuvring model, the MMG-based method was used to simulate the ship manoeuvring motion with three degrees-of-freedom. The engine model and manoeuvring model were coupled through the propeller model that transferring propeller speed and torque between the two models. The coupled model was validated against the engine shop test data and the sea trial results. By applying this coupled model, a series of simulations of turning circle manoeuvres under various scenarios were performed. The simulation results presented the dynamic response of engine internal sub-systems during turning circle manoeuvring, explained the effect of the torque limiter on engine performance and ship manoeuvring motion, and analyse the influence of different propulsion system control strategies on the ship turning circle manoeuvrability. Although the presented case study has been validated on a specific ship, most of the discussed models have a general application.

Identify determinants of container ship size investment choice

ABSTRACT In one of the most capital-intensive industries in the world, the investment decisions of container shipping companies, especially concerning new ships, are crucial to the success of companies. This study investigates shipowners’ ship choice decisions and ship size preference through multinomial logit models using a dataset compiled by Clarkson Research Services Limited. The model incorporates the factors that affect ship size choice from three aspects: the internal traits of companies (company trait), the environment of the shipping market (market-driven strategy) and the performance of rivals (competition strategy). Different factors have different influences on shipping companies’ ship choice behaviour and ship size preference in different market situations. From a market-driven perspective, the high new-built ship price makes companies choose small ships. In a prosperous market, when freight rates are high, medium-sized vessels are preferred, and investment in large vessels is less likely. From the company attributes perspective, the empirical estimation shows that larger container ships are preferred by larger shipping companies. When it comes to competitive strategy, shipping companies will be more inclined to choose larger ships when they see capacity expansion among their competitors. These results confirm the nature of an oligopolistic market structure of the container market.

Comparative feasibility study of combined cycles for marine power system in a large container ship considering energy efficiency design index (EEDI)

This study investigates an appropriate combined cycle as the electric propulsion system in a large container ship. A gas turbine combined cycle and molten carbonate fuel cell-steam turbine cycle are considered; the gas turbine uses LNG or hythane fuels. Because it is difficult to choose an appropriate propulsion system from only one perspective, comprehensive and unbiased analyses refer to the system performance, eco-efficiency, and economic feasibility for three configurations. An LNG-fueled COGES (combined gas turbine and steam integrated electric drive system) seems to be a promising alternative with regards to economic feasibility as well as a greenhouse gas regulation. The following alternative is the molten carbonate fuel cell-steam turbine cycle. A hythane-fueled COGES has a relatively low economic feasibility but will be the sole propulsion system if the regulation of greenhouse gas emission from shipping is stringent. On the other hand, the carbon taxation and implementation of an incentive for hydrogen fuel may facilitate a greener shipping environment; the additional eco-friendly policy for the shipping industry needs to be provided, shortly soon.

Proposed Design Criteria for a Bilge Pumping System for Large Container Ships

The IMO’s Goal-Based Standards (GBS) in the Safety of Life at Sea Convention (SOLAS) sets the high-level goals (GBS Tier 1 and 2) and classification societies acting as recognized organizations (ROs) should develop detailed rules and regulations in order to meet the goals (GBS Tier 4). Even though the GBS requirements are applicable to new build construction standards of bulk carriers and oil tankers at present, given that IMO may develop goal-based standards for other safety areas, it will be meaningful to examine the bilge pumping system requirements in the context of principles of Goal-Based Standards. The bilge pumping system is one of the most important systems in ships but there is no requirement for its performance except for the 2 m/s speed of water requirement and the internal diameter of bilge main prescribed in SOLAS. The purpose of this study is to quantitatively evaluate bilge pumping performance of actual ships in service and to propose an alternative set of performance standards. The rules of Classification Societies were investigated, and the bilge pumping performance was quantitatively evaluated using specifications of a 14,000 TEU class container ship. As a result of the investigation, it was found that satisfying the 2 m/s requirement under many operating conditions was impossible, and the rules and regulations to determine the internal diameter of bilge main and the capacity of bilge pump did not meet intended purpose of the 2 m/s speed of water requirement. Finally, a set of design criteria are proposed to fulfil the intended purpose of the 2 m/s requirement of SOLAS.

Guabiju tree propagation by mini-cutting: ontogeny of the matrix, cutting length and indole-butyric acid

Guabiju tree is usually propagated by seeds, although this method presents disadvantages, such as a long juvenile period and great genetic variability, resulting in uneven plants which makes management and the establishment of commercial orchards difficult, in addition to the delay in the production entry. The objective of this work was to test the propagation technique by mini-cutting in guabiju tree. The experimental design used was completely randomized, with a 2 x 2 x 3 factorial (ontogeny of the matrix plant x cut length x IBA concentration), with four replications and 20 mini-cuttings per experimental unit. A hundred and twenty days after the implantation of the experiment, the rooting percentage and callogenesis of the mini-cuttings, the secondary root total length, the aerial part and number of leaves were evaluated. The rooted mini-cuttings were transplanted into larger containers with substrate, and after 60 days of transplantation, their survival percentage was analyzed. The highest rooting percentage was obtained with 0 mg L-1 of IBA with an 57.69% average. Mini-cuttings had a high percentage of survival, with 87.5% being the lowest, presenting a satisfactory result. For the guabiju tree propagation by mini-cutting, it is recommended not to use IBA and adopt a length of four centimeters, using a juvenile matrix plant.

Spatial and Temporal Patterns of Stony Coral Tissue Loss Disease Outbreaks in The Bahamas

Coral reefs of Grand Bahama and New Providence islands in The Bahamas have been surveyed several times over the past decade, and long-term monitoring indicates declines in coral cover associated with hurricanes, bleaching events, and local threats. However, the greatest declines in coral populations in The Bahamas over the past decade may be attributed to the recent introduction of stony coral tissue loss disease (SCTLD). In 2019, a comprehensive assessment of both islands was conducted using Atlantic and Gulf Rapid Reef Assessment (AGRRA) methods to characterize reefs before SCTLD was reported in The Bahamas. Following reports of SCTLD in late 2019, timed roving diver assessments of corals were conducted for Grand Bahama in March 2020 and New Providence in June 2020 to determine which species were affected by the disease and the proportion of corals that were healthy, infected with SCTLD, and those that appeared to have experienced recent mortality for the most abundant intermediate or highly susceptible species. Additional surveys were conducted for both islands in January 2021 to further assess the extent of the outbreak, and repeated assessments of several sites for each island were used to determine the impact of the disease on corals over the previous 6.5 to 10.5 months. Infection rates varied among species following patterns described for Florida and elsewhere, with higher infection rates occurring in vulnerable species for both Grand Bahama and New Providence. Pseudodiploria strigosa appears to be the most affected species with 45.6% of colonies on Grand Bahama infected and 23.1% infected on New Providence and recent mortality rates of 31.5 and 42.7%, respectively, at the time of surveys. Spatial patterns of mortality and infection rates for the most vulnerable species were greatest close to international commercial shipping ports on both islands, suggesting SCTLD has been present in those locations for a longer time, and the proportion of healthy colonies increased with distance from the port. For Grand Bahama, there was also a significant effect of depth, with shallow reefs having a higher proportion of colonies that was infected or experienced recent mortality. For New Providence, sites to the east of the port saw a sharp decline in infection and mortality rates with distance compared to sites west of the port, where nearly the entire coastline was affected by SCTLD. Temporal analyses showed an increase in recent mortality and a decrease in active infection for most species on both islands, but little change in the proportion of healthy corals, suggesting some degree of resistance to the disease. Because Freeport and Nassau are the two largest container ports in The Bahamas and are over 200 km apart with multiple islands between them where SCTLD has not yet been reported, it is probable that SCTLD arrived in The Bahamas via commercial shipping, followed by rapid spread within islands via local currents and other vectors. Results from this study stress the need for early detection and suggest that preventing the spread of the disease between islands via vessel traffic is of utmost importance.

Key Performance Indicators Analysis for Quay Container Crane Performance Assessment (Case Study at Jakarta International Container Terminal)

<p><span lang="PT-BR">PT Jakarta International Container Terminal (JICT) is the largest container port in Indonesia. Currently, JICT capacity is 2.5 million TEUs (Twenty-foot Equivalent Units) per year, it continues to strive to improve international services and is supported by adequate container loading and unloading equipment. The requirement to establish common standards in different types of container port equipment and identify performance indicators to assess the performance of container handling equipment has increased. Although the Quay Container Crane (QCC) operating system may be different at each container terminal, there are similarities in its main movements, namely: Main Hoist, Trolley, Gantry, and Boom. By knowing the clock metric for each movement, it is possible to determine the Key Performance Indicator (KPI) that has been adopted and assess the performance of the Quay Container Crane (QCC). The results of the study identified that the value of MMBF (Mean Move Between Failures) decreased due to the accumulation of long-lasting heavy load operations, while the number of maintenance activities for machine parts and working hours continued to increase. Key Performance Indicator (KPI) as a management tool can guide QCC inspections and the results can provide useful insights for improving the performance of equipment and container loading and unloading operations in the future.</span></p>

Emanueli chamber: moist chamber for germination and initial seedling development

Water is one of the essential requirements to start the germination process and should be supplied to seeds without oscillations to permit comparisons among laboratories. One way to achieve this is by means of a moist chamber for each experimental plot. Emanueli chamber is a low-cost device, designed to evaluate the germination process and the first phases of seedling development. Its advantage is that it reduces daily oscillations in the water content of the germination substrate (filter paper). It is made of two plastic cylindric containers. The larger contains water or other test solution and the smaller, bottomless, stays inside the larger one. The upper part of this smaller container is the support of the filter paper that is maintained uniform and constantly moistened by means of a continuous stem submerged in the liquid of the larger container.

Methods for assessing the ship rudder stability under lock-in phenomena considering fluid-structure interactions

Ship rudders, as well as other common underwater appendages, take the form of hydrofoils with a finite trailing-edge thickness to produce wake vortex shedding, which causes vibrations, due to the fluid-structure interactions. Notably, underdetermined phenomena, such as the lock-in phenomenon, raise significant concerns about the structural stability of rudders of large container ships. However, methods to accurately evaluate the stability at the lock-in region are unavailable, because of its high instability, which requires high computational costs, especially for underwater applications. In this study, to address these deficiencies, methods to estimate ship rudders’ structural response and stability at lock-in regions were developed by incorporating hybrid-coupling techniques. The effect of the lock-in phenomenon was investigated using an S-N curve and the fatigue structural-failure probability to quantify the risks. The structural response to the stability analysis was obtained using hybrid-coupling fluid-structure interaction analysis methods by preconditioning the solutions to reduce the numerical instability for first bending and twisting modes with the modified Theodorsen function and to share a single interface between the structure and flow solvers on the OpenFOAM computational fluid dynamics (CFD) toolbox. The accuracy of the structural responses was validated with experiments for the lock-in frequencies, velocity range, and, most importantly, amplitudes of the structural responses of a cantilever hydrofoil. Structural-stability analysis results using the proposed methods demonstrated a significant increase in the probability of premature structural failure, thereby demonstrating the usability of the methods by structural designers in the early design stages.

Reduction of UKC for Very Large Tanker and Container Ship in Shallow Water

The decrease in under keel clearance (UKC) due to the increase of draft that occurs during advancing and turning of very large vessels of different types was analyzed based on computational fluid dynamics (CFD). The trim change in the Duisburg test case (DTC) container ship was much smaller than that of the KRISO very large crude oil carrier 2 (KVLCC2). The sinkage of both ships increased gradually as the water depth became shallower. The amount of sinkage change in DTC was greater than that in KVLCC2. The maximum heel angle was much larger for DTC than for KVLCC2. Both ships showed outward heel angles up to medium-deep water. However, when the water depth became shallow, an inward heel was generated by the shallow water effect. The inward heel increased rapidly in very shallow water. For DTC, the reduction ratio was very large at very shallow water. DTC appeared to be larger than KVLCC2 in terms of the decreased UKC because of shallow water in advancing and turning. In this study, a new result was derived showing that a ship turning in a steady state due to the influence of shallow water can incline inward, which is the turning direction.

A concept of critical safety area applicable for an obstacle-avoidance process for manned and autonomous ships

In times of increased automation of maritime transportation, ship collision with a stationary obstacle (allision) remains a significant problem. There are many existing solutions rooted primarily in the concept of ship domain and path-planning algorithms. However, among these, a geometrical approach to the determination of a required maneuvering area considering the dynamic nature of ship operations in close-quarters situations is still missing. Therefore, an improved concept of the CADCA (Collision Avoidance Dynamic Critical Area) is introduced for the case of ship allision. The CADCA is a deterministic zone that geometrically delimits required maneuvering space of a vessel. Its shape changes depending on the operational parameters of a ship, such as the magnitude of rudder angle, initial forward speed, or planned alteration of the course. In contrast to ship domain, the CADCA is determined using the critical distance between two objects called MDTC (Minimum Distance to Collision). Therefore, the CADCA concept can be used to appoint a position of no-return in a close-quarters situation, so as to determine the time and distance of the last-minute maneuver. An improved method of CADCA determination is introduced, along with an investigation of operational factors influencing the ship's critical area in allision scenarios. The simulations have been conducted for large passenger and container ship in encounters with various stationary obstacles differing in size and shape. The results indicate that from the operational point of view, a deflection of the rudder is the most influencing factor on the size of the CADCA, while the impact of ship speed is negligible for the investigated vessels. Besides, various applications of the CADCA are proposed and discussed for both manned and prospective autonomous vessels.

Assessment of wave induced higher order resonant vibrations of ships at forward speed

An efficient nonlinear time domain method computed higher order springing induced vertical bending vibrations of ships in waves. A weakly nonlinear time domain approach obtained the hydrodynamic response of the elastic hull girder, and a linear finite element model based on Timoshenko’s beam theory calculated its structural response. Coupling of the fully nonlinear stationary forward speed problem with the weakly nonlinear elastic body seakeeping problem constituted the major progress. We demonstrated that accounting for the nonlinear stationary forward speed problem significantly affected the prediction of springing-induced vibrations. Rigid body motions were computed via a nonlinear equations of motion. Elastic vibrations were computed using the modal superposition technique based on linear elastic motion equations. Radiation forces of the moving and vibrating hull structure (rigid body and elastic) were computed via convolution integrals, and Froude–Krylov and hydrostatic forces were combined and integrated over the instantaneous wetted surface. A waterline integral accounted for nonlinear effects of radiation and diffraction forces due to the changing wetted surface. A two-way coupling algorithm ensured accurate convergence. Comparisons of the numerically calculated midship vertical bending moment of a large container ship with experimental results showed good agreement. Investigations of the subject container ship advancing at forward speeds of 15 and 22kn in regular head waves focused on second, third, and fourth order springing.

Long-Term Subsidence Monitoring of the Alluvial Plain of the Scheldt River in Antwerp (Belgium) Using Radar Interferometry

The coupled effects of climate change, sea-level rise, and land sinking in estuaries/alluvial plains prone to inundation and flooding mean that reliable estimation of land movements/subsidence is becoming more crucial. During the last few decades, land subsidence has been monitored by precise and continuous geodetic measurements either from space or using terrestrial techniques. Among them, the Persistent Scaterrer Interferometry (PSInSAR) technique is used on the entire Belgian territory to detect, map and interpret the identified ground movements observed since 1992. Here the research focuses on one of the biggest cities in Belgium that became the second European harbour with giant docks and the deepening of the Scheldt river allowing the navigation of the largest container vessels. The areas along the embankments of the Scheldt river and the harbour facilities are associated to Holocene fluviatile deposits overlain by recent landfills. These sedimentary deposits and human-made landfills are affected by important and ongoing land subsidence phenomena. The land subsidence process is highlighted by an annual average Line of Sight (LOS) velocity of about −3.4 mm/year during the years 1992–2001 (ERS1/2 datasets), followed by an annual average LOS velocity of about −2.71 mm/year and −2.11 mm/year, respectively, during the years 2003–2010 (ENVISAT) and 2016–2019 (Sentinel 1A). The Synthetic Aperture Radar (SAR) imagery data indicate a progressive decrease in the average annual velocities on a global scale independently of important local variations in different districts along the Scheldt river. On the contrary, the city centre and the old historic centre of Antwerp are not affected by negative LOS velocities, indicating stable ground conditions. A geological interpretation of this difference in settlement behaviour between the different areas is provided.

Combined backbone application on numerical simulations and a model experiment of a 20,000 TEU container ship

For the large-scale development and large opening characteristics of container ships, the characteristics of springing in waves has become more complex. It is thus urgent to find reasonable equivalent principles to solve the dilemma of simultaneously simulating vertical, horizontal and torsional vibrations in model tests. Meanwhile, to avoid the complexity and time-consuming nature of full three-dimensional modelling, a large-scale combined beam model is adopted to simulate three-dimensional coupled vibrations and the positions of the neutral axis and torsion centre. Combined with the finite element method, a 3D equivalent modelling method of the combined model is analysed in detail, and the stiffness influence of transverse bulkheads on the coupled vibrations mode is revealed. Furthermore, the elastic modal responses, vibration principles and waves load in the fluid-structure interaction vibrations are assessed and investigated by the three-dimensional linear hydroelastic mechanics method in the frequency- and time-domains. Then, the scheme and load measurement method in the model test in the wave basin are put forward, and the experimental data and numerical calculation results are compared and found to be consistent. The proposed the equivalent combined beam model is of great significance for model tests and numerical analyses of very large container ships.

Assessing the Impact of Disruptive Events on Port Performance and Choice: The Case of Gothenburg

This paper assesses the impact of a major disruptive event at the port of Gothenburg, Scandinavia’s largest container port. Automatic Identification System (AIS) data is analyzed, in combination with official port statistics on container handling in the four main container ports in Sweden, from 2014–2018. Particular attention is paid to the relationship between container volumes handled and calculated performance metrics at the specific times of the intense labour dispute at the port of Gothenburg during the periods Q2 (2016) and Q4 (2016)–Q2 (2017). The paper concludes that the decline in container volumes handled at Gothenburg over the period is specifically due to fewer ships calling at the port following each of the intense periods of the labour dispute. It is also concluded that the effect on competitor ports in the region were significant in terms of both increased volumes of gateway container traffic and the resulting short-term and medium term impacts on both port user profiles and port efficiency levels.

大型コンテナ船の必要舵面積について －(その1)主要目及び操縦性指数の推定－

大型コンテナ船の必要舵面積について －(その1)主要目及び操縦性指数の推定－

Design methodology in transverse webs of the torsional box structure in an ultra large container ship

Container ships has a transverse section in the form of an open profile, making it very sensitive to torsion phenomena. To minimize this effect, a structure known as a torsion box exists, which is subject to high stresses influenced by the fatigue phenomenon and the existence of cut-outs, for the passage of the longitudinal stiffeners, acting as stress concentrators. The aim of this study is to propose a two-stage design methodology to aid designers in satisfying the structural requirements and contribute with to a better understanding of the considered structure. The transverse webs of a torsional box structure are examined by comparing different cut-out geometries from numerical models with different regular load conditions to obtain the variables of the fatigue safety factor through linear regression models. The most appropriate geometry of the torsion box is established in terms of minimum weight, from nonlinear multivariable optimization models.

A Study of Brittle Crack Arrestability Test Method

This study evaluated the brittle crack arrest temperature (CAT) through an isothermal crack arrest test. The concept of evaluating CAT by an isothermal crack arrest test was proposed by C. Wiesner for application to low temperature steels for LPG tanks. The proposed test method consists of arresting a double-tension-type brittle crack with EB melt-run, which acts as a crack initiator and crack runway. There are some disadvantages when evaluating CAT with electron beam welding (EBW), which requires a local brittle zone to initiate a brittle crack. A local temperature gradient (LTG) system is developed to overcome the limitations of the EBW method. LTG systems do not require additional EBW to develop a brittle zone to initiate brittle crack. Recently, brittle crack arrest (BCA) steels are being used in large container ship such as in the upper deck or hatch side coaming of 22,000 twenty-foot equivalent units to prevent fatal brittle fracture accident of those ships. The International Association of Classification Societies (IACS) defined BCA steels using Kca requirement or CAT requirement in their unified rule (UR) S33. Therefore, when a shipyard uses BCA steel in the construction of large container ships, CAT or Kca should be evaluated. In this study, a new CAT test method is introduced to evaluate brittle crack arrest temperature more easily. Furthermore, both test methods were compared for the same specimens to verify the validity of the test method. Key words: Brittle fracture, Crack Arrest Temperature (CAT), Electron Beam Welding (EBW), Embrittled zone, Local Temperature Gradient (LTG)

Lashing Force Prediction Model with Multimodal Deep Learning and AutoML for Stowage Planning Automation in Containerships

The calculation of lashing forces on containerships is one of the most important aspects in terms of cargo safety, as well as slot utilization, especially for large containerships such as more than 10,000 TEU (Twenty-foot Equivalent Unit). It is a challenge for stowage planners when large containerships are in the last port of region because mostly the ship is full and the stacks on deck are very high. However, the lashing force calculation is highly dependent on the Classification society (Class) where the ship is certified; its formula is not published and it is different per each Class (e.g., Lloyd, DNVGL, ABS, BV, and so on). Therefore, the lashing result calculation can only be verified by the Class certified by the Onboard Stability Program (OSP). To ensure that the lashing result is compiled in the stowage plan submitted, stowage planners in office must rely on the same copy of OSP. This study introduces the model to extract the features and to predict the lashing forces with machine learning without explicit calculation of lashing force. The multimodal deep learning with the ANN, CNN and RNN, and AutoML approach is proposed for the machine learning model. The trained model is able to predict the lashing force result and its result is close to the result from its Class.

Experimental and numerical studies on linear and nonlinear seakeeping phenomena of the DTC ship in regular waves

ABSTRACT The paper presents a comprehensive numerical and experimental study on linear and nonlinear seakeeping phenomena, including six degree of freedom (DOF) ship motions, added resistance, drift forces and moments of the DTC containership in regular waves. Obtained numerical results by the 3D panel method NEWDRIFT+ of NTUA-SDL are systematically compared with corresponding experimental data generated within the SHOPERA project (2013–2016) at MARINTEK for various wave headings at low to moderate speeds. The herein presented experimental data are useful not only for validating the employed seakeeping software and others as a benchmark yardstick, but also for the deeper analysis of various open nonlinear seakeeping issues encountered in the prediction of the added resistance and drift forces of modern large containerships in waves.